LilJayV10

iTrader: (5)

my combo is in my sig. i have talked to comp cams, and talked to dana at probuilt and a few other people, and they all have recomended 2600stall for my setup.(although i found out i have 3.23 and not 3.42's like i thought, i put a rearend girdle on it and checked last week)so i dont know how much difference in stall recomendation that will make. I can not swing 600 for a convertor right now no matter how much i would like to. I was talking to a shop here in town that does only convertors. I was telling him that i needed a honest 2600 stall and not a 2600 that really stalls at 2200. I asked him how much a 10in would be, and he said that I wouldnt like it on the street, and that the 12in would hit just as hard, and be just as good. I didnt question him because I was there asking for his help, i didnt want to seem like a know it all. Everything i have read, the smaller convertors are easier on the tranny, and they hit harder. Whats the honest difference? Thanks for the help. This is the last thing I have to buy for my car.

mod313

Go with what you were originally looking at. The 10" is better for a couple reasons. The 10" weighs less for one and therefore is much easier to spin for the motor. The heavier converter will cause the engine's rpm acceleration rate to be slower due to its inertia. Also, a converter that is matched to your combo is the only way to go. I finally stepped up and bought a converter that was set up for my car combo and it made a world of difference in the way the car does everything at the track. In my case, I went with an ATI unit but any of the really good converter companies can set you up with what you need. Save up for it as it's definately money well spent.

LilJayV10

iTrader: (5)

anyone else? and anyone know why i wouldnt like it?

LilJayV10

iTrader: (5)

LilJayV10

iTrader: (5)

anyone know why I wouldnt like it?

LilJayV10

iTrader: (5)

i cant believe this, no one?

Pro Built Automatics

The 12" TC (2,600 rpm stall) will feel slippery, generate more heat, and not multiply torque as well as the 10" TC. with the same stall. As long as both have lockup, the gas mileage might be better around town when not locked up (same when locked up).

LilJayV10

iTrader: (5)

dana, thank you very much for your reply. sounds like a 10in would be better. Is there ANY disadvantages, or any reason I wouldnt like it? thanks again for your time.

LilJayV10

iTrader: (5)

well, the guy that runs the convertor shop called me friday afternoon and we finally got a chance to talk. He said that morning I wouldnt be happy with the 10in, that afternoon he called after some checking and said that where he gets his kits from, are releasing a new 9.5 race convertor kit, or something like that.He said the kit was versatile and he could do anything I wanted He started talking about cam specs, rear gear and so on and he mentioned something in passing about efficency.
He seems to think i will be happy with this convertor. I havent had a chance to talk to him again, I have alot of questions. This is what I have found out so far on my own.
Stalling a 12in converter higher, most converter builders will bend the pump blades back to a negative angle to feed less fluid to the turbine. This means the pump will have to turn more rpms to force the turbine with the same amount of fluid as before. As you can imagine, the efficiency starts to drop off rapidly as you bend the blades more
and more negative. You will lose rwhp.
A converter pump will tend to have a higher efficiency when its blades have a positive angle to them. The positive angle feeds the most amount of fluid to the turbine. The more fluid you feed the turbine, the harder it pushes on it. The harder the turbine is pushed, the more torque is
transferred to the transmission.
A 9.5" converter stalls higher because it generates less fluid by virtue of it's smaller size. It takes more stall to achieve the same
amount of hydraulic force of a larger 12" converter. Good thing about a 9.5" converter is that you can achieve very high efficiency
in higher stall applications because the pump blades still maintain a very forward pitch to them (positive angle). So in essence, by
bending the blades negative on a 12" converter, you are turning it into a heavy, inefficient, higher stall converter in comparison to
a smaller diameter converter.
Now that the 9.5 thing makes more sense, my next question is about effeciency. I have read that the looser the converter, even though its hell off the line, you can loose mph because it doesnt lockup completly or something like that. Buy dropping the STR(say from 2.5 to 1.5 or 2.0), the efficency increases and will pull harder up top. and unless you have sticky tires, it wont blow the tires off as much. Doesnt you rear gear ratio have a relationship with the STR?
Also, I am keeping lock up, but I have no computer right now the shop that built my tranny has it lock up in 4th over 55 buy itself. He said I might like this and can easily be changed to a switch. I have been reading about LS1 cars that have 3000stall vigilantes and yanks and notice no difference in driving and mileage. I realize without my convertoer locking up all the time, such as a PCM does it, I will notice a difference?
Sorry for the long list of questions, but I found some stuff out that I had no idea exsisted. Ahh the enlightenment I am sure others would like to know more about these things too. Thanks for any help or answers you have Dana.

91L98Z28

presuming you have TCC lockup on the highway, you will not notice any diffrence in MPG (unless you do a lot of driving around town in a non-lockup situation).

the 9.5" converter size is definately catching on. I have a 2400 stall behind my L98, and it's totally drivable in the 1500-2000 rpm range. Sure, it's a bit slippier than stock, but it will still accelerate below stall speed. as soon as you hit the stall speed, it tightens right up.

if i was you i'd give both of the top converter manufactuers a call (yank and vigilante) and talk to them. who better to talk to than the manufactuers themselves?

As for the different diameters, yeah, the smaller diameters weigh less, are less abusive to the tranny, less heat, more efficient when the stall point is raised, etc. etc.

If the guy you are dealing with is brand new to 9.5" converters and just started building them, I'd steer clear and instead go with someone who knows what they are doing and has been doing it a while...

Gumby

I use to work at a TC shop that rebuilt them. They really do not do very much to them. cut it open, wash it out, hammer down the fin tabs so they are tight, replace a few washer [more washers, more stall] weld it back together, air check it for leaks, balance it, n paint it.


I cut them open, welded them back together and air checked them. and painted them sometimes.

I would buy from a big company befor i bought form a local rebuild guy. They really do not do anything to them, 5 bucks in new parts n labor. they buy em for 2 buck each n sell them for 80+. only thing that can go wrong is if you cut it open wrong or the tranny seal end is out of specs. even deep scars in the trans seal area is just sanded smooth wih some emery cloth. it takes some really deep gouges to make it bad.

Id buy a TCI TC.

he could be pushingthe 12in cause he has them and he knows to to adjust them for stall right.

really there is nothing that can go wrong with a TC except that the fins get lose sometimes. So a used TC in a junk yard half burried in dirt can but just as good as new, just clean it out well.

Pro Built Automatics

The lower the rear end gears, (3.73, 3.90, 4.11 etc.) the lower the number on the STR should be. With 3.42, 3.23, 3.08, 2.93, 2.77, etc.) the higher the number the STR number. This should give you an idea on what to do.

LilJayV10

iTrader: (5)

dana, so a 2.0-2.5 with 3.23's? What about the effeciency thing, could you explain that? thanks.

LilJayV10

iTrader: (5)

Pro Built Automatics

This gets involved, call me at 800 7763288.