Possible Plenum Replacement

Contour Enthusiasts Group Archives

Now that I have an Aeromotive FPR on, my stock plenum doesn't fit. This kinda sucks because it makes the idle chunky and it hurts part throttle response.

Instead of using a 90 degree elbow on the throttle body, how about a "T"? One side of the T would be connected to the incoming air. The other side would be connected to a capped pipe that has the same volume as the stock plenum.

Would this work/help?

I can't draw, but this is what I'm talking about...

I think having the plenum like that it would hurt throttle response also.

My first question has to be....with the FPR and the huge fuel pump do you think you might be getting too much fuel which will hurt your idle AND throttle response.

No, I don't think so. I actually think that the pump and FPR have improved my throttle response. My theory is that the old pump had a hard time with quick changes in demand. With the new pump, when you stomp on the gas the pump can easily keep up with the needed pressure/volume.

As for the plenum pipe, I think I may give it a shot. I don't think that it can really hurt anything.

BP

That setup will help idle, but hurt throttle response.
Plenum needs to be over the TB.

reminds me of a map of a Mario Bros World...

Originally posted by RTStabler51:
reminds me of a map of a Mario Bros World...

LOL

Originally posted by ButtonPuncher:
My theory is that the old pump had a hard time with quick changes in demand. With the new pump, when you stomp on the gas the pump can easily keep up with the needed pressure/volume.

What kind of mods do you have? Anything short of forced induction/nitrous, and I don't think a properly functioning stock setup will have any problems keeping up with demand. As a result I wouldn't expect a higher-capacity pump to really do anything. The 255lph unit is major overkill for a Zetec. My Thunderbird had a 2.3 liter engine running 18 psi of boost and 36 lb/hr injectors (I think the Zetec is 17 lb/hr), and it had no problems at all with its stock 190 lph pump.

What pressure are you running at now? If you're running at more than a couple psi over stock, I'd try backing it down. Running too rich will definitely cause bogging and poor throttle response.

Looks like your trying to bypass the throttle body????

There is a hose on the back of your intake manifold that you could use for a test, If not I may still have the intake manifold off of my old Zetec if you wanna experiment...

A higher volume pump is not overkill at all, just simple insurance. A 255lph pump is capable of supporting roughly 700hp(forced induction). Most of the time the 255lph in tank pump is cheaper than buying a stock replacement as well. Usually about $100-$125 at your local parts store. The stock fuel pump for the 87-88 Tbird turbo was rated at only 88 lph (23.25 GPH). More fuel availability is ALWAYS good. Remember, your only creating a supply of fuel, it is still running at a stock fuel pressure so it is not injecting anymore than it did before. I would rather have a pump that supplies more fuel than I need than not enough. A lean condition is not desireable in the least. Besides, if you drop a higher flowing pump in now, it will save you from having to drop a higher flowing piece in when you decide to boost or spray your motor later on.

Evocontour, I couldn't have said it better! The pump and FPR are just bulletproofing for my future turbo upgrade. Also, you're right, the 255lph pump was only $125.

Originally posted by Bk4293L:
Looks like your trying to bypass the throttle body????

All that I'm doing is trying to add volume to the intake. The "U" shaped pipe is capped off. I am trying to replace the lost volume by not using my stock plenum.

My problem right now is that I can't find anyone that makes a silicone "T".

BP

Originally posted by evocontour:
A higher volume pump is not overkill at all, just simple insurance. A 255lph pump is capable of supporting roughly 700hp(forced induction). Most of the time the 255lph in tank pump is cheaper than buying a stock replacement as well. Usually about $100-$125 at your local parts store. The stock fuel pump for the 87-88 Tbird turbo was rated at only 88 lph (23.25 GPH). More fuel availability is ALWAYS good. Remember, your only creating a supply of fuel, it is still running at a stock fuel pressure so it is not injecting anymore than it did before. I would rather have a pump that supplies more fuel than I need than not enough. A lean condition is not desireable in the least. Besides, if you drop a higher flowing pump in now, it will save you from having to drop a higher flowing piece in when you decide to boost or spray your motor later on.

D'oh! Yeah you're right, it did have an 88lph pump.

I see what you're saying.. A pump that big certainly won't hurt anything, and it won't have to work very hard at all. But unless you have a lot of mods, it's not going to perform any better than the stock setup because both can easily meet the demand from the engine. So don't expect it to make your car run better, unless your old pump was going bad. A 5-amp toaster is gonna work just fine regardless of whether you have it on a 15-amp or a 200-amp circuit.. Same thing.

I didn't know it's cheaper than the stock replacement though! In that case there's really no reason not to get one.