91 tpi swap into 89 tbi305 t5 car
11-11-2018, 12:06 PM
#1
Junior Member
Thread Starter
Join Date: May 2008
Location: massachsetts
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 firebird formula
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 323
91 tpi swap into 89 tbi305 t5 car
Hi I was wondering if anyone has done this swap and what is involved I have a complete 91 formula 5.7 tpi donor car with a auto trans my car is a 89 formula tbi 305 t5 car at the end of the day I would like it to be a 5.7 tpi t5 car I have tried looking into this swap and cant really find much on it people have said you need to have a chip made or burned what company's would be able to do that as a t5 wasn't available in 91 cars besides that what else would have to be done and needed to complete this swap thanks for any information in advance
11-12-2018, 06:32 PM
#2
Supreme Member
iTrader: (2)
Join Date: Mar 2002
Location: San Antonio TX
Posts: 2,516
Likes: 0
Received 3 Likes
on
3 Posts
Car: 1990 G92 IROC Z Miniram
Engine: 388cu 6.4 Liters
Transmission: G-Force T5
Axle/Gears: 3.73 Gears
Re: 91 tpi swap into 89 tbi305 t5 car
To do it right, you have to swap the entire wire harness from the 91 to the 89. That means all the plug&play wires under the dash. Swap the fuel lines and change the fuel pump for TPI.
11-12-2018, 06:59 PM
#3
Junior Member
Thread Starter
Join Date: May 2008
Location: massachsetts
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 firebird formula
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 323
Re: 91 tpi swap into 89 tbi305 t5 car
VincentZ28 which wires under the dash would need to be done to do it right as far as the fuel lines I thought they are the same except the front rubber lines to the tpi setup and I know about the pump do you have any info regarding rewiring the trans harness from the auto to the t5 so the clutch start switch and the reverse lights will work correctly is there a way to unpin the t5 harness off the old harness and pin it into the new 91 harness so it's like factory
11-12-2018, 10:42 PM
#4
Supreme Member
iTrader: (2)
Join Date: Mar 2014
Location: South Ms
Posts: 4,422
Received 721 Likes
on
490 Posts
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: 91 tpi swap into 89 tbi305 t5 car
I thought over swapping my L98 over to my TBI car and I've decided to run TBI on the L98 engine for a much simpler route. The TPI is a gorgeous setup if you can pull it off and I may regret not doing it myself later on. Good luck and I look forward to seeing you go through with it.
11-13-2018, 01:14 PM
#5
Junior Member
Thread Starter
Join Date: May 2008
Location: massachsetts
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 firebird formula
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 323
Re: 91 tpi swap into 89 tbi305 t5 car
dmccain I have done that swap before tbi350 and when I did it the hardest part was finding the 90 chevy caprice 9c1 ecm to make it run right but now Its a little easier to find memcals and people to tune them nowadays compared to when I did it 20 years ago
11-13-2018, 01:39 PM
#6
11-13-2018, 01:56 PM
#7
Re: 91 tpi swap into 89 tbi305 t5 car
TBI and TPI use the same fuel lines, up to the engine anyway, just need to change the fuel pump in the tank. Good time to look at upgrading to the "1LE" TPI fuel strainer while you're in there.
There is a write-up on repinning and rewiring a TBI harness to SD TPI (somewhere), but it'd probably be easier to just rip the entire engine harness out and use the one from the donor car. You'll want to grab the GM Service Manual and check the C100 and C207 pin-outs to be sure the rest of the wiring in your car has what you need for the TPI harness. Since your donor is an automatic, the TPI engine harness won't be wired for backup lights, and you'll have extra wiring for the torque converter clutch, etc. Easy enough to get the reverse light plug parts from Mouser and build a pigtail long enough to reach from the trans to C100. A person could go the extra mile and remove the TCC wiring at the same time and rewrap the harness. Or repurpose the pink and purple wires to be green and blue and just change the connector(s)/pins.
You can approach the 5.7L 5spd issue like it's a regular 350 swap on a LB9/5spd car, or like it's a 5.7L TPI car getting a T56. The long and short is you can let the ECM believe it's a 305, which sorta works. Or you can trick the 5.7L Auto ECM into thinking the car is in Park/Neutral or Drive all the time, and deal with funny results - again, sorta works. Or you can get a Bit-Butcher to burn a custom chip to combine the attributes, which ought to sorta work.
The bigger issues are the stupid stuff that you'll never have thought of... Like the TBI exhaust is completely different from TPI, and the battery moving from the right to the left, single vs dual fans... Most people never really do a swap like this 100%. Most people cut corners, and settle for sorta works.
There is a write-up on repinning and rewiring a TBI harness to SD TPI (somewhere), but it'd probably be easier to just rip the entire engine harness out and use the one from the donor car. You'll want to grab the GM Service Manual and check the C100 and C207 pin-outs to be sure the rest of the wiring in your car has what you need for the TPI harness. Since your donor is an automatic, the TPI engine harness won't be wired for backup lights, and you'll have extra wiring for the torque converter clutch, etc. Easy enough to get the reverse light plug parts from Mouser and build a pigtail long enough to reach from the trans to C100. A person could go the extra mile and remove the TCC wiring at the same time and rewrap the harness. Or repurpose the pink and purple wires to be green and blue and just change the connector(s)/pins.
