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  • Make your car run like a winner by knowing behind-the-wheel lessons. A car engine does not work well without proper and clean air, oil and fuel facilities. Therefore, never ignore car filters; they are the most important part of efficient cars. Car filters help you......

  • From the moment that goods that require delivery enter your possession to the moment they are safely placed in the hands of the recipient, they are the responsibility of the courier. This means that if the goods get damaged, lost or stolen during transit, the courier can be held liable for the replacement of the item or items. Replacing just one item can be costly and replacing multiple items can be a huge financial loss, especially for a new courier. Insuring goods is therefore highly recommended for all couriers. This is a type of liability insurance that provides cover for the courier in the event of loss, damage or theft of goods while they are in transit.

    What Is In Transit Insurance?

    In transit insurance (or just plain transit insurance) provides cover for the cost of goods from the moment they leave the premises where they are being loaded to the when they reach their destination. This basically means that the goods in transit insurance provider will pay for the cost of replacing the goods should an event occur that causes damage or loss of the property. Transit insurance generally provides cover for the following events:
    • Goods that are damaged or lost in a collision.
    • Goods that are stolen while in transit.
    • Goods that are damaged due to fire while in transit.
    • Malicious damage of goods while in transit.

    Why Is In Transit Insurance Important?

    It is important to weigh up the risk of an event occurring that is likely to result in the damage or loss of goods that are in transit. Couriers are generally at a higher risk of being in an accident simply because they spend more time on the road and the nature of the job. The risk of malicious damage or theft is also increased for couriers. The higher the risk that loss or damage to goods may occur, the greater the need for cover. It is also necessary to consider what will happen if a courier is held liable to pay or cover the cost of replacing the goods that were damaged or lost. A courier can never be sure about the actual value of the goods that they are carrying at any one time and if an entire van or truckload is lost, they could be liable for hundreds of thousands of pounds. Plainly stated, most couriers simply do not have the funds to cover such a loss and it could result in bankrupting their enterprise. Insurance provides the peace of mind that a courier won't be financially responsible for the loss or damage of goods in transit and that they can carry on with business, as usual, should an unforeseen event occur. This said the reason that most couriers, especially those just starting out, don't have in transit insurance is that they don't want to absorb the additional cost of paying for cover. However, there are a number of options available to make this type of insurance affordable such as adding it to an existing commercial driver insurance policy. It is recommended to compare premiums from different in transit insurance providers for new couriers and get insured as soon as possible....

  • It is important that one understands that there is no written rule to measure power directly. It has a lot of dynamometers which can measure the torque and allow the power to be calculated. This is a basic equation which allows one to develop design and development work. There are two main methods to find the right power which is used in the automotive industry.  

    Puma Race Engines

    There are two small valves like the cast-iron block and head, pushrod valve train. It is hardly a state of the art which is a multivalve aluminium engine which has 50% more power and can weigh two times as much. There is plenty of cash flows which will allow you to have a very reliable service. The crossflow allows you to get some kind of modification. This allows one to have some of the best ad smooth flow. This over a period of time can allow you to get the right speed for the operation on rolling roads. The crossflow was the successor to the pre crossflow and was simply a modular engine. This allows them to stay the same, allowing you to have the right capacity and can get progressively better with longer strokes and cranks. They also have a small engine which is oversized like a bike engine. You can exactly have the same big valve which will allow you to build the real screamer.

    Bottom end

    The crossflow can easily be bored out to ensure that there is a long way to go when it comes to gaining capacity. There is an 83.5 mm which gives 77.6 mm stroke crank although it might seem like it is pushing limits. It is still oversized fro the features that it comes in. There is pressure testing which can be blocked. The capacity does very less to give it the right peak of power and can allow you to have the right torque that can increase the rpm and cab generate drops in the right proportion. The standard piston can be oversized up to 0.090, which can give 83.25mm. This is supplied in an unfinished flat which can be expensive for most. 03 FRP

    Cylinder Head

    This is a port design which is actually pretty good and very straight to the point. It has a very reasonable downdraft and can have a flow per square inch of value can be pretty high. The engine size of the valves is quite smaller. Most engines have bigger valves, and one of the first is the 41.3 mm inlet valve which is available off-shelf which can be found for a lower price. The engine might have its very own problem, but with a bit of variation, one can easily find the right tool allowing the right drill....

  • A necessity or a nice-to-have? The thrill of fast cars is something else. You don’t get that kind of high anywhere else, and nothing can replace the thrill quite like it. If you want to learn about awesome rides, the best deals, and the latest......

