Upgraded the BD twins to… MPI Super B/GT4202

[JStieger]

Maybe i missed it,but have you towed yet?I emailed nathan yesterday asking about this setup,sounds good to me

No towing yet... too busy with work and the weather's been crappy.



I don't anticipate any problems towing. Empty, the GT4202 boost starts showing on the gauge starting at ~1600 rpm soon after the Super B starts building boost. This is at 5,000 feet so I would expect even better performance at your near sea level conditions.

 

[JFranklin]

does the GT 4202 have a larger shaft than the arrora 5000. and can you pm me on what this set up cost. thnaks

 

[JStieger]

does the GT 4202 have a larger shaft than the arrora 5000. and can you pm me on what this set up cost. thnaks

Not sure on the turbo shaft size.



Check out his website for pricing info on various set-ups:



Maximized Performance Inc



Yeah, the GT4202 setup is not mentioned on there and yeah I'm waffling... :-laf

 

[RDietze]

Bd Twins

JStieger,



Most impressive article -- your work made for some great reading (w/pictures)!

I'm quite happy w/ my BD twins and the 500ish hp they help make -- spent mostly working around sea level. It's hard to think of spending even MORE money in that direction of my "money sink. "

I would think the BD's are a better choice if you do most of your driving "dialed-down. "



You have an impressive set-up.



Good to be back on TDR!

ron

 

[JStieger]

I would think the BD's are a better choice if you do most of your driving "dialed-down. "

Ron-



Thanks!



Actually, both of these set-ups perform the same seat-of-pants wise with everything "dialed-down". Total boost would be the same in either set-up. However, the only difference is that both the turbos in the BD set-up would be "on-boost" with everything turned down at low rpm. In comparison, in the MPI set-up with everything turned down only the Super B would be registering boost at low rpm, but the Super B would spool quicker because it's pulling air through a larger primary turbo.



I do agree with you in that if my goal was 550 HP tops, I would have stayed with the BD twins.

 

[V-Metalworx]

It's a T3 undivided spacer. So yeah the exhaust flow goes from the divided manifold through an undivided spacer and back into the divided Super B if that's what you're getting at.



I just went out and look at the BD twin parts on my workbench and they had the same spacer set-up too.

how thick is the spacer from the pic's it looks like a 1/2" unit what does this spacer actually do?

 

[JStieger]

how thick is the spacer from the pic's it looks like a 1/2" unit what does this spacer actually do?

The spacer is 1/2". If I had an external wastegate, the spacer would be thicker to install the wastegate so there is nothing set in stone with the thickness. The only issue would then be how the thickness would affect the layout of the hotpipe etc. The spacer moves the top turbo away from the exhaust manifold so the compressor housing will not hit the manifold.

 

[RMalone]

Give us an update on how those twins are performing. I am considering a 62 over the Garret.

 

[JStieger]

Give us an update on how those twins are performing. I am considering a 62 over the Garret.

They still perform great! However, I haven't been driving my truck too much lately so I still haven't had a chance to tow yet. As far as around town... just great!



There's a guy on NWbombers.com and NWDiesels.com that just had a MPI set up like mine installed except using the stock 04. 5+ turbo over the GT. This equates to ~ same size compressor as the Super B, but the stocker has a smaller exhaust housing than the Super B.



He goes by OSCI on these sites and when he PM'd me he said they spool wicked fast and he lost about 400* EGT. He's a contractor if I remember correctly so he does tow a lot.



Here's his install:



Twins are in - NWDiesels.com



Here's his research:



Which twins and why? - NWDiesels.com



Hope this helps in making your decision... :-laf

 

[olywrench]

what a/r would you use in that set up at sea level?

 

[TCluff]

SWEEET SET UP, I WILL HAVE TO CHECK IT OUT SOMETIME GREAT POST

 

[JStieger]

Maybe i missed it,but have you towed yet?I emailed nathan yesterday asking about this setup,sounds good to me

I finally hooked to a trailer yesterday and today. It was only a car trailer with my Jeep so maybe 8,000 lbs tops + 8,000 lbs for the truck. With the Flux 2 injectors I had it on the 60 HP Smarty timing, TST 1x0 (no timing), and VA = 50% so about 450 rwHP fueling.



The spool up is still insanely fast, but progressive from off-idle if that makes any sense. In other words, it's not like when a big single hits like a 2-stroke in the ~+10 psi range. If I get on it off-idle, the truck really creaks, groans, twists, and torques over :-laf... and the rear wheels do break loose. Visions of busted u-joints were dancing in my head and EGT were the least of my worries. EGT only hit ~1100* pre-turbo when I got on it on a 8% hill out of town. Although the primary GT4202 starts making boost off-idle, it only starts to show noticeable boost rise when the manifold boost is ~10 psi.



The only other thing I did different since installing the MPI twins was going to a dual CP3 set-up. They have made my truck into a totally different animal in terms of greater low end responsiveness. It's like gaining 1-2 more box settings.