Broke down and tried a new converter

[33 IMP]

The pre-broke best with the one above was 6.52/106
Best with its replacement was 6.32/ 108.5
No other changes.

 

[BSB67]

Back to the track yesterday. In short, it was all over the map. Weather/atmospheric conditions almost as good as last week. First run looked like last week - 11.30 @ 121.

Second run, I thought it bogged a little. Lost a tenth in the 60’ and ran an 11.45. I later learned, it was tire slip.

So thinking bog, I amp up the primary pump squiter cam and nozzle size. I put on a real good burn out. The car came out initially very hard, then the tires got loose, it got a little squirrelly, and the rpm got high enough that it shifted automatically into second (I race it in “D”). Had a 1.93 60’ and 11.8 et.

Not sure what I learned. Both tire spin events were in the right lane. Good run in the left. Maybe I’m just pushing harder on the converter. Maybe I’m overheating the tire. Maybe it liked the extra squirter. Maybe some combination of them all.

Here is a pic that Keystone has on their Facebook page.

 

[Gunner1]

I have a supposed 3000 stall 11 inch in mine. But if I lock it in 3rd and gas it at 2200 it only flashes to about 2700. In first it will light the tires even at less than full throttle. I’m betting a good 10 or 9.5 would improve performance but for me is it worth the cost.

 

[Curiousyellow71]

I have a supposed 3000 stall 11 inch in mine. But if I lock it in 3rd and gas it at 2200 it only flashes to about 2700. In first it will light the tires even at less than full throttle. I’m betting a good 10 or 9.5 would improve performance but for me is it worth the cost.

For performance it's certainly worth it. A good convertor will be more efficient out the big end too. Slipping less cruising around makes it more fun to drive and less heat are all good things. But, the next thing you will be doing is trying to get it to hook...that is more expensive then a convertor. If you are happy with it now, I would also leave it alone until the day you want more and have a plan. More convertor and engine in a street car doesn't always mean faster...sometimes it is just more tire smoke.

 

[RemCharger]

Back to the track yesterday. In short, it was all over the map. Weather/atmospheric conditions almost as good as last week. First run looked like last week - 11.30 @ 121.

Second run, I thought it bogged a little. Lost a tenth in the 60’ and ran an 11.45. I later learned, it was tire slip.

So thinking bog, I amp up the primary pump squiter cam and nozzle size. I put on a real good burn out. The car came out initially very hard, then the tires got loose, it got a little squirrelly, and the rpm got high enough that it shifted automatically into second (I race it in “D”). Had a 1.93 60’ and 11.8 et.

Not sure what I learned. Both tire spin events were in the right lane. Good run in the left. Maybe I’m just pushing harder on the converter. Maybe I’m overheating the tire. Maybe it liked the extra squirter. Maybe some combination of them all.

Here is a pic that Keystone has on their Facebook page.

View attachment 1755545

I hope it's just tire spin.. when you mentioned racing in D, that's a lot of torque/ weight that you're relying on the sprag to hold... not sure if I could bring myself to try it. Also at those times, I've found the rim slipping in the tire to be a thing. Although it would be minimal

 

[BSB67]

I hope it's just tire spin.. when you mentioned racing in D, that's a lot of torque/ weight that you're relying on the sprag to hold... not sure if I could bring myself to try it. Also at those times, I've found the rim slipping in the tire to be a thing. Although it would be minimal

Hmmm.

It has Rick Allison's 16 roller Bolt-in Ultimate Sprag. I shift 1st to 2nd in the water box and come out in 2nd. It does have a steel front drum.

What else do I need to know, and watch-out for?

 

[RemCharger]

Hmmm.

It has Rick Allison's 16 roller Bolt-in Ultimate Sprag. I shift 1st to 2nd in the water box and come out in 2nd. It does have a steel front drum.

What else do I need to know, and watch-out for?

Good deal on the A&A sprag. I don't know what the torque holding capabilities is on those. I've always believed in the low band apply. I've felt them spin in stock transmissions. My Dad used to make partial feet for people, so I'm a bit gunshy on drum explosion thing.
I think Doug has some good expertise on the sprag issues.
@dvw

 

[Curiousyellow71]

Back to the track yesterday. In short, it was all over the map. Weather/atmospheric conditions almost as good as last week. First run looked like last week - 11.30 @ 121.

Second run, I thought it bogged a little. Lost a tenth in the 60’ and ran an 11.45. I later learned, it was tire slip.

So thinking bog, I amp up the primary pump squiter cam and nozzle size. I put on a real good burn out. The car came out initially very hard, then the tires got loose, it got a little squirrelly, and the rpm got high enough that it shifted automatically into second (I race it in “D”). Had a 1.93 60’ and 11.8 et.

