FAQs

80 hours is the recommended time for the engine to be used in competition e.g. at full load. In order to preserve engine life, we suggest the engine is not used as a road car, this will put less stress on the engine but obviously you are still running the engine and all engines wear out. If you drove it only as a road engine, the engine could be extended considerably. The 80 hours is advisory and we would normally expect to see minimal wear as we originally described big end bearings. Obviously you should always monitor pressures and temperatures to ensure they always remain consistent and if variation occur checking everything then is a safe preventative measure.

Some of our customer choose to considerably longer times between strip down inspection, but they take particular care with their data analyse and again check the engine if something seems to be different to expected. You might find other engine suppliers or builders may promise you longer inspection times, but we prefer to be ultra safe and do not like to hear the words ‘oh we have never seen that before, I think you now need to buy a completely new engine’ so extending the expected engine inspection time can have huge advances for the engine supplier.

We are only giving you a recommendation to give you the longest possible engine life with minimal maintenance. Most of our customers’ engines last for far greater length of time with minimal maintenance. We use the highest grade of components that are extensively tested by ourselves in serious competition before being released to our customers. 

Question:

I have rebuilt my engine with all the same parts and now have got 25bhp less, what could be the reason?

Answer:

One tiny thing could change the characteristics of the engine causing the bhp loss.

Certainly when we are testing and designing engine kits on the dyno, it is important that only one component or adjustment is made for each test otherwise the results will be confused.

—Is the engine exactly identical in every single way.

—If you have changed anything, e.g. cam timing, air filter, air horn length, cylinder head design, all of these will affect the performance of the engine and sometimes components that you have been told work better, need to be proved on a single test.

—If you have a combination of changes, some might give a loss, some might give a gain. Sometimes the results would give no change in performance because the combined losses and gains cancel each other out. If however all the changes give losses, then you have an overall loss in performance. Sometimes you may find one component such as pistons give no change, but the combination of other small adjustments, which seem like nothing at all give a loss and therefore you suspect that it is the piston you have changed because that is the only physical part you have changed, when it is actually everything else combined that creates the loss.

—If you have bought the design for our exhaust manifold, this must be duplicated exactly. We have seen in the past where customers eventually confirm that their exhaust manufacturer could not make it quite as designed and have told them it will be ok. Sometimes even fitting a different size exhaust system or reducing the size, even small changes can completely destroy the output.

For any of the above, we have seen performance losses of in excess of 70bhp and anywhere up to the level with the smallest of changes or errors. Even things that you would think are unimportant; testing on a different rolling road, different tyres, change of gearbox or airbox, can all have unexpected results.

Question:

I own a road going car and would like to have some information about what could I do to the engine (cams, throttle body, software, injectors, exhaust,…) and still meet the Euro6 emissions. 

Answer:

We regularly get asked about upgrading of engines which have been originally built and passed Euro6 emissions. There is quite often a misunderstanding as to what Euro6 emissions and in fact any Euro emissions test involves, so before going into what could be upgraded on your engine, I will give a brief explanation of what the Euro emissions test are.

When a vehicle is produced to be sold within markets throughout the world or Europe, different emission tests have to be met before the vehicle can be sold. The current Euro6 test is the test that involves the complete vehicle as a finished item, which has to take and pass the test, this is quite a complex and expensive test and the build up to the test involves many months of work with teams of mechanical and electronic engineers that work on each specific vehicle model in preparation for the test. To give a very approximate cost I would expect this kind of work including the test to be in the region of £250,000 – £500,000 as a minimum, depending on vehicle design. The actual final test is in the region of £25,000.

Once the vehicle has passed this test, the manufacturer is then able to sell the car within a specific market. If the manufacturer wishes to make any changes to the vehicle such as a different exhaust system, camshaft or any components associated with the vehicle, before it can sell the upgraded model a lot of the preparation work will have to be carried out again and the same final tests retaken and passed.

