Since i got my std SX back and using it as a daily. I have been thinking how can i make it better. Most new cars run high comp and low boost. Now if you could do this on a CA18DET which is 8.5:1 and get it to something like 9.3:1 you would get better fuel con and more power low down without the turbo.
Only two way i can see of doing this is
1. CA18DE pistons
The CA18DE has no oil squirters but could be "made" to work and 9.5:1 might be a bit high
2. Skim head and block.
Wont get get that much but will be more
Wouldn't you run a risk of too much is too far kind of situation in an engine that isn't designed for high comp?
remember people run 1.2bar boost on a CA18DET with bigger turbo's on std HG now i am not saying up the boost as well maybe even drop it from 0.7 to 0.5
The CA is a strong engine. i remember running 1.2bar maxing the injectors everyday then dropped to 1 bar still maxing the injectors for well over 1 year
You can skim loads off the head, only problem will be you will need to pocket the pistons so they dont hit the valves. Best thing would to buy 9.5:1 CP pistons, DOT ( . ) did on this very forum...
DriftZ: "I swear if a CA18 beats my SR im getting a RB!"
I dyno tuned alot of CA18s within the space of a month or so, most with pretty much the same mods. They all made within 10hp of each bar this one thats head had been skimmed to max, and it made 20hp more than the rest. Only difference between it and the rest was the head skimming.
DriftZ: "I swear if a CA18 beats my SR im getting a RB!"
Also it isn't just mods that will affect the bhp if you are only talking about a difference of 10bhp. Engine's maintenance can make as much of a difference. then there's the obvious exhaust and turbo differences (in type and condition)
Unless these were all freshly built engine by the same shop, it's hard to call that the difference was the head skimming when you are talking about a difference of 10 bhp on a turbo engine.
Fit CA18DE pistons, run 0.5 bar boost. 9.5:1 comp isnt too high for low boost. Std RB25DET is 9:1, and they can run over 1 bar boost. At least by fitting other pistons, u can go back to std again, but by skimming a lot off the head, there is no going back.
