Will we get similar results that TPI/TBI get, better driveability, better wot, etc... If so, how do we start?? Where do we get tables, etc.??


Thanks

 

You could... but that quadrajet doesnt really rely on the ECM for its operation like TPI does. You could make some modifications to the timing tables and you could play around with the fuel tables too but don't expect too much. I havent seen a carb binary yet. All I've got is TPI and TBI bins Try ftp.dyi-efi.org

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92 Z28 L98 350
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Ported stock heads, XR270HR-10 cam, TES headers, Crane AFPR, Flowmaster catback, MSD ignition components.
Best ET 13.5@105 mph
"Take that auto, drop it in first, hold the brakes, stomp the gas and grin from ear to ear! :-)
Click here to see my car at Truspeed.org

Check out TruSpeed at http://www.truspeed.org
Check out the Bin Archive at http://www.truspeed.org/bins.html

 

or you can setup a 7747 to control your spark and mess with that like the article on Diy-efi chronicles but by then ya might as well convert to tbi

 

there are chips for electronic carb cars,there must be something worth changing.

 

I'm with Pablo, if you want to control your mixture with more precision along with your spark, consider converting to TBI.

Frankly, if I were to stay with a carb, I'd dump the compu-carb. For the little it does, you might as well tune it the old fashion way. But ultimately, I believe a TBI conversion will give you better all round driveability, better gas mileage and with tweaking, perform as well as a carb @ WOT. Just requires a little time and testing.

 

I've never seen a two-barrel TBI perform as well as a 4-barrel carb.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

shoot, take a vacation down to miami, youll change your tune real quick, a holley on my motor has no low end whatsoever

 

I am going to concur with Pablo regarding the tbi. First, the tbi has been completely overlooked by many hot-rodders. I believe Pablo has done a lot of good work in dispelling with the myth that tbi cannot be made to perform. If hot-rodders put the same efforts into tbi as they do into other induction systems, I could see tbi becoming the induction system of choice for a lot more applications.

I feel the main reason people swap to carb for hot-rodding is simply economics. For a narrow application like drag racing, tuning a carb solely for WOT operation is fairly simple and relatively inexpensive. But it does not mean that a carb is the best. It just one of the cheapest and simplist. Give a hot-rodder to spend a little time tweaking a tbi, I can see no reason why the tbi cannot perform equally as well for WOT drag racing. In fact, I think it can exceed a carb as you can control a lot more functions.

But, if your vehicle is a daily driver, then there is no question that tbi is the way to go. It can perform over a much wider range of applications than a carb can.

Lastly, certain classes only allow carb, so of course you will only see carbs.

 

shoot lemme get some track times before you talk up my setup but thanks

 

Pablo, those track times would be great as substantive proof. But even without them, the simple fact of all the control you have over the injector pulse width and the spark tables alone, says that you can do things with a tbi that just is not possible with a carb.

If someone had free and unlimited access to a dyno and could tweak their tbi to optimize the HP, and then do a similar thing with a carb. I think you would find the tbi ultimately could produce just as much, if not more, HP than the carb.

AND THEN, ake both for a drive in a variety of highway/traffic situations, consider fuel economy and emission, and tell me which one is the winner.

 

Ok, now let me twist this back around to where it started, what about those of us that would like to keep the quadra-junk on our cars? I just want to, no reason in particular, other than that's what it came with and I want to keep it that way. I know that most of the carb tuning is still in the carb, but I want to modify the timing, lockup, etc.... when I drop the Monster in there.

TIA



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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

ASE Certified Master Tech

Starting to look like the Kicker poster child!

 

I have worked on cars with the stock electronic Q-jet. A few of them have been cars that looked completely original. One is a friends TA. It is getting a 420cid stroker build. It will have a Performer RPM intake with the Edelbrock name ground off and the whole thing sand blasted to make it look like the stock piece. The exhaust manifolds will be extrude honed. Every thing will look like a stock 305 HO including emisions equip. He will keep the stock Q jet, with many tuning tricks though.

You are right JP84Z430HP in saying that most of the fuel tuning is still in the carb. You can mechanically adjust the mixture controls at the carb. For WOT the Elec Q jet is tuned mechanically with the power valve and secondary jets/metering rods & their opening curve. All the old original tuning tricks for Q jets will work. One thing useful to Q jet tuners now is the easy availabillity of parts from Edelbrock for their line of Performer Q jets.
It would be benificial to get into the PROM for timing tuning though. Especialy for timing tuning for a more extreme combo.

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Tracy /AKA IROCKZ4me

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Just use the chip from the ZZZ crate engine retrofit, then get Doug Roe's book on the Q-Jet.
The write a check to the Car Shop for the idle jet and idle channel restrictor kit.
Then accumulate the different dancing needles main jets secondary rod and hangers, and optimise as necessary. You'll also have to rework the idle air bypasses, and optimize the secondary air valve opening, and depending on manifold secondary opening.
Figure 3 years of hard work to get an ultra carb.
But, you'll still have a fuel slosh problem for heavy braking a sustained high G cornering