  • If you're looking for a DIY guide on how to remap an ECU yourself, you've come to the right place. This subject can be quite difficult and even frustrating if you're not aware of what you are doing. If you're looking for a professional opinion about what you should do, find someone who knows what they're talking about and is experienced in this particular area. Otherwise, you'll probably end up doing something that either costs you a lot of money or doesn't work at all. The last thing you want is to waste time and money because you didn't know what you were doing. Let me share with you a simple method that anyone can implement.

    Is it possible to remap an ECU by yourself?

    I'm sure you're wondering what "remapping" means. Basically, it's the process of changing one valve on your end to another. This can be done in several different ways. I'm going to show you two of them in this article. However, each method has its own advantages and disadvantages. Which one you use will depend upon whether you're using it for diagnosing problems with your system or if you're just trying to perform maintenance on your ecu. The first way is by rebuilding the actuator. This is the part of your system that actually moves the fluid through your engine. You can rebuild this actuator by simply cutting off the sealing surface to the actuator. This is done by undoing the nut that attaches the actuator to the valve. The other way is by using a sharp cutting tool to cut off a section of the valve and then replacing the valve itself. To do this, you'll need to remove the gasket that protects your seal (this will make it easier to remove the valve itself). Once the gasket is removed, you'll need to cut a hole in the top of the valve and insert the stainless steel screw into this hole. This will allow you to cut away the old seal and put a new one in place. One of the downsides to this is that you're permanently destroying one of your seals. Another potential downside is that you're potentially voiding your warranty if you're replacing parts improperly. So, if you're not an expert, it's probably not a good idea to do this. If you have the experience, I highly recommend that you either hire someone to remap your system for you or replace the valve completely. Now, if you're doing this for diagnosing a problem in your system then I'd highly recommend that you don't cut the valve itself. Doing this could lead to a seal leak which could void your warranty. Instead, what you want to do is place a very small amount of water between the valve and the actuator. This will keep the liquid from leaking out between the two and thus causing a less leak-prone system. Now that you've figured out how to remap an ECU yourself, the next step is to run diagnostics on your system to pinpoint where the problem actually lies. The most common problems would be poor connections, dirty filters or clogged air flow. If you're able to see that there's something wrong with the ECU, then you can either order some parts and fix it or upgrade to a more powerful unit. Either way, this step isn't very difficult and is often done by plugging in a meter from your computer. Finally, you need to know how to remap an ECU manually. This is often more difficult than replacing or upgrading the unit, but it can still be done. Basically, you have to find where the old one goes and unhook it from the power source. This can be tricky and can sometimes require some old parts to be able to complete the task, so you may want to either call a professional or search around for some vintage or antique parts. https://www.youtube.com/embed/4cFP-PaklH4  ...

  • What is an EGR Valve?

    The EGR valve works by recirculating a determined quantity of the exhaust gases back right into the engine through the air intake system, reducing the number of discharges the engine generates. This gas is continuously being recirculated through the engine, which over time will trigger an accumulation of the carbon deposits in the intake manifold as well as various other components including the EGR shutoff. What is an EGR Cooler? The EGR Cooler is designed to lower the temperature level of the exhaust gases prior to them recirculating back right into the engine.

    EGR Delete or Bypass

    EGR Valve Delete/Removal The EGR shutoff (Exhaust Gas Recirculation) is a discharge control gadget designed to decrease NO2 emissions to help in the direction of the ever before more stringent Euro Emission Regulations. EGR Delete and EGR bypass software is developed to get rid of the performance of the EGR shutoff to ensure it removes the running problems connected with these gadgets.

    Exactly how does an EGR work?

    The EGR, theoretically, works by sending out a tiny part of non-active gas exhaust back into a lorry's cylinders, for this reason ejecting negligible toxic substances into the setting. This minimizes the warmth of combustion, yet the same quantity of stress is still related to this piston while minimizing the quantity of excess oxygen prior to burning. A couple of researches performed on diesel engines demonstrate that the section of nitrous oxide gas emissions is absolutely decreased via using EGR. Concentrations of smoke density can in fact increase. Therefore there seem to be minuses and pluses depending on what's important to you in your details vehicle. This design is called outside EGR. A control shutoff (EGR Valve) within the circuit manages and times the gas circulation.

    EGR Valve Problems

    As the EGR shutoff is regularly collaborating with burned exhaust gases they normally have high residue material. This soot in the gases causes a build-up of carbon down payments around the shutoff operation area which in turn creates the shutoff to have a tendency to embed various placements. For complete engine efficiency, the EGR shutoff is closed which develops a shut loop environment for the turbo system which allows it to pressurise. A troublesome EGR can develop an open loophole setting for the turbo as it gives a feedback straight to the consumption manifold and also as a result can trigger boost problems along with substantial decreases in power as well as likewise fuel economic climate!

