Will a bad converter slow you down ?

[boostmaster]

The reason I ask this is because I'm having trouble finding a performance loss at the track. I posted in the general tech forum but didn't get any good responses. Went to the track and at best all I could do is 14.5's @ 93-95 mph w/2.2-2.3 60ft.s on drag radials. All this @ 24psi with 0KR. I'm thinking probably converter because the engine is tight, turbo is good, the car just isn't moving. I can hold up to 8 psi off the line leave with wheel spin and it's all done hill from there. All I see is the other cars going, going, gone. Lock up effiecency is great, when I lock it I see 4-600rpm drops but it still doesn't help my sluggish performance much. I bought the converter over the board used (10" Pro Torque 2800) and I'm just wondering if I got a worn out converter. Thanks, any real help will be appreciated.

 

[boostmaster]

Really need some help with this one, don't wanna pull the trans and buy a new converter if I don't have to.

 

[TurboDave]

I doubt you're looking at a converter issue. You've got neither mph or et and your 60' times suck real bad for drag radials.

This all sounds more like a tune issue more than anything else, unless the the car is leaving supper soft because the converter stall is way lower than you think, but you'd have to take a look at some Direct Scan logs to see what's happening during launch.
Sounds like it's launching real soft which could indicate either a fuel problem, or bad converter. But it also isn't picking up any mph even though you're locking the converter. So I'd say a tune issue.

But then again you mention wheel spin on launch. Not good. too much boost at the line.

 

[boostmaster]

Haven't done anything with this yet. I was hoping to get a more specific answer on bad torque converter symptoms.

 

[NC87GN]

Bmaster,
Yes it definately can be a convertor problem. We had a 6.50 (1/8 mile track) GN that had a 9.5" vigilante convertor that lost almost 15 mph. Tune was dead on 02's 750mV. Sent the convertor back and 3 days later precision industries sent us a brand new convertor under warranty. At 24 psi your mph should be WAY higher. Even with a tune way off your mph should be over hundred.. Split the convertor and check it out. just my .02..

Mike Banas
87GN

 

[pacecarta]

i have the 10.5 protorque 2800-3200 in my 87 , was installed at start of the season on a fresh rebuild hipro.
unlocked and generally loose 4-5mph and a couple tenths but were talking still in the low 12s ,im just starting to get some higher mph out of it but have seen others have lower et after putting in the protorque only to switch back and run faster due to better short times

when lockd up at line i get drop of of 1400 (same for 1 - 2 and 2-3), unlocked i see about 1000rpm drop.

my car traps really high rpm for my mph and has been that way since day one and it has to be the converter , locked its 5200@107,5400@111 in 3rd , if i dont lock it it will turn closer to 5500 at the traps but at a lower 108mph , at 100mph its only about 200rpm difference between locked and not .
the only way youll know is swap it out