93 suburban EFI conversion

[toolmantim]

I am looking for any information on the best system to convert a 1993 Suburban tow vehicle from the original throttle body system. The engine is a 383 (stroked 350) with a mild RV cam. I would like to hear comparisons on the different available systems, ie F.A.S.T, Holley...I have a donator TPI but it seems as though it will be almost as expensive to convert to that as the others by the time I change the wiring harness, etc. Any advice would be appreciated.

[EagleMark]

I don't know much about aftermarket systems, except old ones are now boat achors because you can no longer get replacemnt parts? Yet you can still buy replacement parts for older GM systems.

What ECM/PCM do you have in there now? Why do you want to change?

They can all be tuned for your new motor. If it's an old 160 baud ECM lot's of guys are swapping to newer 8192 baud PCM. Huge difference, way more options to tune.

[PJG1173]

93 burb if it has the 4l60e should be 16168625 running $E6 so It should be the faster pcm.

[93V8S10]

93 burb if it has the 4l60e should be 16168625 running $E6 so It should be the faster pcm.

And it can be converted to MPFI.

[EagleMark]

And it can be converted to MPFI.

And the PCM can handle that with no mods other then bin changes? Wiring from TBI injectors to MPFI is?

[93V8S10]

Just minor PCM mods required. Injector wiring is simple, 4 injectors to one TBI injector driver and 4 to the other.

http://www.gearhead-efi.com/Fuel-Inj...Information-OD

Post #6

[toolmantim]

I don't know much about aftermarket systems, except old ones are now boat achors because you can no longer get replacemnt parts? Yet you can still buy replacement parts for older GM systems.

What ECM/PCM do you have in there now? Why do you want to change?

They can all be tuned for your new motor. If it's an old 160 baud ECM lot's of guys are swapping to newer 8192 baud PCM. Huge difference, way more options to tune.

Thanks for the reply.
I don't have the equipment to program the old ECM. Is the PCM a part of the ECM? It seems the better system for my engine would be the TPI and I have that from a '89 Vette. But I have no sensors or wiring for this system. I assume I must replace the ECM to operate the TPI.

[EagleMark]

Thanks for the reply.
I don't have the equipment to program the old ECM. Is the PCM a part of the ECM? It seems the better system for my engine would be the TPI and I have that from a '89 Vette. But I have no sensors or wiring for this system. I assume I must replace the ECM to operate the TPI.

PCM is just a newer name for ECM when it also controls transmission.

Changing to TPI will be a huge job even then TPI is for 305 engine but then used on 5.7L engine and has flow limits. So guys are changing the intake out to a LT1 which is bigger and better TPI. You could use your PCM with coding changes mentioned above for MPFI but would still need some wiring harness changes from TBI to TPI/MPFI

Your motor is just bigger cubic inches with mild cam. You could spend thousands of dollars to buy something else but from what is said above looks like your PCM id the faster PCM to begin with and will run just as good if not better than any aftermarket system with a tune.

If you don't want to get into tuning which is not that expensive for this type PCM then talk to Dave at Old School EFI. You'll still need to data log while driving but he can set you up with a good tune.

Or couple hundred bucks for tuning equipment, software and a laptop if you don't have one and you can learn all you need right here?

[toolmantim]

PCM is just a newer name for ECM when it also controls transmission.

Changing to TPI will be a huge job even then TPI is for 305 engine but then used on 5.7L engine and has flow limits. So guys are changing the intake out to a LT1 which is bigger and better TPI. You could use your PCM with coding changes mentioned above for MPFI but would still need some wiring harness changes from TBI to TPI/MPFI

Your motor is just bigger cubic inches with mild cam. You could spend thousands of dollars to buy something else but from what is said above looks like your PCM id the faster PCM to begin with and will run just as good if not better than any aftermarket system with a tune.

If you don't want to get into tuning which is not that expensive for this type PCM then talk to Dave at Old School EFI. You'll still need to data log while driving but he can set you up with a good tune.

Or couple hundred bucks for tuning equipment, software and a laptop if you don't have one and you can learn all you need right here?

