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- Thread starter Jamesv6
- Start date
If the original question is a theoretical one - "what max power output can be achieved from natuaraly aspirated engine" then without complex physics, the Dallara Judd V10 5-litre ran 800 bhp when the air restrictors were off. That means 160bhp per litre. That's pretty much it and engine life is marginally one race. Last a bit longer and a new race saloon like Peugeot's 207R Cup is 280bhp from 2000cc - 140bhp per litre.
If the question is bar-stool related, then in my Evo days we took the same modded car to four rolling roads, all were done in a six week period and at the same time in the morning - and we had a 63 bhp difference in the results. So, just as Tim says, keep hawking it around until you get the figures you want.
If it's directly Clio V6 tuning related, I reckon 300bhp from a road-going vee is not easy (or cheap!) and all this air filter/exhaust stuff is unlikely to get much more than 15-20bhp by bolting on bits. We know that Renault's 255 is a bit suspect so bolt-ons might get you to 260-265. Cams will add a bit but leaving the single plenum means it's all a bit pointless - add another 10 if you are lucky. Where's the other 25 coming from then?
Changing to Trophy spec means you need to find an engine, exhaust, management system, pipework and engine mounts. You'll need to have a flwheel made up to mate the clutch unless you want to run the sequential 'box and as well as emptying the piggy bank, you'll now have a car that doesn't work as a road car.
Past 300 "real" bhp is possible but subject to diminishing returns. Currently the limit on mine is the twin plenums/injectors which are fully open at max power. A T/B setup would allow more fuel but my gut feel is that we will soon run into a real world air-flow problem. The packaging of a big engine between a fixed bulkhead and a tailgate along with the need to shield the underside from road crap means holes and vents start appearing and speed disturbed air is not easy to manage.
We know that more cc's are the cheapest producer of power but that avenue soon closes - 3.5 litre engines exist but get hot-spotted in the cylinder liners. So for now, if you asked me where the limit is, 320-330bhp is tops without serious work - trick fuel, exotic materials, dry sump and, worst of all for me, loss of driveability. My power band is 6000-7800rpm with max power at 7500. Realistically you can't drive with that sort of commitment on the road and to produce more power the torque will all but disappear. When Steve and Scott were sorting my car, the thing we wanted was not power, it was throttle response and I'm pretty sure that we achieved that with Motec - something you can't do with the old Marelli system.
The only economical way to get more power is MikeT's way with forced induction, either Turbo or Supercharger. I do think, though, that big power brings its own problems. Play has been bought to a halt three times with my car - all transmission related and with "only" my N/A torque curve so I'm not saying it will be pain free......
If the question is bar-stool related, then in my Evo days we took the same modded car to four rolling roads, all were done in a six week period and at the same time in the morning - and we had a 63 bhp difference in the results. So, just as Tim says, keep hawking it around until you get the figures you want.
If it's directly Clio V6 tuning related, I reckon 300bhp from a road-going vee is not easy (or cheap!) and all this air filter/exhaust stuff is unlikely to get much more than 15-20bhp by bolting on bits. We know that Renault's 255 is a bit suspect so bolt-ons might get you to 260-265. Cams will add a bit but leaving the single plenum means it's all a bit pointless - add another 10 if you are lucky. Where's the other 25 coming from then?
Changing to Trophy spec means you need to find an engine, exhaust, management system, pipework and engine mounts. You'll need to have a flwheel made up to mate the clutch unless you want to run the sequential 'box and as well as emptying the piggy bank, you'll now have a car that doesn't work as a road car.
Past 300 "real" bhp is possible but subject to diminishing returns. Currently the limit on mine is the twin plenums/injectors which are fully open at max power. A T/B setup would allow more fuel but my gut feel is that we will soon run into a real world air-flow problem. The packaging of a big engine between a fixed bulkhead and a tailgate along with the need to shield the underside from road crap means holes and vents start appearing and speed disturbed air is not easy to manage.
We know that more cc's are the cheapest producer of power but that avenue soon closes - 3.5 litre engines exist but get hot-spotted in the cylinder liners. So for now, if you asked me where the limit is, 320-330bhp is tops without serious work - trick fuel, exotic materials, dry sump and, worst of all for me, loss of driveability. My power band is 6000-7800rpm with max power at 7500. Realistically you can't drive with that sort of commitment on the road and to produce more power the torque will all but disappear. When Steve and Scott were sorting my car, the thing we wanted was not power, it was throttle response and I'm pretty sure that we achieved that with Motec - something you can't do with the old Marelli system.