    Advantages of EGR Removal

    • Restored Engine Power
    • Brought back MPG
    • Cleanser discharges as defective EGR's develop a lot higher residue deposits
    • Can stop DPF failing as the residue is captured in the DPF catch
    • Can prevent EGR substitute which can cost hundreds of pounds
    We are at the forefront of EGR Removal as well as EGR Bypass software and can appropriately eliminate the performance from the software of the majority of ECU types. The EGR shutoff requires correctly disabling to ensure it is not trying to recirculate exhausts gases whilst still physically functioning in the engine. Considering that the EGR system recirculates a part of exhaust gases, gradually the valve can become clogged with carbon deposits that avoid it from running correctly. Clogged EGR valves can in some cases be cleansed, but substitute is frequently essential if the valve is damaged. It can be eliminated, blanked as well as erased from the ECU.

    Is EGR Removal Legal?

    Please note that we just use EGR services for Off-Road Usage. It is not illegal to eliminate the EGR from your vehicle, it is an offense under the Road lorries (Construction as well as Use) Regulations (Regulation 61a( 3 )) 1 to make use of a vehicle which has been changed in such a way that it no much longer conforms with the air pollutant discharges requirements it was created to satisfy. Removal of the EGR will certainly almost invariably refute these needs. The possible penalties for falling short to adhere to Regulation 61a are fines of approximately ₤1,000 for a vehicle or ₤ 2,500 for a light items vehicle.

    Benefits of getting rid of the EGR Valve

    • Lowered Engine Temps
    • Boosted Throttle Response
    • Improved Economy
    • Minimizes Oil Contamination
    • Reduces Carbon Deposits in the engine
    Please Note: The EGR Valve should NOT be removed on automobiles that still have the DPF Filter in location, doing so may obstruct the DPF as the EGR Valve procedure is a prerequisite for DPF Regeneration. Legalities In the UK it is unlawful to eliminate any of the original exhausts devices fitted to an automobile from the factory. Vehicles with the DPF removed will certainly fall short an MOT. It is the consumers responsibility to ensure they abide by legislations and also rules connecting to their house country. We approve no obligation for the use of this component on the public highway where elimination of exhaust controls is banned. When talking about modifying the vehicle's performance, one of the desired ECU Tuning services is the so-called EGR valve replacement. In diesel engines, the EGR valve (exhaust gas reclamation) is actually one of the main but most problematic components. The EGR is supposed to drain off the excessive amount of burnt gases emitted from the tailpipe and combustion chamber to the intake system. But the existence of too much of this kind of gases in the exhaust system causes several problems with it, such as rough idle, combustible exhaust, high oil pressure, loud emission, and the list goes on. https://www.youtube.com/watch?v=zfZFpHZVW3g Although the engine has an automatic fuel injection, there are still chances that the EGR will not operate properly, especially if the engine is cold. During cold weather conditions, there would be less or even no fuel supplied to the engine. In addition, if the temperature rises to its extreme end, then the valve can easily lock up, resulting in the failure of the function. So, how to delete EGR from ecu valves? The first thing to do is to open the ecu valve for a period of time, and make sure that all the CNG pellets inside the cylinder are removed and flushed with water. Then, disconnect the positive electrical connection from the ECU. Remember to remove both the positive and negative connections. If you have troubles using the ecu tuner, then you can consult the user manual for proper instructions on how to do so. Now, remove the two screws of your ecu from its cover. On some models, you have to unscrew the pin in order to gain access to the valve. You can also use a screwdriver or knife. Now, detach the wiring from its connector. Now, locate and remove the two screws of the valve. Once done, locate the black plug inside the valve and remove it. Your next step is to remove the gasket that covers the valve body. Finally, you have to pull out the old ECU valve. After successfully learning how to delete egr from ecu valves, you should notice that the valve body is now open. There are two screws that hold the gasket in place, and you have to remove them. However, this may require additional tools or force. Now you can replace the gasket, securing it with bolts. Install the new ECU valve and bolt it to its proper location. Make sure that the hole for the drain is properly lined up before closing the valve. Then, you can upgrade your system by installing new ones. If you want to learn how to delete egr from ecu valves, then follow the same procedure as stated above. However, this time, you will notice that there are holes on both sides of your valve, with the holes facing each other. Tap them with pliers and remove the screws. Then replace your gasket and screw them back in place. Then, you need to reconnect the battery. Turn your ecu on and check if the device shows power levels. If not, you need to replace the battery or re-check the connections. These are basic information on how to delete egr from ecu and its corresponding troubleshooting. Now turn your attention to the side connectors. See if the wiring is loose or damaged. You can use a magnifying glass to inspect the connections for frayed wires or broken seals. If the valve is working properly, then the connections should be strong and tightly sealed. Now you can start learning how to delete egr from ecu if the device shows a drained sensor. This means that the ecu's level is too low when you try to drain it. Check the connections between the drain and the valve body. If the seal is still intact, then you can remove the old valve and install the new one. On the other hand, if you see that the drain connection is broken, you should consider replacing the valve. Finally, when you learn how to delete egr from ecu, you will also have to consider the maintenance of the device. Usually, an ecu has a limited number of connections. If those are not maintained well, the device may malfunction. You can follow the maintenance guide for your specific model to know the proper maintenance procedures....

