Ported Chevy 083 heads, the tpi project

[Gregory]

Just to join the conversation, we built a dyno mule engine to test/learn different EFI systems. It is a 383, AFR 195 street heads, Edelbrock base, heavily
massaged cast runners that cut their length in half, 1000 CFM throttle body, Howard’s HR (CL180255-12), 231/235 @50 112 LSA, 1.65/1.55 rockers
and Mahle Power Pack pistons for a 11:1 compression. This also has a coil on plug system.
Best pull to date is 467 HP @5500 and 496 T @4200. Best results were with the smallest headers we had - 1.62/1.72 with a 3” collector - thank you
Calvin Elston.
Like others on this Forum, I just always liked the TPI system - maybe it’s just their cool look.
Greg
Home of the RaceEngineChallenge.com

[RobZ28]

Just for reference...
Jim Halls 355.
L98 350 bored .030" 9.6:1 compression (Verified compression ratio via FB)
AFR Vortec 190 aluminum heads
SDPC/Edelbrock TPI base - Ports matched to heads
Arizona Speed and Marine runners 1.660" ID
Factory plenum port matched to runners
TPIS lil Chubs roller cam. 220/224 .500 .500 110
Ran on dyno headers with MAF meter

Acttual dyno sheet print out

Dyno chart I made from the printout using a spreadsheet

The 355 getting ready to run


Below is a typical heavily modified TPI car dyno chart taken at the rear wheels.This is for RPM comparison but you can see how it signs off a lot earlier. This is also Allens(1989GTATransAm's) car before he started with the first/enlarged plenum/etc. but with the following mods:
355 10.5:1 compression, SMOG LEGAL Cali car, Custom Cold air intake with 3.5 inch tubing and an LT1 elbow. With a MAF stuck in the middle. Screens and fins removed on MAF, 52MM throttle body which actually measures 50.8MM, Modified factory TPI plenum, Modified SLP TPI runners, Edelbrock TPI manifold, Extrude Honed, 1.70" runners, Trickflow 23 degree heads, ZZ9 style cam and 1.6 roller rockers, SLP 1 5/8" Tri-Y headers, Dyno Don custom exhaust mandrel bent with dual cats. 2 1/2 inch to the cats from the headers. 2 1/2 inch to the custom Y pipe from the cats. Then 3 inch back to the SLP muffler from the Y pipe. Heres a link to how modified the runners are
https://www.thirdgen.org/forums/tpi/281 ... ost2216114


Another typical TPI dyno run that signs off around 5000rpm. .030 over 350 with forged flat top pistons, stock rods & crank, 461 Fuelie heads, 214/224 flat tappet cam, Heddman headers & y pipe and 3" exhaust. The top end has an accel TPI base, SLP siamesed runners, ported plenum and 52mm holley throttle body. Drivetrain consists of a T5 transmission and 10 bolt rear with 3.42 gears.

In my opinion, the curve Jim Hall and Richard Holdener have obtained are a MUST HAVE if youre going to run a street driven TPI car! Those cars do better than most of the siamesed TPI cars do and they do it with full length runners. Im guessing timing is retarded some with maybe some help from a narrower LSA?? Why??

[Bill Chase]

Not to get off in left field here, but I recently picked this one up for $50.00. if any of you guys want it, just 50 plus actual shipping costs.

It was so cheap I couldn't leave it. If someone is wanting to cut one up and modify that's about as cheap as they get.

[RobZ28]

Good price!

[Roundybout]

This has been a great trip down memory lane. I got my license in ‘84 and cut my teeth so to speak on this. Being a computer geek and the new fangled fuel injection went hand in hand. Spent a lot of time, money and effort to squeeze out performance with TPI systems. Hours spent burning chips for a degree of timing here and there lol.

It’s nice to see people still doing it. I have a nice collection of Arizona Speed & Marine, SLP, Scoggin lowers and Vortec heads along with a few Lingenfelter cams from back in the day.

It’s funny to think all that work to run 12’s when I can run 11’s with the A/C on in my 164 cu/in F150 with a couple of turbos on a low boost map.

[Carnut1]

I have a TPI project comimg in soon so I dug out this long dead project for some testing before the parts get here. Shortblock will be a low mile L98 so it will be cast pistons. Most likely get a custom cam ground after all the flow work has been sorted. It will keep the long runners of the tpi with aftermarket pieces. I will port as needed to get where I think it will need to be. The heads we picked are Dart 007 67cc 165cc heads which I know pretty well. I have a few TPI videos getting set up for this project. Test heads used in the videos are Dart 007 2.02/1.6 heads ported that flow about 275cfm. I would be interested in what would be the best way to attack a combo that is tuned to the second harmonic.
Thanks, Charlie

[Bill Chase]

Take a look here... viewtopic.php?t=30094

And here... https://www.thirdgen.org/forums/tpi/601 ... unner.html

Pretty sure everything he did was to take advantage of the 2nd harmonic. Camking did the cam for it. Most of the work he did was aimed at getting higher rpm peak, but he did gain a lot of area under the curve too. Both threads are a good read, think Stan Weiss even chimed in and did some simulations for his runners.

[Carnut1]

Excellent. Thanks

[Bill Chase]

Excellent. Thanks

If you want one to cut up, measure cross section etc. I'll donate it to the cause, just pay shipping. I posted pics of it in the other tpi thread here. Paid $50 for it, in the name of science and all we can learn from your work.. gimme an address, you can mail me the shipping cost later. Use it man. Think I've got a throttle body with some shaft bushing wear here somewhere. I'll send it to. I get a lot out of your videos Charlie. My way of saying thanks.

Edit*** Sorry, in this thread about 5 posts up, are photos of it.

[Carnut1]

Thanks for the offer Bill. At this time I have no plans to cut one up unless I ruin the one I have!

[Erland Cox]

I don¨´t think that going up and down in area just because there is a turn is a good idea.
I have some TPI manifolds myself so I will taker a look wit a burr.

Erland

[Carnut1]

I feel in order to increase mass flow the csa has to go up around turns. What this does to the resonance I am not sure. Thanks

[Erland Cox]

I think that shape and area becomes before flow.
It is not good to go up and down in area along aa flow path.
But I will give TPI porting a try.
I would use a GM hot cam as I have several, 218-228-112.
And either a stock iron head or an aluminum L98 head with 1,94-1,50 valves.
I have made 502 hp with a head like that so it is more than enough for a TPI manifold.
240CFM intake flow at .500" lift.

Erland

[Tom68]

I feel in order to increase mass flow the csa has to go up around turns. What this does to the resonance I am not sure. Thanks

It will at least be more important than the resonance.

[RobZ28]

I would think creating a curved roof on the intake port at the angle TPI meets the heads intake runner would make the resonance wave at that enlarged point, taller and slower, becoming misshapen…and probably dissipate the top… A larger resonance wave is slower than a small one so that part of the area would lag behind. So what does that mean when you’ve got 2 S turns and a 180 degree upward tube to go through all while changing your shape from rectangle, to square and to circular?

Probably not much given the big picture.

Of course, I could be totally wrong and everything I wrote is bull****. But at least it was articulate.