Port injection or dual tbi???

[buddrow]

Here is TA's single 4bbl port injection setup.

http://taperformance.com/proddetail.asp?prod=TA%5F1206F

A bit pricey for my blood though at $3750.

[dave w]

If you have access to the dual quad intake? Then I'd use twin TBI throttle bodys with TBI adapters and have the machining done to add MPFI injectors and fuel rails.

Dual 4 barrel intake.

http://www.ebay.com/itm/BUICK-455-43...e5002d&vxp=mtr

dave w

[Six_Shooter]

This link?

http://lukeskaff.com/?page_id=380

That's a pretty nice write up. I've only followed along a few forum posts on TGO and c59.org.

Yes, the '7427 will run dual IACs. That is how my Grandfather's '71 pick up with a Cross Fire and 4L60E is set up and works just fine. I would suggest running dual IACs when running two independant throttle bodies to have idle air distribution as even across the cylinders as can be. Especially considering that many of the dual quad intakes do not have a common plenum. It's even been found on engines, like ones with a crossfire intake, that have a common plenum using only one IAC can cause some idle issues.

I mostly posted the frankenbody to show that dual or 4 bbl TBI can be done and be reliable. The Cutlass that uses the 4bbl TBI that is in the earlier pictures gets driven HARD for several thousand miles per year. In an average weekend we can easily rake up a couple hundred miles on our cars, add in the daily driver status that we like to get on our cars and how we like to drive to shows out of town, the miles add up. We build our cars to drive, not to sit in the local coffee shop parking lot. ;)

[buddrow]

Dual 4 barrel intake.

http://www.ebay.com/itm/BUICK-455-43...e5002d&vxp=mtr

dave w

I can buy a new 2x4 offy from TA perf bout the same price. But im always looking for a deal so keep your eyes out ;)

[dave w]

Dave, the bb Buicks like a LOT of air, like 850+cfm when built, that i dont believe the 454 throttle body would supply. I would think dual 350 tbi's on an adapter plate on the dual quad manifold would be sufficient. I have a hard time paying what they want for an aftermarket 4bbl throttle body. Ya im cheap although you could t tell if you look at the cost of building a bb Buick lol. Did i mention I am also thinking DIS? I appreciate and value your input. I have no problem exchanging cash for your time so just lemme know when you get something drawn up for me. ;)

I went looking around EFI Connections for some ideas. I find it interesting that the SBC 24x system has the 1x signal machined from the upper timing chain sprocket. The 24x signal trigger wheel is on mounted in front of crankshaft timing chain sprocket. With some tig welding, maybe the 455 Pontiac timing cover could be modified to hold the cam sensor and crank sensor. Maybe a Pontiac 455 aftermarket camshaft timing sprocket could be modified for the 1x trigger.

The 24x trigger could be a larger diameter, and mounted on the harmonic balancer.

dave w

[bonnieclyde100]

i wouldnt mind seeing a write up on how to make the frankenbody. i was hoping to do something like that instead of getting a dual four barrel intake and run 2 tbis

[buddrow]

I know i have some reading to do on the '7427 but can it run sequential injection or only batch/bank fire? Just for giggles if it will i could use a *gulp* Ford 3.8 style cam sensor. Basically its a distributor stub shaft with a shutter wheel and pickup on top. Since Im likely going DIS anyway and wont need the dist. ;)

[buddrow]

i wouldnt mind seeing a write up on how to make the frankenbody. i was hoping to do something like that instead of getting a dual four barrel intake and run 2 tbis

Indeed. Some construction photos, etc. ijs ;)

[buddrow]

I do have a dual quad setup for a sbc, but im thinking the truck needs a turbo not duals ;)

[Six_Shooter]

No, the '7427 will not run SFI. It only has two injector drivers, so it will only run in bank to bank. The MPFI changes may change that to batch, but either way, the same basic fueling is there.

There won't be any write up on the Frankenbody, it's not gard to figure out, just need to make the cuts in the right spot and the install the shafts in such a way that they turn together, custom link bar and fuel lines and you're there.

[JeepsAndGuns]

Question on dual TBI's and dual IAC's. When set up and running both IAC's from the same source, is there a chance they could get out of sync and one be open more than the other? I could see a possiable issue with that.

