is runnin low compression pistons better for jrsc - Honda Prelude Forum

TJN_Prelude · 06-22-2003, 01:26 AM

is runnin with low compression pisotns better for jrsc.
like type s pistons

sharkcohen · 06-22-2003, 12:33 PM

Type S pistons are higher compression.

schwett · 06-22-2003, 04:23 PM

the type-s motor as a whole is 11.0:1, so i would assume type-s pistons in a usdm motor would be the same or close to the same... unless the heads are significantly different. (the bottom end is the same)

anyway, though, generally you would not want to run lower compression with the jrsc unless you are planning on running it at higher boost levels, and even then not by much.

ExtremeVtec · 06-22-2003, 06:17 PM

yeh, my jdm h22a (rebuilt) is at 9.0:1 and that sucks big time with the jrsc at 6psi.

stay away from low comp with supercharging

Paluce · 06-22-2003, 08:49 PM

Quote:

Originally posted by ExtremeVtec
yeh, my jdm h22a (rebuilt) is at 9.0:1 and that sucks big time with the jrsc at 6psi.

stay away from low comp with supercharging

it's probably better to say, stay away from lower compression and Forced industion in general. SC or Turbo, boost is boost. you lower your compression so you can raise to boost higher.

TJN_Prelude · 06-22-2003, 09:38 PM

thats what i was thinking. lower compression higher boost.
what do you guys recommend.

SooCo100pf · 06-23-2003, 12:14 AM

If youâ€™re using the JRSC you are limited by the blower, it maxes out at 11psi on our engines. I would stay away from low compression with a supercharger, unless you get a non-roots type blower on a prelude somehow.

99Prelude_LC · 06-23-2003, 02:31 AM

Another route is what I did, run higher compression in my case 10.6:1 on a stock jdm motor and 6psi. I put down more power than the 9psi preludes on 10:1 compression. It ran awesome with no detonation even at full timing on the dyno in crappy weather. Dyno link is in my sig

However I would reccomend a standalone fuel management or if you do my ghetto rigged fuel invest in an aftermarket ignition setup!! My 1st gear slipped towards 10krpms and i killed the motor

an aftermarket rev limiter might of been a good thing to have if i could have forseen something like that since its never happened before.

Even if you run higher boost on a jrsc you are going to be increasing the temperatures which is going to work against you.

achemze · 06-23-2003, 02:45 AM

This is true. In a turbo situation you can make lowered compression work for you. In fact i run around at 8.5:1 (which is definately to much but live and learn) and the horsepower per lb of boost is shocking to your stock compression guys :P

i would agree that raising boost on a S/C is not the best solution,Intake Temps will sore with minimal benefit.

Intercoolers are your friend.

bkw97lude · 06-23-2003, 06:22 AM

The best route with the JRSC would be to get stock compression Ratio pistons and then run the 9psi pulley. This would get you in the 250whp range. On top of that the only way to get a lot more power would be to run a nitrous setup. This would easily be in the 300+ whp range.