Thank you for your reply.
As I understand the LT1 is better for top end and the TPI is better for torque from the comments I have received. I had not heard the LT1 system referred to as a TPI although I know it has injectors in each port. Looking at the TPI I can see tuned runners. I can't see the inside of the LT1 plenum so I don't know if it has tuned runners or not.
I have information from Dynamic EFI (dynamicefi.com) and he offers a computer and tuning interface for $500. This seems like a good way to go. I am poised to pull the pin and order it unless I hear something negative soon. He has the pinouts and wiring instructions and splits the PCM from the ECM so I keep my original computer for the tranny control and use his ECM and tune it for the engine control. I am not looking for top end with this system. I simply want a tunable system and I want to start with the best one.

[1project2many]

Howdy.

TPI or Tuned Port Induction was a marketing name for the long runner port fuel injection system used from 85 to 91 on Camaros and Corvettes. It was designed to make peak power at low rpm and produce high torque numbers. On a 350 it begins to have problems with flow somewhere around 4000 to 4500 rpm depending on the cam. The LT1 uses a short runner port fuel injection manifold designed to make peak power at a higher rpm than the TPI engine. It is also "tuned" but for a different power band. My personal feeling is that the tuned port engines were seome of the greatest truck engines that GM never put in trucks. For a truck that tows or works, the TPI can be a very good addition.

It's really unnecessary work and expense to replace a very capable, very versatile, and completely usable computer with one that is less flexible. Additionally, with two computers you'll have a mongrel system which may scare off even the most adventurous technicians if you have a problem. The stock computer in your truck is able to do the job of controlling the TPI intake just fine. If you're willing to do the work to build or replace the wiring harness for a "dual computer" system, then making a few simple modifications for the tuned port installation shouldn't be an issue. In non-electronic terms the solution recommended by affordable efi might be similar to a hot rod shop telling you they can replace your smallblock Chevy engine with a flathead Ford because they know how to work on the Ford but they just don't know how to make the Chevy do what you want.

The option for support and one-stop shopping to get started is very attractive. If you can get the tools to tune including a laptop, emulator, burner, and datalogging / scantool software for the pcm currently in your truck for $500 then it's probably worth it. If there's no emulator you're going to want one. If there's no tool to burn chips then you're at someone else's mercy each time you want a chip made. If you're getting Tunerpro tuning software in the laptop then it's easily downloadable anywhere and can be used for free if you're just tuning your own vehicle. I'd find out what hardware and software you're getting for the money.

In short I would use the pcm you already have (better, faster, and stronger unit), ditch the idea of mating two computers on one harness (soooo 1988!) and start gathering the tools you'll need for the tuning (laptop, cable, emulator, and software).

[gregs78cam]

Rbob/DynamicEFI has real good stuff, and it would no doubt work fine, but from sounds of it you don't need to go full tilt, unless you have big plans in the future. I would have to agree with most everyone else, stay with GM PCM, it is more than adequate for what you have. GM likely put more man hours into getting EFI right than probably all aftermarket EFI companies put together. And yes TPI really should have been put in trucks as well. The only possible issue I see with putting the TPI on a 383 is airflow, the factory 350's ran out of air by 4500rpm, and even a slightly warmed over 383 will run out of air way before that. So if you don't plan on keeping your foot in it to redline, it should work great. But the torque will be AWESOME!!!!

Is this engine just stroked and cam, or does it have heads and intake as well?

If you can find the correct JY harness for the 'vette TPI(w/ or w/o cold start injector, and speed density or MAF) then it shouldn't be real hard to repin the connectors to plug right into your PCM. Your may have to add a couple of wires, but that should be easy. thirdgen.org should have lots of info on wiring and differences. Once you have the proper schematic it is just a matter of swapping pins.

[EagleMark]

You'll never here anything negative about Dynamic EFI products or tech support so put that issue to rest. Road trip mechanic is out of the question and may have emissions test problems.

But you have everything you need right now, just tune it and it will be more then you need with TBI. You'll never feel difference in going TPI unless you get dyno numbers. road trip mechanic readily available and emissions should pass.

