Which one of these would be a better bottom turbo for compounds? I looking at 2 kits one from MPI which runs the S400 or Relentless Diesels which uses the BHT3B. Both come with everything, but Relentless is $500 cheaper. So is it worth the extra 500 to use the s400?

 

Let's just say that when I asked Nathan @ MPI if he would build me a set using the HT3B instead of the S400 (to save a few bucks), he said nope.

The fit and finish on the MPI kit is top notch. It's a complete kit and you don't have to worry about pieces not fitting together exactly right. That's not to say that the Relentless isn't top notch, I just don't have any experience with it.

 

S400 is more efficient.

 

S400 all the way. Better all around.

 

S400 is more efficient and flows a fair amount of air more (can support more HP)... and can be had in a few different configurations to tailor to the individual use... A very popular and very good primary turbo for 3rd gens right now. I would choose it over the BHT3B right now.

The BHT3B (not HT3B) will spool a little faster, has a wider map, and is arguably more durable and cheaper to rebuild if need be. It is an old, but proven, design and in the right twins configuration is able to support 700hp. (The old PDR race set used HX40 over BHT3B to achieve that).

One thing of note-- the snails on these things are opposite of one another... important to the guy building the pipes!

 

that and the BHT3B is a bulletproof turbo for a twins set, but its off an 855 cummins. thats pretty old technology compared to what a s400 will do for ya. but the relentless kit is a really good kit. a friebd has one and it is nice.