Not sure what I learned. Both tire spin events were in the right lane. Good run in the left. Maybe I’m just pushing harder on the converter. Maybe I’m overheating the tire. Maybe it liked the extra squirter. Maybe some combination of them all.

Here is a pic that Keystone has on their Facebook page.

View attachment 1755545

If your running a street tire, which I thought you had a 255 BFG?..I think your experiencing track prep differences between lanes and weekends. Their is a huge difference in traction from a race oriented around street cars and a track prepped for bracket racing.
Love the picture.. beautiful car !

 

[BSB67]

The tires are MT 255 ET Street-R.

 

[Curiousyellow71]

That makes more sense then BFG.Lol
Are you walking it out or laying the coals to it at the line?
Back in the day our transbrake 727 did not have low band apply or a good front drum, only a bolt in sprag. Now we have a cope billet front drum, still no low band apply. I think you will be fine.

30 years ago a friend was in the left lane when a mopar in the right lane exploded the front drum at the line. This Last year the man that had the transmission grenade passed away and my friend was asked to race that particular car. He actually was not sure if it was the same car that blew up..until he saw the shrapnel hole ripped through the dash pad!

 

[BSB67]

That make more sense then BFG.Lol
Are you walking it out or laying the coals to it at the line?

I’m hitting it pretty hard. No walking at all. I’ve tried different stage rpm’s, but in every case go full hammer when it’s go time.

 

[dvw]

What would happen if your running the car in D and the sprag wasn't holding? The rpm would ramp up imediately and the trans would shift into 2nd. As a side note: The "Super Sprags" are actually Ford C6 rollers and springs with a modified 727 in race thats had it's diameter reduced. The outer cam is a unique part. In my experiece I've never damaged a stock sprag. Even in my racecar (1.2x 60ft). But it has broken 2 super sprags. Both still functioned (no low band apply). In both cases it broke the sheet metal tabs. I believe the failures resulted from the tabs rubbing on the inner cam. We will see on the next inspection. I'm assuming the car in question is running M/T Drag radials. Stated with stock suspension with no metion of what type of shock. Doesn't surprise me that it's on the ragged edge of traction at this power level.
Doug

 

[Photon440]

What would happen if your running the car in D and the sprag wasn't holding? The rpm would ramp up imediately and the trans would shift into 2nd. As a side note: The "Super Sprags" are actually Ford C6 rollers and springs with a modified 727 in race thats had it's diameter reduced. The outer cam is a unique part. In my experiece I've never damaged a stock sprag. Even in my racecar (1.2x 60ft). But it has broken 2 super sprags. Both still functioned (no low band apply). In both cases it broke the sheet metal tabs. I believe the failures resulted from the tabs rubbing on the inner cam. We will see on the next inspection. I'm assuming the car in question is running M/T Drag radials. Stated with stock suspension with no metion of what type of shock. Doesn't surprise me that it's on the ragged edge of traction at this power level.
Doug

I had a sprag fail, and although the rpm did increase suddenly, it the transmission didn't shift into 2nd gear because the output shaft was still too slow and the governor wasn't telling the transmission to shift yet.

 

[Gunner1]

I have no low apply in mine. The builder didn’t tell me what he was doing. I trusted him to do me right. He was an old timer trans builder. Art Carr. He just passed this year.

 

[lewtot184]

I just noticed this post last night and didn't get a chance to read it all. Anyhow, Russ you're doing good! Glad for you. You've work hard on that car.

 

[BSB67]

I just noticed this post last night and didn't get a chance to read it all. Anyhow, Russ you're doing good! Glad for you. You've work hard on that car.

Thanks Lew.

It was taken awhile, but that's what happens when you take a 12 year break in the middle.

The new converter does everything that I wanted it to do, to my surprise. But the change is kinda hard on the old girl, and I'm not to sure I want to keep subjecting her to that. Season is over here, so I'll think on that over the winter.

 

[lewtot184]

Thanks Lew.

It was taken awhile, but that's what happens when you take a 12 year break in the middle.

The new converter does everything that I wanted it to do, to my surprise. But the change is kinda hard on the old girl, and I'm not to sure I want to keep subjecting her to that. Season is over here, so I'll think on that over the winter.

I'm surprised the converter made that much difference. I thought 11.70's/120 was pretty good for a big street car. 11.20's is a different ball game.

 

[496 polara]

Can you fit a 275/60R15 under there or are you maxed out?

 

[BSB67]

Yep, I think so.

 

[496 polara]

Yep, I think so.

May be worth a try when you need new tires.