TH400 Torque converter recommendations needed

[Pablo]

I'm going to a TH400 with a trans brake and reverse manual valve body. I need some recommendations as far as a torque converter is concerned.

The car is built for street/strip, I like to drive it on the street but it is not a daily. Raceweight is 3400 lbs, the engine is a girdled 109 with ported irons (190cfm), a comp 212/212, a TE45A. I have nitrous to spool the turbo and on nitrous, spool up was not a problem with a 3400ish stall converter that I had in my 2004r. Off the footbrake, with nitrous spool up, I cut a 1.54 60' and ran an 11.2@118 completely blowing through my old converter, crossed the line over 5100 in overdrive. I hope to run at least mid tens when I get things sorted out.

I was thinking something in the mid 3000 rpm range again for the 400 but I have no idea what is the ideal rpm or what the best brand is out there.

Any suggestions would be greatly appreciated.

Thanks,
Pablo

 

[daverr]

I had no problems with Coan torque convertors in the past. I just bought a new Coan torque convertor couple weeks ago for my new turbo drag radial build . Give Art at Coan a call .

 

[Otto J]

Contact Dusty Bradford here, He will set you up with a PTC convertor that is second to none in getting power to the ground.
I have back to back tested the PTC convertor againt a few other manufactures on a chassis dyno and they usually match peak power but hte PTC always put more power down across the board until they peak together and that gets you down the track faster, the PTC also always shows a higher MPH at almost any RPM than any other tested.

 

[Dusty Bradford]

One of my 9.5 converters will easily spool that turbo and couple the power. I'll be back later this week if your interested.

 

[Alky V6]

If you're using nitrous to spool, depending a little on the turbo you're using, you won't need very much stall speed.
I used a 2400 stall with a T76. That combination worked very good. Without nitrous, I would have needed at least a 3200-3500 stall TC.
I'm presently using a 3200 stall with a 91mm. Without nitrous, I would most likely need a 5200 rpm stall speed TC. This combination is working very good at the launch, but is on the loose side on the top end. Yeah. A 3200 stall is too loose.

Having nitrous in the picture is going to demand a different stall than what is ordinarily discussed.

 

[Pablo]

Thanks for the advice. I ended up ordering a PTC 9.5 with the steel stator. The guy who took the order (I forgot his name) was quite helpful and friendly. Great customer service so far. He said that they consult with dusty on a lot of these turbo Buick converters.

So if they mention an order for a car with a 109, ported irons, 212/212 and a te45A, that's me.

I don't plan on using nitrous all the time so I want a converter built as if the nitrous wasn't there.
I'm hoping to beef up the rear end so I can do some serious trans brake launches without worrying about destroying anything. The nitrous is for footbrake launches right now. I haven't experimented with the trans brake and nitrous (on my old tranny anyway)

 

[forcefed3.8's]

You shouldn't need nitrous to spool that turbo. If you do, something is wrong.

 

[jasjamz]

You shouldn't need nitrous to spool that turbo. If you do, something is wrong.

He's right. And you plan to leave off the transbrake? I don't feel the spray is needed either but its all in what you feel is quick spooling.

 

[toofastforyou]

I plan to go from the 200-4R to a TH 400 shortly, and probably will go with an ATI converter...A good friend of mine tried both an ATI and a PTC and his car ran better than ever with the ATI...:redface:

Claude.

 

[Alky V6]

These guys have a very good point. Why do you need nitrous with such a small turbo?

 

[Pablo]

Well I wouldn't consider a non bb 66 mm turbo fast spooling. In order to launch off the footbrake you need almost instant boost. In my case I could not hold much boost with the brakes even with s10 cylinders. Max effort best launch off footbrake and no n2o was 1.65. Only one pass with the N2o and I cut a 1.54 not even trying.
I am launching off the footbrake for now because I have a stock ds, axles, carrier and cover. I have broken axles on a slower car and that was not a pleasant experience.
Aside from all this, I drive it on the street, and when I'm toying with a stick car from a roll I need instant boost which will not happen with my turbo. I am a fairly skilled tuner (started burning proms in 98) so I'm fairly confident I was not far off of the physical limitations of my combo in my tune.
To slightly complicate things I purposely built the engine with low compression. I am probably @ 8 to 1 (maybe even less). There is a method to my madness.
Maybe with the new trans and converter I will see an improvement in spool up. To be clear though, its not that my spool is slow, I just like instant boost just from flat footing it.

 

[Alky V6]

Do some experimenting with the transbrake and the nitrous. Dare ya.

 

[Pablo]

Do some experimenting with the transbrake and the nitrous. Dare ya.

I'll look into it :biggrin: See you soon at Barona!

 

[Alky V6]

Coool!

 

[norbs]

I am happy with my converter from dusty, its a PTC but its designed to be tight on the street 2400 rpm cruise speed, very nicely and will hit near5000 rpm on the transbrake.

 

[Dusty Bradford]

Thanks for the advice. I ended up ordering a PTC 9.5 with the steel stator. The guy who took the order (I forgot his name) was quite helpful and friendly. Great customer service so far. He said that they consult with dusty on a lot of these turbo Buick converters.

So if they mention an order for a car with a 109, ported irons, 212/212 and a te45A, that's me.

I don't plan on using nitrous all the time so I want a converter built as if the nitrous wasn't there.
I'm hoping to beef up the rear end so I can do some serious trans brake launches without worrying about destroying anything. The nitrous is for footbrake launches right now. I haven't experimented with the trans brake and nitrous (on my old tranny anyway)

They did mention it. I was out of town for the week.