Cams and converter choices

[49-blues]

What's the relativity between which cam you run-as in shift point rpms and the converter stall that works best? I know Dusty has said when using a stock cam that it's better to not go over a 2800 stall because of the overlap of the stall and the shift points of the cam or the rpm range of the cam. Are there any charts or guidelines you should follow when upgrading a converter as to which one will work best with what cam you have? Like if I choose a 212/212 cam and it revs to 5800 what stall converter works best?

 

[Dusty Bradford]

What's the relativity between which cam you run-as in shift point rpms and the converter stall that works best? I know Dusty has said when using a stock cam that it's better to not go over a 2800 stall because of the overlap of the stall and the shift points of the cam or the rpm range of the cam. Are there any charts or guidelines you should follow when upgrading a converter as to which one will work best with what cam you have? Like if I choose a 212/212 cam and it revs to 5800 what stall converter works best?

With a 212/212 shifting at 5800 I'd run a 2800 stall with a 61 or 62mm turbo. This will give you good spool-up with good top end pull as well. It will work very well together.

The problem comes when guys over-turbo an engine and that engines rpm range. For example a 67mm on a stock cam motor. It really needs a 3000-3200 stall but will have to shift at 5000-5200. The converter can't couple with a stall rpm that close to the shift rpm.

But the intentions of the car also come into play. Some guys with a stock cam may want or have a 67mm and just want to enjoy the car. You can put a 3200 stall in the car and have really quick throttle response and be a fun car to drive....it just won't set any mph records at the track. A really loose converter can still et well but be off 5 or more mph at the track. If all anyone is worried about is having a fun street car, then you can go looser on the stall to get throttle response.

 

[49-blues]

Thanks for the good info Dusty-anyone else?

 

[Lturbo6]

Dusty what about an 45a with 206-206 cam champion heads?

 

[Dusty Bradford]

Dusty what about an 45a with 206-206 cam champion heads?

The only converter I like with a 45A is the 9.5 non lock. Those turbo's need a good bit of stall rpm to get them going but make great power. Because of that, they don't work so well with a 10" 3200. It will spool the 45a but will push through it so slip is fairly high. The 9.5 is much more efficient over 5000 rpm with the same 3200 stall speed so it works much better.

 

[49-blues]

Dusty-what would you recommend for a converter stall for a stock block with a 206/206 flat tappet cam , iron champion heads and a T-70 turbo? Will a 3500 lock up work alright or is there a better choice? I will be looking to changing out the shortblock to a production 4.1 stroked motor with billet caps,214/224 cam , forged crank & rods is the reason for keeping the T-70 on there.

 

[buttonfly]

With a 212/212 shifting at 5800 I'd run a 2800 stall with a 61 or 62mm turbo. This will give you good spool-up with good top end pull as well. It will work very well together.

The problem comes when guys over-turbo an engine and that engines rpm range. For example a 67mm on a stock cam motor. It really needs a 3000-3200 stall but will have to shift at 5000-5200. The converter can't couple with a stall rpm that close to the shift rpm.

But the intentions of the car also come into play. Some guys with a stock cam may want or have a 67mm and just want to enjoy the car. You can put a 3200 stall in the car and have really quick throttle response and be a fun car to drive....it just won't set any mph records at the track. A really loose converter can still et well but be off 5 or more mph at the track. If all anyone is worried about is having a fun street car, then you can go looser on the stall to get throttle response.

Dusty is on the money with this. I was getting to be a little frustrated with my converter. 6152 with a stock cam, and 2800 10" PTC. Per Dusty's advice before changing the converter swap in a cam to better utilize the converter. We choose the 212/212 and wow, what a difference. I went from 400 rpm drop to 650-700 rpm drop, shifting at 5800-6000. Car pulled like never before, and I am sure it was partial due to the cam, but mostly due to the converter. All I can say is it loved the added rpm's. Thanx again Dusty!!!

 

[49-blues]

Will a stock converter also benefit from a cam change like this to get the rpms up for better spool up? I'm thinking like a 214/224 flat tappet cam with a precision TE-60 and a stock converter?

 

[Dusty Bradford]

Dusty-what would you recommend for a converter stall for a stock block with a 206/206 flat tappet cam , iron champion heads and a T-70 turbo? Will a 3500 lock up work alright or is there a better choice? I will be looking to changing out the shortblock to a production 4.1 stroked motor with billet caps,214/224 cam , forged crank & rods is the reason for keeping the T-70 on there.

I wouldn't even consider a lock-up combined with a T-70. If you get it loose enough to spool the T-70 it will drive terrible because it would require something like a 3400 10" stall. With a non lock 9.5 I could get away with a 3200 and spool it to help driveability. Either way, the combo will suffer until you get a motor than can spin to 6000+.

 

[Dusty Bradford]

Will a stock converter also benefit from a cam change like this to get the rpms up for better spool up? I'm thinking like a 214/224 flat tappet cam with a precision TE-60 and a stock converter?

The converter is what gets the rpms up for spooling, not the cam. The cam and valve springs extend the rpm range of the engine. The looser you get a converter to help spool a turbo, the higher the shift rpm needs to be to give the converter time to couple.

For example, a poor combination is a stock cam with a 67mm turbo and a 3200 stall. The converter might flash to 4800 rpm then shift at 5200. This only gives you 400 rpm worth of drop. The converter never has time to couple. Now install a cam and turn the motor to 5600 rpm and now you have a much more efficient converter and will see a 800 rpm drop.

 

[87WE4BOOSTED]

For example, a poor combination is a stock cam with a 67mm turbo and a 3200 stall. .

This is what I was trying to do when I first bought my car. After scouring this site, I now see the LIGHT!!

 

[dank GN]

I am going to put in a 9.5 3200 stall lock up is this a good choice with my 212/212 cam?

 

[Dusty Bradford]

I am going to put in a 9.5 3200 stall lock up is this a good choice with my 212/212 cam?

The cam is only a small part of the picture. You can have a large cam but if the engine shifts at 5400 your not really gaining anything from the converters point of view.

A converter that stalls 3200 at 0-1# of boost will need to see a min shift point of 5800 rpm if your wanting to see some good mph out of it at the track. If your just looking for a fast spooling street car without concern for the track mph, the 3200 may be what you want. It's all about what your intentions are with the car.