Tiger Rag

I don't think you can argue with the versatility of the BD twins. They tow great with very low egts (never seen anything higher than 1250 pulling 15k up a grade), and have solid performance. They are excellent for daily driving. Now if you are going to go for 650+ hp, you may run out of air around there......not sure. I think BD claims 700.

You will have to do some tweaking to get the plumbing right after install. You'll most likely have to get aftermarket intercooler boots, and the overall install is probably 3 times as long as a single. BD claims you can run them with stock head bolts with the wastegate set at 50 psi from the factory. I put studs in just to be safe. I've seen the the BD twins for a little under $3 g's last summer, then consider another $200 for intercooler boots, and $400 for studs. This is one of the more affordable twins sets and still is a considerable investment over a nice single.

From what I've been reading the silver bullet spools excellent (better than sp66) and moves a lot of air (more than the 66). If I were to do it over again, I'd seriously consider the the silver bullet, just in ease of install and from a cash standpoint (although I realize it is an expensive single). Having the BD twins now though......I don't think I could go back. It is hard to beat the overall package I have. Everything is a compromise though. Figure out what fits your needs best.

dodgediesel

I'm curious as to the drive pressure difference between the Silver 62 and a set of BD twins??? The Silver 62 has no problem hitting 50 lbs...

getblown5.9

i cant wait to get my silver bullet on, even tho not having an OD gear in the tranny will make it no fun for the top end power they are known for.

working on solving that issue now too

silverbullet830

i'm waiting to see how BD's Super B Special twins do. maybe a little more lag but they claim they'll flow quite a bit more.

RowJ

Glad others are discussing twins...so this is not a total hyjack...

-20 psi..... 1600 rpm (Forrest said 1500)
-45 psi..... 2100 rpm (Forrest was at 2300)
-50 psi..... needle moving to fast to watch 2 gauges. (Forrest said 2500 rpm)
-65 psi .... 2500 rpm with my BD's.

Observations: Forrest is correct about the big light off of a single being quicker than twins.... but isn't that possibly surge or more accurately 'spike'? Just guessing. My boost needle climbs quickly and steadily to max (minus 2-3 psi) but does not leap up after 20 psi, like I remember from a big single. FWIW... I timed it; from dead stop to full boost at WOT (everything turned on and up...no power braking). My stop watch said 4.2 seconds. Good?... Bad?... Better than big Single....? Feels quicker than anything I've had in the past but who knows for sure?

RJ

dodgediesel

Hey rjohnson, any information is good information... It's not a hijack if were all talking turbos. It's all good!!!

Tiger Rag

Check this thread out on the specials. Gonna be a while, plus gonna be for BIG horsepower. 800-1000hp. I'd think 12 valve territory only.

http://www.cumminsforum.com/forum/bd...tml#post173506

Tiger Rag

rjohnson has checked drive pressures on his truck with the current BD super B twins and found that it runs basically 1:1 with the boost pressure. Just what you would hope for out of an engineered set of twins.

Forrest Nearing

drive pressure on my sps62 and my silver66 has been lower than 1:1

on a cold night w/ the sb66, I was seeing 48psi boost and 41psi DP!

my sps62 is consistantly 5psi lower on drive pressure than on boost. low drive pressure = "free" horsepower