help lack of compression

[shihad]

I dont know jack bout cars so any help is gud.my silvertop had a compression test and all 4 cylinders were bout 135 (psi???) ive been told they should be round the 160 mark.would the reason for me losing compression be worn rings? how much for new rings?

[Dell'Orto]

Does the car lack power? Smoke really badly?
If the compression results were even, thats more important to an extent than a number.

[fx gt]

put oil in the pots then new plugs and wala

[Lloyd]

As above, if they're all the same and it goes alright then probably dont worry about it. If they're all that low them chances are it could have been done with the throttle closed or something similiar which would cause all the results to be fairly low.

[shihad]

the car seems to really lack power but doesnt seem to smoke much

[shihad]

the engines in a ae92 trueno and is running off red top clutch and gearbox.if that would reduce power???

[Dell'Orto]

Nope, that wont make a difference.
How majorly lacking in power is it? Like, have you noticed a power decrease since installing the motor?

[shihad]

the motor was installed in febrary i think but i brought the car in may did the test in june i think. found out recently what the compression should be.i dont think its lost power since ive owned it but i would have thought it would go alot hard for a 160hp.ive been in a redtop fxgt and it seemed to have bout the same power.was once raced against a stock 1600 dohc vtec teg and got smoked i thought seeing as the power was bout the same that my car would have kept up

[Dell'Orto]

Nah, silvertops dont make 160hp...dyno one stock, you'll see anywhere from 75-95kw at the front wheels...which unless you use Pommy calculation, doesnt get close to 160 at the fly.

[shihad]

well if my car is fine then silvertops are shit.it seems to have very little power in the low revs.

[shihad]

do all silvertops have flat spots just b4 vvt?

[Dell'Orto]

well if my car is fine then silvertops are sh*t.it seems to have very little power in the low revs.

Welcome to the world of 20v's

[shihad]

this very website quotes under engine stats that silvertops putout 120kw.

[Dell'Orto]

160hp/120kw is Toyota's quoted power figure, and its been proven time and again to be overstated.

do all silvertops have flat spots just b4 vvt?

I dont think they're meant to, but it seems awfully common.

[shihad]

oh well that sucks is a blacktops power figure 165 hp allso bullshit?

[shihad]

ok seeing as my engine is slow what mods do u recomend cause i need more power to keep up with those dohc vtec boys.i already got exhaust and pod filter

[Drifter4ag]

replace the ecu & pistons
Or just get a 16v and modify that...
black top is good .. it has got the stated power from factory ...

[shihad]

is a 16v beter 4 modding? how much for ecu? wat pistons u recomend

[Mr Revhead]

nothing at all wrong with the silvertop.....

run it on 98 octane. or if you insist on using 95 back the timing off to 8deg.
try and use mobil fuel as that seems to go better... shell is arse.

check the coil lead, this is prone to wearing out and making them run rough.

they are designed to be run on 100 octane fuel so they are really struggling on our shit.

when you say youv got an exhaust.. what have you done? the only part that needs touching on the 20v is the part that goes over the subframe.

does your pod live in a cold air box with a proper intake?

[Lanius]

And what are you revving it out to? Peak power in a silvertop should up around 7500rpm somewhere, peak torque at about 5500rpm.

Get your engine tuned, as has been mentioned. Replace all the fluids, the plugs etc. Get the timing checked. Theres no real reason for it to be "slow", but don't expect to beat Type R's in it or anything. Its going to cost a fair bit of money to get pistons and ECU done (it doesn't sound like you're a mechanic yourself ... ?), so try for the cheaper / basic mods first.

Get your cold air feed sorted, make sure your exhaust has been correctly modified (as Mr Rev pointed out), get your suspension and brakes checked out. Theres heaps of information about modifying a silvertop on the net (and on here), just gotta have a look for it.