Performance 84-86 Iron Duke TBI Units! (Page 1/3)
82-T/A [At Work] OCT 28, 06:15 PM
Hey guys, I know a lot of you have, in the past, wanted that Holley 3739 TBI unit from back in the day (which is basically unobtainium). Well... I recently picked up a 1984 Chevrolet Corvette, which has Cross-Fire Injection on a 350 V8. I remember from back in the day, that my 82 TransAm (which also had at one point CFI), had the same TBI units. I was looking for some performance options for the Cross Fire Injection (since I find that system to be so unique) and ran across this company called, X-Fire Performance.

https://www.xfireperformance.com/


They provide a boring service for the Cross-Fire Injection throttle bodies, which happen to be the exact same TBI unit that's on our 1984-1986 Pontiac Fiero. They offer the service for $900, but that's for TWO of them (since the 82-84 Corvettes have two of these throttle bodies in the Cross-Fire Injection system). I just mentioned this to the owner, and he said he'd be happy to offer the service for 4 cyl Fiero owners.

If you've been looking for one of those aftermarket Holley 3739 performance TBI units... you don't need to spend $1,000 anymore, because you can get one bored (larger) for less than half that. Feel free to reach out to them via their contact form.
jdv OCT 28, 06:46 PM
Tod if you are going to be tuning the vette http://www.dynamicefi.com/ makes the boards that works with that computer.
Patrick OCT 28, 11:57 PM

quote
Originally posted by 82-T/A [At Work]:

They provide a boring service...



Hey... give them a break, Todd. Not every type of service needs to be exciting!
82-T/A [At Work] OCT 29, 06:27 AM

quote
Originally posted by jdv:

Todd if you are going to be tuning the vette http://www.dynamicefi.com/ makes the boards that works with that computer.



Unfortunately, the owner (Bob), passed away a couple of weeks ago... so even though the site is still up, you can't actually order anything anymore.



quote
Originally posted by Patrick:

Hey... give them a break, Todd. Not every type of service needs to be exciting!



Haha... it's the most excitement you can have as a result of a boring task!
jdv OCT 29, 02:30 PM
I didn't know. Have not gone to thirdgen.org in ages. It is one of the more knowledgeable tuning sites. Bob helped many people out even if they didn't buy his own product.
Rip Bob
Dennis LaGrua OCT 29, 09:21 PM
If the modified TBI unit accepts the Fiero injector it will make the tuning job much easier. Editor Programs are available that will allow changes to the fueling table in the ECM but it may not be needed. Run with it, monitor the O2 sensor with a scanner and see.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

82-T/A [At Work] OCT 30, 06:02 AM

quote
Originally posted by Dennis LaGrua:

If the modified TBI unit accepts the Fiero injector it will make the tuning job much easier. Editor Programs are available that will allow changes to the fueling table in the ECM but it may not be needed. Run with it, monitor the O2 sensor with a scanner and see.





It does! You send them just the base plate (they don't do anything with the fuel metering part) and they send it back to you restored and bored out. You can send them the top part (if you want it refinished like the bottom part), but that's an extra charge. There are also aftermarket injectors that will fit this TBI unit in stock of the factory injector (if you prefer).
Dennis LaGrua OCT 31, 08:33 PM

quote
Originally posted by 82-T/A [At Work]:
It does! You send them just the base plate (they don't do anything with the fuel metering part) and they send it back to you restored and bored out. You can send them the top part (if you want it refinished like the bottom part), but that's an extra charge. There are also aftermarket injectors that will fit this TBI unit in stock of the factory injector (if you prefer).



I was alluding to correct injector flow but it looks like you have that solved. THis TB conversion may be exactly what Duke Fiero owners are looking for especially if a turbo is added. With a cam, 5 psi of boost and some port work, a 135HP Duke is possible and would make life easier for some.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

82-T/A [At Work] NOV 23, 06:16 PM
Ok, so... my daughter and I got the car back together and we drove it around for what seemed like an hour. I put about 40 miles on it.

