How many of you ran tpi or have tpi?

[INSIDIOUS '86]

I have an 84 k5 blazer. I'm planning a 283 sbc with a tpi system and a700r4 with most likely 3:73 gears how many of you had it or run it and like it?
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[SSC's76]

for a 4x4 it would be awesome great power to 4500 rpm i dident like it on my camaro it got sold for a carb. I know alot of guys like to port the runners but I think a stock tpi would be great on your engine choice


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[INSIDIOUS '86]

Yah it's just going to be my daily driver. The 283 is gutless but its new so I got som tbi heads and the tpi figure the torque and small engine should net me 30mpg if I get everything right I'm just hoping it won't be to hard to get it wired and running
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[kalbert]

I'd think you'll end up with something about like a 90's Caprice with the LT1ish W 4.3 V8.

[SSC's76]

Originally Posted by INSIDIOUS '86

Yah it's just going to be my daily driver. The 283 is gutless but its new so I got som tbi heads and the tpi figure the torque and small engine should net me 30mpg if I get everything right I'm just hoping it won't be to hard to get it wired and running
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I bet fuel economy is way up there with that setup. what are you planning on doing for a wiring harness? the guy I sold mine to used a painless setup. that worked good for him in his little buggy


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[OutlawDrifter]

2 ways you can go, speed density or maf...my 91 z/28 was speed density, it ran ok, but was out of breath by 4500rpm. honestly, i would skip the headache of the tpi system. they aren't very user friendly, and definitely not inexpensive to work on. if you have the moates software, that would help. if economy and daily driving is what you're looking for, throw a 2 barrel on it.....less to wire up!

[77c10]

Have a buddy of mine who just swapped a 350TPI/700R4 out of a Camaro into his 62 Chevy II. It runs great.

[68Timber]

Tuned port motors are cool if you grew up in the 80's like me. If you have one laying around it could make a fun project if you just felt like doing it but I wouldn't put any money in it. TBI would be cheaper, easier, and probably run as well.

[Rich84]

I have an lb9 TPI in my stepside...I love it. Turn the key it fires right up. Idles smooth as silk. Smokes the tires. Gets about 20mpg...And they look really cool too!
Aftermarket standalone harness is plug and play. Very simple.

I was just reading yesterday on chevythunder that he is making a plug and play harness to use the LS computer instead of the crappy 80's computers. That to me would be the best of both worlds.
I have a maf system with a 468 lift cam and the 416 305 heads, duals with the stock manifolds, 373 rear gears, 700r, taurus electric fan. It is a torquey little sucker. True it will fall on its face over 4500rpm but i do 95% of my driving way under that.

[kalbert]

Originally Posted by BRUISER

Tuned port motors are cool if you grew up in the 80's like me. If you have one laying around it could make a fun project if you just felt like doing it but I wouldn't put any money in it. TBI would be cheaper, easier, and probably run as well.

Agreed! Remember how cool old street rods of the 80's-90's were with polished TPI manifolds under the hood? Too bad TPI is such a complicated mess to assemble and tune. At least it looks cool!

TBI would net quality performance, but you'd still have to tune it for the 283 and that means a custom PROM that could cost more than it's worth. It probably wouldn't offer any better fuel economy than a good tune on a carburetor.

I still think in the end what you've got is a B body with a 4.3 V8. A big heavy slow turd that might get 20 MPG on the highway at best. Underpowered is just as bad for fuel economy as over powered. Albeit nothing is happy dragging a 5,000 pound box behind it, an iron LT1 B body could actually pass people on the highway and got around 20 MPG too.

[Rich84]

I am no expert, but I dont understand how TBI is easier..They both use a relic of an ecu. They both use simalar sensors. You need to make provisions for an electric fuel pump on both..It's kind of the same swap as long as you have the entire TPI intake.

[snm95ls]

Originally Posted by Rich84

I am no expert, but I dont understand how TBI is easier..They both use a relic of an ecu. They both use simalar sensors. You need to make provisions for an electric fuel pump on both..It's kind of the same swap as long as you have the entire TPI intake.

Correct.

It has been years since I have given OBD1 or older era GM fuel injection a look, but there might be fewer tables in a TBI ROM.

I think a lot of the "complication" with tuning a fuel injected system is inexperience and fear of change.

Hell, you can get the stuff to do real time tuning with the faster 7730 ECM (speed density TPI) for about 500 including a decent wideband. I know a lot of guys aren't necessarily proficient with a soldering iron, nor do they truly understand fuel injection enough to be able to tune it themselves, so I understand that.

ASSuming you have a laptop that isn't absolutely arcane, that is the last major piece you need.

Carbs have their place, but I will always prefer electronic port fuel injection over them when budget allows. The TBI system has so many inherent limitations, but they can be circumvented to an extent. You still dealing with a wet flow manifold which will always have its problems versus a dry flow manifold which is found in port fuel injection systems.

The torque production that a TPI system can make seems ideal for a truck application. Dunno how well it actually works though.

[classicchev]

Got it in my Crew cab with 700 r4 and 411 gears, its decent, but the only reason I put it in was because I had it.. Everything dies at 4500 rpm. I thought that was crap until I put the truck on the dyno, amazing how it drops.

[snm95ls]

Originally Posted by classicchev

Got it in my Crew cab with 700 r4 and 411 gears, its decent, but the only reason I put it in was because I had it.. Everything dies at 4500 rpm. I thought that was crap until I put the truck on the dyno, amazing how it drops.

