awormofearth

I'm about to put a b18c1 into my 93 ls, but I wanted to do some internal engine work to the new motor before installing it. I dont plan on ever turbo-ing it, so raising the compression ratio sounds like a plan. The GSR starts at 10, and the tegra type R has 10.6. My friend was telling me about people who have gone to 12... I don't know enough about getting thicker pistons to know what all there is to consider. Should I stop at the tegra Type R's 10.6, or should I go higher? I've also heard that the civic type R's ratio is higher than the integras, but I dunno what it is. What do you think?

sherwood

you can go higher, but the higher the compression ratio the harder it is to tune it to run on pump gas. i'd stick with something less than 12:1, it really depends on how much time you are willing to spend on trying to make it work well on pump gas and how much power you are looking for.

11-12:1 with headwork and some new cams i would imagine to be an ideal situation. you would subsequently need to increase the redline and also upgrade other misc. parts of the rotating assembly.

as far as the compression ratios go-- the gsr head will net you a higher compression ratio than a type-r head. so putting in JDM spec type-r pistons will probably push you to about 11.4:1


on a more personal note--
if you are going to do internal work you might as well go for forged internals and then boost. the time and money spent on headwork alone will equal the ammount of a good turbo setup, and dollor for dollar, horse for horse, the turbo setup, with new internals and tune time will net you major gains. not only that but they are fully scalable, allowing you to run pump gas and then still have a different ECU map for the track, or any other of the million ses for differnt powerbands.

Provocateur

Paired with an aggressive pair of cams, a higher compression ratio will be a cood combination. You will need some sort of fuel management with raised compression since the fuel and ignition curves will change.

The P30 (JDM B16A) piston seems to be a good choice since it will raise your static compression ratio to around a pump gas friendly 11.5:1. The PCT (JDM B16B) piston will raise static compression to around 12:1 which will require a decent tune in order to run the car without detonation and you may run into valve-piston clearance problems with large cams.

awormofearth

What kind of HP gains could I expect if I ONLY did the b16a pistons?

Thanks

urbanSTREETZ

higher compression = high octane gas = a lot of money
buy some skunk2 pro2 cams they kick ass
i put them in my 91 crx and gained like 70 hp my motor woke the fuck up and buy some cnc heads b ut there like 3grand which is expensive

urbanSTREETZ

none really there just pistons nothing special about them if u want pistons find some dome pistons it will do more than stock

Provocateur

Your advice sucks.

70hp with S2S2 cams? Right. Too bad Skunk2 states that with proper tuning, increased compression and a high flow manifold, the gains will be less than 25 hp.

urbanSTREETZ

dude bullshit ill even email you the dyno sheet it raised my hp from 170 to about 250 with them 2 cams so i have no clue where u looked at but i know what the the fuck it did to my motor

sherwood

:bs: there is no way in hell-- and you say you already had 170 to the wheels?

urbanSTREETZ

yea um maybe someone knows what he is doing to get hp out of his car :dunno: