Back ground: 98 12 valve, 5 speed.4000gsk, hx35-12 and ht3b. 370 injectors, #10 plate (in stock position) Bhaf, 5 inch down pipe no cat, to 4 inch exhuast.

Before twins.....lots of smoke ( i liked it), max boost was 22-28 with no wastegate. (plugged) I m at 2500 ft.HIGH EGT's

With twins on test drive.....empty no load, wet roads (it just rained), its hard to tell a difference. 30 psi at 1/4- 1/2 throttle....egt's go to 1200 pretty easy. Smoke is almost gone, unless I really romp on it. There is a small flat spot at light acceleration at about 2500-2700, like its out of fuel. I don t know for sure, but I expect more boost with a load (trailer) and hopefully lower egt's. I have a 12 housing, should I get a 14?

anode? plate? reccomendations?

I still need to play with the waste gate on the hx 35....I m pretty sure its not opening, so that should cause higher egt's, I expect alittle lower egt when I get it right.

 

Do you have an external wastegate to bypass the HX35?
With that you should be able to keep the fast spoolup of the 35/12 and have the "second air" of the HT3b, not necessarily running too high boost. (It's often better to have cool boost@low backpressure than shooting for the high numbers only)

HTH

AlpineRAM

 

When the roads dry up take it out for another ride. The EGTs should drop once you get more boost built. They will climb some until the boost builds and then fall back off.

 

It sounds like the first thing I saw 2 years ago now, a small housing and no external wastegate to by-pass any air to drive the big turbo harder with do a few things.

1. EGT's will still be high
2. Drive pressures will still be high
3. Overall performance will be limited
4. Air temps at he hat will be higher......over worked top turbo.

When I first started out I ran a 16cm housing with no by-pass to the big charger, then later changed it over to by-pass to the tune of a 250 degree drop, then changed over to a 18.5 housing and took that combo 35/3B to 670hp on #2. Yes it's too much power for that combo but it's all I had.

Jim

 

you should have been able to hit 40 plus psi with the hx35 before you put on the twin set up. you might want to plumb in a external wastegate between the manifold and hx35 to feed in before the ht3b. but it sounds like you have other problems other than the twins. check to make sure you arm is riding up the plate correctly.