38 replies to this topic

[benw]

The Honda S2000 engine is 2 litres and 240 odd bhp The Audi RS2 is 2.2 litres and 315Bhp And there's a whole load of 1.8's with 180/190 Bhp So what is it about our little 2.2's engine that makes it so comparatively powerless?

[UKspeedster]

Ben, I think this might have been raised in the past, but I think it's because the engine is very unstressed and can consequently have very long service intervals. It also only revs to just beyond 6000rpm before the limiter cuts in and has been designed to provide a decent range of torque. The Honda engine is a work of art that revs to 9000rpm, but is pretty average before the VTEC kicks in. And the Audi engine is helped by a turbo or two N.

[Jim_Cross]

Many factors. It's very unstressed (helps reliability), lots of low down torque (there is a trade-off between power and torque), stricter emissions regulations for it to meet.

[Duncan]

Enzo Ferrari once said that you were doing well to get over 100 bhp /litre out of an NA. Admittedly that was in the old days but it still rings kinda true now. ANything with more than that tends to lack low down torque or reliability.

[benw]

I vaguely remember it coming up before but I couldn't think of any search terms MORE THAN 3 F'ING LETTERS that would find it for me! The S2000 engine has a smaller capacity but both more power and torque than the NA. The difference has to be more than software. Are we literally talking fundamental differences - longer con-rods, wider cranks etc. Sorry, I just have to get my head around things I don't understand othrwise it'll drive me crazy!

[TurboTomato]

Give me 145 reliable bhp any day over 177 VHPD crank snapping b'stard

[WoodenDummy]

The S2000 engine is valved timed, simple really. It's also a very expensive engine with very expensive parts, it also had it's fair share of problems in the beginning. RS2 engine is turboed so that's hardly a fair comparison, and the 1.8's you are talking about are also Valved Timed (Toyota) or Turboed (VAG) I don't get the point people make with this?! It's like the old days when you rated your dads car with your mates over engine size. Vauxhall wanted a engine that put out 140bhp, it didn't matter that it was 2.2. Because the engine is 2.2 but with a smallish power out put you get very under stressed parts and components, so it's very reliable. These days engine size isnt that big a factor. It's what the engine does with it that counts.

[Gedi]

I asked this when I first came on as my old 306 GTI-6 was running 208bhp on a 2.0ltr engine with the original cams. The engine is still relatively unstressed as the only work done to it over standard was breathing modifications. I was told that it was because the internal design of the engine (piston design, stroke, crank, cams, head, etc) was designed to be economical, it would take a complete overhaul with performance in mind to up the power level above 200bhp.

[WoodenDummy]

I asked this when I first came on as my old 306 GTI-6 was running 208bhp on a 2.0ltr engine with the original cams. The engine is still relatively unstressed as the only work done to it over standard was breathing modifications.

I was told that it was because the internal design of the engine (piston design, stroke, crank, cams, head, etc) was designed to be economical, it would take a complete overhaul with performance in mind to up the power level above 200bhp.

Which I guess is the AmD stage 3. I don't think Vauxhall had thought about making a VX that much faster than the Elise at the time so it didn't seem like an issue. The turbo came as an after thought.

I'll never understand why they didn't just supercharge the 2.2 instead of dealing with all the heat issues of the turbo.

[Makinen]

I would have loved to have the engine and gearbox from my old Civic TypeR in the Speedster. You can make a reliable engine with 100hp/liter, but it's not as cheap as just using a tractor engine like the one Opel used. I really miss listening to the engine at 8300 rpm before every gearshift.

[Gedi]

Which I guess is the AmD stage 3.

No, AmD only touches the top end of the engine.
Piston and crank design (and all the other bottom end parts) stay the same, which is why AmD (and other tuning companies) can only manage to produce 190bhp.

Spending that kind of money on other NA engines initially designed for performance would see it up in the 250bhp+ area

Edited by Gedi, 27 July 2004 - 07:41 AM.

[WoodenDummy]

I would have loved to have the engine and gearbox from my old Civic TypeR in the Speedster. You can make a reliable engine with 100hp/liter, but it's not as cheap as just using a tractor engine like the one Opel used.

I really miss listening to the engine at 8300 rpm before every gearshift.

It would change the car, it wouldnt be the same. People who want that can buy the 2ZZ powered Elise, if they can find the cash.

I love the 2.2 engine, when it's not spitting oil at my rear wheels.

[WoodenDummy]

Which I guess is the AmD stage 3.

No, AmD only touches the top end of the engine.
Piston and crank design (and all the other bottom end parts) stay the same, which is why AmD (and other tuning companies) can only manage to produce 190bhp.

Spending that kind of money on other NA engines initially designed for performance would see it up in the 250bhp+ area

I thought they did more in the stage 3, I've never really looked at the Stage 3 as the Supercharger seemed like a better idea if power ever became an issue.

Although I think the stage 3s are meant to drive quiet nicely even with that extra power.

