Right then, best option for extra HP.
Turbo charging seems the best cost per HP and the easiest to install. But what about heat ?
I often read about the heat soak from the superchargers, would it be any worse with a turbo ?
Turbos seem to put less strain on the engine as they don’t use engine power to run, but the turbo lag although I read that this is not really noticeable, but does any one have first hand experience of turbo vs super charger ?
Any thoughts ( Like I need to ask ? )
Graham
I’m no expert but i thought you had to build the engine with a lower compression ration for turbo charging were as superchargers bolt straight on.
If you want big power would it not be easier to drop in an Audi motor.
Mike
Vision function e building one in the US, it will make more power for the same boost as a SC as there is no parasitic loss from the SC to worry about, however power delivery is not as linear which could be exciting on track 
Forgot to say Audi power in an S2 Exige is still a pipe dream, you would need to start with a K powered car and rebody it after the transplant 
So that answers the question about compression ratios, if you run low boost like the supercharger it will bolt straight on and give more power.
But then you would be back to having problems with the gearbox i guess ?
How come the Audi does not fit an S2 or is it that it just hasn’t been done yet ?
Mike
No you wouldn’t Ade. Audi power in a Toyota powered Elise / Exige is available today!!!
Yep, but turbos always do, you will still have to be careful at 10psi with engine internals, I would be tempted to run 8 or 9 max.
You are right the gearbox has issues with around 200lb/ft of torque and the turbo has way more than that, most 3rd gear failures appear to happen at peak torque. I also suspect the gearbox failure rate would be higher for cars used soley on the road as the higher torque is more easily accessable on a turbo car.
Track cars usually seem to fail after prolonged use on track pointed a bit more to excessive temperatures similar to Noble GTO3Rs
As for the Audi stuff, it appear to be more to do with the wiring than fitting, the Honda boys are having the same issues with the Toyota powered cars
No you wouldn’t Ade. Audi power in a Toyota powered Elise / Exige is available today!!! [/quote]
Who owns\has done one? I now know of a Honda powered 2-11 and that has taken an age to get the dash etc working correctly due to the can bus system?
So the general consensus is turbo = more torque but gearbox failure is a sure thing.
Where as supercharger = safe bet but less get up and go, but gearbox problems seem quite common?
Is there a stronger gearbox? I assume as the Toyota engine is quite common in racing there must be a gearbox to cope with the extra HP.
Graham
I’ve done it and it works great…It just may be the fastest most powerfull S2 Lotus on the freakin planet…
Frank what’s the history behind your gearbox? I have only picked up on slight comments and a thread regarding a Kaaz gearset on another forum but I am genuinely interested although have a different agenda completety?
Having said that this thread could be very interesting.
Ade I’d drop my car into JSR for an Audi conversion tomorrow …but for my agenda lol
Frank is running a 5 speed Toyota box. I am sure he will be on again and give you the detail.
Turbo/SC is nothing to do with the gaerbox failure. If you put too much torque through the std 6 speed it will break.
Ex77
Yes Frank is running a 5 speed E153 Toyota gearbox from an MR2 Turbo, the setup is not easy and the costs are substantial along with the custom parts.
But the final nail in the cofin for me were the gear ratios, you have to be running similar power to Frank 400+hp to make them work, they are so tall and not much good for a track car sadly, I rekon you could only use one gear round Brands for instance
Jubu gears and oil cooler seems to be ok so far, got 2 more days this year so watch this space
What power is yours putting out now Ade ? Do Jubu suggest what power/torque their gears will take.
[quote=jonnyfox]Frank what’s the history behind your gearbox? I have only picked up on slight comments and a thread regarding a Kaaz gearset on another forum but I am genuinely interested although have a different agenda completety?
Having said that this thread could be very interesting.
Ade I’d drop my car into JSR for an Audi conversion tomorrow …but for my agenda lol [/quote]As Ade said it is the E153 MR2 Turbo gearbox. The gears are not too tall sayin that is just plain wrong… and you could always drop in a V6 at a later date…
[quote=ade]
As for the Audi stuff, it appear to be more to do with the wiring than fitting, the Honda boys are having the same issues with the Toyota powered cars [/quote]
yota conversions are available now, and JSR can do an audi to boot
http://www.pistonheads.com/gassing/topic.asp?h=0&f=15&t=886406&mid=0&i=0&nmt=K20Z%20Honda&mid=0
To clarify an earlier point…
A supercharger is an inlet compressor to pump more air into the inlet of an engine so more fuel can be put in to produce more power.
A positive displacement supercharger (roots blower type) as used on supercharged Toyota’s and Jackson Honda’s are crank driven compressors. They generally are horribly inefficient and produce alot of hot air using lots of engine power and requiring very retarded timing and plenty of fuel enrichment.
A centrifugal supercharger Vortech or similar is also crank driven but it far more effient than a positive displacement charger but has the disadvantage of only producing decent boost at higher rpm. However the crank effort to spin the charger is far reduced and the outlet temps can be far lower.
A Turbo (Turbine driven centrifugal supercharger) can be anything from very inefficient to very efficient depending on the size of the turbo chosen. Small turbo > low lag (lag = time taken for the charger to spin fast enough to produce required pressure) generally poor high rpm power. Big turbo > increased lag generally poor low end power but potentially big high rpm power. Overall a correctly sized turbo cannot be beaten for efficiency, although driveablility can suffer due to turbo lag.
For any engine the most efficient charging device will be the safest as it will require the least boost, least extra fuel and least timing retard to produce equivalent power. However all different charging setups have their own advantages and disadvantages. Supercharger > more like NA, Turbo > spring like delayed power from desired.
Now I need my bed because I have drank far too much and probably chatted complete garbage here…
Feel free to correct.
Phil
Phil, I wish to correct you.
You’ve not had too much to drink! 
Yup that is serious PWD [posting while drunk]… I can’t find one correct statment…
I hope your head is feelin better…
Phil , are you a politician ?
So much written and so little said !!!
Thought I was drunk when I tried to read it …