Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.
So now that have figured out the headers I have time to discuss and fabricate an ITB intake for my motor. I have done some rough drawings. I'm going to be reusing the lower manifold but cutting the runners off and just saving the injector bases. So using the stock lower manifold for head plates and the thermostat housing.
I will using stock 2.8l Fiero throttle bodies. They are the same size and part number of the ones off of the older Chrysler 3.5 motor that has dual throttle bodies. I can also send them in to have them ported and halfshafted from a guy on eBay.
I'm going to add some hand drawn pics of the intake setup once I reduce the picture size.
fiero intake top view.jpg (118.72 KiB) Viewed 4732 times
fiero intake front view 5.jpg (235.82 KiB) Viewed 4732 times
Last edited by Gambler87 on Sun Nov 16, 2014 1:44 pm, edited 1 time in total.
what are your plans for iac? how do you plan to couple the TB's?
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
the Chrysler 3.5 litre motors only ran iac on one of the throttle bodies, I have six of those throttle bodies. so what I planned on running a idle stop on the middle throttle body on the firewall side (that will be the one that has the throttle cable attached to it). the rest of the throttle bodies on that side will be connected with a solid shaft. then the throttle bodies on the other side will have a lever attached to another lever on the firewall side throttle bodies that will roll the shaft for the trunk side ones. everything will be synchronized using a vacuum synchronizer the same way they do mechanical fuel injection setups
Won't 6 stock sized TB's be entirely to big for an ITB setup? maybe not at WOT or in the mid range, but what about the moment all those TB's crack open,
the throttle bodies are 50mm. which is the size of most aftermarket itb kits. it is also the size of the itb kit u can buy for a Honda nsx. which I think that my engine which the slr regrinds, 11 to 1 pistons and ported and polished heads and custom headers my engine should flow enough to use those throttle bodies. once the intake and headers are on it (hopefully around Christmas) there will be a lot of dyno time to work the whole system out. and then we will go from there. Im also planning on flow benching the entire intake from plenum opening to intake valves once I get the intake all fabricated. then i will know what the restriction is in the airstream.
Gambler87 wrote:the Chrysler 3.5 litre motors only ran iac on one of the throttle bodies, I have six of those throttle bodies. so what I planned on running a idle stop on the middle throttle body on the firewall side (that will be the one that has the throttle cable attached to it). the rest of the throttle bodies on that side will be connected with a solid shaft. then the throttle bodies on the other side will have a lever attached to another lever on the firewall side throttle bodies that will roll the shaft for the trunk side ones. everything will be synchronized using a vacuum synchronizer the same way they do mechanical fuel injection setups
I would recommend a remote IAC setup. that was all the cylinders still get equal airflow.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
1fast2m6 wrote:Won't 6 stock sized TB's be entirely to big for an ITB setup? maybe not at WOT or in the mid range, but what about the moment all those TB's crack open,
it would be a great application for a cam style linkage.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
thanks for the advice. I might try that. is there any reason that a throttle stop wouldn't work? seems easier to do. this is only a spring through fall driven car
1fast2m6 wrote:Won't 6 stock sized TB's be entirely to big for an ITB setup? maybe not at WOT or in the mid range, but what about the moment all those TB's crack open,
it would be a great application for a cam style linkage.
ericjon can u get me some pics of a cam style linkage. it sounds interesting
1fast2m6 wrote:Won't 6 stock sized TB's be entirely to big for an ITB setup? maybe not at WOT or in the mid range, but what about the moment all those TB's crack open,
it would be a great application for a cam style linkage.
ericjon can u get me some pics of a cam style linkage. it sounds interesting
I don't have any pictures of one, but it's the way most modern cable throttles are setup. looks kinda like a snail in fact, the cable rides in a half circle goove that is offset from the axis of rotation of the throttle, so that as the cable pulls, it gets closer to the shaft, and, for a given amount of pull, opens the throttle quicker.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Gambler87 wrote: I'm going to be reusing the lower manifold but cutting the runners off and just saving the injector bases.
I think you'll save yourself a lot of fabrication headache if you keep the lower manifold intact and built your setup with a flange to bolt to the unmodified lower manifold.
Gambler87 wrote: I'm going to be reusing the lower manifold but cutting the runners off and just saving the injector bases.
I think you'll save yourself a lot of fabrication headache if you keep the lower manifold intact and built your setup with a flange to bolt to the unmodified lower manifold.
agreed. that or starting clean sheet would probably be easier.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
The problem with the stock lower manifold is that it will cause your runner length to increase dramatically, and maybe to lengths longer than you want. It will also add quite a bit of height to the system.
I think cutting the runners off to use the stock lower flange is a great idea personally. Just be careful of warping when welding the pipes to it, probably best to have them bolted to a head when they're being welded.
Good luck, I don't believe anyone has actually finished an ITB kit yet. I'd love to finish mine someday, but it honestly likely won't happen, at least not on the 3.4.
Aaron wrote:The problem with the stock lower manifold is that it will cause your runner length to increase dramatically, and maybe to lengths longer than you want. It will also add quite a bit of height to the system.
I think cutting the runners off to use the stock lower flange is a great idea personally. Just be careful of warping when welding the pipes to it, probably best to have them bolted to a head when they're being welded.
Good luck, I don't believe anyone has actually finished an ITB kit yet. I'd love to finish mine someday, but it honestly likely won't happen, at least not on the 3.4.
The stock upper fits under the decklid... look at the sketch; what he's looking at will lie flat like the stock upper.
Using the stock lower manifold means putting another 60° bend in the system. Using the stock lower and cutting the runners off of it still gets me the coolant crossover and good gasket surfaces, plus let's me use the stock thermostat and housing. But instead of running all the runners straight up and then 90° bend to level them out. I can use 1 60° bend and then run it right o the head and into the back of the valves instead of most of the flow being on the floor of the runner it will use the whole runner because there will be space between the turn and the head. Then I can gain a little more velocity by having that straight run to the valve after the turn.
Aaron yes the lower manifold will be bolt to the heads as to not warp in the process of tig welding.
The Dark Side of Will wrote:
The stock upper fits under the decklid... look at the sketch; what he's looking at will lie flat like the stock upper.
Of course it does, but not by much and the factory UIM is about 2" thick, and runs very close to the highest edge of the rear valve cover. His TB's will probably end up needing 3" clearance, an extra inch. To be honest I don't know if the decklid has enough clearance for that, it'd be close. He could always redo his engine mounts to lower the engine, but that's a lot of work.
I think also the front valve cover runs closer to the decklid than the rear, it's not as low profile design as the rear cover. If you can't measure it let me know, I'll measure mine.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
