mikemassi

(94 camaro z28,A4,full exhuast)i recently just bought a ported intake manifold off my friend. will i notice any differeence in power with this. i also am goin to purchase a throttlebody and injectors and get it tuned. what kind of power increase should i be expecting with everything all said and done? thnaks

96capricemgr

If the ports are opened up larger than the head ports you could notice a LOSS of power.

Intake is not something that should be an early mod on an LT1, even on heads and cam cars porting seems to only be of modest value.

rskrause

Besides major mods to the intake, about all that is useful is matching it to a larger throttle body and port matching to your heads. These are worthwhile, power gains will vary with the combo.

Rich

BCdawg57

about how much power would you lose if a bad port job was done to your heads?

MikeGyver

possibly ALL of it if bad enough

BCdawg57

Im just asking cause i ported my intake myself last year, and i matched it to the gasket. I did not however match it to the heads. My heads are ported and i dont know if they match the gasket or not, so i was just curious how much hp i might be losing.

rskrause

Well, if the manifold is bigger than the port in the head, that's a bad situation where a lot of power can be lost. Most people actually like to leave the a lip on the manifold that is 0.020-0.030" smaller than the port to help prevent reversion and to surely avoid the opposite situation (a lip on the head protruding into the port) which screws up airflow.

Rich

Injuneer

Whether you will gain anything by changing the injectors depends on the engine's power level. You haven't told us anything about the mod's except "full exhaust". If you aren't over 360HP at the flywheel, the stock injectors are more than adequate. Many have taken them beyond that power level and not had problems. The "tune" is always a good idea. Even on a stock engine you may gain as much as 15HP simply by leaning out the power enrichment (PE) mode target A/F ratio.

If all you have is an exhaust, leave the throttle body and the intake manifold alone.

mikemassi

the mods done to my car arent to extreme. i have full exhuast, undrives, a/c delete. egr delete,cai,3.73's,msd ignition, and rebuilt stock heads with RR's. The intake manifold is ported but only the throttle body opening seems to be alot bigger, all the ports match the stock intake mani gasket perfectly. will i lose power?

96capricemgr

If the intake is gasket matched and the heads not that would certainly be a bad thing.

The underdrive is pointless as is the MSD.

MikeGyver

a reversion lip on the intake runner?

96capricemgr

There is such a thing as intake reversion. Without that argument though it still makes some sense to leave the manifold smaller than the head because since they are not doweled there is likely some missalignment.

rskrause

Yes. It's a bit of a safety factor against slight misalignment. Just 20 thou or so is what many people (myself included) do when port matching a manifold. Gives a little anti-reversion, which is good, and prevents the manifold being larger than the port, which is very, very bad.

Rich

1989TransAm

X2. Or is it X3?

slowride94z

a picture is worth a thousand posts, what you see here is wrong.

backwards of what these professionals are telling you,

experts, heroes, true