liquidh8

I have read on this board over time about using TBI's and turbo's. Nobody seems to want to try it, for the lack of fueling. Well, my brother and I are using his 79 monte carlo as the test mule. He has a 90 350 chevy block, .060 over, 882 heads, HOTT cam, edlebrock intake, tbi adapter, BBC tbi, RBobs ebl classic. We are plumbing up 2 stock GN turbos. fabricating a hat. For now I have an aux injector plate w/2 injectors, and a boost referenced controller from a vortec SC blow thru kit. I would like to use the plate, and maybe have the EBL controll all for injectors, instead of the piggyback controller. RBob, any thoughts here? I'll use a stock GN 2 bar MAP. O, and I have to drill two relief holes on the bottom of the TBI right in line with the throttle shaft, and in the manifold in the same place. That will keep the shaft from leaking.

We have the front clip off this car to finish the paint and body. It is a new, (under 10k) engine, wih a 4 gear and 3 inch exhuast. It was converted to TBI last year.

We aren't trying to make 1000 hp or nothing, but 500 or so is doable, just need to keep it fueled.

I'll keep everyone posted as we get ready to dive into this, we are still collecting some tubing and all. Any questions are comments are welcome.

91chevz71

sounds like a hoot!!!!
pics asap

gonna run 90 lb inj's and VRFPR I assume?
Fuel pressure at idle?
sounds awesome!!!


why not run dual TBI's on a dual carb manifold??
that should give you plenty of fuel

va454ss

iTrader: (1)

If you're using the BBC injectors, you shouldn't need the auxilliary injectors.

liquidh8

Yes, 90 pph injectors, using the VAFPR, idle FP 14psi, WOT @26 PSI. I have been trying for a stiffer spring to get the FP up, I may just get a higher PSI pump. I had tossed around the dual TB idea, I had seen a rustang in a mag a bit ago that was twin blow-thru supercharged, with a charger going into each carb, it was wicked looking!

Here are some pics of the aux injector plate.



Look closely to see the holes where the throttle shaft would coincide. There are vaccum lines there to suck in any fuel that is pushed thru the shafts.


This is the aux fuel controller. It is boost referenced, and has 2 pots to control the duration and amount of fuel sprayed through the injectors.



Sorry for the crappy pic.

That's a start, when I get more pics I'll post em. This is gonna be slow. The piping is going to take some time.

91chevz71

awesome. nice fabrication

liquidh8

No fabrication of mine, thank though. I picked up the plate with the injectors from a Vortec TBI Supercharger kit. I figured I would use it and see how it works. If I dont need the fueling, i can take it off. I will start out with low boost levels to see how fast my injectors go static. They are close now with 26 PSI @ WOT. But if I cycle them into async, I can get some more out of them, and a higher FP.

My other though was to make a 4 bbl plate, and mount 4 big motron injectors in it, have the ebl control them, and use the BBC tbi with out the gm injectors. that is a 670 cfm, but with turbo I don't need a bigger TB. Just a thought there. I can make the plate at work.

RBob

iTrader: (1)

You will probably need some sort of aux fuel.

One thing about a blow through with TBI is that the injectors are subject to the boost. This means that the fuel pressure needs to rise at the same rate as the boost to maintain the same fuel delivery. There is no gain in delivery, it is the same.

As an example if the FP is set to 30 psi with engine off (no VRFPR), and the boost is 14 psi, the resulting FP needs to be 44 psi for the same fuel delivery.

A stock FPR will do this, as it is referenced within the TBI unit.

An external FP regulator can be either just boost referenced, such as a stock FPR. Or, it may be referenced to the manifold (VRFPR). Which will cause it to reduce FP under less then boost conditions. And increase FP under boost.

I would try it set up as a VRFPR and see how that works out. The BPC vs VAC table can be set up accordingly. And the BPC vs BOOST table set up with the same value through out the table. Which would be the same value as the 0 KPA VAC value of the BPC vs VAC table.

Note that a VRFPR can have some oddities. Such as when the throttle is slammed shut under boost. The FPR will see vacuum, while the injectors will see boost. A BOV will help tame this.

Aux fuel: this can be gasoline with the plate you have, or alcohol from a unit such as the AlkyControl.com. Now normally, this type of alky injection is for cooling the charge and increasing the octane. However, it is progressive, it uses a 3-bar MAP sensor (EBL only uses a 2-bar, so need a separate one!), but can also add a lot of fuel.

The EBL has a boost PW multiplier table by RPM & MAP (> 100 KPA), so fuel can be pulled and added. This can account for either a static or progressive aux fuel delivery. Just need to ease into the boost for tuning. That can be difficult, as so many seem to want to plant the foot at the first go around.

Then, the addiction, if you think tuning gets addictive, wait until you play with boost.

RBob.

liquidh8

Thank you RBob. I had planned on using the Gm VAFPR that is on there now and see how that works out, utilizing the EBL boost tables, i.e., PW multiplier table by RPM & MAP and the BPC vs BOOST tables. The Aux injector plate has a seperate controller for those injectors. The pod hanging off that plate is a boost referenced regulator, rises with boost. I may not use that at first, but if the GM regulator doesn't work, I believe that regulator gets hooked up after the fatory one, I forget actually. Worst comes to worse, I'll remove the factory regulator and use an external boost referenced.

Aux plate: I would like to stay with fuel. So I don't have to have a different tank to fill with alky. I would also know I have the additional fuel when needed. This will be a daily driver, so drivability is sorta important.

I was looking around at PnH injectors, I found some delphi and MSD ones that are 85 and 95 PPH. I could uses four of those with the 2 onboard injector drivers, as they are low ohm injectors. And mount them in a plate uunder the TB, not using the factory injectors. This is another option.

There are a few different ways to fuel this, if it works out, and I can get it work without a piggy back ECU (the one I have), I will be turbo charging my wagon too.

liquidh8

Nothing new here yet guys.

I picked up a stock Grand National turbo, need to get another. I converted my wagons a/c from the big A6 compressor to the smaller R4. That will give me more room for plumbing. I swaped out the steering box for a Z coded monte ss unit. When the weather breaks I would like to mount both my optima batteries in the rear, get a new nitrous 'noid, and another turbo. I figured I would use log type headers/manifolds. They are easy to fab up, take up little space, and it this power level they shouldn't hamper my performance.

Well, figured I'd keep you all posted.