I am currently compiling research for a future Tubro B Series build and I am curious about transmissions. My power goals aren't over ~350 right now, so from what I've seen I feel safe. BUT, I cannot be sure. Normally searching for tech info in the honda world is pretty easy, but I feel like I have come to a bit of dead end. A bunch of Stock Trans guides, but no information on power limits or full performance builds. I will not lie and pretend like I am a transmission expert. I have followed a guide here online and replaced some bearing in a D Series trans before, but that is basically the extent of my transmission experience.

I see MFactory makes various final drive sets, a few companies are selling LSDs, and there are carbon Syncros available. Of course tons of OEM replacement parts. I saw one company selling race built transmission for the price of a running swapped car, and it said "Handles ~500 HP." What about the cars pushing 1000+?

I know for builds with other makes, Transmissions are one of the first things that need to be addressed however I don't hear much in the honda world. The only things that i've seen people replacing are Blown LSDs and Syncros. My power goals aren't over ~350 right now, so from what I've seen I feel safe. BUT, I cannot be sure. Also I've become pretty interested through my search, so my questions are...

How much power can the various B Series transmissions hold?
What parts go first, what should be upgraded, and who makes the parts to do it?

Any information is much appreciated!

 

B-Series transmissions that are in good shape and have been taken care of can hold a fair amount of power. I have seen stock transmission handle well over 600 hp. Its more of how long and that is never set in stone.

Since you are planning to make around 350 hp. I would first suggest a good LSD. MFactory makes a great LSD that is rated up to 1000 hp and they work awesome. Stay away from cheap LSDs that are prone to failure or ones that require a "fix" from the get go. Do it right the first time! I would also go through the transmission and replace all the bearings and seals including the differential bearings while you have the transmission opened. Inspect the trans and replace any damaged hard parts. You want to start fresh. If you have extra money...get a set of carbon synchros and call it a day!

If you plan to turn up the boost in the future, a shaft brace that replaces 5th gears would be a good idea. Cheap insurance! High HP cars go over to dog engagement boxes for more reliability. But, they are not cheap!

 

No specific magic number as there are too many variables, it’s in your best interest to put as much attention into the box as it is the internals of the engine, the stock Honda hydro boxes are an awful lot stronger than the early cable units (excluding an number of cable boxes with hydro internals)
My first box came apart and had everything measured to factory tolerances, anything that required replacement got it, new seals and bearings as a matter of course. After 6 years at 350+hp input shaft bearing was noisy so my box received the complete rebuild again, only this time carbon syncro’s and Torco fluid.
Also keep in mind that decent mounts and clutch will aid the life of the gear box as will treating it will a certain amount of mechanical sympathy, preload if you plan to launch hard etc.

 

i wouldn't worry about it. my stock gsr transmission with mfactory lsd is fine at 480whp/320trq.

 

Alright thanks guys! Its nice to know that is one less thing I'll have to worry about. I come from the muscle world so transmissions a lot of times are the first things to go. That's the biggest reason I was wondering. Thanks again!

 

Is it a street/strip car or a street/track car? If the later, you're more likely to break gears with less than 300whp.

 

I mean the idea is an all around performance car, but realistically it would see little strip time. I actually see the car competing in autocross if anything, but of course its all just for fun, nothing serious.

Is there a certain reason the gears are more prone to breaking under less power?

 

More heat, more use, more abuse.

 

you should be fine with the sort of power on the road once the gearbox is in good condition in the first place