SickaS14

Hey guys

for some strange reason i did a compression test on this sr20de i got in my silvia and im getting strangly low compression results.. the car is at operating temperature and im getting 150 PSI in every cylinder, which appears healthy but its so low? i would have thought an N/A motor would have higher compression that that, im wondering if i have a DET block and DE head on my car?

SickaS14

Bump.. anyone know what the stock PSI of each cylinder must be on a s14 silvia? 1998?

Please i need to know

McCoy

I wouldn't worry about the overall numbers being low/high... really what your looking for on a compression test is the % difference between the cylinders, if you're getting different #'s in each cylinder then I would start to worry.

Here was my last set of #'s taken off an S13 SR20DE when it was cold. I had detonation and major damage to all 4 pistons.

#1 161
#2 145
#3 122
#4 121

SickaS14

Cheers man, real big help my % looks good but im sure the factory standard should be more psi, coincidence that all cylinders are worn? i dropped some oil in and it cranked to around 190psi on the first cylinder from 150 so worn rings and bores from all cylinders? cars only done 120 000 km

seishuku

Well, the standard PSI for an SR20DET is 156PSI, 179PSI for a KA24DE (9.5:1), so around 190PSI would probably be right.
I donno for sure on that though, I've never seen an FSM for the S14 SR20DE.

With 80k miles on it, it could be worn that much, depending on how well the original owner broke it in, or how it was treated.

__________________
1987 Nissan 200SX/Silvia (S12) Specs:

• SR20DE+T (94 S14, VCT)
• 9.5:1 Compression (Sentra pistons)
• T25 @ 11PSI
• 450CC DeatschWerks Injectors @ 60PSI (528CC/min)
• Bosch 023 Fuel Pump
• MegaSquirt Extra 029y4
• Custom FMIC
• Currently maxing out injectors!

McCoy

I am quite sure the insides of the S14 SR20DE are the same as the S13/B13/B14 SR20DE. Your compression #'s do seem like you are running a DET motor.

B14 SR20DE FSM says low is 149 and high is 178. Difference between cylinders, maximum of 15psi.

S14 SR20DET FSM says low 128 and high of 156.

holeshot1

150 is pretty good numbers ive had 120 across the board and car was fast as hell. all my rwd sr20s were always like 130ish and below

seishuku

Keep in mind the S14 DE is higher compression (10:1).

S13/S14/S15 SR20DE and DET's all have the same internals, with these exceptions:
Pistons (DE's have NA pistons, 9.5:1 for S13, 10:1 for S14 and S15)
Oil jets (DETs have them, DEs don't)
Cams (DE's have slightly longer duration)