TPI vs TBI
#1
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Car: 89 RS
Engine: 5.7 T.B.I.
Transmission: 700R4
TPI vs TBI
I am currently running a Holley TBI on a 5.7 but I do own an 86 TPI system off of a Trans Am. Should I swap and use the TPI, I have the ECM for the TPI also. I know I would have to swap for splayed center bolt heads since they are pre-87 but would all that be worth the effort?
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Car: 89 RS
Engine: 5.7 T.B.I.
Transmission: 700R4
Re: TPI vs TBI
The factory ecm, the last owner put a chip in but it's not programmed by an individual or anything it's just off the shelf
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: TPI vs TBI
TBI allows you to retain the "looks like a carb" style of intake however TBI does have a lot of limitations. Only 2 injectors to flow fuel into the engine is a big restriction. It's unlikely, the 2 injectors could flow enough fuel to feed a 300 HP. Probably limited to 200-250 HP. Trying to put an open air filter onto it usually means using a drop base air cleaner or putting on a low cowl hood for clearance.
TPI however has a lot of advantages. With a typical front mounted throttle body, it allows for a low hood profile and it's easier to get cool air from the front of the car. The 8 injectors and throttle body can easily be upgraded to provide more fuel and air into the engine than what a TBI system is capable of doing so there's a lot more potential available.
TPI however has a lot of advantages. With a typical front mounted throttle body, it allows for a low hood profile and it's easier to get cool air from the front of the car. The 8 injectors and throttle body can easily be upgraded to provide more fuel and air into the engine than what a TBI system is capable of doing so there's a lot more potential available.
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Car: 89 RS
Engine: 5.7 T.B.I.
Transmission: 700R4
Re: TPI vs TBI
The engine did come from a Caprice, I bought it from the E.Peoria, IL police auction. When they switched to the front wheel drive Impala's years ago. I do have a cowl hood for the air cleaner to fit. And given the HP limitations of TBI and the complexity of adding TPI a carb is becoming attractive. There is already a hole in the trunk for a fuel pump to be easily swapped though. This engine with the Holley 2 barrel 670CFM is making what, maybe 220 HP?
Last edited by The Big Hat; 04-27-2018 at 05:37 AM.
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Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: TPI vs TBI
There have been some strong builds with TBI. I'm sure Fast355 or Robert Frank can steer you in the right direction. I plan to keep mine TBI but I'm only looking for somewhere between 250-285 hp. But yeah, if you wanted a 400hp build I wouldn't go TPI or TBI.. I would go carb it would be MUCH easier. A set of Vortecs with upgraded springs and retainers and the right cam with your roller 9c1 engine would be a strong performer.
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