TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Hey all,
I'm about ready to install the SLP runners, but I noticed the small tube that feeds the EGR is blocked off with plugs. Should I leave them in, or take them out? I'm in NJ, where emissions are a concern.
Please advise.
__________________ Steve Ragusa - North Jersey
'88 SS - Budget ProTourer - ZZ4-cammed and Tuned Port Injected 355, WC T5, 1LE 12" front brakes, 17" SLP wheels, Eibachs/Bilsteins, and other stuff. Heart and Soul of a Thirdgen, swapped into a G-body.
What year is your TPI and what year are the runners supposed to be for???? When I bought my SLP runners for my 89 GTA they had the passage on the right side runners blocked off. It was not the EGR passage which was still open on the left runners IIRC. I believe the blocked off passage was used for the CSI in the 85-88 tpi setups.
Originally posted by razor What year is your TPI and what year are the runners supposed to be for???? When I bought my SLP runners for my 89 GTA they had the passage on the right side runners blocked off. It was not the EGR passage which was still open on the left runners IIRC. I believe the blocked off passage was used for the CSI in the 85-88 tpi setups.
My setup is an '87 with CSI. The runners I bought have the CSI port open on the driver's side runner (which I need). These plugs are in the passenger's side runner, it seems like they cover the EGR port on the lower intake and the air access port in the upper plenum; this is the small tube next to the runners for cylinders 6 and 8.
__________________ Steve Ragusa - North Jersey
'88 SS - Budget ProTourer - ZZ4-cammed and Tuned Port Injected 355, WC T5, 1LE 12" front brakes, 17" SLP wheels, Eibachs/Bilsteins, and other stuff. Heart and Soul of a Thirdgen, swapped into a G-body.
Something doesn't sound right. I am not sure if you have a mismatched set of runners or just what, but if you can remove the plugs to utilize the EGR passages then go for it. If you can post a few pics that would be great. If not, just uncork the EGR passages and bolt them on.
Originally posted by 87IROC350 The tube is for the cold start injector used on 88 and older MAF TPI. On the 89 and newer models the CSI was eliminated.
I understand that already. My car is using an '87 LB9 setup (motor, harness, etc.) Check my previous post, the tube I'm having an issue with is next to the #6 runner, on the passenger side. It has a plug screwed in to cover the air hole in the plenum up top, and a plug screwed in to cover the air hole in the base.
The CSI is open on the runners I bought, that's by #5 on the driver side.
__________________ Steve Ragusa - North Jersey
'88 SS - Budget ProTourer - ZZ4-cammed and Tuned Port Injected 355, WC T5, 1LE 12" front brakes, 17" SLP wheels, Eibachs/Bilsteins, and other stuff. Heart and Soul of a Thirdgen, swapped into a G-body.
Here's a pic of the plug I'm talking about - it's a hex-head fitting, next to the lower middle bolt hole. What's this for? There's a matching plug at the bottom on the manifold baseplate side. This is on the passenger side of the motor, 1987 LB9.
__________________ Steve Ragusa - North Jersey
'88 SS - Budget ProTourer - ZZ4-cammed and Tuned Port Injected 355, WC T5, 1LE 12" front brakes, 17" SLP wheels, Eibachs/Bilsteins, and other stuff. Heart and Soul of a Thirdgen, swapped into a G-body.
Yeah thats your EGR passage. It should mate up to a passage on the bottom of your plenum that re-introduces the exhaust gas to the plenum right where the T/B bolts on. There should be two small holes, one behind each T/B blade in the plenum. There will be a little bump in front of each hole. Grind this bump flat and open the bores going into the plenum. This will help get you a little more throttle response. Are you going to siamese the plenum as well for the runners???
Originally posted by razor Yeah thats your EGR passage. It should mate up to a passage on the bottom of your plenum that re-introduces the exhaust gas to the plenum right where the T/B bolts on. There should be two small holes, one behind each T/B blade in the plenum. There will be a little bump in front of each hole. Grind this bump flat and open the bores going into the plenum. This will help get you a little more throttle response. Are you going to siamese the plenum as well for the runners???
I did grind those bumps down behind the TB opening a few years back when this motor was in my old car. I figured since it was going into a new car, I should spice it up a bit more. I'm adding the SLP runners and an underdrive crank pulley to my combo. The motor already has the Crane 2031 roller cam and World Products S/R Torquer 305 heads.
So far, I cut the divider walls out for the runners, but I need to shape them tomorrow at work.
And the question remains, should I remove those plugs, or leave 'em in? I thought the EGR worked through the crossover ports in the heads, but I don't know for sure.
__________________ Steve Ragusa - North Jersey
'88 SS - Budget ProTourer - ZZ4-cammed and Tuned Port Injected 355, WC T5, 1LE 12" front brakes, 17" SLP wheels, Eibachs/Bilsteins, and other stuff. Heart and Soul of a Thirdgen, swapped into a G-body.
Well did your old runners have an open passage on the passenger side???? If they did then open em up. If your old runners didn't have the passage, then leave em closed
Now, any idea what would cause a lot of oil to collect in the manifold at that point? Maybe because I had a high-volume/high-pressure pump in there originally? Would it hurt anything to leave it closed and avoid getting more oil in there? Or will that defeat how the EGR operates?
__________________ Steve Ragusa - North Jersey
'88 SS - Budget ProTourer - ZZ4-cammed and Tuned Port Injected 355, WC T5, 1LE 12" front brakes, 17" SLP wheels, Eibachs/Bilsteins, and other stuff. Heart and Soul of a Thirdgen, swapped into a G-body.
My SLP runners had that hole opened on the passenger side where it mates up to the plenum and runs to the TB along the passenger side bottom of the plenum.
The drivers side on mine still has blocked and I don't seen anything on the plenum it would match up to.
This is from what I can remember when I installed them. I ask because when I apply vacuum to my EGR my idle does not change and I'm failing emissions for my EGR not working now.
I installed my SLP runners and Accel base manifold both at the same time and either I screwed up on this fitting in the runners, or I used the wrong gasket on the base and I have the EGR ports in the base/heads blocked off
I replaced my EGR and solenoid with brand new GM units when I did the instal and right after the install I got the EGR code but just got rid of the check in my chip but now that it's smog time it's haunting me! I pulled my plenum over this last weekend and tested both my solenoid and EGR and all vacuum lines and passages. I even hooked up a manual vacuum straight to the EGR and reassembled the intake to start the car and test to see if the idle changed. Nope, the EGR works as it should but the idle does change and my smog cert readings verify this. Something is blocked and I'd HATE to remove the entire intake system, distributor, and valve covers just to check...
__________________ www.TheFoat.com/92GTA1992 Trans Am GTA SLP: GMPP optioned "SLP Performance Parts Package" GTA, 220K Miles, Dark Jade Gray Metallic, LB9, 4L60, T-Tops, and Gray Leather. Documentation includes Window Sticker, Factory Invoice, Etc.
The driver's side is for the cold-start injector, the passenger side is the EGR.
If you installed the gaskets incorrectly, you'd have a vacuum leak. I still think you have the wrong intake manifold gaskets that dont have the EGR passage opened in the center.