  • One of the first things you might ask yourself after getting your new car is "How do I reset the ECU?". An ECU is the electronic control unit of your vehicle and if it goes wrong or malfunctions, then it can cost you quite a lot to get it fixed. So you should know what does each stand for? What is an ECU?

    How to reset a car's ECU?

    An ECU is what the technicians call an Electronic Control Unit or ECU. It is the brain of your vehicle - a computer that tells your car what to do and when to do it. The ECU is what keeps your engine from jumping out of sync, from smoking while you are driving, and from making that irritating squeal when you jump out of your car in traffic. And if the end malfunctions, well then it is definitely a problem and a reason for you to find out how to reset the ECU. How do you reset the ECU? In order to reset the ECU, you need to remove the battery from your car. Then disconnect the electric power connection from the ECU. Then you need to take the screwdriver that comes with your menu and tap into the little plastic slot on the backside of the eye. The plastic flap may pop open and reveal a wire that is colored blue or black - this is the wire that you will need to unplug and release the power from the vehicle. Now that you have removed the electric power, release the ground from the positive and negative terminals on the wire. You can do this by either unplugging the wire from the receptacle or by pulling up on the switch to release the positive and negative tension from the wire. It is a good idea to have someone help you do this as not to damage the switch or the receptacle itself. Once you have done this, remove the screws that are holding the switch in place from the vehicle. Now you can remove the switch and recheck the wiring to ensure that it is still connected to the vehicle. Next, you need to reconnect the battery to the vehicle. It may be required that you reset the ECU battery to make room for the new one. Once the battery is connected, the next step on your How to reset a car's ECU? agenda is to connect the sensor switch to the Ecu. https://www.youtube.com/watch?v=WlMLam-MLsQ There are actually five wires that make up the Ecu sensor switch. These wires are black, red, white, ground, and neutral. You will need to identify which wire goes to which terminal on the Ecu. If you cannot figure this out, then you may want to enlist the help of someone with automotive knowledge. Most vehicles have the standard black wire, but there are some newer vehicles that have what is called "hot" wires that go to different terminals. In order to determine what kind of wire is needed for your vehicle, you will need to consult the owner's manual or look it up online. Once you have successfully connected to the switch, you can then proceed to reset the ignition switch. This involves removing the key from the ignition and detaching the wiring from the switch. Then you must remove the new switch and attach the new wiring. Once you do this, you must replace the key into the ignition and reinstall the switch. Then, you must plug the vehicle back in and reattach all of the wires. Finally, you will want to replace the bad battery. This is also an easy task as long as you have the correct tools. In most cases, you can use the screwdriver to remove the cap on the battery and place the new one in. Following this, you can reconnect the wiring to the car's ECU. If you followed these steps, you should be able to reset your car's ignition and run it with a fresh battery....

