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Re: Effect on converter stall speed
[Re: gregsdart]
#3222095
03/22/24 11:49 AM
03/22/24 11:49 AM
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Joined: Apr 2009
Posts: 3,414
Toronto
mshred
OP
master
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OP
master
Joined: Apr 2009
Posts: 3,414
Toronto
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A 230@.050 cam is a lot of duration for a heavy car with a 8.5-1 360 and a
3.08 axle. Been there, you will not like it. Not a happy combo on the street
Doug i agree.it will really hurt torque. A cam like a Comp 268h would be ideal,,,,, Again, this is what a cam grinder spec'd for me when I gave all the details and intended usage... I really don't think it will be too bad, but I guess I will find out. I ran an 8.5:1 360 years ago with a 230 at .050" cam, 4 speed, 4.10's and 3400lbs and that setup ran 12.30's all day long I know the gear and weight are less than ideal right now, but this would be the 2nd 8.5cr build I have done where now 2 different cam grinders have recommended cams with similar duration, so I'll give them the benefit of the doubt and hope it works out.
Last edited by mshred; 03/22/24 11:51 AM.
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Re: Effect on converter stall speed
[Re: mshred]
#3222217
03/22/24 06:45 PM
03/22/24 06:45 PM
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Joined: Mar 2006
Posts: 9,827
MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,827
MI, usa
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Runing a low gear like the 3.08 doesnt allow the rpm to get high enough to couple. We ran Dizusters turbo car with a 2.76 gear. It ran 10.50's but the slip was as I recall was over 25%. Why? The car wasn't done accelerating. My street car ran a 5300 with a 3.55. Slipped like mad. Felt like it had a V V T trans. Same converter with a 4.30 it drives great on the street. Cam, converter, gear all have to be in sync to drive nice.
Doug So in this case, would the 2500 stall or the 4000 stall be ideal? Cam company said 2500+ stall for converter giving them all the combo details. Maybe the lower stall would work better as to couple sooner? Here's your issue, big cam, low compression, high rear axle ratio. Now tring to crutch all that which is a poor fit with a converter. High stall will help crutch the low end. But it'll slip at speed. Its possible that your engine guy is smarter than me. I ran a 8.5-1 360 with a .509 108 lca hyd Mopar cam (I know it's more than 230@.050). 3.55 4 speed. LD 340 , 650 Holley. It was horrible on the street. It was no quicker to 4000rpm than the dead stock 1973 340 it replaced, which was a stone pig. At the track the 360 did manage a 13.50. Swapped in a 220@.050 hyd roller and used .028 shim gaskets to get it to 8.9-1. Everything else was the exact same. It's run 12.70's and runs on 87 swill. Doug
Last edited by dvw; 03/22/24 06:46 PM.
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Re: Effect on converter stall speed
[Re: dvw]
#3222594
03/24/24 08:18 PM
03/24/24 08:18 PM
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Joined: Apr 2009
Posts: 3,414
Toronto
mshred
OP
master
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OP
master
Joined: Apr 2009
Posts: 3,414
Toronto
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Runing a low gear like the 3.08 doesnt allow the rpm to get high enough to couple. We ran Dizusters turbo car with a 2.76 gear. It ran 10.50's but the slip was as I recall was over 25%. Why? The car wasn't done accelerating. My street car ran a 5300 with a 3.55. Slipped like mad. Felt like it had a V V T trans. Same converter with a 4.30 it drives great on the street. Cam, converter, gear all have to be in sync to drive nice.
Doug So in this case, would the 2500 stall or the 4000 stall be ideal? Cam company said 2500+ stall for converter giving them all the combo details. Maybe the lower stall would work better as to couple sooner? Here's your issue, big cam, low compression, high rear axle ratio. Now tring to crutch all that which is a poor fit with a converter. High stall will help crutch the low end. But it'll slip at speed. Its possible that your engine guy is smarter than me. I ran a 8.5-1 360 with a .509 108 lca hyd Mopar cam (I know it's more than 230@.050). 3.55 4 speed. LD 340 , 650 Holley. It was horrible on the street. It was no quicker to 4000rpm than the dead stock 1973 340 it replaced, which was a stone pig. At the track the 360 did manage a 13.50. Swapped in a 220@.050 hyd roller and used .028 shim gaskets to get it to 8.9-1. Everything else was the exact same. It's run 12.70's and runs on 87 swill. Doug Yes, definitely not ideal, I know. I want more rear end gear, but I currently drive a lot of highway with this combo, so at most I see myself with 3.55's out back. Im leaning towards the higher stall converter over the factory high stall, and cross my fingers it stalls in a good spot and doesn't slip excessively. This 360 has 65cc heads, the .028" head gaskets, and pistons down in the hole .110" so its right at 8.5:1 with the calculations I made, as much as I would have loved to have more.
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