Carb to TPI conversion
Thread Starter
Instructor
Joined: Nov 1999
Posts: 155
Likes: 0
From: Eureka NV
Carb to TPI conversion
I posted this on the C4 forum but thought it might be of some interest here also.
Greetings gang,
I hesitate to dredge this topic up again, considering the beating I took from CFI-EFI in regard to using MegaSquirt for engine management but some of you may find my results interesting.
I just finished converting my 79 from carb to TPI (which I plan to do with my 84 Crossfire also). I used a TPI setup from an 85 and put it on top of a redrilled Vortec roller cam motor. The engine is de-smoged except for the stock narrow band O2, IAT and coolant sensors. I chose a MegaSquirt II Version 3.0 ECU for engine management. The MS II is controlling not only the TPI but the HEI, TCC and cooling fan.
After a bit of around town tuning I took the car out on the hiway for a 90 mile run. I maintained about 70 mph (2000) rpm during the trip and attained 25+ mpg. I am sure that I can improve on that number as I learn more about tuning the MS.
CFI-EFI was right about one thing for certain. MS is NOT for guys who want a plug & play ECM that they can plug in and roar off down the street! I had to learn some things about VE maps, ignition maps and AFR tables and I am still learning of course. I am still addressing a few tuning issues, trying to get more horse power etc. But as it stands now I am VERY happy with the overall performance AND economy of the TPI using the MS II.
If any one out there is considering MegaSquirt just drop me a line and I will help any way I can.
Take care and be safe,
Ken
Greetings gang,
I hesitate to dredge this topic up again, considering the beating I took from CFI-EFI in regard to using MegaSquirt for engine management but some of you may find my results interesting.
I just finished converting my 79 from carb to TPI (which I plan to do with my 84 Crossfire also). I used a TPI setup from an 85 and put it on top of a redrilled Vortec roller cam motor. The engine is de-smoged except for the stock narrow band O2, IAT and coolant sensors. I chose a MegaSquirt II Version 3.0 ECU for engine management. The MS II is controlling not only the TPI but the HEI, TCC and cooling fan.
After a bit of around town tuning I took the car out on the hiway for a 90 mile run. I maintained about 70 mph (2000) rpm during the trip and attained 25+ mpg. I am sure that I can improve on that number as I learn more about tuning the MS.
CFI-EFI was right about one thing for certain. MS is NOT for guys who want a plug & play ECM that they can plug in and roar off down the street! I had to learn some things about VE maps, ignition maps and AFR tables and I am still learning of course. I am still addressing a few tuning issues, trying to get more horse power etc. But as it stands now I am VERY happy with the overall performance AND economy of the TPI using the MS II.
If any one out there is considering MegaSquirt just drop me a line and I will help any way I can.
Take care and be safe,
Ken
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
Good job !!
It really does pay to be adventurous doesnt it.
I am currently looking at a Holley 950-22s for mine.
Just like yours it probably wont be plug and play but it looks like it is pretty configurable once it is up and running.
I am currently looking at a Holley 950-22s for mine.
Just like yours it probably wont be plug and play but it looks like it is pretty configurable once it is up and running.
Thread Starter
Instructor
Joined: Nov 1999
Posts: 155
Likes: 0
From: Eureka NV
adam,
The MS will control ANY throttle body OR multipoint fuel injection (including LT1) PLUS a LOT more. ie. ignition timing, converter lockup to name just a couple. It also lets you eliminate MAF in favor of speed density.
I went first cabin with mine and have just under $400 in the management system.
I bought 2 sets of TPI (one for the 79 and another for my 84) on Ebay for about $705 total so I am into the 79 about half of the $700 plus the $400 for the MS II for a total of about $750. (of course I had some misc. stuff to buy like a couple new sensors, new IAC, different throttle cable, gaskets, and a new fuel pump ($160) that I won't need for the 84 because the pump is already in the tank.)
I should point out that ALL your GM sensors will work! I got one bad IAC in the deal (figures when buying on Ebay! hahahaha) and didn't want to take a chance on the old IAT & CLT sensors so I just replaced them both. I already had an O2 sensor in my parts bucket so I used it.
I also resealed the fuel rails & injectors.
If you already have multipoint fuel injection you won't need anyof the above stuff except for the MS ECU!
I will be happy to provide more info if you need it.
Take care and be safe,
Ken
The MS will control ANY throttle body OR multipoint fuel injection (including LT1) PLUS a LOT more. ie. ignition timing, converter lockup to name just a couple. It also lets you eliminate MAF in favor of speed density.
I went first cabin with mine and have just under $400 in the management system.
I bought 2 sets of TPI (one for the 79 and another for my 84) on Ebay for about $705 total so I am into the 79 about half of the $700 plus the $400 for the MS II for a total of about $750. (of course I had some misc. stuff to buy like a couple new sensors, new IAC, different throttle cable, gaskets, and a new fuel pump ($160) that I won't need for the 84 because the pump is already in the tank.)
I should point out that ALL your GM sensors will work! I got one bad IAC in the deal (figures when buying on Ebay! hahahaha) and didn't want to take a chance on the old IAT & CLT sensors so I just replaced them both. I already had an O2 sensor in my parts bucket so I used it.
I also resealed the fuel rails & injectors.
If you already have multipoint fuel injection you won't need anyof the above stuff except for the MS ECU!
I will be happy to provide more info if you need it.
Take care and be safe,
Ken
Last edited by KJones; Sep 5, 2006 at 11:26 PM.
Thread Starter
Instructor
Joined: Nov 1999
Posts: 155
Likes: 0
From: Eureka NV
Instead of a long post here I put up some pics in a folder on my web site.
www.kandlservices.com/tpi
Ken
www.kandlservices.com/tpi
Ken
Intermediate
Joined: Jun 2006
Posts: 26
Likes: 0
From: Kennesaw Georgia
Sweeeeet!
Wow that looks really nice!
I'll be doing a similar upgrade to my '81. I've also got the complete tpi from an 85 vette. I've got stock heads from my 81, so it should bolt right up. anyway, I was going to try using the ecm from the '85 at first and then upgrade later to the megasquirt that you've got. I'll have to keep the system mass air instead of speed density for now too. Do you know anything about the stock 85 ecm? the ECM is for an automatic, and I've got the th350 w/lockup, but I think the 85's had a auto with overdrive and lockup. Did you change anything on the fuel delivery system? I noticed that your fuel pump is up front. I've seen most folk put them close to or in the tank. Is there a difference? I've so many questions
If it's ok i'm probably going to bombard you with questions from time to time.
I'll be doing a similar upgrade to my '81. I've also got the complete tpi from an 85 vette. I've got stock heads from my 81, so it should bolt right up. anyway, I was going to try using the ecm from the '85 at first and then upgrade later to the megasquirt that you've got. I'll have to keep the system mass air instead of speed density for now too. Do you know anything about the stock 85 ecm? the ECM is for an automatic, and I've got the th350 w/lockup, but I think the 85's had a auto with overdrive and lockup. Did you change anything on the fuel delivery system? I noticed that your fuel pump is up front. I've seen most folk put them close to or in the tank. Is there a difference? I've so many questions
If it's ok i'm probably going to bombard you with questions from time to time.
