[transman]

More technical information on this subject we all can put to use.

A: Maximum performance can only be obtained when the entire combination of engine components are matched to work together.
B: Determine the converter stall spped requirements based on the powerband of your camshaft.
C: Order your converter only when you know all the specific factors that will affect the stall speed design.
D: As a general rule for street use obtain a stall speed with a minimum of 500 rpm into your powerband. This will allow your engine to get into the area where it is designed to operate and your engine will make enough power to drive the converter to its' stall range.

Some examples.

Cam Duration 260
Powerband rpm 1200 - 4200 rpm
Cruise rpm @ 100KM/H 2000-2500
Recommended stall 2000-2500 rpm

Cam Duration 272
Powerband rpm 2000 - 5000 rpm
Cruise rpm @ 100KM/H 2500 -3000
Recommended stall 2500 - 3000 rpm

There are other examples, and if anybody wants them please let me know. These are just general examples of course, but should give the board members some general guidelines to start with.
I picked this information up a recent performance seminar and thought I should pass it along.

Graham

[dave-r]

One of my desktop dyno thingies tells me I should be using a 4500 stall converter for best quarter mile ETs. I am sure it is right as with the TCI 10 inch "street fighter" (about 3000rpm stall on my car) it still sounds like it is leaving the line at too low an rpm.

However I would be very concerned about driving around town all the time with a stall as high as 4000-4500. I am I right to be concerned do you think or should I go for it at some point in the future?

[72 Challenger (Hans)]

Go for it Dave! But do use a deep trans pan, oil cooler and so on to be on the safe side. Right now I have a TCS (ask graham) which flashes towards 4000rpm, brakes to 3000rpm behind the 340 and the trans temp sender sais only 180 running in traffic with stoplights and so on. Driving temp is about 160.

But if you wanna be sure, wait till the summer. I'll have a 4800 flash converter behind the hemi then and still streetdrive it as much as I can. And probably with a tranny blanket also. Lofgen or similair I guess, don't know yet. Graham?

[transman]

I agree with Hans. Go for the 4500 rpm if that's what you want to do Dave, but I can tell you that on the street it won't be a lot of fun driving it.
At any rpm below 4500, the converter will be very inefficient, and will generate a lot of heat, so follow the advise of Hans and make sure you've got a transmission cooler that can disapate all that heat.
My best guess (from the limited information you've given) if you're going for the 4500 rpm stall is you will be looking at an 8 inch converter. It is possible to get 4500 out of a 9 inch unit, but at that stall a 9" is on the ragged edge. You may find that with the 9" converter, while you get the 4500 rpm stall, at midtrack, the vehicle may nose over (feels like you're in sand). The engine still is getting the rpm, but will quit pulling because of the design of the converter.
I know of a couple of locals here that have small (8 and 9")converters in their cars that see street use Dave, but the amount of street use is VERY limited. Very high stall converters (from any manufacteur) are designed for race use.
Graham

[dave-r]

That is more or less the way I had it figured Graham. Thanks.

I do have a deep trans pan and cooler but most of my driving is done around the city and unlike a lot of 'street' cars this one sees nearly 3000 miles of road use every summer so I think I will stick to the 10 inch converter. After all. This is not a race car. If I had intended to build a race car I would have bought a trailer and built something light that would run mid-low 9s. That would have been the cheaper way to do it too!