Well I have definitely realized that the Super B Special is too big of a turbo for my truck. On the highway I struggle to even keep up my speed without melting my motor.

Now, what I am thinking of doing is using my HX35 as the top turbo in a twins set, and keep my Super B special as the bottom turbo.

Has anyone run this yet? If so, did you like the outcome as a good street/track/towing truck?

Does anyone know if there is a piping kit that I can just buy to make these instead of having to get them custom made?

I am trying to keep the price down on this issue without giving up the Super B special so buying all different turbo(s) is pretty much out of the question. I would hate to have to put back on the HX35 as my only turbo, but as of now, that is my only other option.

 

A super B special is way to small of a primary unless you dont want more than about 500hp and that might be a bit optimistic.

 

500hp is more than I would really ever need other than for toying with some sports cars. I use this truck as my primary daily driver and work vehicle. So half way decent fuel economy and reliability is more important to me.

And isn't the Super B Special the bottom turbo in the BD twin kit?

 

I would look at selling your super B and buying a turbo more appropriate to twins, like a K31, or an S475. They can be had in the $500 range depending on where you look. You'd be money ahead, and I think you'd have a better running setup with a bigger primary.

 

are u sure you dont have any boost leaks? a super b should fit your truck fine its only what a 64? I have a 64 as well with no problems and less fuel, and less of a gsk. did you put a quick spool manifold on? if not thats part of your problem right there

 

My guess is you have a manual tranny?
An automatic, like 'kevellis32' has, with a bigger single, is a whole different can of worms. Can't wind out the gears to keep it spooled and living with a huge difference between third gear and a very tall overdrive gear (.69).

Super B Special is great turbo for manual trannys and would be too small for twin primary. Suggest following 'Tates' advise.

RJ

 

Tate,
Where is it that I would want to be looking for those turbo's?
I agree with what everyone has said so far except for the idea of any boost leaks. When it spools, it spools and you hang on, and as RowJ said, I am fine driving around the city with O/D off and don't have any issues, but on the highway when it kicks into O/D I can't accelerate without my EGT's going sky high. With the HX35 I would cruise at 75mph at roughly 8lbs boost, with this turbo I am sittin on 0 and cannot get it to spool unless I kick it out of O/D which isn't a great idea in the highway.

 

yes where do you look for turbos that cheap? I'd love to have twins.

 

What size turbo's does BD use in their twins system? I have searched all over google for it and can't figure it out. I thought that the super B special was the secondary turbo in that system but I'm guessing that I'm wrong.

 

I'd start by looking on Ebay, kjiji, craigslist, and looking at the big truck wreckers.

 

I have BD twins and they are both s300 turbos. Having your s400 under an s300 or your stocker would work great, in my opinion. These twins spool at 1300 rpm and i'm safely pushing 70lbs out of them. I agree, the specail is too big as a single.

 

when you say having my s400 under an s300, what exactly do you mean? Which turbo's are those? Sorry, I am a complete newby when it comes to the turbo lingo

 

The s400 would be the bottom turbo (larger) and the S300 is the top turbo(smaller) in the twins set up, they are very commonly used in the smaller twins applications. As for your super b special, I enjoy mine, I do have a 24v so more air flow to it.

 

Ah ok, well it looks like I will be selling the Special and going a long a similar route as everyone has suggested.
The reason I got the special was because a friend of mine with a 24v has it on his truck and it works good for him except for when he tow's heavy or up long gradual hills. And he has a 6spd too.
Don't get me wrong, when I get it spooled, its amazing, but with what I need my truck to do I just can't use this turbo at all.

 

For 2nd Gens, the super B is the top turbo (an S300 measuring 58/65/13, .80 A/R). Not the special.
The bottom turbo is an S300 also, but much bigger housings - 66/77/20, with an A/R of 1.10.
A/R being the constant ratio of the area vs the radius of the turbine housing. If interested in learning more, read here....
http://www.turbominivan.com/tech/turbo201.htm

FYI - Best info I have is a Super B Special is a 64/71/14, with a .90 A/R.


The BD R-700 Race Twins (3rd Gen only) have a Super B Special on top and, I believe, an S400 under it.

RJ