Also, what about the 4 barrel aftermarket holley TBI's? I have no clue what CFM they are though.

[EagleMark]

Six seems to have had good luck with dual. I've only worked on 2 setups with dual and both were issues, both had IAC screaming noise from one and nothing from the other. Not sure if wiring in series or parallel could be the issue? My concern was the PCM was only designed for one and if you have 2 it is to much load on the driver...

I think, if wired correctly (ask Six) and the driver holds up... cycling key on, then off a few times would get them both parked and operating the same.

With some careful syncing of both set's of throttle blades it controlled idle very well with about 20 IAC count at idle warmed up and driven, then parked and checked. Cold start and running gives much more. But these were both tuned for cams that were not extreme. In the end you could dis connect the one IAC and you needed scan data to tell if RPM was off when warm... I'm sure cold would show low ROM signs...

Finding an old holley four barrel TBI unit is usually a good deal! There's a lot for sale because the older ones had injector issues and never ran well. Well that and they are four huge injectors which is usually to much for other then monster HP engines, plenty of fuel for WOT but way to much for idle. Pull the injector pod and your set for MPFI throttle plates.

[dave w]

I know i have some reading to do on the '7427 but can it run sequential injection or only batch/bank fire? Just for giggles if it will i could use a *gulp* Ford 3.8 style cam sensor. Basically its a distributor stub shaft with a shutter wheel and pickup on top. Since Im likely going DIS anyway and wont need the dist. ;)

Sequential and DIS would be an option with the LS1 12200411 PCM; which uses a 24x crank sensor, 1x cam sensor, and LS1 per cylinder coils.

The LS1 computer would also operate the 4L80E.

dave w

[Six_Shooter]

Six seems to have had good luck with dual. I've only worked on 2 setups with dual and both were issues, both had IAC screaming noise from one and nothing from the other. Not sure if wiring in series or parallel could be the issue? My concern was the PCM was only designed for one and if you have 2 it is to much load on the driver...

I think, if wired correctly (ask Six) and the driver holds up... cycling key on, then off a few times would get them both parked and operating the same.

With some careful syncing of both set's of throttle blades it controlled idle very well with about 20 IAC count at idle warmed up and driven, then parked and checked. Cold start and running gives much more. But these were both tuned for cams that were not extreme. In the end you could dis connect the one IAC and you needed scan data to tell if RPM was off when warm... I'm sure cold would show low ROM signs...

They need to be in parallel. Wiring them in series will definitely get them out of sync. This has to do with inductive and charge properties of coils, too much theory to go into, but just suffice it to say parallel is the only way they will work correctly. I'm pretty sure I looked into it a while ago and compared specs of the original crossfire IAC drivers and those found in later ECM/PCMs and found then to have similar current capabilities. Either way, dual IACs on the '7427 have not been an issue.

One way to ensure that they stay in sync, or should, provided both are of equal operating condition, is to set park steps high enough that they will either both bottom out or open fully key off.

You really should not need to disconnect one of the IACs, even for diagnostics, unless you suspect that one of the IACs is an issue.

[bonnieclyde100]

i have one of those holley four barrels. how can i use that what do i need to do to or with it ?

Six seems to have had good luck with dual. I've only worked on 2 setups with dual and both were issues, both had IAC screaming noise from one and nothing from the other. Not sure if wiring in series or parallel could be the issue? My concern was the PCM was only designed for one and if you have 2 it is to much load on the driver...

I think, if wired correctly (ask Six) and the driver holds up... cycling key on, then off a few times would get them both parked and operating the same.

With some careful syncing of both set's of throttle blades it controlled idle very well with about 20 IAC count at idle warmed up and driven, then parked and checked. Cold start and running gives much more. But these were both tuned for cams that were not extreme. In the end you could dis connect the one IAC and you needed scan data to tell if RPM was off when warm... I'm sure cold would show low ROM signs...

Finding an old holley four barrel TBI unit is usually a good deal! There's a lot for sale because the older ones had injector issues and never ran well. Well that and they are four huge injectors which is usually to much for other then monster HP engines, plenty of fuel for WOT but way to much for idle. Pull the injector pod and your set for MPFI throttle plates.