Let me state that I'm not a complete noob when it comes to this, but I don't know near enough to properly understand how they work. If you have any good threads you could share, or articles I love building my knowledge. Or feel free to give your personal insight.

I have had a lot of manuals, but I thought it would be fun to put together a th-350/400 for my current build that had full manual shifting and engine braking. A few reasons, so I could pop in drive when I was putting around and slam through the gears when I was hooning.

I understand the stall concept, no explanation needed there. but what I have a hard time with is the lockup style, what's it purpose, when is it needed? Also I don't quite understand the the anti ballooning feature some converters offer.

I'm really just trying to get an idea of exactly what kind of converter I will need for my setup. It's not a drag car, I will probably do some of that but thats not it's only purpose. Second reason for auto over manual is I want my wife to be able to drive and do autox with it without having to worry about shifting.

It's a 1988 BMW e30, I'm building a high CR lm7 for it. Since it's not strictly drag use what would you recommend?

• Stall speed?
• lockup needed?
• anti-ballooning? (may not even be relevant)

Any insight would be appreciated guys!

Thanks.

 

The anti balloon plate is a plate that is welded in the converter to keep the case from swelling under a lot of HP. If the converter swells the tolerances get loose and keeps the converter from coupling and that makes the converter less efficient .
The lockup feature is mainly for highway cruising and makes the auto act like a manual in overdrive. It is a clutch like setup that is engaged electrically. Some high HP setups will use multi disc clutches in the converter to lockup at WOT, but its not recommended on average HP hotrods because it will slow the acceleration down vrs the converters normal coupling.
Your stall speed will be determined by your engine rpm range and is better left to the people that build them. Just give all your specs to a trusted converter company and let them take care of the rest.
I hope this helps. This is just the basic stuff, someone here with more knowledge may be able to explain the concepts better.

 

Thanks man I appreciate the response. That explains a lot. My hp range will be moderate I would say, maybe 350 to the wheels. It won't take much to make that tiny car quick. I guess the anti ballooning plate and lockup won't be needed.

What are some of the ideal manufacturers for converters for th-350/400 transmissions?

 

In my research the anti ballooning plate is more for cars that are doing some sort of forced induction or nitrous. The lockup is not needed but the way it was explained to me is when your cruising if you don't have a lockup it may slip and cause unwanted down shifts. As far as brand I've heard great things about TCI and Boss Hog.

 

Thanks man.