TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

TBI is simple and fun!

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Old Sep 2, 2013 | 05:58 PM
  #1  
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
TBI is simple and fun!

Here some examples that demonstrate that TBI can be made to work very well for fun street cars.

DIY 360ci TBI with Edge 1800rpm stall converter.

http://www.dailymotion.com/video/x143um9_350rwhp-trans-am-vs-diy-360ci-tbi-trans-am_techhttp://www.dailymotion.com/video/x143v0d_ls1-gto-vs-diy-360ci-tbi-trans-am_techhttp://www.dailymotion.com/video/x143vfi_lt1-trans-am-vs-diy-360ci-tbi-trans-am_tech
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Old Sep 2, 2013 | 06:51 PM
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From: ms. gulf coast
Car: 91 R/S , 89 dodge p/u
Engine: L31 GM crate re-cammed , 318
Transmission: T-5 , 4 speed auto
Axle/Gears: 3.42 , ?
Re: TBI is simple and fun!

looks like a really fun time . congrats. on a great car . good luck .
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Old Sep 2, 2013 | 09:47 PM
  #3  
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From: Cleveland, Ohio
Car: 1992 Camaro RS
Engine: 3.1L
Transmission: 700R4
Axle/Gears: 3.23
Re: TBI is simple and fun!

your car is turboed right? how much rwhp?
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Old Sep 3, 2013 | 02:46 AM
  #4  
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: TBI is simple and fun!

Originally Posted by williemcfly
your car is turboed right? how much rwhp?
Nope, N/A and never been on a dyno.
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Old Jun 3, 2014 | 07:18 AM
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From: Austria
Car: 84 TA / 89 Formula
Engine: LS1 / L03
Transmission: T56 / 700R4
Axle/Gears: 3.73 / 3.27
Re: TBI is simple and fun!

hey thomas,
just stumbled upon this thread with your videos - very good job there! not many TBI thirdgens out there that can beat LS cars like that

may i ask some questions on your build? not sure if there's a thread for that already, if there is, please post a link i'm doing a 350 TBI build for a vette.. do you have any ballpark numbers for your engine output? i'd guess maybe close to 350hp peaking at somewhere between 5 and 5.5 krpm with that heads and cam?
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Old Jun 3, 2014 | 06:00 PM
  #6  
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: TBI is simple and fun!

Thanks for the compliments, peak probably around 5200 and shifting at 5500, I also had it shift at 5700 which was ideal for the 1-2 shift but not for the 2-3 shift.

I prefer not to guess the hp, all I know is that the stock LS1 owners report average of 300 rwhp.
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Old Jun 3, 2014 | 06:18 PM
  #7  
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From: MICHIGAN
Car: 1988 Trans Am
Engine: L03
Transmission: 700R4
Axle/Gears: 10 Bolt 2.73 Open
Re: TBI is simple and fun!

Wow...I had not seen this thread before. Very impressive...and inspirational.
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Old Jun 4, 2014 | 04:08 PM
  #8  
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From: Austria
Car: 84 TA / 89 Formula
Engine: LS1 / L03
Transmission: T56 / 700R4
Axle/Gears: 3.73 / 3.27
Re: TBI is simple and fun!

it sure looks to be going strong i have no idea why somebody would build a motor and then prefer to not know its output, but to each their own

that said, may i ask what your DC and MAP readings are around peak hp? curious how much of a restriction, or not, that size TBI and manifold you're using would be on such a setup. also milage and if you have, any quartermile times would be interesting.. thanks!
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Old Jun 4, 2014 | 06:29 PM
  #9  
thomas1976's Avatar
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: TBI is simple and fun!

Ownor, please don't get me wrong, the car has never been on a dyno and I have never had the chance to do a timed 1/4 mile, reason why I will not spread out any numbers.

The injectors are wide open, 2 years ago the map was 92 kpa @5700 rpm with 46mm bores and gasket matching, I will let you know the current map readings next time I have time to play with the tune.
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Old Jun 5, 2014 | 02:26 AM
  #10  
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From: Austria
Car: 84 TA / 89 Formula
Engine: LS1 / L03
Transmission: T56 / 700R4
Axle/Gears: 3.73 / 3.27
Re: TBI is simple and fun!

ah, i see. good reason not to spread any numbers, but can always give an estimate based on the injector DC i'd guess somewhere around 370 or upper 300hp anyways..? pretty good for that cam and such a low power peak, imho. yeah, please let me know when you get some MAP readings at redline, and BARO for comparison. 92 MAP shows the intake a bit of a restriction when assuming somewhere around 97 for BARO, but then again that reading's already at 5700 rpm. thanks!
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Old Jun 5, 2014 | 04:42 PM
  #11  
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: TBI is simple and fun!

What if wide open = DC 100% +
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Old Jun 6, 2014 | 02:26 AM
  #12  
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From: Austria
Car: 84 TA / 89 Formula
Engine: LS1 / L03
Transmission: T56 / 700R4
Axle/Gears: 3.73 / 3.27
Re: TBI is simple and fun!

you know what it means, you're running out of fuel (and hence power) up top So it's probably not enough to reach a rich PE mixture. For power calculation, I think RBob's BPC spreadsheet is only going for 85% DC with the "Max supported horsepower" calculation. But then again it also doesn't take a richer mixture into account (BSFC is also just an approximation here imho). So I'm guestimating that's probably about the HP you're likely to arrive at? Do you have your fuel pressure monitored? At 92 MAP you'd get a little bit less fuel than the static set fuel pressure anyways (because the vac-ref signal to the VRFPR is lower than ambient air pressure).
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Old Jun 14, 2014 | 03:37 PM
  #13  
thomas1976's Avatar
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Joined: Jun 2006
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From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: TBI is simple and fun!

I believe your guestimating sounds reasonable, will add some input when I have time to play with it.
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