Compression Ratio choice

[thilaksharma]

If I were to change to pistons, which would be the best choice for from this two

2G 8.5:1
EVO3 9:1

I run RON97(Octane 97 daily on my 4G63T VR4, Frank 1 (50trim Compressor/td05h turbine), 25-28psi of boost. I also run a 1.5mm MMC metal head gasket. Or should i just stick to this low 7.8:1 compression.

 

[Black95awd]

9:1...

 

[dsm-onster]

Lowering compression, or keeping compression low to run more boost is a band-aid. A high compression chamber burns faster. Retarding the timing has LESS of a negative effect on power. And the rate of burn can use all of the fuel before detontion even occurs, if the timing isn't too retarded-- before the fuel falls out of suspension. Large droplets of fuel is very detonation-prone. IMO, this phenomenon is why we get rich knock. And because of a fast burn rate, you can generate a lower brake specific fuel consumption or more horsepower extracted per unit airflow and fuelflow. It's a honda trademark.

 

[codeofdastreets]

i just moved to florida, (tampa area) and e85 is out of my way, so now pump 93 and c16 will me my option..My car will be on a 93 for most of the time and I was thinking off doing a 10.1 wieso hd custom piston, turbo choice is between a 6266 pte dbb and a bw s366 batmowheel..Can I play safely on this compression?? If not what compression would you recomend on a 2.0??

 

[Mrdocprofessor]

its all n the tune wee need more info of you setup codeofdastreets

 

[codeofdastreets]

manley turbo tuff rods, build ported head, l19s, ecmlink v3 sd 1600cc injectors, full fuel system etc.. I will be planning on driving the car on the street

 

[habitatguy187]

Buy or build a meth kit and don't worry about it.

 

[zedicus]

im building a 10:1 stroker as we speek. all i can get is 91 octanne crap gas. (farm community, middle of no-where) and all ive got for tuning right now is an SAFC2.
if my maths are right, it should work out.

if you could fully tune (dsmlink or something) and trust in math, upper limit would be 12:1 and a ev03 16G on 91 oct. tune would have to be PERFECT though. boost and compression work to achieve more power, if you lower 1 to raise the other, your staying in the middle.

also some big, quality injectors will be required, and supporting stuff. but saying "dont go higher then X:1 compression for a turbo, blown, meth, nitro, diesel, rotary, ICE engine" is just dumb.