LT1FUN

Some of you may already have been following the progress of my after-market TPI upgrade I've been putting together over the past few month's (as money would allow) (links are in my signature).

I have a set of AS&M big tube runners I got through a GP on this forum, an Edelbrock intake base I bought shortly afterwards and then purchased a used plenum to port in my spare time.

Today, I finally finished porting the base as best I could. The flex-shaft on my dremel died before I could smooth out the surface of the ports a bit further but what I managed to do before then, should be more then enough to get the job done. They're a heck of a lot cleaner than they came "out of the box". Besides, the heads and cam on my L98 are still stock, so there's no need to go all-out on the intake base anyway...

The plenum's ports were opened up from the stock 32mm, to 36mm to match the AS&M runners. The EGR walls were also grinded down to improve flow/throttle response.

I then painted the plenum a "cast Iron" grey which is an exact match to the color I painted my valve covers so it should look pretty sharp when everythings finally put on the car.

Since I was going to be removing the entire intake, I decided now would be the best time to replace the nearly 20 year old injectors. I picked up a set of Ford/Bosch fuel injectors (flow matched) which have the same rating as the stock 22lb injectors which I'm currently running. An Accel Cold Start plug will be installed to eliminate the 9th injector (which never worked anyway) and I'll be ditching the EGR system as well so there'll be a lot less mess under my intake.

I've already got all the gaskets I need for the install. A new GM coil. New bolts to assemble everything together (thanks TPI parts!) Tomorrow I'll be picking up a new ignition module and plugs from the dealership.

I hope to have everything installed on the car before the end of the week. A local car club is having a "dyno day" this Saturday and I want to see what this TPI set-up is worth on a "bolt-on" L98.

Here are some pictures I just took of the parts ported, painted and assembled. Should give you a good idea of what it'll all look like once it's on the car.

Any comments and/or suggestions are welcome.

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DZcode

A suggestion.
When I installed a Lingenfelter base I used "raised"-head 12 point bolts. The heads of the bolts interfered with the runners seating properly to the base. I had to switch to plain flathead manifold bolts.

If you have an oil pressure sensor on the back of the block close to the rear china wall and distributor hole, make sure the manifold clears the sensor properly. I had to use a short piece of copper tube and a 90 degree fitting to mount the sensor. Make sure to use a good sealant and make it tight. It's pain to remove the whole TPI setup for a small oil leak in the back.

Shift06

I painted my intake and plenum and runners the same way

TPI383Camaro

truely a work of art!

damn nice job man

1989GTATransAm

iTrader: (3)

I agree. Looks very nice. Job well done.

Reid Fleming

iTrader: (2)

It's definitely clean. But I can't figure out why with those super shiny brand new LTR's why you'd paint the plenum black?

355tpipickup

iTrader: (5)

cant wait to find out the dyno numbers!! lookin good! do you have any dyno numbers now so we can see a befor and after?

LT1FUN

The car previously put out 206hp and about 290lb of torque at the wheels. The car at the time had headers, exhaust and a set of roller-rockers I had just finished installing 2 days before. That was it. Pretty good for a car with only 3 mods and nearly 180 thousand km on the odometer.

Check out my old thread about the results located here:
https://www.thirdgen.org/forums/tpi/...no#post3070111

I'm hoping to put out at least another 20-25 hp and 30-35lb of torque at the wheels with the new intake. In other words, I hope my new numbers are close to 230-235hp and 320-325lb of torque. Obviously a custom tune will be the only way to really see the true potential of this set-up as I'm sure the massive increase in air flow will really throw off the stock ECM's factory calibrations.

I realize that the ECM does have the ability to "learn" and "adapt" for most "bolt-on" modifications, but I think an entire intake upgrade will probably be more than it can handle. A good tune should be worth another 10-15hp at least.

We'll see next weekend. Stay tuned.

As to why I'd paint the plenum a darker color than the runners, I did it just to add some contrast to the motor. I'm not a fan of chrome or polished parts under the hoods of these car's and had I painted them silver to match the look of the AS&M runners, there'd be too much of the same color and look boring. The "cast Iron gray" the plenum is painted in, is a HD high heat engine enamel which is really strong and can hold up to heat, gas stains oil etc. etc. It's is the same color and paint I used on my valve covers. When it's all put together, the color scheme should look really good. Just wait till you see it. You might change your mind as to how you think it looks....