Josh91Bird

I have a small fuel delivery question for the TBI faithful. I currently have the great LO3. I have a 412ci/sb waiting to be transplanted. This motor has Sportsman II heads and a 224/234 cam with about 10.2:1 comp.
Right now I have a Q-jet I plan on placing on the setup. But I am leaving the TBI door open. I have talked to snuf about his TB and I am considering using a 454 unit in the meantime. I am not going to spend 300 on Holley's 670. What are some ideas advice you can offer up? Does anyone have a TBI setup with same or close power levels?

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• 412ci/sb

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Pablo

iTrader: (1)

get a pump capable of high fuel pressure, an external regulator with a 0-30 gauge, your own chip burning equipment.

Thats gonna need alot of fuel pressure with a decent size injector. Just work out the BPW and tune it from there. According to those in the know, the GMECMS work much better with alot more injector than is needed. I guess the programming is more comfortable with lower duty cycles. Theres no real magic to it other than keeping the idle IAC steps to a minimum, raising the injector pod a little. Typically the tbi motors have a much broader torque curve than the same motor with a carb

Pablo

iTrader: (1)

btw even if you bought holleys TB youd want to mod it to accept the GM injector pod (i did it to mine) the holley injectors SUCK

FastBroker

Josh, I would think that a 412 could make 400hp with an RPM manifold and the OEM 454 2" TBI unit with 80pph injectors cranked up to 17psi and some SEVERE PROM work. NOt sure about the cam, though. 224/234 sounds like a generic SIS cam??? I would get an XE Comp Cam that has 12deg Lobe Sep. This will help a LOT. OR use Comp Roller cam with 112 lobe sep, but not sure if you want to change cams. Make sure you have matched springs, too, and the heads are in GOOD SHAPE. I'd carb-it first to see that the HP goal is attainable, then try to make the BI fit the combo.

Should be fun!!! I'm over 300hp/400lb-ft with a 9.0CR 350cid, 1-11/16" TBI, 55pph injectors and an XE250 Comp Cam, Air Gap manifold, tru duals. Well, on the dyno, anyhow. Prolly not in the car... And I "cheated" by running the engine on the dyno with a carb/HEI first to get the ignition curve nailed down in the high rpms, burned a chip, and went from there, adjusting FP when the engine was running. sweet...

Josh91Bird

Fast, The cam is Summit K1105. I do have an Performer RPM manifold. Heads are new with a comp cams 305K kit, it came with a 305/305 dur. cam so everything is built.

Did you program your own chips? I was thinking that instead of buying the equipment I would see if Howell-EFI could do the guesswork? Anyone have experience with them and thier guesswork?

Pablo, what all did it take to get the GM injector pods to work on the Holley? Is the Holley a better alternative than the 454 unit?
Keep in mind cost is an issue just like all things...

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• 412ci/sb

My Homepage

[This message has been edited by Josh91Bird (edited April 03, 2001).]

FastBroker

You gotta burn your own chips. OR send a Diacom (or such) data stream "movie" to the guys so they know where/how to make changes... Especially with a setup like yours. I have people take care of the burning/erasing for me... I do the rest with SnapOn tool. Wish I had Diacom, though!!!!!!!!

I agree that Holley TBI with BBC GM injectors is the way to go. Looks better and works great...

That's a big cam, man!!! GOOD LUCK with it.

Brent

iTrader: (1)

I agree with this statement. You will need a stronger fuelpump. The stocker won't do 400hp. Might as well get the Walbro 255 for $90 from APE or something similar. Then you have the option to go to MPFI if you ever desire, using the same pump.

The ODB

either way you try to go with EFI it will cost you some money. why not pick up a used carb for cheap and lose some headaches?

Tas

I'd do a single plane EFI intake for sure. you can use a lot of TPI pieces to keep cost down along with a 670 TB on top without injectors.. check my EFI page. The Holley single plane is only $255 vs. $900 for a mini-Ram

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-Tas
'89 Formula WS-6
[soon to have Hooker 1-5/8" 50 state legal headers installed]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz

FastBroker

I agree with Tas... Weiand/Holley has dedicated MPFI intakes for standard and Vortec paterns. Posted the info off of one of my build spreadsheets below. Need to buy the rail/regulator kit and possibly injectors BUNGS as well, for about $75...


$77.39 534-85 Weiand MPFI Intake manifold fuel injector BUNG-KIT
$188.39 9900-172 Weiand fuel injector rail kit, complete w/regulator and all fittings
$255.39 9901-101-1 Weiand MPFI Intake manifold, bare, for "standard" intake manifold bolt patterns (Vortec manifold is same price)


hope the paste is legible. Get the HUGE 600 page Holley catalog. Has EVERYTHING in it, man. EVERYTHING!!!

[This message has been edited by FastBroker (edited April 04, 2001).]

Tas

I don't think they make that vortec one anymore.

FastBroker

They don't make the "single-hole towered" Vortec one (discontinued the single/large TB unit that went on top, pretty cool) but they still make the "carb tower" version for their 4bbl TB (non-injector, airflow only) units...