TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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i was in the process of replacing injectors, so i thought i would pull the intake off as well and port it along with the runners and plenum. someone who owned this car before me did some crazy stuff to it. i dont know what car these parts came off of. the intake has provisions for the egr on drivers side and passengers side next to the runners, the runners also have both egr tubes along with the cold start injector hole, and it is blocked off and so is the egr tube on the drivers side, it has no where to go seeing as it would just hang below the plenum, because the plenum only has the provision for the egr tube on the passengers side. it appears to me that the runners are for the 88 and earlier type systems. am i right? what else looks wrong with this system? would this have caused issues with the egr system as it was blocked off on the drivers side? i didnt have any check engine codes.
Edit: this is for a 91 speed density 5.7 car
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Yeah you have the older runners. I'm trying to remember when I just had my intake off. I *think* the EGR was on the drivers side runner from the intake to the plenum. You said BOTH of the runners were plugged off? Definantly would had caused issues, was you SES light getting set?
__________________ www.TheFOAT.com/92GTA 1992 Trans Am GTA SLP: GMPP optioned "SLP Performance Parts Package" GTA, 210K Miles, Dark Jade Gray Metallic, LB9, 4L60, T-Tops, and Gray Leather. Documentation includes Window Sticker, Factory Invoice, Etc. Added a few tasteful mods. Owned for 10 years since 69K miles. 2nd place trophies. - Currently undergoing restoration to brand new condition with as many NOS parts as I could find!!! -
i have searched the forums quiet a bit on this issue, and have come to find out that on the 89 and later, it only have the passenger side tube, and 88 and earlier it had them on both sides. the intake has the provision for the drivers and passenger side egr, but was blocked off by the gasket on the drivers side, you can see an indent on the gasket where it had been pushed on by air through that tube on the intake. does this meen i have the earlier style intake also? only the drivers side one was plugged off by the gasket, the one on the passenger side was in the correct order. no SES light was set.
I'm not sure on the intake, but my stock 92 intake was set up just like yours. The EGR only went up one side, the other was blocked off by the gasket because the other runner did not have this. Sounds like maybe you have the correct intake but different runners. Do you have the older plenum or the newer on out of curiosity?
yes i have a set of all of the year plenum's 85-88 plenum, 89 plenum, and 90-92 plenum. they are all bolted on my cars though, i didnt want to take them off just to get a look at them. but if i remember correctly the 89 intake does not have the provision on the intake.
just realized you were from bakersfield also, i live in the rosedale area by rosedale hwy and allen road
was there any difference between the years on the tpi intake base? or were they all the same for 85-92, and just had different runners and plenum throughout the years.
Pics? You may have aftermarket runners, my AS&M ones had provisions for everything and I had to plug the cold start. Don't really remember on the baseplate besides the bolt holes changing the angle of the middle holes.
i dont thin they are after market runners, i think they are the 85-88 corvette runners, if i remember correctly, the runners on the corvette have a rougher exterior surface than the runners and the camaro, and these runners are much rougher. i have attached pictures.....
Were the bottom bolts a bitch to get at? I wanna say those look like the AS&M LTRs. :shrug:. I could pull mine out of the garage in a few days to check, but those don't look stock.
now that you mention it, the bottom bolts here a bitch to get at.... i had to use a swivel with the torx bit on the end, i never had to do that on any of the other runners that i took off before, they do look bigger than the other ones that i have seen, i thought that this was because they were off of a corvette, but i am not sure.
Originally posted by QuickStyle they do look bigger than the other ones that i have seen, i thought that this was because they were off of a corvette, but i am not sure.
The corvette had the same runners as the camaro's.
Thoese are AS&M large tubes runners, very good runners.
i had did a search on the forums about differences in the runners on corvettes and camaros, and a few people metioned that the exterior was a rougher surface on corvettes, that is what i was going off of.
i found only one place on the web that sells the as&m runners and they sell for $395 a set, and claim 30lbs of tq and 25hp over stock, i asume that is if you also have the ported plenum and intake too.
so what should i do about them? do they sell a special plug to cap the drivers side tube off, or can i just put that peice of metal back in there with a gasket that covers hole on the base.
Originally posted by QuickStyle i had did a search on the forums about differences in the runners on corvettes and camaros, and a few people metioned that the exterior was a rougher surface on corvettes, that is what i was going off of.
Correct, all TPI F-Bodies have a smooth surface runner while the Y-Body got a cast finish runner that matched the plenum. Only late 92 production (like after June '92) got the Y-Body runners because the factory ran out of the normal F-Body ones. Some of these later build cars also have black TBI valve covers instead of silver TPI valve covers. Just and FYI. I've got an engine pic of an original red Trans Am 'vert built the very last week of 3rd gen production to help proove this if it is needed...
If you are running this on a 91, you don't have a use for the cold start injector. You can plug the hole for it with a freeze plug from your local auto parts. As mentioned before, those are not stock runners, but they seem to me to be for 85 to 88 plenums. If you bolted these runners to an 89 and up plenum, you would have a vacuum leak at one side.
Yep, the welds match, those are the AS&M LTR. My personal favs. Email tham and see if they sell a plug. IIRC they use the same runners for the all the different years and just plug where needed. Mine have a black plug that looks like it was made out of epoxy.
thanks for all of you your help everybody. i noticed when i put the stock runner gaskets up to them that the gaskets were a bit to small for them, but they also have an outlined indent and which looks like if it cuz them out along that indent that i would be made to fit them, should i cut them out or buy some large tube runners gaskets from tpis.
I just cut my new factory GM gaskets to match my setup. Next time though I'll be buying the larger aftermarket gaskets to use as stencils for port matching...
Originally posted by 92GTA I just cut my new factory GM gaskets to match my setup. Next time though I'll be buying the larger aftermarket gaskets to use as stencils for port matching...
what did you use to cut out the gaskets? i tried a brand new razor blade, but there is metal material in the middle of the gasket and wont go through it.
Email tham and see if they sell a plug. IIRC they use the same runners for the all the different years and just plug where needed. Mine have a black plug that looks like it was made out of epoxy. 
