Shift RPM and torque convertor selection?
#1
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Shift RPM and torque convertor selection?
Hey guys,
Just curious on what you guys think my shift points and stall should be. I'm going to be getting my 700R4 rebuilt with one of Dana's kits.
Dart SHP 427 SBC
AFR 220 Heads (65cc)
Hydraulic roller cam: Duration @ .050" Lift: 242/248. Lift: .576/.600. 112LSA. RPM range: 2800 to 6100
HSR Intake
The guy at comp cams said since it's going in a 427 the rpm range will be around 2500-6000. So I'm thinking a 9.5" 3000rpm stall and 6500rpm shift point? Any suggestions?
Just curious on what you guys think my shift points and stall should be. I'm going to be getting my 700R4 rebuilt with one of Dana's kits.
Dart SHP 427 SBC
AFR 220 Heads (65cc)
Hydraulic roller cam: Duration @ .050" Lift: 242/248. Lift: .576/.600. 112LSA. RPM range: 2800 to 6100
HSR Intake
The guy at comp cams said since it's going in a 427 the rpm range will be around 2500-6000. So I'm thinking a 9.5" 3000rpm stall and 6500rpm shift point? Any suggestions?
#2
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Re: Shift RPM and torque convertor selection?
More street or mix of strip? My buddy had that cam in a long stroke 408 motor with afr comp 195's and it was done by 6200 but i think the heads and dual plane carb intake restricted it.
I have similar duration, 246 in my 400 and its suppose to peak 6400 rpm. On yours i think 6200 may be a good spot, but have to experiment. May turn a tad higher.
With hsr and those heads its gonna make a broad torque curve so 3000 will be great on street. For more strip detail i'd go 3600, maybe 3800. Hsr should put torque peaks between 3800-4200 and be relatively flat all around.
I have similar duration, 246 in my 400 and its suppose to peak 6400 rpm. On yours i think 6200 may be a good spot, but have to experiment. May turn a tad higher.
With hsr and those heads its gonna make a broad torque curve so 3000 will be great on street. For more strip detail i'd go 3600, maybe 3800. Hsr should put torque peaks between 3800-4200 and be relatively flat all around.
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Engine: Vortec 4200 Inline 6 PT70 Turbo..
Transmission: 4L65E
Axle/Gears: 3.73
Re: Shift RPM and torque convertor selection?
With such a steep first gear in the 700R4, a tighter stall will be ok.. No less than 3000 but I would still shoot for 3500.
That cam in a 350 would do well with a 4000 stall and even most stock LS1 cars run best with a 4000 so keep that in mind and they are all washed up at 6000.
Your problem will be traction! Goodluck! That thing will need a serious ET Drag Radial or equivalent. A normal street tire will spin well into 3rd gear.
That cam in a 350 would do well with a 4000 stall and even most stock LS1 cars run best with a 4000 so keep that in mind and they are all washed up at 6000.
Your problem will be traction! Goodluck! That thing will need a serious ET Drag Radial or equivalent. A normal street tire will spin well into 3rd gear.
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Car: 89 Formula
Engine: 383 SBC/HSR
Transmission: 700R4
Axle/Gears: 3.73
Re: Shift RPM and torque convertor selection?
I'd definitely go with a 3500 stall....and with those heads, your shift points should be around 6200-6400. Your cam has more lift and my cam has 110 LSA.
He's right about the traction issues you're going to have. The low gears in the 700R4 are pretty mean off the line. Your tires won't stand a chance.
I just updated my sig with my best times at the track....notice my 60 ft. and the stall. It pulls the front wheels.......you'll love it!
He's right about the traction issues you're going to have. The low gears in the 700R4 are pretty mean off the line. Your tires won't stand a chance.
I just updated my sig with my best times at the track....notice my 60 ft. and the stall. It pulls the front wheels.......you'll love it!
Last edited by heat seeker; 02-21-2013 at 12:48 PM.
#5
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Re: Shift RPM and torque convertor selection?
Good et street bias ply should take everything that combo will make. My 383 on a 150 hit makes more power and torque than that 427 would all motor and 3600 stall/3.42/700r4 blasted first gear to a 1.41 60 ft and no slip. Very violent. Felt like blacking out
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Re: Shift RPM and torque convertor selection?
With such a steep first gear in the 700R4, a tighter stall will be ok.. No less than 3000 but I would still shoot for 3500.
That cam in a 350 would do well with a 4000 stall and even most stock LS1 cars run best with a 4000 so keep that in mind and they are all washed up at 6000.
Your problem will be traction! Goodluck! That thing will need a serious ET Drag Radial or equivalent. A normal street tire will spin well into 3rd gear.
That cam in a 350 would do well with a 4000 stall and even most stock LS1 cars run best with a 4000 so keep that in mind and they are all washed up at 6000.
Your problem will be traction! Goodluck! That thing will need a serious ET Drag Radial or equivalent. A normal street tire will spin well into 3rd gear.
#7
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Re: Shift RPM and torque convertor selection?
Thanks for the replies guys. It's going to be mostly street. I go to the track once or twice a year. Comp cam recommended a smaller cam. When I decided to go with that one. They were like "you're going to make more hp but lose some bottom end". I'm like that's fine. Tractions going to be tough. Lol.
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Re: Shift RPM and torque convertor selection?