FWIW, the stock TBI engines do the same, but they have far less power under the curve, so it is more noticeable with TPI I think.

[INSIDIOUS '86]

The tpi and tbi heads I'm putting on the 283 should make a good amount of torque for that small motor. Shouldn't be going past 4500rpm anyways since its just going to be a daily. I'm sure with the low first gear 700r4 and the 373 diff it shouldn't be a slouch either. I have a tpi sitting already with a 305 computer I just need to do wiring. Not sure if I should pull it off another car or buy new harness. I will Prob have a custom prom chip made to enhance its match to the engine

As much as I like carbs I just want to be able to get in turn key and quirky leave whenever. My neighbors especially. Since my current daily driver has no choke horn and can wake the dead lol
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[Rich84]

Get an aftermarket harness.. You really don't want to mess around with 25 year old wires..and they are notorious for having problems. i think I paid about $280.00 it took about 30 minutes to connect everything.
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[pontgta]

Have it my 1990 TRANS AM GTA.....Runs smooth and have never had a problem with it. I like the speed density over the mass air flow setup.
I would never swap in a carb.....that would be going backward...Now a LS1, ls2,ls3..... probably....if only i had the time...

[Rich84]

If I was starting over with my tpi setup with no harness, I would look into getting the harness for the ls computer. Sequential injection faster smarter computer. Cheaper to program..but right now it runs too good to mess around with.
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[Ziegelsteinfaust]

I helped a friend drop a 350 TPI, and 700R4 into a 71 C10.

Yes it would torque pretty hard till 4500rpm, and yes it fell flat on its face. Where it shined was just cruising around, and towing. It never felt like it was lugging or short on torque, but it was not fast.

I had thought about the same engine as your building for my truck, but getting broader power I want gets stupid expensive fast. So if you want a decent little driver with mpg as the big goal. I can't seeing it disappointing you if it was a 350, but I feel a 283 would be better suited to a 2wd. A 4wd needs more torque.

[Firebirdjones]

Had a factory L98 350 TPI Iroc that I drove and tuned for years with Moates software.

They are okay systems, originally designed for the 305 and wasn't redesigned later when GM decided to toss it on the 350's, so that's where they get the bad rap of running out of breath before 5,000 rpms. However they performed admirably on what they were designed for (the 305). My old L98 (350) Iroc with it's original 2.77 gears, exhaust, and a little tuning (otherwise a bone stocker) ran 13.80's at 99 mph, not too shabby for that time period. So they can perform decent. To put that into perspective, my wifes (brand new at the time) 97 LT1 Z28 with a 6 speed and 3.42's, would only muster 14.20's at 101 mph bone stock before tuning, My old Iroc gave that car fits

Anyway, since the system was designed for the 305, it might be a sweet little package on a 283. However it would still need to be tuned to be optimized.

My personal opinion, having several LS powered cars now, the old batch fire injection systems (like TPI) with a very primitive computer is a turn off for me. If you need a harness I'd do as suggested already.
Get yourself a new plug and play harness along with an LS style computer for better tunability, sequential fire, and it should make better and smoother power as a result as well as being easier to tune and understand with HPtuner software. Alot of people are swapping over to the newer computers on the older setups and reporting better running engines with better fuel economy. You have many more tuning options as well
Frankly though, to do it this way, (which is the right way in my opinion and the only way I'll do swaps for customers) things start to get expensive and it makes you weigh other options. Especially if you don't have tuning software, that's an added expense. But....if you plan to tinker with fuel injection the rest of your life, then at some point you'll need to invest in tuning software not just for the tuning features, but for the diagnostic abilities as well. Or pay tuners to do it for you at $5-$600 a pop.

[INSIDIOUS '86]

You know I may look into that further on down the road. I think with the reduced air demand of the 283 that it won't feel like its hitting a wall when you go up in rpm. I assume that a computer from a ls Tahoe or truck with an lq4-9 will work?
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[JCampbell]

This is turning out to be a very interesting thread.

[OutlawDrifter]

Originally Posted by INSIDIOUS '86

You know I may look into that further on down the road. I think with the reduced air demand of the 283 that it won't feel like its hitting a wall when you go up in rpm. I assume that a computer from a ls Tahoe or truck with an lq4-9 will work?
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i don't think it's reduced enough to make a big difference. the long runner design of the tpi system is good for torque at low speeds, not hp at higher rpm.

[Bloodhound]

I have a 1989 Trans Am 350 TPI with a '90 Vette 700R4 in my '81 C-10 longbed. I installed it in 1995 and I've never had one motor issue with it. Has an archaic Accel computer still running strong. I also have 3.73 on 31 in tires. It's got loads of torque, great for cruising around. On the track it pulls till, yes, about 4500rpms. But the fastest it ever ran is 15.7, which isn't bad for a stock motor.

[INSIDIOUS '86]

Originally Posted by OutlawDrifter

i don't think it's reduced enough to make a big difference. the long runner design of the tpi system is good for torque at low speeds, not hp at higher rpm.

Yah I figure that and the swirl port tbi heads that are on it would compliment eachother to make a motor that can cruise with low rpm and the gearing would be such that it would just make the best daily possible ESP for long road trips.

Who would you guys recommend for prom chips? till I get a better computer system I think I will end up going vintage for now.
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