73 Duster build named Fred

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-Boosted- said:
No. The car is still leaving soft. I’m beginning to think I have an issue with the converter.
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my next question was about the converter, 8”? 9”? what’s it doing when you floor it? Not reacting hard enough, lazy, feel like not enough stall, etc?
 
There's a tenth or so still available at a 104 eighth. Wallace says 6.54 at 104, 10.30s at 127 for the quarter. When my car was running 6.50s at 104/105, a new converter got me in the 6.30s at 108.
 
Well the good thing is now that Bill knows more about his car he can get the converter dialed in exactly for his car, peak torque, peak power, weight all things he didn't know when he bought it unless he has visions
 
71Demon528 said:
my next question was about the converter, 8”? 9”? what’s it doing when you floor it? Not reacting hard enough, lazy, feel like not enough stall, etc?
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8” 5800 PTC.

It flashes at 5750 but doesn’t hit hard like you would expect it to. Kinda feels like a slipping clutch off the line. Once it gets going, it pulls hard as you can see in the weak 60’ and decent mph
 
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-Boosted- said:
8” 5800 PTC.

It flashes at 5750 but doesn’t hit hard like you would expect it to. Kinda feels like a slipping clutch off the line. Once it gets going, it pulls hard as you can see in the weak 60’ and decent mph
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Yes for sure after the 60’ it’s moving and the MPH is good. Any in car videos from this weekend? Does your trans have a stock 2.45 first gear or 2.74?

having the converter re-stalled could help the 60’ after you verify where the cam is degreed in at. I don’t suspect the converter has a broken sprag because in that case the car would be very slow, MPH way down, and very inconsistent. If you suspect converter is the issue, I’d be calling your preferred manufacturer with all your Combo specs after you verify cam degree, and see what they recommend for stall speed, as well as what else they would look to be the issue. Carburetor and converter are two most important parts of these bracket cars in my opinion. I’m happy you had a good weekend and learned a lot about your combo and it went fast. Gotta feel good.
 
What were all the changed since the last time out?

Heads ported
Fiberglass hood with scoop and deck lid? How much weight savings was that?
 
moparstud440 said:
What were all the changed since the last time out?

Heads ported
Fiberglass hood with scoop and deck lid? How much weight savings was that?
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Heads and intake ported, compression ratio up from 11.88 to 12.25, lighter glass hood with scoop, glass trunk lid and bumpers. I took 200 lbs off the car.

Ran a best of 6.85 @ 98.77 mph in Vegas before the changes back in January to a 6.63 @ 104.62 mph after the changes here at home this past weekend.
 
-Boosted- said:
Heads and intake ported, compression ratio up from 11.88 to 12.25, lighter glass hood with scoop, glass trunk lid and bumpers. I took 200 lbs off the car.

Ran a best of 6.85 @ 98.77 mph in Vegas before the changes back in January to a 6.63 @ 104.62 mph after the changes here at home this past weekend.
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How does the air compared from Vegas to your home track?

The 200lb lost was prob worth .14 of your pickup as my cars seems 100 lbs make a .07 difference in the 1/8th.
 
-Boosted- said:
8” 5800 PTC.

It flashes at 5750 but doesn’t hit hard like you would expect it to. Kinda feels like a slipping clutch off the line. Once it gets going, it pulls hard as you can see in the weak 60’ and decent mph
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Try using the calculator and see what you slippage is, that will tell you something, if its at 15 you got a problem.
 
Ok, here is proof that I am not going crazy.... lol

From the first pass ever on the car (in Vegas), I have felt that it was not leaving as hard as it should and it wasn't the tuning on the Caltracs that was holding it back.

I spec'd out and ordered the converter directly from PTC. They said it would be a 5800+ stall converter in my car with my combo. Several people have expressed that with my combo, that should be the minimum amount of stall for what I am trying to do. As the video shows (and I have 8 total in car videos that all show the same thing), this is not the case in my car.

In this video, you can clearly see the converter is flashing between 5000-5200 and not 5800+. I have also been slowly raising my launch RPM to try and get the car to go quicker (which it has) but regardless of launch RPM, it has never left hard. I have made a grand total of 20 passes on the car starting with a 2000 launch RPM and now up to 3800. ET and mph has improved slightly but nothing else....still leaves like a Yugo. lol. You will also notice the RPM drop 1000-1200 on the 1-2 shift which is way too much. I'd like to see 400-600.

I've also done a bunch of tuning on the Caltracs, all of which has done absolutely nothing with how the car leaves. I even went to the upper hole to get the tires to hit harder which it does.... to the point I had to go up on tire pressure to keep them from rolling over.

I am making the decision to cancel a few upcoming races and instead, I am pulling the trans and converter out, sending the converter to be re-flashed and having the trans gone through just in case. I figure might as well since it is out of the car anyways.

For those that don't know much about me, I have been drag racing for many years and know a thing or two about all this stuff with 25+ years of experience building and racing Chevys, Oldmobiles and late model Mopars. I am however new to older Mopars and I am learning a bunch from all of you here which I appreciate.

***This video is from Bremerton Raceways this past weekend***

 
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Here's a video from Vegas in January....the first time out with the car. You can see I was leaving at 2000 rpm's there. Same issue with converter flash and shift drop.

 
I get what you are asking about the stall speed. I would like to mention, my car/engine is similar to yours and I 60' 1.42. My converter flashes around 5k as well. It has not changed with 2 different converter's, a turbo action that I got from and one I had redone by PTC that was a turbo action that I had broken. I am foot braking, no 2 step or t-brake. 3k launch.

Edit to add: You have more motor than what I have and I feel that you should be 1.40 or better. Also my 60' didn't change when switching from super stock springs to the Calvert set-up.
 
Going from a 8 inch 5760 converter to a 9 inch 5200 stall slowed my duster approximately.25 in the 1/8 with a powerglide. My son picked up .40-.60 in the 1/4 going from a 4600 stall to a 5600 stall. These engines love high stall converters.
 
73smallblock said:
I get what you are asking about the stall speed. I would like to mention, my car/engine is similar to yours and I 60' 1.42. My converter flashes around 5k as well. It has not changed with 2 different converter's, a turbo action that I got from and one I had redone by PTC that was a turbo action that I had broken. I am foot braking, no 2 step or t-brake. 3k launch.

Edit to add: You have more motor than what I have and I feel that you should be 1.40 or better. Also my 60' didn't change when switching from super stock springs to the Calvert set-up.
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Yeah, the best 60' was a 1.49 which is horrible for what I have in my opinion. I just don't think the converter is flashing where it needs to be for where my engine makes power. I footbrake and have tried with and without 2-step. No difference on how the car leaves. Just way more consistent on the 2-step.
 
when you had it on the chassis dyno, where was the peak torque? 5800 should be lots as i doubt it made peak torque higher then 5800
 
pittsburghracer said:
Going from a 8 inch 5760 converter to a 9 inch 5200 stall slowed my duster approximately.25 in the 1/8 with a powerglide. My son picked up .40-.60 in the 1/4 going from a 4600 stall to a 5600 stall. These engines love high stall converters.
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Was the 5600 stall the one I got from you when I bought the trans/converter from you?
 
I would assume a larger port in the cylinder head and more volume in the intake manifold that peak tq rpm would have raised not not lowered by 20 rpm & your compression is up .5
This is interesting
 
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