Deusxmachine said:
I have noticed a lot of ported Plenums on ebay. They are all for MAF vettes and F-bodys. Is there a differance between a plenum for a mass air flow or speed density equiped car. I have a 90 and i am getting the big mouth manifold and large tube runners along with a 52 mil throttle body. What would i have to do to make a plenum from a MAF car work on my SD car, or would it be easier to port my own plenum. How would i go about porting it.
First, there was no discussion about how the engine in this 90 is modified, so I'll assume it's stock or near stock. If that's the case, you don't need a big-mouth manifold, big runners or a 52mm TB. In fact, putting that stuff on a stock or near stock engine may actually reduce performance at the low-end while doing little in the mid-range or up high.
On the other hand, if this engine has head work, a more aggressive camshaft, headers and a low restriction exhaust with either no cat or dual aftermarket cats, then you need to look at those mods.
Once you add all those things, you'll need to have the ECM calibration (the chip) changed. Also, you may need higher flow injectors.
Lastly, there is no difference in plenums and runners on MAF or speed-dens. motors. The intake manifolds don't differ in that respect, either, however, there may or may not be a difference in manifolds between those for 5.0L (F-car) and 5.7L (Y-car) applications.
