Decent exhaust system for the Cup 240
Decent exhaust system for the Cup 240
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Discussion

garyfitz

Original Poster:

26 posts

252 months

Thursday 9th March 2006
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Dear all, I have been told by my Lotus guy here in Tokyo that the right systems to fit is a HKS system, but there is not one available yet for the Super Charged engine. Does this sound right? Will the exhaust system be different for the supercharged engine than the standard engine?

bruh_la

319 posts

285 months

Thursday 9th March 2006
quotequote all
I would also be very interested to know the answer to that one.

I spoke to a driver at a Lotus Cup race who reckoned that the best exhaust for a NA car is not always the best for a Supercharged car. I do not know why.

Can anyone enlighten us.

gooby

9,269 posts

265 months

Thursday 9th March 2006
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I would chat to the guys at Larini

GTRene

22,767 posts

255 months

Thursday 9th March 2006
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garyfitz said:
Dear all, I have been told by my Lotus guy here in Tokyo that the right systems to fit is a HKS system, but there is not one available yet for the Super Charged engine. Does this sound right? Will the exhaust system be different for the supercharged engine than the standard engine?

Well I guess so, because a supercharged engine gets in a lot more air then a normal aspirated engine same size, so that way it has to loose more air too down the exhaust, that way you need bigger bore pipes to get faster flow in the pipes! other wise its like try to blow a lot air through a straw...sounds like astma
GTRene

bruh_la

319 posts

285 months

Thursday 9th March 2006
quotequote all
He seemed to suggest that regular NA tuning teqniques when used on forced induction set-ups do not work as well.

Maybe its just myth. The 240r can be ordered with exactly the same exhausts from Lotus as the NA car.

bogie

17,102 posts

303 months

Thursday 9th March 2006
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well theres no difference on supercharged K20As - you can run just about what you like...as long as the exhaust is not too restrictive


I would have a thought a Lotus Stage 1 would be just fine...its not as if you are doubling the power of the engine...its only 50bhp more than stock


_topcat

1,938 posts

280 months

Thursday 9th March 2006
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pedantic mode on... its actually 80 hp more, the roots super charger takes 30 hp to run. pedantic mode off.....

chris_n

1,232 posts

289 months

Thursday 9th March 2006
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As I understand it, coming up with an exhaust system that maximises performance is mainly about the manifold which should be designed to use pulse tuning to help extract exhaust gases. And So as long as the rest of the system is not too restrictive it shouldn't really make all that much difference.

As most of the available systems for the Toyota engine don't change the manifold AFAIK, then weight/looks/sound are really what we're buying when we fit replacement exhausts from the cat back. So if as I believe is the case the manifold is the same between the normally aspirated and superchared cars then I'm sure the same aftermarket exhaust can be used without much impact either way.

If you really wanted best possible performance you would mess about with the tuned lengths of the manifold pipes so they are optimum for the specifics of the engine. Having said that I think I'm right in saying pulse tuning is not as critical for a forced induction engine as it's not so crucial to scavenge exhaust gases from the cylinder effectively on the exhaust stroke when you have a pump cramming the air/fuel mixture in on the induction stroke rather than just relying on atmospheric pressure to fill the cylinder.

Anyway I've *exhausted* my understanding of this subject now so I'll shut up!

Chris

Edited cos I said *with* when I meant *without*

>> Edited by chris_n on Thursday 9th March 18:47

simonk

908 posts

256 months

Thursday 9th March 2006
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Chris, i dont understand the first thing about exhausts but having looked your profile i have to say what a FANTASTIC collection of cars youve owned! The Mk 1 golf and the two porsches probably being my favourites.

Simon

chris_n

1,232 posts

289 months

Thursday 9th March 2006
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Thanks! I'm afraid I got bit by the bug at a young age and have spent most of my time and money messing around with cars ever since (probably like most people on here)!

I left some of my earlier efforts off the list - rusty minis, escorts, fiestas etc (even a metro ), but they were all just as much fun in their own ways. I'm beside myself with excitement waiting for delivery of my Exige S though!

Chris

garyfitz

Original Poster:

26 posts

252 months

Friday 10th March 2006
quotequote all
Ok, so if teh conventional wisdom is correct, then what we are talking about is a system from teh headers to the tip of the exhaust pipe. I am happy with that, but the question still remains, do you guys know where I should look to find somebody to do this?