I don't know if I've made it very well known or not, but now that the turbo project is complete, I'm working on a new upper plenum for our V6s. The stock one, is horrid, to put it mildly.

Now, what I'd like to find out, is how much clearance anyone with a strut tower brace has, over the plenum? That way, the new plenum will clear as well

 

dean has an edelbrock one(boxed), he had to shim it up with washers to clear. I belive he said it hits the hood slightly.

Shannon has one, hits custom hood bad I belive.

I was looking at the Edelbrock 5227 tube one, that bends forward to clear the carbed aircleaner. Dimensions I was given, this should clear everything.

 

Why I run the single bar type and also run it sideways sort of where the metal is still double thick. So it is in front of the engine/TB. And not on top of it.

There isnt much room.

 

I have about 1/4 inch between the bar and the plenum.

 

That's why I don't care to run run one. I'd rather have a nice intake maifold than somthing that only helps in Auto-X. Is the manifold gonna use the stock TB Doward? I hear it outflows even a 3.4...is this true? I will CERTAINLY be on the buyers list for a good manifold, but it has to be one that keeps fuel puddling to a minimum when I spray (I'd be interested reguardless, as long as Mr. Dyno says it's helpful).

 

stock 52mm TB? buwahahhahahaha!! Nope, the plenum will include a new 62mm throttle body, or maybe a 65mm, depending on how I feel

 

I would run mine across the motor top but it would crush off my ram air ducts. Wasn't much of a choice.

how cheesy it would be but had a vision of a stock intake that peeks about half way out of the hood. Cut around it nice with the cone filter and a chrome TB exposed. But it would take some long long spacers.

 

Mine is not shimed but it does touch the hood. What I did is flipped the bolts upside down and drilled the hood heatshield metal with cutout reliefs so the nuts invade into it. Then I mounted the 3pt braces underneath the main bar instead of on top. the hood barely touches the main bar at two little spots just inside of each nut towards the center of the engine bay.

 

Wonder if you could make it suck better with a dual TB kind of like a 4bb carb. The bigger air flap doesn't open till a given pressure/vacuum.

The trick to the Qjet is to remove the vacuum control and set the spring tension right. So it just flops open at the right time and its mega air.

 

Well, here's the thing, as long as you can hold vacuum down to 0 all the way until redline, then you don't need a bigger TB, that means that there is plenty of air flowing through there. Now, with the new plenum, you would have to do some testing to see if it actaully does need the bigger TB because of the lack of bends, but I doubt you would see a difference unless you have bigger valves installed or at least something other than an intake.


It sure would look a hell of a lot cooler though, I'm sure. Now, when you're running boost, it doesn't even really matter because you are shoving the same amount of air into the cylinder anyway, 7lbs of boost in the manifold is 7lbs of boost whether you have a dime sized opening or a football sized opening, as long as you are reading boost behind the plate, then that's all you need.

When you start pulling a vacuum behind the TB at WOT, then you need the bigger bore so that you can get more air into the manifold, but once it's there, it doesn't make a difference.

On N/A motors, you'll lose bottom end because you lose velocity, but on boosted motors, who cares, you have boost

 

I know mine shows quite a bit of vacuum at WOT (about 7"hg). That's telling me somthing right there.

 

AT WOT you have 7" of vacuum...WOW!!! You definitly have a restriction somewhere, but I doubt its from the TB since I show 0". That might have something to do with your stumble too. Are yousure taht it actually pulls to all the way open when you floor it? Maybe a worn cable because I have never seen one of our motors that pulls 7" of vacuum at WOT.

 

That's at about 4000~ rpm (revving in neutral). My engine is a cammed 3.4L, but yeah, shouldn't be that much, you're right (hence why I want a better manifold).

 

attach the vacuum guage to the manifold source and give yourself some extra hose so that you can stick the guage in through the window, then go out and hit WOT. In neutral with no load isn't really a good way to check that because the engine comes up to 4K so quickly that you have to let out the pedal to keep it from hitting the rev limiter. Put a load on it and I bet that number comes WAy down when the pedal is on the floor.

 

I was thinking the 2nd throttle plate would only work under boost.

 

That's true, but as long as you are flowing enough to get 7 lbs of boost into the cylinder, then the TB is big enough...as long as your goal is 7 lbs.

 

If I had the 400+ bucks laying around to carb, that would be a good solution right there..... Of course, that IROC hood would need to be replaced with somthing taller....

 

carbs are cool. Even the best FI cars lack that giant rump and sound you get when you snap open them big secondaries.

 

hey doward, if u do want to toy with the idea of a dual throttle body intake, there was one on the fiero boards a couple years back, and i think i still might have all the measurements for it, and i believe it ended up making 30 extra hp, it was made by one of the fiero guys, shoot, i can see it already, twin tb, twin turbo, 450hp 2.8's and 3.1's!!!!!!!!!!!!!!!!!

 

Amen, I miss that quick snap when you jump on it

 

^^^ and the bog down when it isn't tuned right

I've seen to different versions of the twin tb fiero engine, and each had their own way to synchronise teh tb butterfly.

 

Heres my clearance...took this for cardomain awhile ago.



Some clearance from the plenum as you can see. And it doesnt hit my custom hood at all, but I do have a 4" cowl so maybe thats why.