We installed a K&N air filter. The factory K&N air filter is no longer available, but I made one by cutting up a similar height one that has a larger diameter. Worked perfectly. We also installed a hotter ignition coil from Summit Racing. It's only a modest upgrade over the stock coil, and puts out 35,000 volts, which is a bit higher than the stock coil which is usually anywhere from 25-30k volts. We also installed a new fuel filter from K&N (really, just a quality replacement), but also installed the 50mm bored out intake manifold and the 46mm bored throttle body unit.

The only real big issue I ran into was that... God knows why... I forgot to install the gasket between the two halves of the top of the TBI unit. Both my daughter and I have rebuilt a dozen of these... and for some reason I forgot. I wonder if it maybe slipped off when I was installing it. It's all I can think of. Anyway, we turned the key, got fuel pressure and it cascaded fuel all over the top of the engine. It dulled the paint on the valve cover, which bummed me out... but we got it cleaned out, let it dry out, and then put the gasket back on.

Once we got it started, it was a little rough, but after a couple of minutes, it was running perfect. We burped the coolant a few times, and then drove around for 10 minutes. It ran quite well... no smoke, nothing. I let it cool off, put a few more things back together, and then drove it around for like almost an hour, and we took it through several sweeping backroads.

The front suspension is totally shot, and the doors don't have bump stops on them so they bang when you hit a bump, but other than that... the rest of the car is totally restored, and the engine sounded AMAZING... I mean, really, really amazing. It doesn't at all sound like a typical clattery Iron Duke.


Next weekend, we're going to hook up Paul Romsky's ALDL ECM reader and check the AFR to see how it's behaving. Per CarterCarb's recommendations, I haven't been driving it hard. Never more than 3k rpms at the absolute most... mostly shifting at 2,000 rpms. But there's lots of power, and I can absolutely tell a difference. I think it's running a little rich based on smell, but man, the car runs so well and everything is SUPER smooth...
cartercarbaficionado NOV 23, 06:57 PM

quote
Originally posted by 82-T/A [At Work]:

Ok, so... my daughter and I got the car back together and we drove it around for what seemed like an hour. I put about 40 miles on it.

We installed a K&N air filter. The factory K&N air filter is no longer available, but I made one by cutting up a similar height one that has a larger diameter. Worked perfectly. We also installed a hotter ignition coil from Summit Racing. It's only a modest upgrade over the stock coil, and puts out 35,000 volts, which is a bit higher than the stock coil which is usually anywhere from 25-30k volts. We also installed a new fuel filter from K&N (really, just a quality replacement), but also installed the 50mm bored out intake manifold and the 46mm bored throttle body unit.

The only real big issue I ran into was that... God knows why... I forgot to install the gasket between the two halves of the top of the TBI unit. Both my daughter and I have rebuilt a dozen of these... and for some reason I forgot. I wonder if it maybe slipped off when I was installing it. It's all I can think of. Anyway, we turned the key, got fuel pressure and it cascaded fuel all over the top of the engine. It dulled the paint on the valve cover, which bummed me out... but we got it cleaned out, let it dry out, and then put the gasket back on.

Once we got it started, it was a little rough, but after a couple of minutes, it was running perfect. We burped the coolant a few times, and then drove around for 10 minutes. It ran quite well... no smoke, nothing. I let it cool off, put a few more things back together, and then drove it around for like almost an hour, and we took it through several sweeping backroads.

The front suspension is totally shot, and the doors don't have bump stops on them so they bang when you hit a bump, but other than that... the rest of the car is totally restored, and the engine sounded AMAZING... I mean, really, really amazing. It doesn't at all sound like a typical clattery Iron Duke.


Next weekend, we're going to hook up Paul Romsky's ALDL ECM reader and check the AFR to see how it's behaving. Per CarterCarb's recommendations, I haven't been driving it hard. Never more than 3k rpms at the absolute most... mostly shifting at 2,000 rpms. But there's lots of power, and I can absolutely tell a difference. I think it's running a little rich based on smell, but man, the car runs so well and everything is SUPER smooth...


get her broke in and then hammer it. the engine that head came off had no shortage of power and definitely spun up to 6500 a few times (stupid automatic.) but it should beat out a stock v6 manual pretty easy.