High compression turbocharged engines.


Kozy

Kozy

Bench Racer
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Seen a couple of high compression boosted builds on Honda-Tech, I am a bit baffled as to how these run without exploding. I see some guys wanting to run 15psi and a 14:1 CR, is this even possible?
 
Wow never seen as high as 14 cr, i know 10-11 is easily done but dam, 14
..

No idea how :p complete custom build??
 
Garrett have a small article on compression ratios, but I wouldn't have thought it was possible to run that high a CR without blowing a HG unless you were running 100+ octane and retarded ignition timing?

Although I'm sure someone with a better knowledge will correct me :)
 
If you can make it work its great, smaller increments in boost result in good power increments! Maybe using meth you could avoid det ?
 
It's fine... all you need is the octane to backup the compression. There are loads of FI race engine's out there running what we consider as "high compression". It's all about octane...
 
Gotcha. That build is on E85, that would probably explain it.
 
Yep, that's exactly why. Ask him to run it on their 91 regular petrol and see what happens.
 
They use a different scale to measure their octane rating remember. Their 91 is like our 94... or something like that...
 
They use AKI, IIRC it doesn't correlate exactly with RON, but yes their 91 is like our 95 I think.

E85 sounds like pretty pokey stuff then if you've got the engine built for it! :nice:
 
E85 would be close to 110 octane over here. Amazing stuff especially on turbo engines. Pity they stopped selling it here in Ireland at the pump:mad:
 
It's actually the opposite to "pokey " lol. I think it's energy content is around 30% less compared to petrol. BUT the use of high compression improves the engine's efficiency which allows you to get that 30% back in some cases.
 
Rich777 said:
It's actually the opposite to "pokey " lol. I think it's energy content is around 30% less compared to petrol. BUT the use of high compression improves the engine's efficiency which allows you to get that 30% back in some cases.
Click to expand...

Yes I did see that actually, strange how fuels can have less energy content and yet produce more power! :shocked:
 
a larger delta to play with, wider spectrum with e85
its just harder to locate...
 
£5 a litre though, likes to eat oil seals/rubber too I hear. Great for boost though! :)
 
Because the fuel is more resistant to knock, there for you can be a whole lot more aggressive with the timing which will make more power.
 
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