  • We've seen in the previous article how torque and power are defined and calculated - now let's look more closely at how they relate to engine design. The concept of an engine's torque output seems to be confusing to many people judging by newsgroup threads but it needs to be clearly understood if one is to design the best ways to improve power output. Torque can be thought of as the instantaneous turning force generated at the crankshaft. As such it is a measure of the amount of energy being developed in the engine during EACH operating cycle - in other words a function of the amount of air/fuel mixture being burned per cycle. Copyright David Baker and Puma Race Engines Power can be thought of as a measure of the amount of energy being developed in the engine per minute - in other words a function of the amount of air/fuel mixture being burned per cycle multiplied by the number of cycles per minute. So power is torque times speed as we have already seen. To increase torque we need to either process more air/fuel mixture per cycle or extract more energy from the air/fuel that is processed. We can do the latter in a variety of ways including: 1) Improving mechanical efficiency with attention to design of such things as bearings, piston rings etc. 2) Increasing compression ratio which extracts more energy from the mixture being burned. 3) Optimising fueling and ignition timing. We'll look at the above another time - for now lets concentrate on getting more air/fuel mixture into the engine. We can simplify even further by leaving out the fuel part of "air/fuel" mixture as this is really a calibration issue and falls under 3) above. It is increasing the air consumption that is the real problem and in fact it is not a bad idea to think of an engine as an air pump. The better we can make this pump work the more torque and power we can generate. Our problem of increasing torque output has now ended up as a problem of getting more air into the engine each cycle. There are only 2 ways to do this: 1) To increase the engine size. This is not always an option or at least not always a cost effective option. We may be running in a racing class where the engine size is limited or we may own an engine where parts such as longer stroke crankshafts or bigger pistons are expensive. As a general rule though, a bigger cylinder will process more air per cycle than a smaller one unless limited by other factors. 2) To increase the filling efficiency of the cylinders - i.e. to increase "Volumetric Efficiency". If a cylinder is 500cc in volume but processes only 400cc of air each cycle we can say that the volumetric efficiency is 80%. In fact to be absolutely correct it is normal to express VE in terms of mass of air not volume but that is getting more complicated than is needed for now. To get into the cylinder, the air has to pass through the carb or injection system, the inlet manifold and finally through the port and valve. The more restrictive to flow each of these components is, the harder it is for the air to get through them. By testing each of these items on a flow bench and modifying them to increase their flow capacity we can allow the air an easier passage into the cylinder and this will increase not only VE and therefore torque but also allow the engine to run at higher speeds and increase peak horsepower. Copyright David Baker and Puma Race Engines In fact the ultimate horsepower potential of any engine is really a function of the flow capacity of the induction system. By just increasing engine size, say with a longer stroke crank, we will increase torque at low rpm but not necessarily increase peak horsepower by much at all. The flow capacity of the induction system imposes the ultimate limit on the amount of air that the engine can process per minute and whether we have a small engine running at high speed or a big engine running at low speed, it is total airflow per minute that matters. The only real difference between a 3 litre car engine producing 200 bhp and a 3 litre Formula 1 engine producing 800 bhp is the flow capacity of the cylinder head. We can also increase airflow per cycle by opening the valves for longer or to a higher lift. This has its downside though because long duration camshafts don't work well at low engine speeds and while this might be ok for a race engine it is not what we want for a road engine. Increasing the airflow capacity of the induction system has very little downside although there can still be minor adverse effects on low speed performance. As a general rule it is much better to have a high flow induction system and be able to use a short duration camshaft to achieve the desired horsepower than vice versa. The most restrictive part of the induction system and therefore the part that often shows the greatest benefits from being improved is the cylinder head. In fact the flow efficiency of the cylinder head is the key to good engine design and is the reason why modern engines are increasingly being designed with 4 or more valves per cylinder rather than 2. More valves mean more valve area and it is valve area that limits flow. Cylinder head design merits its own section and we'll discuss it in detail in other articles. Although both power and torque per litre are higher than for 2 valve engines we see a similar story with a much greater spread of power outputs than torque outputs. In fact only the BMW stands out for its high torque output (perhaps even a tad suspiciously so) although there is a 52% spread of power per litre figures. We ought by now to be realising that increasing torque per litre is much harder to do than increasing power. In fact torque per litre figures can be used as a very good guide to the truth or otherwise of quoted power claims. It is hard to get even a race 2 valve engine to produce much more than 75 to 78 ft lbs per litre and for a 4 valve engine more than 85 to 88 ft lbs per litre. For big budget engines where a lot of time and money has been spent on dyno testing of inlet and exhaust manifold lengths and diameters then of course it is possible to push the limits higher. With well developed cylinder heads, good inductions systems (i.e. sidedraft carbs or even better, multi butterfly throttle body systems) and efficient full race camshafts it is possible to modify small bore road car engines into race ones producing around 80 ft lbs per litre for 2 valve designs and low 90s ft lbs per litre for 4 valve designs. You'll very rarely see figures that high though unless serious development work has been done. Obviously it's much easier to get high torque and power outputs if the starting point is a custom designed big bore small stroke racing engine with lots of valve area rather than a small bore long stroke road car one. The general tuning article looks at power and torque targets for modified road car engines in more detail. Copyright David Baker and Puma Race Engines It is possible to increase peak torque even further by selecting the intake and exhaust lengths to "pulse tune" the engine most efficiently at peak torque rpm. This will reduce peak power though and as maximising power is the primary goal for a competition engine this strategy is not normally of any use. Occasionally there are race series where the engines have to abide by an rpm limit which is lower than that at which they could otherwise produce best power. In such cases the engines will be tuned to maximize output at the limited rpm which can lead to torque/litre figures approaching 100 ft/lbs per litre. The reduction in peak power this creates is of no consequence if the engine is not allowed to rev that high. Such torque figures should not be used as a guide to what is possible from conventional best tuning on a non rev limited engine though. I have still to come across reliable data for any engine producing more than about 93 to 94 ft/lbs per litre where ultimate power was the aim - except of course for unreliable estimated "flywheel" power and torque figures derived from rolling road wheel bhp measurements in which case the sky is the limit. I once saw a rolling road power curve where peak torque was supposedly 120 ft/lbs per litre from a 4 valve engine of fairly uninspiring design. Even the operator finally admitted something didn't look right when we went through the maths together. The conclusion was that there had been massive wheelspin during that power run and none of the figures generated were of any use at all. When you see power claims that look suspicious, calculate the torque values using the formulae in the previous article. If you see peak torque values higher than those suggested above then I suggest you start to get, if not suspicious, then at least very analytical. Modern motorbike engines are quite similar to custom race car engines in terms of them being short stroke, 4 valve etc and although I have no data to hand I think it would be interesting to see the sort of torque per litre figures being claimed for them given that they achieve well over 100 bhp per litre. If anyone wants to summarize some power specs for me I would be grateful. Copyright David Baker and Puma Race Engines You might think that it is only possible to get 100% Volumetric Efficiency from an engine - after all when a cylinder is full of air at atmospheric pressure surely that is the end of the story. What this fails to take into account though is what is called "Pulse Tuning" which is taking advantage of the pressure waves which exist in the induction and exhaust system. These pressure pulses can actually ram air into the cylinder to achieve up to 130% VE although it takes very carefully designed pipe lengths and diameters to achieve this and the effect only works over fairly narrow rpm bands - usually with a corresponding adverse effect somewhere else in the rpm range. We can see by now that there is a close relationship between VE and torque per litre and it might be reasonable to ask if it is possible to calculate one from the other. Well the full answer is no because the torque achieved also depends on burn efficiency, mechanical efficiency and other things. A rough guide though is that if you multiply the torque per litre by 1.4 you get a close approximation of the VE as a percentage. So the 4 valve engines running at 72 ft lbs per litre are perhaps achieving about 100% VE in road tune. 130% VE would equate to 93 ft lbs per litre which also ties together the maximum figures I have seen from different sources for both of these measures quite nicely. ...