Now if you want to go to the TPI intake you still have everything you need except wiring in MPFI injectors and changing the fuel pump in tank to TPI pump needed for TPI/MPFI pressure. Then are going to probably loose some top end power WOT high RPM... road trip mechanic will be hard and depending on what state your in for emissions tests may fail.

Your PCM can be tuned for the (TPI BTW it is MPFI with tuned port runners) you can spend $200. for everything needed to tune or $500 with AutoProm which is an emulator, chip burner and data logger and TunerPro software. Benefit of that is you still have everything needed to tune many more cars. Dynamic is one per car.

[toolmantim]

So are you suggesting I stay with the original TBI system and tune it? I am looking for torque for a towing vehicle.

[toolmantim]

Howdy.

TPI or Tuned Port Induction was a marketing name for the long runner port fuel injection system used from 85 to 91 on Camaros and Corvettes. It was designed to make peak power at low rpm and produce high torque numbers. On a 350 it begins to have problems with flow somewhere around 4000 to 4500 rpm depending on the cam. The LT1 uses a short runner port fuel injection manifold designed to make peak power at a higher rpm than the TPI engine. It is also "tuned" but for a different power band. My personal feeling is that the tuned port engines were seome of the greatest truck engines that GM never put in trucks. For a truck that tows or works, the TPI can be a very good addition.

It's really unnecessary work and expense to replace a very capable, very versatile, and completely usable computer with one that is less flexible. Additionally, with two computers you'll have a mongrel system which may scare off even the most adventurous technicians if you have a problem. The stock computer in your truck is able to do the job of controlling the TPI intake just fine. If you're willing to do the work to build or replace the wiring harness for a "dual computer" system, then making a few simple modifications for the tuned port installation shouldn't be an issue. In non-electronic terms the solution recommended by affordable efi might be similar to a hot rod shop telling you they can replace your smallblock Chevy engine with a flathead Ford because they know how to work on the Ford but they just don't know how to make the Chevy do what you want.

The option for support and one-stop shopping to get started is very attractive. If you can get the tools to tune including a laptop, emulator, burner, and datalogging / scantool software for the pcm currently in your truck for $500 then it's probably worth it. If there's no emulator you're going to want one. If there's no tool to burn chips then you're at someone else's mercy each time you want a chip made. If you're getting Tunerpro tuning software in the laptop then it's easily downloadable anywhere and can be used for free if you're just tuning your own vehicle. I'd find out what hardware and software you're getting for the money.

In short I would use the pcm you already have (better, faster, and stronger unit), ditch the idea of mating two computers on one harness (soooo 1988!) and start gathering the tools you'll need for the tuning (laptop, cable, emulator, and software).

So are you suggesting I stay with the original TBI system and tune it? I am looking for torque for a towing vehicle.

[toolmantim]

Rbob/DynamicEFI has real good stuff, and it would no doubt work fine, but from sounds of it you don't need to go full tilt, unless you have big plans in the future. I would have to agree with most everyone else, stay with GM PCM, it is more than adequate for what you have. GM likely put more man hours into getting EFI right than probably all aftermarket EFI companies put together. And yes TPI really should have been put in trucks as well. The only possible issue I see with putting the TPI on a 383 is airflow, the factory 350's ran out of air by 4500rpm, and even a slightly warmed over 383 will run out of air way before that. So if you don't plan on keeping your foot in it to redline, it should work great. But the torque will be AWESOME!!!!

Is this engine just stroked and cam, or does it have heads and intake as well?

If you can find the correct JY harness for the 'vette TPI(w/ or w/o cold start injector, and speed density or MAF) then it shouldn't be real hard to repin the connectors to plug right into your PCM. Your may have to add a couple of wires, but that should be easy. thirdgen.org should have lots of info on wiring and differences. Once you have the proper schematic it is just a matter of swapping pins.

I have an aftermarket set of aluminum heads that should flow well but are not overkill, RV cam and 10:3/1 compression. I will be using whatever intake works with the system I choose.