Questions about twins

[JLinder]

Right now I have a comp and DDII's on my truck with the stock HX35. It dyno'd at 435 hp, which I am happy with. The truck runs a little hot when the comp is on "nuclear", so a turbo upgrade is next.



I don't think I'll add to much for fuel in the future, maybe some DDIII's but prolly just the II's. Now, about the twins... The way I understand it, properly setup twins spool instantly. And, flow enough air to keep EGT's down when adding insane amounts of fuel. What about for a milder application like mine? Do I have enough fuel to spool them instantly? I tow regularly, so keeping EGT's in check is a priority but the cool factor of the twins makes me lean that way over a PDR40. Oh yeah, I also put on about 40k miles per year.



So what do you guys think? For a mild truck like mine (~450hp), are twins the ticket, or are they overkill?

 

[Jim Fulmer]

Linder, that's about were my truck is by a guess and I have NO spooling problems, NO driveablity problems and the setup works great, even though I have no EGT issues don't buy off on the thought that Twins are the end all to performance, if fueled properly you would still have EGT's, not from lack of boost but intake temp. If we(Twins bubba's) ran our air though a huge liquid to air cooler we could dramatically drop temps... . big time! There is nothing like seeing someone run a huge single (106MM) at 40 PSI through a 4" pipe and the intake temp is below 100 degrees, that is what I call cool air.



Jim

 

[work2muchplay2little]

Twins are a good solution to the two main problems with a single turbo - one if you get a big enough one to cure the EGT problems, it has a lot of bottom end lag - and two, a smaller turbo spools well but cant' handle the upper end EGT's. You have enough fueling to benefit from twins and will allow more in the future. My twins were built to allow for quick low-end response - but would not say they spool instantly. As a matter of fact - they spool slightly slower than a regular HX-35 but considerably better than the HX-40 I had prior to them. The real thrill with these twins is that from about 1800 rpm the boost quickly climbs to 50+ psi and the EGT's stay down. With my DDIII's and the FMS box on max, my EGT's stay below 1200. The best of both worlds you might say.

 

[JLinder]

Are you guys running some kind of wastegate? I'm wondering if you can get away with keeping the boost down far enough so you don't have to o-ring the head? Or would that defeat the purpose?

 

[J.R. Adkins]

The twins need to wastegated. Even with dd3's you can make more boost than you need. O-rings work well if boost is kept under 70 psi.





J. R.

 

[Proram]

Twins

OK, Another Question, What are the recommended turbos for this type setup? do I pitch the fact. hx-35 and Buy 2 new turbo's?

Or can you use the 35 in the setup? I have DD-3's ,a drag UFM

going w/ an ATS man. and 5" (thinking about stepping up to DD-super mentals in future) TIA

Proram

 

[J.R. Adkins]

Proram,



Do a search on "Twins", there are plenty of pictures and info out there.







J. R.

 

[Gizmo 007]

I'm using the stock HX35 as my primary turbo, and it works great! No need to throw it away. For my secondary, I used a custom hybrid Garrett turbo (that I build myself).



Several members are using the stock HX35 and a Holset HT3B turbocharger. Seem to work really well. And the HT3B isn't all that expensive either!



I have just a little low end lag, but with what mods i have (see sig), they spool quite well. Kinda like Kurt, from about 1800 RPMs on, they spool like crazy up to about 55psi (where I have them wastegated). With the wastegate disabled, I've touched 80psi . I don't think the stock headgasket is gonna take much more .



When I step up to DD Super Mental injectors, i expect two things: (1) It's gonna spool faster than the stock HX35, (2) I'm gonna need a new head gasket



Good luck. Building your own set of compound turbos takes a lot of blood, sweat, and tears, but most of all, it FUN! It's a great experience.

 

[JTroiano]

Air Flow Systems Inc. has brand new HT3B Switzer (sp?) turbos for around $450. I have one sitting on the bench and have almost all the other pieces needed. I can't wait! Ask for Mario, he is a really nice guy.

Oregon 1-800-762-9876 www.airflo.com



Jon T