  • The first two articles have covered the main items that need to be considered when trying to evaluate the power potential of an engine. All that needs to be done now is to look at the equations that turn valve area into potential bhp. We will assume that all ancilliary parts of the engine design such as induction system, exhaust system, compression ratio etc can be modified such as to impose no further restriction on the power potential. What we are going to calculate is the potential peak power of a fully modified engine in race tune with excellent port work and "perfect" induction and exhaust system design. This analysis applies mainly to engines designed originally for normal road use but we will also consider briefly how a custom designed race engine like an F1 engine might fit into this scenario. Copyright David Baker and Puma Race Engines

    Step 1 - calculate the valve area

    The area we need here is the total area of all of the inlet valves in square millimetres. Hopefully everyone reading these technical articles will know how to do this but I suppose for the sake of completeness... Valve Area of each valve = diameter squared x pi ÷ 4 - then multiply by the number of inlet valves in the engine. For a fully modified engine we must consider not the standard valve sizes but the maximum valve size that might be fitted. As a rule of thumb, most road engines have enough space to enable valves 7% bigger in diameter to be fitted into the combustion chamber but of course this varies from engine to engine.

    Step 2 - Adjustment for the type of engine design

    We have seen that different engine designs have different power potentials for a given valve area. A basic adjustment to "weight" the valve area for these considerations needs to be done. Copyright David Baker and Puma Race Engines 2 valve per cylinder, parallel valve - reduce area by 10% 2 valve per cylinder, inclined valve - leave area as is 4 valve per cylinder - increase area by 10% Custom designed, money no object 4 valve per cylinder race engine - increase area by 25% This rather rough and ready "weighting" gives us a broad brush approach to refining the power prediction based on just engine type and valve area. We make no consideration as yet of engine size or the effect of the camshaft design and valve train type. Some common sense is going to have to be applied if it can readily be seen that a particular engine has a severe design limitation in some particular area such as valve lifter diameter. The venerable MGB engine for example is so limited by its siamese port design and pushrod valve train that it doesn't get anywhere near the power potential predicted here. Some of the parallel valve engines with overhead cams can rival the inclined valve engines in power output though. With enough development work on port design and cam profile the bhp targets can eventually often be beaten. In the USA the Chevrolet V8 engine has been refined over the years by dozens of engine tuners spending thousand of man hours on research. Its power output, given the age of its initial pushrod design, now beggars belief and rivals that of some OHC 4 valve engines. Copyright David Baker and Puma Race Engines