The only economical way to get more power is MikeT's way with forced induction, either Turbo or Supercharger. I do think, though, that big power brings its own problems. Play has been bought to a halt three times with my car - all transmission related and with "only" my N/A torque curve so I'm not saying it will be pain free......
Andy luvs V6s
New Member
loads of people say that turbo cars are easy to tune...then why not (budget allowing) stick a turbo on and tune away....? i know its not as simple as that but surely there must be another reason why turbo cars are so much easier to tune?
In its simplest form, forced induction gets you beyond the limitations of nature - in a N/A engine, normal atmospheric pressure means air doesn't want to flow in or out of an engine.
Forced induction means you can ram in what you like under pressure and it is forced through the engine.
The reason it's relatively cheap as a tuning method is that you only need to buy an air pump and a means of controlling it so that it doesn't grenade
Pretty effective though
Forced induction means you can ram in what you like under pressure and it is forced through the engine.
The reason it's relatively cheap as a tuning method is that you only need to buy an air pump and a means of controlling it so that it doesn't grenade
Pretty effective though
Andy luvs V6s
New Member
thanks for clearing that up
just going to find a dictionary and look up ramification :geek:
just going to find a dictionary and look up ramification :geek:
A
Anonymous
Sounds like fun. Wouldnt mind doing this after having the new map put on the carscotty6r4":3jv4tomd said:
A
Anonymous
All this talk about Trophy engine and spec has got me wondering. Does anyone know the full spec for the mk2 rally v6's i.e. 0-60, kerb weight, comparison in lap times to the road car etc, etc. Or does anyone have 300bhp+ and stripped their mk2 out completely? A 1250-1300kg mk2 v6 kicking out 300bhp has got to be in M3 CSL territory! Who's got the most powerful naturally aspirated mk2 out there?!
Fair amount of mis-information here.
Ultimately, using natural aspiration, current limits using road type petroleum is circa 300bhp/ltr.
Forced induction using super fuels are approaching 1000bhp/ltr.
FI isnt 'easier' to tune, its infact harder due to the precise control you require over burn rates primarily. This means that every factor you have to know, understand and be able to influence to a degree. FI is easier to get initial power out of though. Once you start pushing things though, they are nowhere near as safe as an NA engine.
Andy, as said, the initial BHP for about 150/170bhp/ltr is easy to obtain without any real considerations for abnormal combustion so long as the 'system' is built well. And by that it will mean that you will have to take as much care over the FI setup that you do over a comparative NA setup. Efficiency is the name of the game, and if you simply ignore design efficiency because you are running positive relative presure, then it wont be that good at all.
Marky, the trophy spec engine isnt that far from stock. It remailed robot assembled so they only changed components that could be installed like cams/valve springs, manifolding etc. Base castings remain the same. Not sure of any Renault sport rally cars, but a few lads use V6 bases for their rallycross cars either uses trophy twin plenum setups or the huger 380bhp engines.
In regards of how hard it is to get 300bhp out of a stock engine........not that hard at all. The stock engine minus the inlet and ex system are all that need to be replaced. If you want to keep the stock engine cover then it'll take a bit more ingenuity......which takes money.
Ultimately, using natural aspiration, current limits using road type petroleum is circa 300bhp/ltr.
Forced induction using super fuels are approaching 1000bhp/ltr.
FI isnt 'easier' to tune, its infact harder due to the precise control you require over burn rates primarily. This means that every factor you have to know, understand and be able to influence to a degree. FI is easier to get initial power out of though. Once you start pushing things though, they are nowhere near as safe as an NA engine.
Andy, as said, the initial BHP for about 150/170bhp/ltr is easy to obtain without any real considerations for abnormal combustion so long as the 'system' is built well. And by that it will mean that you will have to take as much care over the FI setup that you do over a comparative NA setup. Efficiency is the name of the game, and if you simply ignore design efficiency because you are running positive relative presure, then it wont be that good at all.
Marky, the trophy spec engine isnt that far from stock. It remailed robot assembled so they only changed components that could be installed like cams/valve springs, manifolding etc. Base castings remain the same. Not sure of any Renault sport rally cars, but a few lads use V6 bases for their rallycross cars either uses trophy twin plenum setups or the huger 380bhp engines.
In regards of how hard it is to get 300bhp out of a stock engine........not that hard at all. The stock engine minus the inlet and ex system are all that need to be replaced. If you want to keep the stock engine cover then it'll take a bit more ingenuity......which takes money.
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