Tuned Port Injection
- Thread starter ronnyinwaxhaw
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My 87' Luxury Sport I purchased in 2002 and by 2003 I swapped over to TPI, I have forgotten many details but over the years I dialed it in and made some changes, the last 7-8 haven't done a thing with the engine. As stated, reliable, attractive and is nice for a cruiser, not everyone needs 400-500hp or the peak numbers to hit at 7,000 RPM 
. I think after about 4,400 mine falls on it's face, from what I recall and the dyno chart.
Mine is a MAF setup but many years later I copied something I found online and added the correct sensors/parts and made an adapter harness with ECM to switch between MAF and SD, if I so desire. Just because. MAF was street tuned, then dyno tuned later on, the SD tune is a street tune. Finding someone who knows TPI very well to tune was a challenge and that was years ago, doubt it's gotten easier.
One thing I've thought about is if I could find a Procharger setup cheap enough, that would be something fun/cool to toss on and keep at low boost to help the engine live.
. I think after about 4,400 mine falls on it's face, from what I recall and the dyno chart. Mine is a MAF setup but many years later I copied something I found online and added the correct sensors/parts and made an adapter harness with ECM to switch between MAF and SD, if I so desire. Just because. MAF was street tuned, then dyno tuned later on, the SD tune is a street tune. Finding someone who knows TPI very well to tune was a challenge and that was years ago, doubt it's gotten easier.
One thing I've thought about is if I could find a Procharger setup cheap enough, that would be something fun/cool to toss on and keep at low boost to help the engine live.
I was never a fan. The TPI set up seemed like the engineers could not get it right with all the changes they made between 85 and 92. I think (and I know people will get mad or disagree) that the 92-97 LT1 was a far superior set up in almost every way. Ratings of 265-300 in stock form, aluminum heads, roller cam, short runner intake and 94-97 had a great factory PCM. I knew quite a few local guys that were well into the 12's with bone stock set ups and ran 11's very easy with cams, exhaust and tunes.
Hands down the LT1 was far superior in performance and the aftermarket began to take off with LT1 parts, but then something happened at GM - an LS1.
The issue with LT1's is the cost and limited access to performance parts. The reason I favor all TPI's over an LT1 - All Gen1 SBC parts bolt to a TPI which means that you can find every part under the sun on the cheap because they are the same, other than intake, plenum and runners. And now the LS market is heading to be the next Gen1 SBC market IMHO of course.
Lastly, If GM could've engineered the LT1 in time to meet the late 80's emission standards, then I'm confident that they would've been released then, rather than waiting until '92.
As Driven mentioned, the TPI is a great truck motor, but that is what most of the 'hotrod crowd' is after - tire burning, bottom end torque (and it will get the mileage of an LS too).
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I have a build thread here that started out with TPI on top of 327 with a turbo. But we had that motor in something else that got totaled. Before it had a turbo, on 2 different chassis dynos, the 327 made 240 whp and 320 ft/lbs of torque - yes 320!!!!! That's about 400 at the crank - that thing would light a tire for a full 1/8 mile, just had to keep the rev limiter at 5700.
Keep looking - they're out there cheaper - we have 3. One that is powdercoated still on top of the 327 is heading into '67 C20 (with a small turbo of course).
The worst thing about the TPI was the intake. Anyone that went really fast naturally aspirated had some kind of aftermarket intake. So you are going to put a bigger, bad *ss engine under the stock TPI intake?
As for the LT1 there are guys that have been deep into the 8's with the stock heads and intake with junk yard engines. Good example is this guy who I believe has been in the 7's since this video was made
As for the LT1 there are guys that have been deep into the 8's with the stock heads and intake with junk yard engines. Good example is this guy who I believe has been in the 7's since this video was made
I guess my beef with TPI is that there are EFI set ups such as FiTech or Holley Sniper or FAST EZ EFI that will bolt on to an existing 4 barrel intake. They will self tune the fuel and are easy to make on the fly changes and have a throttle body that will probably out flow most intakes thus the performance potential far exceeds that of a stock GM TPI set up. All of this IMHO.
Sure, there are better options for power. But you could do a TPI swap for very little if done right, plus as I indicated, at least for myself, the performance it provides is enough.
I bought an 87’ Trans Am to part out as my donor, probably made a little money getting the TPI setup and got every nut and bolt I wanted.
Many of those aforementioned setups weren’t around 15-20 years ago or more, when most TPI swaps were done. LT1’s were still new and pricey and no one besides guys like John Bzdel were bothering with an LS1 swap since you had to hand make all the parts 😁
I used to see TPI stuff pop up all over and for awhile the cars made their ways into yards, the engines used to get pulled when I did my conversion.
My take is TPI was really designed for the 305, works nice on a 350 but I‘d guess it was intended for 305’s primarily.
Now with that opinion wouldn't also be good for the other smaller SBC's like the 283 & 307? I would of tossed the 262 & 267 in but out of the two the 267 only an OK engine with a old Rochester 2bbl on it for something to move from point A to B.
TPI your talking GM first real MPI fuel injection
You want to say the LT1 is superior, well of course it would be better on they would not have moved on to it
TPI is super simple and reliable
1985 tech vs 1992
You want to say the LT1 is superior, well of course it would be better on they would not have moved on to it
TPI is super simple and reliable
1985 tech vs 1992
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