Engine/Transmission (1998.5 - 2002) stock HX35 and boost levels

[WadePatton]

What about over-boost? I'm hitting 38-40 on 4-5 and know that that's a bit much. My elbow doesn't appear to have any adjustment. It has a tiny orafice and a small hole to the outside, but I don't see a screw as some have talked about.



The boost elbow I'm using was not supplied with the DDUFM. It was an "extra" from DHP.



I could drill it out a bit. I have access to some carburetor orafice drills.

 

[jlccc]

Originally posted by WadePatton

What about over-boost? I'm hitting 38-40 on 4-5 and know that that's a bit much. My elbow doesn't appear to have any adjustment. It has a tiny orafice and a small hole to the outside, but I don't see a screw as some have talked about.



The boost elbow I'm using was not supplied with the DDUFM. It was an "extra" from DHP.



I could drill it out a bit. I have access to some carburetor orafice drills.

As long as you don't make the hole to the outside bigger you should be OK. You want to make the orifice bigger, not the vent hole.

 

[WadePatton]

thanks. When I get around to it, I'll report back

 

[WadePatton]

elbow with adjustment?

Is there one? Or was that a dream?



Am I right in that 40+psi is too much for an HX-35?



Or should I let it peak there and realize that it's working at the 30-38 range mostly.

 

[LSMITH]

Don't waste your time fooling around with drilling out an elbow. Get a "tee" fitting, put it in the boost line to the wastegate actuator. Take the third leg and put an adjustable needle valve in it. You now have a dial a boost elbow. Be aware when spec'ing out fittings that there will be times when the air is very hot, as in over 400* hot when at 38 psi. Dial in the peak boost you want to see and that is it. You can even put the fitting in the cab with a long hose to get the adjustments set right. I have played with this and it does work, but I have not installed a permanent version.

 

[Rob Thomas]

There is a elbow with an adjustment screw available, I got mine from TST. Also before I added the B-1, I was runnin' 45#'s from my stock HX-35, and it still works, FWIW.





Later, Rob

 

[Steve Campbell]

Lsmith...

Good Idea Thank you

 

[WadePatton]

but if'n I do drill...

I picked up a second boost elbow to play with, so I probably will do some drilling.



Questions: Which hole orafice to modify? Or exactly how does the vent to atomosphere play in this deal?



Isn't the vent aspect what you're playing with on the "T" and needle valve?



I'm not quite clear on the elbow system. The internal orafice is reduced from stock and a vent is added. My guess is that the restricted internal passage slows the wastegate response and the vent really limits the boost seen by the wastegate actuater. Thus more boost and more faster. (without getting into the fuel aspect of boost development)



Am I barking up the wrong brass fitting yet?



I'm trying to stay in the efficiency window of the 35 to keep from superheating the air and loosing density--as well as preventing extra stress on the turbo and associated components.



Rob - I could probably get 45# with a real clutch, but from all I've read that's not good for power.

 

[C. Harlan]

I know one thing... . They Grenade at 48-49 PSI!!! Look at my gallery for pics, and PM me for more pics!!!



-Chris-