Anyone tried upgrading a TBI engine to EFI?

[Mackman]

Hello, I am new to this site. I am hoping to gain some knowledge from others that may have achieved upgrading their TBI engine to one of the new EFI systems such as the Holley Terminator, FiTech, FAST or E-Street 2? I am thinking that this would be an improved system over the factory GM TBI. I am confused on how the transmission would react to these systems or if a transmission controller would have to be utilized. Any info would be appriciated.

[Kudzupatch]

I believe everything you mentioned is TBI, Throttle Body Injection. So your not really talking anything dramatically different.

Assuming a mostly stock engine to mid performance motor I don't see how you gain much if anything. The replacements will flow more air but you can also buy a replacement Holley TBI unit that will flow 600 CFm (if I remember correctly) and it is a bolt on direct replacement unit. That is plenty for most street engines.

You still have to tune the the aftermarket unit to get the most out of it. So why not learn to tune the existing unit? Replace the chip with a Moates Ostrich emulator and you can tune it from you laptop.

When I finally get to replace my engine that is exactly what I am going to do. Use stock TBI and just tune it to the new engine. If I need the air flow I will replace it with the Holley unit. Should be able to the do the same thing as the replacement without all the expense.

Not 100% sure but I believe you have to have a separate transmission controller with most of those. Your adding a level of complexity that unless you are really into the High Output motor I can't see the point.

[franken]

TBI is EFI...

[OutlawDrifter]

Originally Posted by Kudzupatch

I believe everything you mentioned is TBI, Throttle Body Injection. So your not really talking anything dramatically different.

Assuming a mostly stock engine to mid performance motor I don't see how you gain much if anything. The replacements will flow more air but you can also buy a replacement Holley TBI unit that will flow 600 CFm (if I remember correctly) and it is a bolt on direct replacement unit. That is plenty for most street engines.

You still have to tune the the aftermarket unit to get the most out of it. So why not learn to tune the existing unit? Replace the chip with a Moates Ostrich emulator and you can tune it from you laptop.

When I finally get to replace my engine that is exactly what I am going to do. Use stock TBI and just tune it to the new engine. If I need the air flow I will replace it with the Holley unit. Should be able to the do the same thing as the replacement without all the expense.

Not 100% sure but I believe you have to have a separate transmission controller with most of those. Your adding a level of complexity that unless you are really into the High Output motor I can't see the point.

Skip the Holley unit. Not worth the money. There is a company out there that will increase the bores in your unit, or you could score a 454 unit for cheaper than the Holley.

Depends on the age of the TBI vehicle as to how the trans is controlled. The later ones rely on the same ECU.

I wouldn't waste the time, and if you were going to spend the money, throw it towards something with multi-port fueling capabilities.

[bonnieclyde100]

Originally Posted by Mackman

Hello, I am new to this site. I am hoping to gain some knowledge from others that may have achieved upgrading their TBI engine to one of the new EFI systems such as the Holley Terminator, FiTech, FAST or E-Street 2? I am thinking that this would be an improved system over the factory GM TBI. I am confused on how the transmission would react to these systems or if a transmission controller would have to be utilized. Any info would be appriciated.

What year is your truck ? if it is an obd1 setup there is a lot you can do with that system to increase it. there is a forum http://www.gearhead-efi.com/Fuel-Injection/forum.php that you can learn how to modify it fairly easy. I even took 2 throttle bodies and attached them together to make 1 four barrel tbi and my computer with some tuning runs it. its in a 69 chevy truck the titles on forum is frankenbody . I didn't come up with the name others did the same thing first. here is a link to a video of my truck. https://www.youtube.com/watch?v=PbOHadlT-jM

[bonnieclyde100]

Originally Posted by bonnieclyde100

What year is your truck ? if it is an obd1 setup there is a lot you can do with that system to increase it. there is a forum http://www.gearhead-efi.com/Fuel-Injection/forum.php that you can learn how to modify it fairly easy. I even took 2 throttle bodies and attached them together to make 1 four barrel tbi and my computer with some tuning runs it. its in a 69 chevy truck the titles on forum is frankenbody . I didn't come up with the name others did the same thing first. here is a link to a video of my truck. https://www.youtube.com/watch?v=PbOHadlT-jM

here are some pic that others built.

[LT7A]

The good news is that those factory throttle bodies are actually pretty good as compared with the aftermarket. And designed and calibrated for our trucks. Is your objective better performance? I'm assuming so, but you didn't say. From a hot rod shop that works on many late model cars as well as many upgraded older cars, the owner's recommendation to me was to work with the factory fuel injection as much as possible. There are many ways to improve the performance of the TBI as mentioned above as well as some less radical mods. Do an internet search of Ultimate TBI Mods and check out TBICHIPS.com as well as the resources above. If you are looking for better performance and want to start another thread, I'll happily chime in.