Hi all,
I have a 05 n/a exige. im toying with the idea of a vf supercharger kit. Is there any benefit from dropping the compression ratio? Im thinking more about in terms of durability/reliability but also in terms of performance gains.
I know the more expensive way to drop compression ratios is with piston changes. The easier was would be with a decompression plate. If one doesnt drop the compression ratio too much then the std custom maps would be ok i think.
Just ive always thought itd be a cheap mod and dont know y nobody has tried. Gives one a lot of scope to go up on the psi…gearbox permitting.
Not really needed IMHO if 300hp is enough for you, if it is not then the gearbox will need sorting anyway. You would need a custom tune as well to go with the lower comp ratio.
Ta
The lower the compression ratio the more ignition advance and boost you can safely run, and ignition advance and boost mean power. However, off cam / boost it will be less spritely when picking up.
You are only going to get the real benefits and make the engine all it can be by having it mapped peoperly after you have made the change.
You can normally machine the tops of the standard pistons to lower the CR a few points, although I must add, I am not at all familiar with the standard Toyota pistons.
As Ade says, for 300BHP there are few proven solutions out there with standard CR.
Ideally, you want to keep the CR as high as possible (although for the above reasons this is not always possible) to aid low down driveability
The piston lands are the weak link on the standard pistons, any more than 9-10psi of boost and the will break, when you fit lower comp pistons you have to add more boost to get similar power again and also you will see a bit of lag creeping in due to having a low comp engine running big boost even if it is with a SC.