Are there any mods that I can do to get my stock HX35 wih a non-wastegated 16cm exhaust housing to spool up sooner? Right now it spools up at about 1700rpm all the way to 3000rpm, it's a real violent spool up, not a slow steady increase. Is there anything I can do to see the same boost in the lower gears that I see in 5th gear (35psi). I want a little more low end throttle response.

 

good question i would like to know some answers to this one to......

 

Turn up the starwheel

In a diesel fuel is boost, more fuel u burn, the more boost you can make. The simplest thing to do is just get turn up the starwheel, loosen it up, means more smoke and faster spool up, tighten it up and slower spool, less boost. Tinker with it till you are happy, if that dont work, i woud suggest a fuel plate, but bein taht you have done both, now id like to know some answers too... But i would suggest a smaller exhaust housing, it will have to create more backpressure to spool i would imagine... Anyone else have a stab? Plugging the wastegate if it exists, but you are non wastegated.. good one..

Tx

 

Smaller housing for both of you. I have no personal expirience but keep reading threads saying the 14 cm2 works much better, all around, than the 16 cm2.

Scarecrow - your only option for faster spoolup (if you stay with the 16 cm2 housing) is bigger injectors.

RJ

 

I have tried the same setup with the stock exhaust housing with the wastegate disabled, the results were even slower spoolup, that is why I went to the 16cm housing, for less restriction, faster airflow, means a quicker spoolup. I wonder if the answer is some internal mods to the injector pump.

 

I went from a 16nonw/g to a 12w/g with the w/g disabled and the spool up is way quicker now!! Try and imagine it with a 21cm!!

 

Imagine what with a 21cm housing, you said you gained performance going down in housing size. So I don't see how a 21cm would benefit you. So imagine what with a 21cm housing?

 

I have a hy35, that comes with a 8cm housing I think. whish I had the 16cm that was on my old truck!

 

Scarecrow, I've got the answer for your 24 valve truck...not sure on the 12 valvers. You've probably read about the CaTCHER ECM over on TDR, well I installed mine this weekend...it's insane how quick the boost builds compared to stock. All the low end response you could want, and I'm assuming it only gets better with injectors. If I had a Southbend like you, I'd have the Mach 1.6's on order to go with this ECM.

 

Rjohnson is correct.....You are not moving anywhere near enough fuel to light that 16cm housing soon enough.....the stock 12cm should work well with just #11 plate.....unless you step up to a bigger injector, you need to drop to a smaller housing to gain some spool-up speed.

Smaller exhaust housing=quicker spool-up and higher drive pressures, larger exhaust housing=slower spool-up and lower drive pressures.

 

Imagine how much spool time there would be with a 21cm, takes half a block!

 

actually its not that bad at all..........

i ran a 21 over my 16 and aside from the initial lag in the intersection which i barely noticed i had very little difference between it and my 16.

it did work well for towing.

 

we have put two 16cm housings on and both owners hated them and want to pull them off. i run a 14wg housing and it works great all around[but they are expensive]. but i have a couple of 12cm housing that i have port matched, increase the waste gate opening to 7/8" and drilled a 3/4" hole in the divider to bleed off the back 3 cylinders. we are putting one on this weekend and i will tell you the results.