But you as the new owner of the vehicle are normally only expected to take and pass an annual inspection for vehicle safety and emissions, the level of this test varies throughout Europe and the World but effectively the tests are much simpler and easier to pass, so when you as the owner wish to upgrade your vehicle provided it is able to pass your emissions tests, either annual or if the vehicle is checked on a spot random test, this will be sufficient. Unfortunately as the tests and emissions become ever tighter, this becomes harder to achieve, which means any components that are changed on your vehicle that enable you to release performance become ever more complex and harder to fit e.g. the more power you want the less likely the vehicle is to pass the emissions and the more complex the component combination would need to be fitted to produce performance and yet maintain emissions.

This is usually related to limited production cars such as Caterhams, when you get something like a Ford or BMW, they become even more complicated which is the reason we stick with motorsport.

Question:

What performance gains I would see from keeping my engine standard and only changing the camshafts?

Answer:

It really depends on the engine you have, for example the 1.4L, 1.6L & 2.0L Vauxhall engines have only minimal valve to piston clearance in standard form and if you replace the camshafts, they either have to be so mild that a minimum safe clearance is maintained or that they are retarded so as to avoid valve to piston contact. In both cases, any gains are minimal if at all. When using a larger duration camshaft that is timed in a retarded state normally there will be a reduction in bottom end torque and only a slight gain in peak bhp and the overall result normally makes the car slower. So with these particular engines, it is not worth the money.

Some engines such as the 2.0L Duratec and the Hayabusa engine, have slightly more valve to piston clearance in standard form and therefore allow the use of a mild camshaft and will see reasonable gains, but to see any substantial gains in performance, additional components that give increased compression, clearance and strength will be required.

Your intake system and management system are equally important in any improvement. In any engine using a single throttle body, these are particularly restrictive and have been designed by the manufacturer for a specific purpose. Engines such as the Hayabusa, which have 4 individual throttle bodies allow for a reasonable improvement in performance, but the management system fitted to most engines limits what can be done with your engine. 

Question:

Why do you sell camshaft kits where inlet and exhaust is different?

Answer:

Choosing different camshafts for the inlet and exhaust is quite common, it allows the engine designer to produce different characteristics from an engine. Competition engines have a different set of requirements to road engines, road engines are all about emissions first where competition engines are about power and performance. 

There are no hard and fast rules, but a basic guide is that the milder the exhaust cam in relation to the inlet cam, the earlier in the rpm range the engine will produce torque. The more aggressive the inlet cam, the higher up the rpm range, the engine will be able to carry on producing power but there always has to be a compromise. You cannot just fit a very small exhaust cam and a very big inlet cam. 

The only way to discover where the cams should be timed to, so to tune them to optimal performance is to start at some safe values and then swing the inlet cam and the exhaust cam through the range settings (obviously safe to ensure no mechanical contact) on a rolling road noting the results from every setting and every combination to see which produces the best overall performance to suit your requirements. Unfortunately you will need to experiment with not only cam profiles and combinations, but you could then go further with the exhaust design optimising for each setting. This, as you can imagine, is a very time consuming and expensive task, not only are you wearing the engine out, but with the cost of the dyno, fuel and the person mapping the engine, this can very easily cost many thousands of pounds. 

We sell many products not only to the retail customer but also to the trade customers, because we have developed and tested our components and evolved packages over time. 

Question:

Which is the best way to installing steel con-rods, using a torque wrench or stretch gauge?

Answer:

Using a stretch gauge is the best way to get the bolt to the correct length. When doing a torque setting for a bolt, the way this is worked out is to take a bolt, lubricate it with the type of lubricant you are intending on using, slowly tightening the bolt until the desired stretch is reached. Then recording the torque setting used to reach this stretch. This is a fairly accurate way to achieve the correct stretch. But obviously the best way to get the bolt to the correct length is by measuring it, so a stretch gauge is always the correct way to do it and use the best lubricant. We always use stretch gauges here.

We stock an ARP Steel Body Stretch Gauge, RB-STRETCH-G-02.