Hi guys-

I have a tbi220 unit and a procharger on an L05. It's a higher mileage engine so I'm not expecting to get the full 12 lbs of boost that the kit claims. The problem is right now, I'm getting more like 6 psi. I think I've identified one boost leak. It appears that fuel is running out the side of my butterfly shaft on my tbi unit. I noticed that the spring on the drivers side is discolored and there is a pool of unburned, dirty gas on my intake manifold over the center 2 bolts (driver side). This means that air must be escaping there as well. I know it's not possible to lose 6 psi there, but i bet it could be responsible for 1 or 2. So has anyone faced this issue before? Does anyone know how to seal it up? I rebuilt the rest of my tbi with a kit before I put the procharger on, but I never took the butterflys off. If I'm going to do that, I'll do the ultimate tbi mods as well.

Thanks for any advice. I'll try and post a picture later...


PS.
Please don't hate me cause I have a tahoe. I have virtually the same engine as you tbi guys here. I have seen posts where people get lectured that this is a third gen site bla bla bla. The fact of the matter is that anyone running a TBI 220 unit and a procharger could face this issue, so it is third gen applicable.

 

You would either have to find some way to seal the throttle shafts, or pressurize them. The Carb Shop (www.customcarbs.com) does something like that. they drill some sort of passage to the shafts and pressurize them to keep them from leaking. I would imagine they could do the same thing for a TBI unit.

 

you think a simple o-ring would work? The last thing I need are my throttle shafts stuck open...

 

I'm not sure if o-ring would work or not. You'd probably have to machine a groove or something for the o-ring to sit in or it would blow out.

 

Thats a great idea!

Since I have access to a machine shop (or at least a lathe), it shouldn't be too hard...

 

Maybe this will help.....?

http://www.joby.se/corvette/mods//2001-0X01_tbi_mod/

Looks like you could do something like this with a drill and a lathe!

 

WHAT KINDOF POWER HAVE YOU NOTICED WITH THE CHARGER. I WAS THINKING ABOUT PUTTING ONE ON THE TBI TRUCK I GOT, BUT LOOKING AT DYNO NUMBERS, THERE ARE NOT TOO IMPRESSIVE FOR THE MONEY. BUT.. SINCE YOU HAVE ONE ON YOURSELF, WHAT DO YOU THINK ABOUT IT AND WHAT CAN YOU COMPARE IT TO???

 

I emailed jonas to ask him about his setup. THanks!!!

 

I'm not sure about the gains you would see. I have a tahoe, so increases in my ET's will not map to increases in ET's that a pickup would see.

Procharger claims the kit I have can make 12 lbs of boost and I have never seen more than 7. (I measure it after the throttle body however). If you were to measure it at the blower Im sure you would see about 2-3 psi more (intercooler loss). Also, i'm convinced that I am loosing pressure out my throttle shaft. I have also never really boosted all the way thru 2nd gear. (I still retain about 3 psi between shifts.)

I am nervous to really hammer on it without a WB 02. I have 130,000 miles, so I don't need to press my luck.

A word about the Fuel pressure regulator that ATI includes. Its for a TPI system. I found that if I adust the top end correctly, I end up with about 20PSI of pressure at idle. I went with an aeromotive bypass regulator to fix the problem. I still need to burn a chip to get the fuel right. I can tell that I have too much fuel in the mid rpm range.

 

well if anyone else has this problem-

Jonas sent me the vortech instructions. They want you to drill two holes thru the TBI unit untill just contacing the throttle shaft. The other end of the holes are exposed to engine vacuum such that pressure is equalized under boosted conditions and excess fuel will be sucked thru the holes into the engine. Now I'm really looking for a tbi to muck with!

Sean

 

 

Stuck,
My intake is dirty all the time from the throttle shaft leaking. My motor has 185k on it and the blower was installed at 60k. These tbi motors seem to last forever. Iam also looking for an extra throttle body to play with. I will add seals of some kind but I really dought that even .1 psi of boost leaks past the shaft even worn out.
These blowers put out massive amounts of air and there is just not the room for any quantity of air to leak past.
I am installing a boost gauge tomorrow to see what I get. I've had a fuel pressure gauge all along and I've been supprised to see the fuel pressure go up to 45 psi at full throttle. What is your max fuel pressure?
Thanks,
Steve

 

I have the aeromotive unit and I've never seen it above 20... I actually need a bigger spring so it will go from about 12-40 psi.

I doubt I'm running out of fuel... It absolutely screams to redline. Just dont see that much boost... ATI recommends 1.2 psi increase/lb of boost.. I get about 1.1 up to 21 psi...

 

I installed the boost gauge today and it only read 7 PSI at full throttle. I hooked it up to the throttle body so that is actually manifold boost. Mine too has a 12 PSI pully on it. I am thinking about drilling a hole in the bonnet to get a reading above the throttle body.
My fmu unit is set with the bleed wide open and it still seems to over fuel just a little. No smoke but a little hesitation just before shifting. Any thouughts?
Thanks,
Steve

 

I'm glad you're active on the boards now, especially since you and I have the same engine and procharger. I'd love to get a scan of that chip you've got... Do you have an autoprom or e-prom reader? I've asked for the chip that came with this kit and it's not availiable anymore... It would be great if I could get a copy of your bin...

As for the rich condition, that's why I dumped my ati regulator and went with the aeromotive unit. I kept the restrictor, but replaced the FMU with the aeromotive unit. Eventually, I want to get an injector tower off a newer 454. Those used higher fuel pressures, and used bigger injectors. This way, I can tune the fuel curves without an FMU all together. Unfortunately I need about 600 in equipment before I can do that. (Autoprom and WB 02 sensor...)


Sean

 

No I don't have a chip burner yet. The chip I have is a hypertech that does not have the typical ignition advance at full throttle.
I will pull it out to get the part number on it for you, if that would help.
454 injectors- the 94 up injectors that run at a higher pressure are actually smaller than the pre 94 injectors that run at lower pressure.
Steve

 

Thats fine. They're still bigger than the stock 5.7 injectors. Also, at 12 psi, the pressure difference w/o a FPR is only 1 psi. Hardly any fuel will flow. In order to eliminate the fuel pressure reg, I need a higher nominal fuel pressure. I've also been paying attention to the guys trying to get the 7749 to work with a TBI. That would be great!

 

Blah.. Get the '749 to work with a mpfi setup.

 

Actually I was thinking of that too. Just get a performer intake and drill and tig in some injector bungs. That would be great. However I still need to solve the problem of transmission control.

 

Problem of transmission control?

-- Joe

 

Yeah I can't just swap ecms... I have a computer controlled Transmission. (Not just TCC lock-up)

 

Ahh. Thats an easy one. You can run your existing ecm to control the tranny, and the '749 to control the car. Run a manual $58/$60 bin on the '749.

-- Joe

 

What should I do about emissions stuff? I can't just delete it...
Should I keep it just for show? NY is running more strick emissions test now, but I think I'm just safe since I'm 1995...

 

'95 should be dyno test, not obd-II.

Leave it all hooked up. You can run the '749 just for fueling/spark/fan control, and leave the old ECM for other things.

-- Joe