ls/vtec
-pr3 head (not milled)
-arias 11.0:1 piston
-eagle rods
-stock crank
-stock head gasket

compression ratio is calculated at 11.6 or 11.7:1

did a compression test after about 35k of driving and results were:

#1 cyl - 235 psi
#2 cyl - 230 psi
#3 cyl - 230 psi
#4 cyl - 230 psi

just wanted to know if that is where it is suppose to be or is it low for the setup. cause i didn't do a compression test when i first had it built and ii don't know anyone who has the same setup and has done a compression test to compare #'s.

 

My cousin got the same results with same compression. Was sort of wondering the same thing. Too many sames

 

what cams are u running? the numbers seem slightly low for that compression, but may be due to overlap. but they are very consistent across the board, so you probably don't have anything to worry about.

 

i'm just running ctr cams didn't know that cams can effect a compression test

 

If you dont mind me asking, have you dynoed your motor? Want to compare your dyno with my cousins.

 

they can, but only if they have a lot of overlap. at low rpms you lose a lot of compression due to the intake and exhaust valve being open together on the compression stroke. on my old dumbestic race car i was running 13:1 compression but with a cam that had 280 degrees of duration intake and exhaust so i had like 60 something degrees of overlap. during a compression test i was lucky to make 180psi, lol. i had to set my idle at 2500rpm just to get a decent vacuum.

 

you know i have never strapped it up to a dyno though, still on the things to do. but if you don't mind me asking what did your cousin hit on the dyno?

 

hey that does make a lot of sense. i don't know if my motor has a lot of overlap if any at all. you know how i can find out though?

 

Well he has a b18c block with 11.5-.7 compression, stock 2000 si head, stock cams, skunk2 manifold, and a jdm 4-1 type r header. He made 176 hp and 126 ft lbs of torque on fastrip 91 octane. This was on a dyno jet and it was tuned with hondata. He is hoping to hit the 200 mark with cams and headwork.

 

i just did a quick description on my motor in the begining. my setup is:

-pr3 mild port with 3 angle valve job
-complete crower valve train
-ctr cams
-itr manifold
-98 lude injectors(290cc)
-ls block w/ arais 11.0:1 on eagle rods, gsr girdle
-gsr tranny
-arp head studs

just chipped p28 rite now untuned. waiting on the dyno anytime soon hoping for at least 190 whp on hondata.