Posted by raymond roland (IP: 63.10.151.172) on July 11, 1999 at 20:12:41:
In Reply to: Re: cure ignorance of stall converters posted by Jim Glover on July 10, 1999 at 21:52:09:
: : Could one of you knowledgeable and patient folks out there explain the effects of different stall converters. I'm building a fairly potent 302 for my son's Mav (there is some chance I might borrow it on occaision too)but I don't know how a higher rpm stall converter affects street driving? Does a 2500 rpm converter mean that you necessarily smoke the tires every time you drive out of the drive way? Just looking for some practical advice. Thanks.
: Whatever the stall speed of your converter, remember that the higher the stall speed the more heat that is generated in the transmission fluid. So make sure when installing a high stall converter, to also install a transmission cooler as well, preferably in series with the stock radiator cooler.
----------
The advertised stahl of a torque converter is the relative rpm in which the converter locks up in a theoretical 1 to 1 ratio. Up until this point the torque converter actually multiplies torque (generally in the neighborhood of just over 2 to 1 (necessary for low associated 1st gear ratio in an automatics. A good performance converter with street manners relative to a Maverick is a 10 inch unit with a stahl of around 2500-3000 rpm. You will not smoke the tires every time out of the driveway, don't worry. The rpm your used will change and become a bit higher, but this is the price for performance. Yet, with enough rear end gear ratio and horsepower (about 250) you can break a normal set of 245/60-R15 tires loose on command when 'you' want. The reply above about heat is correct, the smaller the converter (ie. 11, 10, 9 inch and so forth) the more heat the converter will build. I do not recommend smaller than a 10 inch converter for a Maverick due to 2 items: 1-the down flow radiator mavericks' have which don't cool near as well as a cross flow radiator. 2-to retain decent gas mileage and street manners a 10 inch is as small as you probably will want to go. I personally used a TCI of the shelf converter ("street fighter") costing around $300 and had excellent results with a 1/4 mile time of 12.86 with my stock eliminator Maverick with 3.70 rear gears. In full street trim (ie. mechanical cooling fan, power steering and street tires the mild 302 will turns 13.20's with no cooling problems. An aftermarket transmission cooler should be considered mandatory when going with a higher stahl/smaller diameter converter. However, it is this racer's opinion that running the external cooler alone is more effective than the above suggestion of running the cooler in series. HERE's WHY. When the cooler is run in series or conjunction with the cooler in the radiator, the trans fluid is then 'preheated' to the engine's relative water temperature (not very effective in the reduction of heat which is also the most common cause of transmission problems/failures necessitating rebuilds). The 'only' time this won't apply is if you live in a very 'cold' climate. I'm in the hot and humid south so heat is the enemy. My Maverick is currently the only IHRA stock eliminator Maverick I know of, in fact I think I'm the only non-Mustang Ford in Stock. Good luck. If you need more info, email me.