Converter or other problem?

[GrndNatnl]

Had the Buick at the track this past Friday for the first time with the TE-44, etc. Decided to get an idea of how its running.

I know my converter is tight, but I would think it could still break the wheels lose at some point, even after I've beefed up the rear brakes to hold boost (which I couldnt for the longest time).

While just holding the car with the foot brake firmly on the line, I can have the throttle to the floor, and it would only build ~ 4 psi boost, and that was it. I let it go, it would 60' horribly (not traction, just no power), then finally pick up and go by about the 60' mark or shortly after. Once it took off, it took off like a mother. I was getting 2.2 60' fts, and 13.1 ET's at 110 mph.

It seems overly rich while brake boosting, but whats with the gas on the floor and no more then 4 psi boost?? I dont remember exactly, I should have had my T-Link with me or at least written it down, but I'd say it would max out at 1900 RPM. It's a "factory replacment" D5, which is more then likely tight as hell. It was even slow to spool with the stock turbo. But I went the time in my sig with the stock turbo and a race chip. This friday, It was on my TT street chip. Not bad MPH for a street chip.

 

[MaxVO2]

Sounds like a mismatched convertor, or grossly rich low end. The 4psi sounds way low given your foot is on the floor and you have a TE-44. If you are only getting 1900 rpm stall, you are about 500 rpm too low from a stock D5 given the combo in your sig - that can make a huge difference, and is the reason our cars came with the convertor they came with. When my car was stock, it brake stalled to about 2400 rpm or so. It got a bit higher as I added more go fast goodies, and then I just upgraded the convertor to something better when I got a much bigger turbo.. Anyway, your MPH is about enough for 11's if you can 60 ft better so the power is definitely there.

Scan tool data would help a lot., especially what is happening just prior to launch. TPS, O2 volts, MAF, RPM. An EGT gauge can also give you an idea of whether you are very rich down low just before and immediately after launch. A chip can be burned with a leaner low end to raise EGT's down low so the turbo spools a bit quicker, but with your combo, and the stock D5 our cars came with, it should just GO.

Good luck

Billy
Montgomery Village, MD

 

[rb68rr]

Did you replace the convertor yourself or did a shop do it? The reason I ask is because I had a transmission shop replace my stock D-5 with another one and it wouldn't spin the tires for anything. Found out later that they put in a D-7!! R.B.

 

[Slow91z]

I don't know how long before he answers so I'll answer for him so the opinions keep coming...He bought the car with that trany and converter in it.

Matt just put ScoJack's converter in it and get on with it...It''ll scream after that.

You really need to work on the hole computer resetting when you start it thing too, so you can pull some fuel out down low yourself.

Just for clarification he has an adjustable TT chip.

 

[GrndNatnl]

I dont have the ECM resetting problem anymore. It was somehow related to the fried wires to the starter that I repaired a couple weeks before I went to Florida. Problem solved.

I cant adjust "down low" fueling in the chip. You can only add or subtract timing in 1/2 and 3/4 gears, and adjust WOT fuel + or - 10%, but its the total curve, not just certain RPM or load. Eric already adjusted that a little for me with my last revision for the TE-44.

What I was going to do at the track, however, was back the FP down to maybe cut back some of the richness on the line, but turn the WOT chip fueling up to keep it from leaning out top end. I already have the WOT fueling in the chip up 5% of the adjustability, because I was having KR issues on pure pump gas. I could probably have either turned it back down since I was on good gas, or I could have turned the FP down a little.

None of this came to me until after my last pass of the night, in which it was only 20 minutes until lanes closed, and there was still a line. I didnt get to the track until late in the first place; around 7:45.

I wonder if having the chip fueling up would still create a rich condition while brake boosting? Seeing as that I had it at WOT on the line basically.

 

[Eric Stage I]

The WOT fuel adjustment is not applied until above about 12-13psi.

Also, every TT chip is programmed to remove about 10% fuel from the main fuel curve when powerbraking.

Sounds like the converter stall is too low if it's only getting to 1900rpm. I've seen that a lot with replacement converters.

Eric

 

[wickedtt]

change that converter!!!!!also make sure the puck on the elbow is sealing the wastegate hole tightly

 

[frankg]

Get a converter nothing tighter than 3000-3200 and it will fly!!! Frank

 

[GrndNatnl]

Eric: I thought someone mentioned that to me before, about the chip actually leaning on fuel while powerbraking, but I didnt really think about it. Thanks for that fact.

And damn, Eric... 110 mph on the street chip so far, with a lousy converter & 60' ft, and only 23 psi... What do you put in these chips? LoL. Cant wait to get this thing sorted out.

And... It drove all the way to FLA and back, averaging about 23 mpg without even fooling with the fuel pressure or anything. I dont think I'll ever have any chips in my ECM unless they're marked "TT".

 

[Slow91z]

Sweet, glad you got that taken care of...I didn't know you couldn't take out Low RPM fueling, I've never had a TT chip it's a feature my Maxeffort has so I just assumed.

Converter for sure though, 1900 is a joke.

 

[trbojo]

ERIC??? the leaning of the fuel while p.braking: does this rely on a brake switch input? if so, i will definitely need a reburn, as i have added a trans brake with the recent overhaul.

 

[Eric Stage I]

Nope it doesn't rely on brake input, it will work fine.

Eric