    Step 3 - Predict the flywheel bhp

    Take the adjusted valve area from step 2 and divide by 30

    This now gives us our predicted flywheel bhp in full race tune. In other words, high compression ratio, top notch carburation or throttle bodies, good exhaust system, race camshafts and fully ported, flow bench developed cylinder head. For fast road tune a good target would be 75% of the above figure and for rally tune about 85% to 90% of it. Note that engine size has never entered this analysis at all. In fact engine size does play a role in potential power output but nothing like as much as is commonly believed. That's a story for another article though. Copyright David Baker and Puma Race Engines


    1) - The venerable 2 litre Ford Pinto engine has been tuned by so many people that its power potential is pretty well known. A really good one can just beat the 200 bhp mark and David Vizard in his excellent book on the engine achieved 212 bhp after years of development work. Lets see how the numbers stack up. Std inlet valve size is 42mm but the normal big valve used in race engines is 44.5mm. Engine type is SOHC with inclined valves so no adjustment to the base valve area is required. Valve area is 44.5 x 44.5 x 3.1416 ÷ 4 = 1,555.3 sq mm per valve x 4 valves per engine = 6,221 sq mm Power potential = 6,221 ÷ 30 = 207 bhp. So not a million miles out then. Copyright David Baker and Puma Race Engines 2) - Let's try a little comparison between two different engine types - the 3.5/3.9 litre Rover V8 and the 1905 cc Peugeot 405 M16. At first glance you might think there would be no contest. The Rover has twice the number of cylinders and twice the engine capacity but does it work out that way? The Rover V8 has 8 cylinders and 40mm inlet valves - total valve area 10,053 sq mm. Being a 2 valve parallel valve pushrod engine we need to reduce this by 10% though and end up with 9,048 sq mm for a power target of 302 bhp. The Peugeot is a 4 valve per cylinder engine with 34.6mm inlet valves. Total valve area 7,522 sq mm. We need to add 10% though for the 4 valve engine type to arrive at 8,274 sq mm and a power target of 276 bhp. Rather less in it than might otherwise have been thought. Of course the 1.9 litre 4 cylinder engine is going to need to turn some pretty serious rpm to develop the power its cylinder head is capable of supplying though. 3) - and finally for a bit of fun. See if you can guess whose engine this is. 3 litre, all aluminium V10, 4 valve per cylinder and 35mm inlet valves - I think we can also safely say that money was no object here 🙂 Total valve area is 19,242 sq mm and we need to bump this up by 25% for the engine type to arrive at 24,053 sq mm Power target is therefore 24,053 ÷ 30 = 802 bhp. Hmm, not too shabby for a 3 litre engine. Vorsprung durch technik as they say in Germany just before sliding into the tyre wall and breaking both legs. Copyright David Baker and Puma Race Engines


    Please don't get the idea that from one simple measure like inlet valve area we can arrive at a definitive power target for an engine. What this analysis should have done is give you the basic tools for understanding how to evaluate an engine and arrive at sensible power targets which will be at least "in the ball park". It hopefully shows though just how important valve area is compared to other factors like engine size or number of cylinders. Actually achieving the power targets depends primarily on the skill of the cylinder head modifier though and that's why most engines never get anywhere near their full potential. The difference between a well modified head and a poor one can be 20% of the engine's power potential. Copyright David Baker and Puma Race Engines...

  • In the first article we reached the following conclusion:

    The single biggest factor that determines an engine's ultimate power potential is the total inlet valve area

    Not all cylinder head designs have the same flow efficiency for a given valve area though - and it is the flow potential rather than the valve area itself that really determines the power potential - but valve area is much easier to measure and provides an ideal starting point for further analysis. There is no point however in having big valves if the port shape or other factors restrict the flow. To discuss this further it is best to consider engines with 2 valves per cylinder separately from 4 valve valve engines (or even 5 valve engines which are gradually appearing in road cars). Copyright David Baker and Puma Race Engines

    2 Valve Per Cylinder Engines

    Engines with only one inlet and one exhaust valve can be further split into two main categories.

