What difference does it make, on a turbo car?

Just thinking this, as the one I got for my V8, and for most cars really, are really big fuckers, then the inlet runners, then the engine.

But then I was looking at Stevie Ross's supercharged LS1 Granada on the cover of Retro Ford, and frankly, it has NO plenum at all.

Got a big 4barrel carb type inlet manifold, then a little 90deg elbow on that, then the throttle.
No plenum at all.

That would suit me just fine as my plenum is massive and gets in the fucking way, but thought you needed one.

So, whats the crack with em?

Stevie?

 

Jesus, what a complicated subject. I did a load of work on this, and basically.... From a power point of view, it's not too much of an issue at all. On N/A, it can shift the curve up and down quite a bit. On forced, it has a much smaller impact. However, on one of the supercharged setups (possibly roots, i'd need to check) a larger plenum makes a big difference.

On a turbo car, the larger plenum helps to balance out the cylinder distribution, esp if u have an inlet biased to one or more cylinders. That's why you use a plenum spacer on a YB.

Rick.

 

Cool, so by the sound of it then I can do a stevie and nob all that shit off if I use a 4barrel type inlet, as the inlet hole is dead in the middle then.

Wish idve took more notice of this engine before I bought my inlet

 

i got a nice increase in power from fitting my plenum and modifying the inlet and throttle.

 

interested to know this also as i need my plenum made up soon


im on throttle bodies, make any difference?