NO boost at power brake

[Brad Bartilson]

So after reporting that I finally got the beast (87TR)
to build boost at power brake after installing the
larger intercooler, I've lost it again and can't find
it. After two awesome runs I blew the tranny, had it
rebuilt, re-installed and now can't build boost at
power brake conditions again. Note I have a 3800
stall,
10" converter.

Troubleshooting to date:
-tried all MAF/translator settings new LS1 MAF
(leaner, richer, advanced/retarded timing)
-installed old MAF used when I had the two great runs
-varied TV cable settings
-inspected and retorqued the crossover
-extensive T/Link monitoring, shows code 45, but 02
results look ok, computer has no codes showing
-flowed all six injectors, looks good
-fuel pressure set at 30psi
-EGT on #1 shows 600F, while EGT on #2 shows 1000F:
this has been this way for a year, can't figure out
why


Here's the tranny test results with line pressure
taken at 2000rpm:
min max
Park 100 260
L1 230 230
L2 230 230
Drive 100 270
O/D 100 270

Ideas?

-Brad 87TR

 

[QuickWrench]

Note I have a 3800 stall, 10" converter.

When you power-brake the car, where does the converter ACTUALLY stall? It sounds like the converter may be suspect. When you had the trans rebuilt, did your builder cut open the converter and inspect it?

How does the car perform under normal driving conditions? Are you able to build boost successfully from a rolling start, or in 2-3?

 

[Brad Bartilson]

No, engine seems to struggle, stuck at 1500rpm during power brake. I am at mile high altitude, been told that my PT54 turbo would be hard to spool up at this altitude, and I responded to the advice of getting a high stall converter, high flow heads, big mouth intake (I even have a blower to assist the intake), low resistance exhaust exhaust and low A/R turbo housing.

I build great boost in 2nd and up, just can't get over the hill at power brake. Seems like its tranny related. But I'm on my 4th converter (TCI). They cut open my last two, found everything ok. What troubles me most is that I got two awesome runs then thats it. I'm wondering if my loss/deterioration of the tranny clutches simply allowed the thing to spool up for those two runs.

-Brad 87TR

 

[2 QK 4 U]

I had this same problem, my egt's were too low to spin the turbo wheel. ended up being a fuel problem combined with a non D5 convertor.

 

[Danster]

I'm no expert but I would think fuel pressure is a little low (30 psi)?


Dannyo

 

[Brad Bartilson]

New news. Tranny shop thinks that the fin angle is wrong on the converter they furnished (150 degrees positive, should have been -49 negative) Apparently, not all 2004r 3800 stall converters are the same, that the turbo car converter needs this negative fin angle. Any confirmation out there?

 

[Geoff87]

Originally posted by Brad Bartilson
......(I even have a blower to assist the intake)........
-Brad 87TR

Okay, I'm curious. What is this, and how does it work?

 

[2 QK 4 U]

Originally posted by Geoff87
Okay, I'm curious. What is this, and how does it work?

SAME HERE!

 

[Brad Bartilson]

I'm at mile high altitude, and we have trouble spooling up due to low air density. After a year of chasing this problem, I drove down to NE (about 3000' elev) and shazam! the car spools up. So I get to thinking, how I can I help this thing get more air (or mass of air). I hooked up my 110V leaf blower (teed it in with the air cleaner), while in the garage of course, and powerbraked it in the garage. It worked! I could now spoolup. Then I researched blowers I could get that were 12V powered and came up with one that works. I had to move the fuel vapor canister over, but it fits and works well. I have a switch in the bottom of my cigarette tray and a relay. Air flow goes from 6gm/s to 12 at idle. I'll have track results next season.