BlackBirds

iTrader: (24)

I called Yank converters and ATI converters to get a couple opinions on which torque converter to go with. My car is a '99 Trans Am with the TRex cam, 4.11 rear gears, 28" slicks, and a TH350 transmission. Yank suggested a 9.5" converter with a 4400 stall, he said the 8" is for cars that rev up to almost 8k RPMs and will make a car that doesn't slower after the 330' mark. ATI on the other hand suggested an 8" at 5200 stall saying the 4400 is way too low.

Who is to be believed? What are you all motor drag only guys running? Thanks.

01FbTaWs6

iTrader: (12)

give greg at FTI a call. Most knowledgeable guy I have talked to yet about converters. He is very helpful, and they have one of the best converters out there IMHO.

Top Fuel

iTrader: (8)

Go with an 8" for sure.

67SS509

iTrader: (25)

8"/5200 would be ok with a powerglide for all motor. With the 350 tran's low gear you will blow the tires off or be on the back bumper.

I have tried the 8"/5200 and 9"/4800 by ATI in my car with powerglide. Mine runs .4 tenths quicker and 4mph faster in the 1/8 with the 9".

Wicked94Z

iTrader: (26)

.4 and 4 mph in the 1/8

I run an 8" Continental, it goes 5600-5700 when it comes off the 'brake. Right now it's a little loose with only a 244 intake lobe, but I have a 255/263@.050 going in which should be perfect. I don't see you needing a 9"+ converter, you won't be making enough steam to make it efficiently go ~5000 like you want with that cam.

casper383

iTrader: (8)

Very interesting thread, I ordered an ATI 8" MRT and they are giving me a stall speed of 4200-4500
Details of setup:
364" LS2 that puts down 530rwhp and 410rwtq
TH350, 12bolt w/ 4.33 gear
247/251 .660/.660 110+2

I was expecting a 5500 stall but he said I do not have enough gear and it would not be efficient up on the top end??

I'm no converter expert so any input would be appreciated

minytrker

iTrader: (13)

You can't go strickly off the stall speed. You can't even just compare stall speeds from one converter to another if they are made differnt. My old converter would only go to 2300 rpms on the trans brake but I still cut 1.30 60ft every pass. It was just made alot differnt than most converters. I would go off advice of who is building your converter.

5.3LJimmy

iTrader: (10)

My car picked up 4 tenths when I switched form a 10" 4000 to an 8" 5500. This is with a TH350 and both converters come from PTC. This is with a 347 running an MS4 and TFS 215 heads. Best with the 10" was 11.01@125 and with the 8" its 10.56@127.

I am sure this is going to be your best apples to apples comparison. Same engine, same tranny, and same converter manufacturer. The only thing changed was the stall from one track day to the next.

SuperSlow02

iTrader: (16)

I called FTI and Greg sent me a 8in 5500, th400, 4.11 and just a cam/nitrous set up. I'll have results next month

This will be replacing a 9.5 4000

BlackBirds

iTrader: (24)

this is very interesting...I ordered the 9" 4000 RPM stall from Yank

He told me that since my engine makes max torque ~4400RPMS then I would want to go with the 4000 stall so I'll still be building torque when I launch but it will be just before the max for a strong launch.

I'm confused why some guys use such high stall speeds like 5500?? I doubt any GM V8 makes max torque at 5.5k RPMS. Also, isn't the higher the stall the lower the efficiency up high?? I'm no torque converter expert and would like this explained.

Wicked94Z

iTrader: (26)

it doesn't matter so much where the torque peak is. you want the maximum average horsepower through the entire run. If that means you fall back into the converter during the shifts then that's what happens. efficiency % doesn't mean **** going down the track, it just makes for better dyno numbers. Look at the comp eliminator guys running 8000+ converters They're not making peak torque at 8500 I assure you

fergymoto

iTrader: (129)

Who builds more racing converters? Easy answer.

billybadd

iTrader: (21)

Call Marty Chance for a third opinion.

fenton06

iTrader: (1)

You could always call Pro Torque, they built the converters for Fiscus and Wolfe, who just busted off 4.3x's on a 315 radial!

camarof41_383

iTrader: (7)

I just bought a torque converter for my n/a 408 and I contacted about 5 different companies. I had stall speed recommendations anywhere from 4600-5200 and both 9.5in converters and 8in converters. One thing I learned too was that some companies call a 230mm converter a 9in and others call it an 8in...keep that in mind when talking with them.

I ended up going with a 230mm Circle D. I was impressed with the attention to detail in wanting to get the converter right for my combination. I would also highly recommend Ultimate Converter Concepts, they do great work too and are very detailed. You really can't go wrong with Circle D, Yank, UCC, or Edge in my opinion. Depending on who you talk to at each company you will get different recommendations, choose who you think is giving you the best converter for your application.

JL ws-6

iTrader: (50)

If you want that cam only car to run right, I'd call greg from fti, call circle d, call lenny from ultimate converter concepts, transmission specialties, or take ati's advise.

I have yet to see someone put a yank converter in a car and have it run right... fwiw

Wicked94Z

iTrader: (26)

I have a great pro torque billet 9" core if anyone is interested. It's a traditional sbc bolt pattern I dunno what you lsx guys have different for spacing and bolt patterns though.

If you're converter shopping forget anything on these boards... go over to the bullet and you'll see UCC, Pro Torque, Chance, Coan, etc who run REAL converters in REAL racecars. We're not talking 9s or 10s, but 7s and faster. I know Continental has a cars in the 6s and 7s, and there's quite a few guys running Stock with them as well so that's who i ended up going with.

JL ws-6

iTrader: (50)

Only guy on here that builds race converters that are in alot of fast stuff is FTI. ATI stuff is very good, just have to get with someone that's a dealer, couple on here.

For the $ that chance wants for a converter I don't know if it's worth it unless you're running at a level that you need to be able to take it apart and adjust it yourself at the track... if that's where you are at, then yes it's worth the 3000 you will spend for a bolt together one from him, otherwise there's other options out there that are plenty viable IMO.

SuperSlow02

iTrader: (16)

But is that 4000 converter going to actually stall up to that? FTI told me to set my 2step at 3800 RPMs and adjust from there. Semi same effect with much more flash ability. I had a "4000" converter and its lazy *** hell for my heavy cam only car.

01_ram-air

iTrader: (3)

Another vote for calling Greg at FTI