horsepower drop

[paolo_m]

helo all, i'm using 4g93 n/a engine with slight mods & recently dynoed my car and noticed that my hp had gone down from 136hp to only 116hp. can anyone diagnose my engine's problem as from the dyno result the a/f ratio was the same as before. thanx in advance.

 

[jinkl]

please post both the dynocharts for us to see
first and 2nd dyno same shop ?

 

[paolo_m]

owh ok, i'll post the dyno chart ASAP..

 

[paolo_m]

dyno done at same shop..

 

[jinkl]

if u did both dyno's on the same machine , GT Auto , then you have indeed
benchmarked before and after on it, it should yield best comparison
it really shows ur car has dropped power , reasons power drop could happen is
1. lost of engine compression caused by pistons rings or valve seals & etc
2. dirty sensors which changes a/f ratio
3. tuning disturbed

 

[NFS]

looks like your a/f is a bit different ...

has it been re-tune? look carefully at the A/F ... and it has a slight different ...

maybe the 1st dyno was when u newly seviced the car ... the later is due already :P

that what happened to mine ... a slight drop ....

 

[JackWaiKit]

if u did both dyno's on the same machine , GT Auto , then you have indeed
benchmarked before and after on it, it should yield best comparison
it really shows ur car has dropped power , reasons power drop could happen is
1. lost of engine compression caused by pistons rings or valve seals & etc
2. dirty sensors which changes a/f ratio
3. tuning disturbed

ya ya....
last time my engine feel lost power since he gasket leaking...
It's happen on the area near inake...so can't check 1st time....then claim for lost eng compreesion!!!

 

[EGNINE]

this happen to me too b4..but i have reason why it drop...
...1st case i change piping route from original route to straight route with border 304...power drop 10hp and torque 1kg/m
...2nd case ...i did change valve seal...so the foremen dismantle my campulley and distributor..eventhough he said he mark it..still i feel the power loss..dynoed my car..power drop same as the above ...

but if u didnt do anything than the power drop by itselt..mmm i dunno lar hehe

 

[paolo_m]

thanx for ur comments guys, i've also been suspecting that my adjustable campulley marking sudah lari bcoz replaced my head gasket b4 the 2nd dyno. So izzit logically explained that my 20hp horsepower drop is caused by timing marking lari?

 

[JackWaiKit]

I don't think adj cam gear can drop u for 20hp...even with hi cam!!!

How bout the others guys?
any comment?

 

[EGNINE]

i think in can be because of the distributor and the campulley...16hp drop for my case....u can retune your car to achieve it back...no problem...

 

[KhonBaRot1]

well.... hi cam + correct afr setting can gain +-20 horses, if the setting run, the power gain goes back to normal cam bench mark i guess.... mebbe this is what happened.... really luv to wait for experts comments...

 

[paolo_m]

i've checked my compression ratio and all cylinder is ok giving average of 11 compression ratio, except my cylinder no 1 (nearest to the timing belt) is 9-10 compression ratio, which i was told is normal for an old engine.. hmm i guess i have to send my car again for dyno tuning to find out whether can get back my 20hp except there is other explaination can clarify the loss.. bcoz i'm scared that even after another dyno tuning the hp will still remain the same as before which will cost me $$$ even without gaining back my horses..

 

[ART///SPEED]

i've checked my compression ratio and all cylinder is ok giving average of 11 compression ratio, except my cylinder no 1 (nearest to the timing belt) is 9-10 compression ratio, which i was told is normal for an old engine.. hmm i guess i have to send my car again for dyno tuning to find out whether can get back my 20hp except there is other explaination can clarify the loss.. bcoz i'm scared that even after another dyno tuning the hp will still remain the same as before which will cost me $$$ even without gaining back my horses..

your compression test so low,4G93 STD piston with metal gasket 0.4mm got 14 compression test

 

[paolo_m]

your compression test so low,4G93 STD piston with metal gasket 0.4mm got 14 compression test

wah so high ka? bcoz previously i'm using standard gasket 1.0mm then after that 1 burned changed to metal gasket 1.0mm..

 

[EGNINE]

same with me.. i also use 1mm gasket with compression gauge indicate 11...my foremen also said it was too low...but performance wise still ok for me

 

[JackWaiKit]

your compression test so low,4G93 STD piston with metal gasket 0.4mm got 14 compression test

Is it too risk to cause engine burst with 1:14 compression?

 

[EGNINE]

i think it is not same between CR and compresion test...correct me if i'm wrong..im also confused

 

[paolo_m]

i think compression test result will be in compression ratio unit..
actually higher compression ratio can extract more power from engine but usually engine knocking will happen and increase possibility of wear & tear..
so guys any comments on the engine compression ratio? which ratio is suitable for 4g93?
and are there any difference between 1mm std gasket with 1mm metal gasket?

 

[ART///SPEED]

if turbo engine compression high will be risk...normally our mod 12v saga 18 compression,4G93 mod compression 16/17 and mivec mod 4G93 block 20 compression test