[4doorjoe]

Hi guys got a question about cooler lines i am thinking of running stainless braided lines from tranni to cooler is there any kits and from whom also i was wondering about cooler size the car is a vega wagon withg a 406 aprox hp 500 355 gears with 3500 stall convertor & 26 inch tire my rpm calculation is 2700 rpm at 60 MPH any thoughts on this combo for cooler size thanks joe

[xntrik]

As big a cooler as will fit in clean airflow and a temp thermostat from Jegs.

[Chazmac]

By your own calculation, your converter will slip 800 RPM at 60 MPH.
Doesn't this strike you as a problem? Would you let a clutch slip 800 RPM at 60 MPH?? Either re-gear the car for more RPM or change the converter to match the RPM range the engine will work in. You WILL sacrifice trans and converter life the way it is now, no matter how big your cooler is.

[predator carb guru]

how do you come up with his converter slipping 800 rpm @ 60 mph? by it's rated stall speed vs his calculated cruise rpm? that's not how they work...........unless his converter is matched to his engine combo, is he really sure it will stall to 3500 rpm? what if it stalls more? torque converters respond to input torque. the more an engine has, the higher the stall speed will be, regardless of rating. also, rated stall speed has NOTHING to do with converter efficiency, or it's ability to "lock up". The easy answer is: stall speed is the RPM a torque converter will allow the engine to attain with a given engine torque input. torque converter efficiency is different altogether. i wish i could remember the website where this was posted, but there are a few racers out there using converters from this company (the name escapes me, but it wasn't one of the "big" guys). what they did was post the run info from the cars he had his converters in to demonstrate how efficient they were. basically, they were custom stalled for each car (5500 + rated stall speed), and they recorded engine rpm at launch, each gear change, and at the finish line. using tire size and driveline speed, they were able to calculate the slip percentage in the converters. his converters were slipping less than 2% at the finish line. remember, as the vehicle acclerates, it takes more hp and torque than it does to maintain speed. as vehicle and engine speed increase, torque multiplication in the converter DECREASES, until the gear change, where it will increase again until vehicle speed "catches" engine speed, and multiplication will again decrease. without a lockup clutch, no converter will ever achieve 1:1, but they can come close. all that being said, just because it's a 3500 rpm RATED converter doesn't mean that it will actually stall that high behind his motor. i've known several people running 5000+ converters on the street without problems. i will agree though, that a steeper gear would be benificial to the car, and that he should get the largest cooler he can fit in the car. also, if he does alot of stop and go driving, THAT will create a bunch of heat that he really doesn't need. the "looser" converter will be in multiplication longer than a tighter one, and that's the slippage he needs to worry about. if all he does is mostly highway driving, then i don't see any reason he can't run the converter he has.........won't help his mileage though......but with his combo, i really don't think he's worried about it.

[Chazmac]

Yea, I know...
If this guy has a "3500 Stall" it is a 10" converter. Way too loose for his gear ratio and more than likely his camshaft.
My point was trying to point out the OBVIOUS ineffeciency in his own math.

BTW, I build torque converters of all types every day. Two questions that are always asked: Camshaft profile, gear ratio & tire size, among plenty more.
Not my first day, first trans or first converter..........

[Crosley]

well, I for one cannot wait for a comment from Chazmac.

never mind

[4doorjoe]

HI guys thanks for your input i guess i didnot explain all the details on car 406 sbc dart heads 210 cc 2080 int 1.600 ex comp cams solid roller 280 -286 duration 576 lift10.5\ 1 comp super vic intake 750 demon carb 2800 pond car we are hoping for 500 hp and simuler tourqe now the biggest reason i am thinking of the 355 gear is more for concern hook up the is not tubbed iwill be running a 26 inch tire with 355 gears my other option is 3.9ratio but worried might a bit much for the amount of tourque or 355 and 3.000 stall just waying out my options here oh yea the is full framed and 10 point cage with ladder bars thank you all for the time to help with my project thanks joe

[Chazmac]

Different story now...
Your choice of a 10" (3500 stall) is appropriate and seems correct (matches the camshaft) for an all out drag race application. Be careful if this is street driven, as the converter slip will still be an issue.
If this is more street than drag race, I would be happier if you had 3.73 to 4.10 gears if you were my customer.
3.55 with your combo is not gonna even put the engine RPM into the power range that camshaft will like to see. It will probably start to pull with the gear you have, but it'll be happier with more ratio.
As for traction, look at the tires available and check your pinion angle...

[predator carb guru]

more info definately helped. i agree, you need more gear. with the correct converter for your application, you always have the option of leaving the line with different rpms to see what happens with the traction. ie: if your converter actually stalls at about 3500, and you leave the line at say, 3000, and you have wheel spin, you can always try leaving at something like 2800 and see if it hooks up better.........also get the best tires you can that will fit. earlier shift points can also help with marginal traction, and won't kill as much et as late ones will..............if you have the budget for it though, i'd get a custom built converter. that way you know that what you have will work with your combo.

[4doorjoe]

HY again well it all makes sence to me now what about the secind option of 3.90 gear and a little lower stall say 32.hundreed stall i have a dodge 8 3 quarter rear end that may make the motor happier thanks for your help joe