[benw]

RS2 engine is turboed so that's hardly a fair comparison

Oops! Didn't know that I just had a scan through The Knowledge in the back of EVO for comparisons!

I don't get the point people make with this?! It's like the old days when you rated your dads car with your mates over engine size.

I'm not trying to make a point, I just want to understand, for my own education, how engines differ.

The S2000 engine is valved timed, simple really. It's also a very expensive engine with very expensive parts, it also had it's fair share of problems in the beginning.

I understand Valve Timing (Which is a good point 'cos I hadn't thought of that!) but why do expensive parts make an engine go fast? What is it about the parts that make them both expensive and good?

[garyk220]

Simple. Make an average engine with 140-150 lbft of torque rev to 8000 or 9000 revs, and you've got well over 230 peak horsepower. A simple rule of thumb is for the same torque level, double the revs equals double the power. F1 engines revving to 18500rpm are 'only' producing approx 250lbft peak torque. The old XE engine (Vectra touring car, Astra GTE) produces 240bhp in relatively mild states of tune, and can get over 300bhp even with a 8500rpm limit. The VTEC engine only puts out around 160lbft of torque, and the K series VHPD struggles to get above 140lbft. So if you could make the VX 2.2 (peak torque 145lbft) rev beyond 8000rpm, you'd be looking at 220ish peak power easy. A stage 3 (cams and gas flowed head) will get you to around 190hbp. Beyond that, the inlet manifold and fuelling are critical, so you'd need throttle bodies and a higher lift cam to get a big improvement. Although you'd get great headline power figures, you'd sacrifice a lot of the low down torque, and would need to rev the engine pretty hard to get the best from it.

Edited by garyk220, 27 July 2004 - 08:12 AM.

[garyk220]

I understand Valve Timing (Which is a good point 'cos I hadn't thought of that!) but why do expensive parts make an engine go fast? What is it about the parts that make them both expensive and good?

Because they allow you to rev over 8000rpm all day without destroying the pistons, crank, etc. Vauxhall bottom ends are notoriously strong, so you'd only need to get the engine balanced and fit forged rods and pistons (as Ricky has done) to achieve this.

Edited by garyk220, 27 July 2004 - 08:09 AM.

[WoodenDummy]

I don't get the point people make with this?! It's like the old days when you rated your dads car with your mates over engine size.

I'm not trying to make a point, I just want to understand, for my own education, how engines differ.

Sorry I didnt mean that point to sound so rude and pushy. It was just part of my .

[Makinen]

I understand Valve Timing (Which is a good point 'cos I hadn't thought of that!) but why do expensive parts make an engine go fast? What is it about the parts that make them both expensive and good?

Expensive parts can take the use of high rpm better and also the loads of high compression. A con rod that's made of better material can be lighter and therefore it will be easier to move fast which will give faster revving up of the engine.

It's also expensive to have engines perfectly tuned since it takes some time and skill to do it. That's why there are some possibilities for aftermarket companies to upgrade the software in new cars.

[WoodenDummy]

Although you'd get great headline power figures, you'd sacrifice a lot of the low down torque, and would need to rev the engine pretty hard to get the best from it.

Which is one reason why I love the engine so much, and also why it suits the car better than the K series and ALSO why I picked it over the Lotus.

[JG]

Hi ben Engine design is a very expensive and time consuming developement procedure ( cica £5m to develope and test new engines). Therefore manufactures are reluctant to design new engines unless they have to . This is why there is so much engine sharing going on between manufactures ( for example the mini is to get a citroen/peugeot engine from next year on, rather than the brazilian built christler unit). As a result of this cost, manufactures will amost always go for a compromise when designing an engine ( try to get it to fit as many applications/different cars as possible. VTEC ( honda) , VANOS (bmw), VVTi ( toyota) etc are all forms of variable valve timing. These are very complicated systems that use cams ( honda), funny shape gears ( bmw) to enable a slight advance or retarding of the inlet valve ( most variable valve timing engines only have is on the inlet) depending on the revs. This makes engines both more economical and gives them a high rev range. The trouble is power and torque are directly proportional. Power = torque times revs. Therefore you can either have a high reving lower torque engine which will produce decent power, or have a low reving high torque engine producing decent power. The higher revs you want an engine to go the higher the stresses it has to cope with. Engine wear and revs have an exponential relationship. This means that if your engine is wearing at a certain amout at 1000 rpm then at 2000 rpm it may be wearing at 4 times that amount. get to 4000 at its 16 times as much, you get the drift ( this is why an F1 engine which runs at 18000 rpm only last a race) wearing is hard to define, but the componants that are most affected by this are the big ends, the conrod bearings and the cylinder bores. All this to say that if you are to design an engine that it to have high revs and some reliability then the components that are used have to be much more hard wearing. The use of titanium and other exotic metals are used in the honda engine for example. This makes the components of the engine , but more importantly the developement for the engine extremely costly. hope i havent bored you, this is what engineering does to you cheers james