For mostly street, do the smaller cam and a tighter converter. Over-camming as a fix for traction problems is a very poor compromise. If you need the extra 10 horses to be happy with the combo, then something's wrong. Driving a car that's annoying when it isn't frustrating gets old quick. For what this build is costing you, you could have had a mild-cammed smaller-cubed turbo combo with a third more power, double the MPG, and 5 times the street driveability.
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Re: Shift RPM and torque convertor selection?
The dyno doesn't show any such thing. Not like you need a 2500 stall with a 427 SB, but those 220 heads, well, the best 195s would give happier results. This might be a good build 20 years ago, for a car that gets cruised to the Sonic for a burger, and a trip to the dragstrip every Saturday. But this is no combo for weekent trips to the lake in the next state, which street builds must be good at to really be street. Likewise an hour of heavy traffic commuting. A street 427 with the best 195 heads and a 2000-stall is appealing, no doubt. As long as you don't want it to have the idle sound of a Nascar racer. Better to cam for a stealthy sleeper idle. But re-reading the post that started this thread, and assuming the OP isn't gonna switch builds at this point, I can't fix this to make it truly fun AND truly street. Good luck.
#11
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Re: Shift RPM and torque convertor selection?
I've done my research and I'm sure I'll be happy with the build. The car is a weekend toy. I have no desire to build a turbo car. I wanted a na big cubed engine. If I was concerned with mpg I would have built a smaller engine and ran boost through it. Or just left it stock.
Last edited by IROCThe5.7L; 02-22-2013 at 08:46 PM.
#12
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Re: Shift RPM and torque convertor selection?
The dyno doesn't show any such thing. Not like you need a 2500 stall with a 427 SB, but those 220 heads, well, the best 195s would give happier results. This might be a good build 20 years ago, for a car that gets cruised to the Sonic for a burger, and a trip to the dragstrip every Saturday. But this is no combo for weekent trips to the lake in the next state, which street builds must be good at to really be street. Likewise an hour of heavy traffic commuting. A street 427 with the best 195 heads and a 2000-stall is appealing, no doubt. As long as you don't want it to have the idle sound of a Nascar racer. Better to cam for a stealthy sleeper idle. But re-reading the post that started this thread, and assuming the OP isn't gonna switch builds at this point, I can't fix this to make it truly fun AND truly street. Good luck.
I went with a huge 245cc head and a much bigger cam. Everyone said i was crazy for doing it and that it wouldnt be streetable. I think it drives much better and alot stronger all over. These big inch motors love to breathe.
Its my opinion afr 220's are great size for this combo, the cam is in the right range and will make loads of fun power with a very broad trq curve. Everyone has their definition for streetable but this combo certainly is not a race setup.
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Car: 1989 GTA
Engine: SuperRam 350
Transmission: Pro Built S/S TH700R4
Axle/Gears: 3.27
Re: Shift RPM and torque convertor selection?
Ungodly low for your application. Pickup trucks run more aftermarket stall than that. Your basic LS1 person typically runs 3600 stall. And very few wish they went with less. With your 3.73 gears, you can get away with more stall without the hassle of more gas pedal. So why build a super motor like that and then go low stall?
2001 Sierra truck with a 3700 stall. These are more street friendly than we think they are.
2001 Sierra truck with a 3700 stall. These are more street friendly than we think they are.
#14
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Re: Shift RPM and torque convertor selection?
I think alot of people are afraid of higher stall speeds. I used to be one til I started driving converters and realized a good converter makes all the difference. I daily drive 3200 in my LS1 and its way to low for best track performance, but a good compromise for street use. However I drag that car dozen times a year just about and hard on it when on the street.
Converters take abit to get used to but really arent that bad, especially in areas with little to no hills. A lockup style trans makes it even nicer. I used to lock my 3600 stall speed converter at 20-25mph so when I go up steep hills it didnt stay open.
I understand the driveability concerns and the desire to keep rpms low, but you will find its not that bad. If you will be playing with the car on the street as I know everyone does who has a performance built car, then you will appreciate more stall. Its more fun.
3000-3600 is plenty for most street strip builds that sees mostly street use.
Like I said before, to me its silly to spend the cash for an aftermarket block, stroker crank for big cubes and expensive aluminum heads to only put in a baby cam and baby converter. Thats just not my style, but more over just seems a waste. Different stokes for different folks
Converters take abit to get used to but really arent that bad, especially in areas with little to no hills. A lockup style trans makes it even nicer. I used to lock my 3600 stall speed converter at 20-25mph so when I go up steep hills it didnt stay open.
I understand the driveability concerns and the desire to keep rpms low, but you will find its not that bad. If you will be playing with the car on the street as I know everyone does who has a performance built car, then you will appreciate more stall. Its more fun.
3000-3600 is plenty for most street strip builds that sees mostly street use.
Like I said before, to me its silly to spend the cash for an aftermarket block, stroker crank for big cubes and expensive aluminum heads to only put in a baby cam and baby converter. Thats just not my style, but more over just seems a waste. Different stokes for different folks
#15
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Re: Shift RPM and torque convertor selection?
I just started with a 3000 stall because after some reading it seemed quite common to get a stall 500rpm into the power-band. I am certainly open for other suggestions and appreciate everyone's input. I've heard about some sloppy convertors, but those seem to be cheaper ones. I got my eye on Vigilante torque converters. Like I said earlier, I built this car to be fast and fun. It's just a weekend warrior.
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