So have an interesting issue going on with my dragster. 498 BBC. Runs 4.98-5.02 Converter stalls at 6400. At launch flashes to 6500 falls back to 6400. Shift at 2.4 seconds (7400) rpm drops back to 6400 and only climbs to 6800 by finish line (1/8th mile) So car has 1000 rpm drop at the shift which is too much. Its keeping the car out of the power range in my opinion.

So at the track this weekend Gary and Troy from FTI were there. So I talked to them about whats going on. They agreed that's way too much of a drop in rpm. So they gave me a new converter that they said would be looser and shouldn't drop like mine currently does. Swapped the converter. Not only did it not get any looser it actually was tighter. 6200 stall and still drops 1000 rpm. And slowed car up .05. Pulled that converter out and they gave me another one that was built to go behind a small block. That converter stalled at 6000 and dropped to 5900 and still same drop to stall after shift. .05 slow. They were completely baffled that a small block converter actually got tighter behind my motor.

Pulled trans 3rd time. installed original converter. Swapped input shaft from single seal ring ring to dual ring. Car performed exactly the same way before I started swapping parts. The checked line pressure at the cooler. 75-80 PSI he said it was perfect.

What would cause a car to stall so low and drop so much at the shift no matter what converter I put in it?

This message has been edited. Last edited by: Stephensx04,

Call Marco Abruzzi and get a converter built for your combo that works

quote:

Originally posted by Big Steve:
Call Marco Abruzzi and get a converter built for your combo that works

That's what makes no sense. We put in a converter that normally goes behind a small block. Troy said it should be so loose it should allow the engine to RPM. He was afraid it was going to be too lose. But it didn't. It was actually tighter than the one I took out by 500 rpm.

MPH been dropping?
Sounds like you are losing HP.

quote:

Originally posted by Goob:
MPH been dropping?
Sounds like you are losing HP.

MPH is normal. 136mph Loses 1mph with the converter changes. Its the 1000rpm drop after the shift with all 3 converters that doesn't make sense. Putting in a what is suppose to be a loose converter and it does the exact opposite.

quote:

Originally posted by Stephensx04:

quote:

Originally posted by Big Steve:
Call Marco Abruzzi and get a converter built for your combo that works

That's what makes no sense. We put in a converter that normally goes behind a small block. Troy said it should be so loose it should allow the engine to RPM. He was afraid it was going to be too lose. But it didn't. It was actually tighter than the one I took out by 500 rpm.

Yea but regardless it was not built for your combo. The try this and try that approach never works. Just wastes time and money Since I switched to Marco, my converters have always been spot on first try.

If nothing else, send Marco your current converter and have it re stalled. Give him a call, you wont regret it

I’ve only used Marco 1x because he advertises here on DDR. Last year I was desperate and needed a converter asap. Called on Monday and sent him a dyno sheet and multiple engine rpm graphs on track with the DA numbers. Arrived Friday and he missed the desired flash stall by 25 rpm…. Very Impressive.

You might want to consider a rear gear change first to get closer to the desired rpm window in high gear if only racing 1/8 mile.

quote:

Originally posted by Big Steve:

quote:

Originally posted by Stephensx04:

quote:

Originally posted by Big Steve:
Call Marco Abruzzi and get a converter built for your combo that works

That's what makes no sense. We put in a converter that normally goes behind a small block. Troy said it should be so loose it should allow the engine to RPM. He was afraid it was going to be too lose. But it didn't. It was actually tighter than the one I took out by 500 rpm.

Yea but regardless it was not built for your combo. The try this and try that approach never works. Just wastes time and money Since I switched to Marco, my converters have always been spot on first try.

If nothing else, send Marco your current converter and have it re stalled. Give him a call, you wont regret it

X2
Marco is awesome and on top of that he is a class act, just a great guy. You will not be let down.

I have tried several converter companies and now I only use Hughes converters and here is why. I gave Kevin my Dyno sheet, he told me where he thought it would be best for stall which happened to be exactly where I thought it should.

Then he built my converter and it stalled EXACTLY where it was supposed to. I did not have to take it out and send it back 2 or 3 times he got it right first time dead on with a zero.

I think may companies may be able to build a decent converter but it only a few have the data to hit the stall just right and Hughes has done it every time for me and I have never had a failure from them.

With all that said if YOU do not know exactly where your peak torque and power is then no company can hit the stall exactly. If you are guessing on torque and horsepower then they are guessing to. You give a good company good data and you should get a good converter.

Another question for you here is what is your rear tire size and rear gear ratio?

quote:

Originally posted by Curly1:
I have tried several converter companies and now I only use Hughes converters and here is why. I gave Kevin my Dyno sheet, he told me where he thought it would be best for stall which happened to be exactly where I thought it should.

Then he built my converter and it stalled EXACTLY where it was supposed to. I did not have to take it out and send it back 2 or 3 times he got it right first time dead on with a zero.

I think may companies may be able to build a decent converter but it only a few have the data to hit the stall just right and Hughes has done it every time for me and I have never had a failure from them.

With all that said if YOU do not know exactly where your peak torque and power is then no company can hit the stall exactly. If you are guessing on torque and horsepower then they are guessing to. You give a good company good data and you should get a good converter.

Another question for you here is what is your rear tire size and rear gear ratio?

4:11 and Little bubbas

quote:

Originally posted by Stephensx04:

quote:

Originally posted by Curly1:
I have tried several converter companies and now I only use Hughes converters and here is why. I gave Kevin my Dyno sheet, he told me where he thought it would be best for stall which happened to be exactly where I thought it should.

Then he built my converter and it stalled EXACTLY where it was supposed to. I did not have to take it out and send it back 2 or 3 times he got it right first time dead on with a zero.

I think may companies may be able to build a decent converter but it only a few have the data to hit the stall just right and Hughes has done it every time for me and I have never had a failure from them.

With all that said if YOU do not know exactly where your peak torque and power is then no company can hit the stall exactly. If you are guessing on torque and horsepower then they are guessing to. You give a good company good data and you should get a good converter.

Another question for you here is what is your rear tire size and rear gear ratio?

4:11 and Little bubbas

So running a 5.0X and only turning 6800 RPM at finish line I would say you have too big of tire and need a 4.56 or even 4.88 rear gear.

I would call Hughes and talk to Kevin, he is a racer and knows what he is doing. I bet he would tell you same thing and get you right stall converter. Looks to me like you have changed converter three times and it still is not right.