24 PSI 0 KR = 14.56@95 mph

[boostmaster]

I think I might be having A trans-torque converter problem, just need some confirmation or other suggestions. Went to the track last night and like I said I cold not break over 95 mph no matter what boost level I was at. I started out @ 20psi O2's in high 7-low 800's 0kr best I could do was 14.7 @ 90mph. My 60ft's suck to say least leaving @ 5psi never had one under 2.1. Each run I would gain about 19-20 mph from the 1/8 to 1/4 but nevre saw a 1/8 trap speed over 75mph. I have run 13.0xx's @ 104 with this same set-up and smaller turbo without alky. Now I have a stock block, Ta49, 204-214, 3" downpipe and alky injection and I'm supper slow. I bought a used 10" 2800 stall Protorque converter over the board lock effienceincy is great but I think it may be time for a freshen. Any suggestions. Ps, no slippage at all on shifts all are quick and firm.

 

[turbot2496]

Adding alcohol to the combo may be the problem. It might take some time to tune it correctly. Too much will kill you. You'll have no knock but you'll also have no power. Take the alcohol out of the equation, use race gas and see if you can run better. Also confirm the car is shifting at the correct rpm.

 

[boostmaster]

I tried taking the alky out off the equation, same result but had to run with lower boost. I played with the fuel pressure to varying degrees and got different results but my trap speed stayed low. By the way the volume of alchol I am spraying is minimal and I barely use 2oz per run just enough to cool the charge. Also I think I am short shifting on the 1-2 (about 3800-4000 rpm) but I didn't think it what make that much of a difference in my ET although I knew it would make some. I tried manually shifting from L2 smae result, would shift 1-2 3800-4000, 2-3 I could hold to 5200 RPM. I felt I should have gained more ground on the 2-3. Anymore help would be appreciated, Thanks in advance.

 

[Nojug]

I ran into a similar problem on my daily driver. It ran 12.80 108 on pump gas and street tires with the 204/214. I had the motor freshened and had the heads ported and put a fresh trans and a restalled D-5 now it runs 14.10@97 best and mine is very slow pulling to 5200.

 

[boostmaster]

Over 100 views and only one other person has had experience with this ?
Come on !!!

 

[soundguy]

have you done a scan looking at retard and other stats? It may be that the ECM is seeing something it doesnt like and is limiting the power output.

 

[tyrod]

The readings you are getting from your engine are dead on as you already know so I think your hunch is correct on suspecting something down the drivetrain. How is your daily driving? Does anything seem extra hot after a pass? Your TC seems to be the latest variable. That would make it suspect #1. If that checks out, backtrack to the last time the car performed right to the first time it did not and see what changes occurred between the two.

 

[rpk250]

Are you sure you don't have any cylinder leakage. leak-down test or compression test.

 

[boostmaster]

Leak down

NO!! At that boost level I would have oil all over the place and that is not the case. I have very little oil coming from the breathers.

 

[Jay Nesbitt]

Cat plugged?
Mine jumped from almost 10 mph when I gutted the cat.

jn

 

[Dominic]

I have had a similar problem with one of my customers GN's. It would go like a raped ape(11.50's@117@24#'s) with a bone stock,untouched motor and 3300 converter/pte front mount/pt54 turbo/houston downpipe/atr exhaust/walbro 340/hotwire kit/50's and a Joe L. chip.

On our next trip to the track we went 13.0 to 13.40 @ 102 to 105 without anything being changed. No matter what we did nothing changed our et or mph past what i noted above, even running 28# it still would not run. The next week we changed the valvesprings and still no improvement, so i decided to pull the trans and check the converter and it was WASTED! I sent it back and they promptly sent me a new one but that only fixed us good enough to go 12.60 @ 108.

The engine seems to idle rough so i put a vacuum gauge on it and sure enough it was erratic so i'm thinking it's a flat cam or bad valve seat. As i was poking around the engine i noticed tranny fluid on the drivers side inner fender where the charcoal canister usually sits, only it wasn't tranny fluid it was a puddle of K&N filter oil! dripping off of the filter! My customer then admits to cleaning the filter and bathing it in oil! He put so much oil on it the turbo sucked it all past the MAF and it got all over the hot wire and circuit board.

I changed the maf and it seems to idle a little better but the et only came around to a 12.40 @ 110 vacuum is still low so i will go ahead as planned with cam change and valve job/surface/timing chain/front cover/oil pump. ect....

 

[XLR8]

A friend of mine lost almost 2 seconds in et from one trup to the track to the next. It turned otu that his MAF was bad. Put in a new MAF and found his 2 seconds.

 

[Brer Rabbit]

spend the money on a torque convertor

Dont go cheap on this item, spend the money and u will be glad u did. I recommend Art Carr, or Precision convertor. I did a lot of brain picking before buying one and all the guys with fast cars said the same thing. Well Prasad never went fast but he said the same as the other guys . Thats only gonna work if the trans is in good shape. Good luck.

 

[daviss]

I'm fighting the exact same problem right now. Car went 12.80's@almost 110 till the trans let go. After a rebuild and a rehab restall D5 I ran 14's@102 with no other changes except the RJC boost controller. The car just won't leave right. Seems like it just rolls out to the 330 then starts to dig. I'm leaning towards the converter. O2's and KR are fine and the motor feels strong. Drives like a dream on the street but dies at the track. Good luck tracking down the problem. I'll be following along for more insight.

 

[WIKEDV6]

Well Prasad never went fast but he said the same as the other guys ..

.

Man, while a brother is down and out why you got to kick him in the a$$?

On a serious note check all your sensors too, I had a buddy that was running 13.60's all day long then he changed coil, module, crank, cam, O2,mass and TPS sensors. The car went 12.60's without doing anything else. Some times nearly 20 year old sensors get weak even though they may work ok.

How good are your valve springs? Is there oil build up in the intake from, turbo/bad PCV?

If everything checks out ok then I will go back to the last thing you changed which I assume is the converter being your culprit.

HTH
Prasad

 

[boostmaster]

Comp CC980 valve springs, new accel coil, new module, new air flow sensor,have tried several tps sensors same result, runs smooth, revs good. I'm thinking converter since the unit I bought was used. I bought from somebody who bought from somebody else supposidly with less than 2k on it . You never know what your gonna get. Any it's an Pro Torque 10" 2800-3000 stall unit. I think I'm gonna send it in to get checked.