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I am waiting on my new fuel injectors which will not be here for a few more days so I decided to pull everything off early and do a little cleaning . First off I should have put in the title CLEANING then porting and polishing because there is a ungodly amount of crud in everything . How parts that have nothing but air flowing through them can get this gummed up is beyond me . But here is where I am right now . I have already started cleaning up the TB. I used TB cleaner to get out the tar crap then mothers aluminum mag polish to make her shine . Take a wild guess which side has been touched and which side has not .





Here are my plans for the actual porting . It will not be anything extreme as this will be my first port and polish job . The areas I want to tackle are shown with the red area and the red highlight . The arrow shows an odd imperfection if you want to call it that to the runner port. I want to get rid of that making it , well not like it is now. You can see where the gasket was in the pic . Second is the front of the plenum . Those areas highlighted just look restricted . If I were a plenum , I wouldn't flow right with stuff like that going on either .



Still not sure what else I want to tackle . If anyone has any suggestions please let me know. I am open to all ideas and If I had the money , I would be getting a set of high flow runners . Trust me.

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Thought I would throw this in too. Tried a little polishing to the inside of the stock runner . Hard to tell but man did it smooth out . Again its pretty obvious which side has been worked on .

Drew

iTrader: (58)

The crud is from EGR and PCV circulating exhaust gas and oil blowby through the engine. You can clean all that off, and within a thousand miles it'll already be coming back.

The walls behind the throttle bores are there for the ports from the EGR system. Knocking them down probably has little impact, but again it doesn't have much impact on performance either.

Truth told, porting the plenum is a 'feel good' mod... It'll make you feel good, like you accomplished something. But at the end of the day, you'll be hard pressed to feel a real difference sitting behind the steering wheel. It's has the same placebo effect as most of the other 'Free' mods.

Roc THIS

Well I guess I will find out for myself. I mean all the stuff is out so why not ? It cant hurt anything . Plus I have heard quite a few people it makes a difference . Not a huge blow your shoes off difference but one big enough to tell.

Drew

iTrader: (58)

I've done it on a few different cars, and never really felt a difference. If you're curious it won't really hurt anything. I just couldn't really say it's worth the trouble. Have fun with it!

Eagle223usa

Drew, We do it cause it makes us feel good! I'm in the middle of doing mine also but I have SLP runners and I'm porting the base and gasket matching the heads.

skiroulertx447

its gotta do something in the higher RPM???

heres some of my porting...







when I put my 350 in gonna work on doing some more porting on this and probably see what I can do on the lower intake manifold

1989GTATransAm

iTrader: (3)

Yep, I opened up my plenum, SLP runners and cleaned up the intake manifold and that sucker makes peak power around 6500 rpm. I expect to be shifting in the 6800 to 7000rpm range after the dyno tune. Hopefully this October as we will have around 5 cars ready.

89fbirdformula

There isnt a chance in hell of a TPI making peak power at 6500...or revving/making power 6800/7000....

thegooseman

I see you dont follow the TPI threads such as Quest for a better flowing TPI. I've been to the Dyno sessions and their pretty awesome.

1989GTATransAm

iTrader: (3)

"There isnt a chance in hell of a TPI making peak power at 6500...or revving/making power 6800/7000"

Thanks Gooseman. I inadvertently left out some information so let me clarify.

The plenum is an opened up factory unit.
The runners are opened up and siamesed SLP.
The intake manifold is an aftermarket unit also opened up for better flow.
My new motor going on the chasis dyno in October is 368 cubic inch. I will post the results at that time. I expect to be over 400rwhp even with my 4000 stall converter unlocked.

Bottom line is you can make the TPI system work as these guys are on the path to doing. How much power you want to make depends on how much metal you want remove.

Eagle223usa

Hey 89GTA you want to share that recipe in a little more detail???? Sounds awesome!

1989GTATransAm

iTrader: (3)

Here are a couple of links with the details of the intake system including pictures.

https://www.thirdgen.org/forums/tpi/...ifold-slp.html

And earlier showing the plenum work and first attemp at modifying the SLP runners.

https://www.thirdgen.org/forums/tpi/...ified-tpi.html

iroc stangs

Looks like an decent project! So dumb question but what tools are you using? And if i wanted to do this i would just need the tool(S), gaskets, and time, Right?

1989GTATransAm

iTrader: (3)

Yes, you can do it with tools, gaskets and TIME but depending on how far you want to go you need to include aluminum welding.

For the plenum I used sanding drums and a drill motor. Also cutting bits with the drill motor. For the runners that was a lot more involved. Welding, cutting bits and sanding drums. I have an electic die grinder but did not like it as well. If you have air tools that is even better.

Steve Mack

iTrader: (5)

Yea there's a guy on the Corvette forum who said that the tpi system couldn't do what you guys did.I told him to read the sticky on how to make a tpi flow.his answer was I don't read stuff.I am looking forward to your Dyno sessions I just bought a fully siamesed set of slp runners cut open and ported like you guys did and a fully ported plenum.It's going on my 406 small block.I am also in the process of porting my Edlebrock base.I had to add some aluminum to the runners because I have 220 cc ports.

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This is what I used to port my stuff . Just a $8 air grinder and $18 pack of sanding drums from Harbor Freight. Worked out very nicely and did not take as long as I thought it would . I will post pics of my progress soon .

cIaRmOaCrZo

when i had my 305 tpi still in my car, i had a few bolts on. and went got an A/F tune only, it only picked up 20 or so hp at the wheels,,,but didnt feel like anything changed much when i drove it...BUT after the tune i ended up porting the hell out of my plenum (super clean,obstruction free entrance,and bladed the holes going into the runners) and DIDNT get it retuned and i able to feel that more than i could feel the A/F tune.

i dont know why people say its not worth doing, but i can tell you it IS. its "free" power, and its decent amount too. at first i didnt think it woulda made much differance compared to all the bolt on i already had but it was feelable lol. it seemed like it had a smoother pull, and pulled slightly higher

1989GTATransAm

iTrader: (3)

"and DIDNT get it retuned"

You have hit on one of the keys to this. To get all the available new horsepower you need to get the car tuned. Luckily here in SoCal we have Kevin91Z available to do this for us.

cIaRmOaCrZo

my A/F tune was free. (someone owed me) anyways i ended doing the 383 hsr swap shortly after. so i didnt care what the tune on the 305 was. plus it wasnt a "full" tune like i tried to mention and make myself clear when i said "A/F" only! my lb9 wasnt worth $500 to do a full blown tune to it, especially since i was only using the lb9 for a few months later anyway.