Engine/Transmission (1998.5 - 2002) Power at 17,000lbs GCW

[pcarlson]

When I came down from Alaska I was at 17,000 GCW, per the scale, and I had plenty of power to pull the hills and 7% or greater required a shift down to 3rd, otherwise pulled like a champ.



Question is that with the EZ and 1. 5's the most I see with the HX is 32 psi. The HY I took off hit 34. Is that all I should see out of the HX? If I have a leak I sure cannot hear it of find it at any of the connections. Like I said there is plenty of power just seems less boost than what others are running and less after the tubo swap.

 

[Sticks]

You may very well have a boost leak, and I am betting it is the boost elbow (I just went through that). Try removing the elbow and putting in a 1/8npt plug. No need to hook up the trailer, you should be able to hit 40+ unloaded on the highway under WOT (back off before you cross the 40psi mark!). If you still only get the 32psi then you need to start checking your boots, intake hat gaskets (grid heaters - 2 of 'em), the line to your boost gauge...

 

[JBlock]

My guess, that the new HX35 has significantly less back pressure and that why you drop 2 psi at WOT. I had the opposite with suppertuner 50HP program and rv275. Pressure when from 26psig to 29psig (with a TAG that a -2psig) when i switch from the HY35.



Joe

 

[Sticks]

With 85hp injectors, he should be able to hit the 35 - 40# no problem. It is not the difference between the HX and HY. It is the boost elbow controll rather than the turnubckle (unless he does in fact have a boost leak elsewhere in his system).



To clarify my first statement, I did what I recomended above, because I could only get 30#'s with my stage II injectors and the Edge EZ. I had two boost elbows, and during the change from the OEM turbo to the warranty replacement, I PIF'd one of my elbows to a local TDR member. I gave away the one that would let me hit 39#'s and ended up with one that would only let me get 30#'s. Found this out Thursday morning when I plugged my boost elbow port on my turbo.

 

[pcarlson]

Sticks,



I will check the elbow and hose. The elbow came out of my EZ box so it should be the right one. I will check for a leak there or at that little hose. If I can find a plug I will put that in and check it.



I found traveling down the psi was the same with or without the TAG. Just spooled quicker with the TAG and gave a really nice turbo sound with the TAG.



EGT's were never an issue as I had to really stand on it once to just hit 1300.

 

[pcarlson]

I think I might have found it. Sticks you had me look at the elbow and low and behold the hose off of the elbow had a hole in it on the back side of it.



Plus I moved the down pipe as the connection boot from the compressor was rubbing on the A/C switch, no hole luck would have it. So I will try this out and see if the boost goes up.

 

[Sticks]

As far as I know all the boost elbows have a bleeder hole in them, as well as the reduced opening to the wastegate. The bleeder hole helps regulate the pressure so the turbo can be hitting a higher boost (in our case 30 psi) and the pressure going to the wastegate is only at 20. I am not sure how they calibrate the elbows, but some of them are set low. I don't know if it involves drilling the bleeder hole larger, or if it is too big. I plan on buying a street elbow and experimenting with it to see if I can make one that will allow 36 - 38 psi pressure (turbo side) at the same time it hits 20 on the wastegate side.