You can approach the 5.7L 5spd issue like it's a regular 350 swap on a LB9/5spd car, or like it's a 5.7L TPI car getting a T56. The long and short is you can let the ECM believe it's a 305, which sorta works. Or you can trick the 5.7L Auto ECM into thinking the car is in Park/Neutral or Drive all the time, and deal with funny results - again, sorta works. Or you can get a Bit-Butcher to burn a custom chip to combine the attributes, which ought to sorta work.
The bigger issues are the stupid stuff that you'll never have thought of... Like the TBI exhaust is completely different from TPI, and the battery moving from the right to the left, single vs dual fans... Most people never really do a swap like this 100%. Most people cut corners, and settle for sorta works.
Trending Topics
11-13-2018, 02:09 PM
#8
Junior Member
Thread Starter
Join Date: May 2008
Location: massachsetts
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 firebird formula
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 323
Re: 91 tpi swap into 89 tbi305 t5 car
TBI and TPI use the same fuel lines, up to the engine anyway, just need to change the fuel pump in the tank. Good time to look at upgrading to the "1LE" TPI fuel strainer while you're in there.
There is a write-up on repinning and rewiring a TBI harness to SD TPI (somewhere), but it'd probably be easier to just rip the entire engine harness out and use the one from the donor car. You'll want to grab the GM Service Manual and check the C100 and C207 pin-outs to be sure the rest of the wiring in your car has what you need for the TPI harness. Since your donor is an automatic, the TPI engine harness won't be wired for backup lights, and you'll have extra wiring for the torque converter clutch, etc. Easy enough to get the reverse light plug parts from Mouser and build a pigtail long enough to reach from the trans to C100. A person could go the extra mile and remove the TCC wiring at the same time and rewrap the harness. Or repurpose the pink and purple wires to be green and blue and just change the connector(s)/pins.
You can approach the 5.7L 5spd issue like it's a regular 350 swap on a LB9/5spd car, or like it's a 5.7L TPI car getting a T56. The long and short is you can let the ECM believe it's a 305, which sorta works. Or you can trick the 5.7L Auto ECM into thinking the car is in Park/Neutral or Drive all the time, and deal with funny results - again, sorta works. Or you can get a Bit-Butcher to burn a custom chip to combine the attributes, which ought to sorta work.
The bigger issues are the stupid stuff that you'll never have thought of... Like the TBI exhaust is completely different from TPI, and the battery moving from the right to the left, single vs dual fans... Most people never really do a swap like this 100%. Most people cut corners, and settle for sorta works.
There is a write-up on repinning and rewiring a TBI harness to SD TPI (somewhere), but it'd probably be easier to just rip the entire engine harness out and use the one from the donor car. You'll want to grab the GM Service Manual and check the C100 and C207 pin-outs to be sure the rest of the wiring in your car has what you need for the TPI harness. Since your donor is an automatic, the TPI engine harness won't be wired for backup lights, and you'll have extra wiring for the torque converter clutch, etc. Easy enough to get the reverse light plug parts from Mouser and build a pigtail long enough to reach from the trans to C100. A person could go the extra mile and remove the TCC wiring at the same time and rewrap the harness. Or repurpose the pink and purple wires to be green and blue and just change the connector(s)/pins.
You can approach the 5.7L 5spd issue like it's a regular 350 swap on a LB9/5spd car, or like it's a 5.7L TPI car getting a T56. The long and short is you can let the ECM believe it's a 305, which sorta works. Or you can trick the 5.7L Auto ECM into thinking the car is in Park/Neutral or Drive all the time, and deal with funny results - again, sorta works. Or you can get a Bit-Butcher to burn a custom chip to combine the attributes, which ought to sorta work.
The bigger issues are the stupid stuff that you'll never have thought of... Like the TBI exhaust is completely different from TPI, and the battery moving from the right to the left, single vs dual fans... Most people never really do a swap like this 100%. Most people cut corners, and settle for sorta works.
11-13-2018, 02:37 PM
#9
Junior Member
Thread Starter
Join Date: May 2008
Location: massachsetts
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 firebird formula
Engine: 383 stroker
Transmission: 700r4
Axle/Gears: 323
Re: 91 tpi swap into 89 tbi305 t5 car
Dmccain I think if I had gone tpi it would have been a better setup as the performace out of the tbi 350 in my 91 I built I don't think was as powerful as my 88 formula 350 I had which was a factory tpi car in my opinion that's why im doing this swap
Thread
Thread Starter
Forum
Replies
Last Post
R_F
Camaros for Sale
10
10-30-2007 03:26 PM
Formula&Z28Toys
TBI
2
08-01-2003 12:17 PM