    Parallel Valve Engines

    In this type of design the valve stems are parallel to each other and usually, but not always, parallel to the cylinder bore axis. Examples might be the Mini, MGB, VW Golf, Peugeot 205 and Ford Crossflow engines. The total valve diameter is directly limited by the bore size because the valves open into the bore. There obviously needs to be some clearance between the two valves and also between each valve and the adjacent bore wall simply to prevent contact. Production engines might have 3mm or 4mm for each of these clearances although this can be reduced on a race engine to around 1.5mm between the valves and 1mm to 1.5 mm between each valve and the bore wall to allow the largest possible valves to be fitted. So at best there is a limit on total valve diameter of about 3.5mm to 4.5mm less than the bore diameter. This remaining space would normally be allocated as about 55% to 57% for the inlet valve and 43% to 45% for the exhaust valve diameter. In other words the exhaust valve would be around 80% of the diameter of the inlet valve for best power output - perhaps even a little less in some cases. Copyright David Baker and Puma Race Engines Combustion chambers can either be of the "bathtub" type where the volume is contained mainly in the cylinder head or the "Heron" design where the head face is flat and the volume is in the piston dish and between the top of the piston and the top of the bore. Regardless of the exact design chosen there is always going to be some loss of flow potential because of shrouding between the valves and the closely adjacent bore wall or combustion chamber walls. In simple terms there is just not enough space for the airflow to get past the valve head into the cylinder cleanly. The bigger the valves and the closer they end up to an adjacent wall the greater the shrouding effect becomes and a law of diminishing returns sets in. In some cases a smaller valve ends up producing more flow than a larger one if the required clearance space around the valve head can't be achieved. The effect of shrouding can be to reduce the flow and power potential by around 10% compared to the same sizes valves with zero shrouding. Early designs of this type of engine had pushrod type valve trains and the Mini and MGB engines were limited even further by their siamese port design. Some of the more modern single overhead cam engines can rival the inclined valve type design in their power output though. A little common sense needs to be applied when evaluating these types of engine.

    Inclined Valve Engines

    In these designs the valves are angled both relative to each other and to the bore axis. Examples include the Ford CVH and Twin Cam engines which have large angles between the valves and the Ford Pinto engine which has a fairly small included angle. This design has two main advantages. Because the valves open away from the bore wall in towards the centre of the cylinder there is little or no shrouding of the flow. As the valve opens further and the airflow increases, so the necessary space around the valve head increases at the same time. Secondly it enables larger valves to be fitted in a given bore diameter than the parallel valve head design. Within limits, the greater the angle between the valves the larger they can become although if the included angle is too large the inlet valve can hit the exhaust valve when they are both open during the overlap period. Copyright David Baker and Puma Race Engines Disadvantages of this design is that the combustion chamber has to be something like a hemisphere, or at least fairly domed, and this shape isn't very compact and doesn't burn well. The advantages of extra valve area and lack of shrouding outweigh this consideration by a large margin though.

    4 Valve Per Cylinder Engines

    The constraints of fitting 4 valves and their related valve trains into a cylinder head means that all 4 valve designs end up being fairly similar - at least in flow terms. The inlet valves are angled away from the exhaust valves, the spark plug ends up central in the chamber and usually twin overhead cams are used - although a few designs manage with a single cam and rockers. There is little or no shrouding with most 4 valve engines and in effect they are like multi valve versions of the inclined design of 2 valve engine. There is a significant difference though between 4 valve and 2 valve engines in terms of flow and power potential for a given total valve area. This is because the ratio of total valve area to total valve circumference is not the same. To understand this better let's look at an example. Copyright David Baker and Puma Race Engines Compare an engine with two small inlet valves of 25mm diameter with a similar sized engine with one large valve of 35.36mm diameter. The total valve area is the same in both cases - about 982 square mm. So the total peak flow when the valves are fully open should be very similar. The total circumference is very different though. The two small valves have a total circumference of 157mm. The single large valve has a circumference of only 111mm. The ratio is 1.41 to 1 - or in other words the square root of 2. This has a big effect on flow at low valve lifts. If all three valves are open by the same small amount - say 1mm - the two small valves have a flow area which is 41% bigger and consequently flow more air. As the valves open fully and the valve area becomes the limiting factor, this effect diminishes and ultimately disappears. The effect of this improved low lift flow is to give the two small inlet valves a power advantage over a single valve of the same area. The effect depends on the cam profile used on each engine but is in the region of 10% to 15%....