Engine/Transmission (1998.5 - 2002) Barking Dodgezilla

[NoSeeUm]

Hoping to have a little help understanding this one.



OK I finally broke down and upgraded my turbo. I installed a 8 Blade / 14cm waste gated Dodgezilla. After the initial break in, my initial results were not what I expected. The first 4th to 5th gear shift at about 25 psi of boost I barked it. This is my first aftermarket turbo, so immediately the lead cannon ball hit the bottom of my stomach.



Further testing proved that anything above a normal driving mode, where I did not treat the throttle pretty gingerly would bark the turbo when I let off if boost was above 20 psi. I have read about 20 bazillion threads on the Dodgezilla, no one ever complained about barking or surging problems. In fact, the City Diesel Tech said I was the second person he had ever heard about and the first one turned out to be turbine related.



Just my luck..... :{



A little back ground:

I broke the first rule (sadly for me, a long string of breaking the first rule), which is "If it is not broke, don't fix it". I had been running a electric waste gate controller, set at 35 psi, on the HX35. It had been working really well, so I hooked it up to the Dodgezilla. But in my defense, I had talked to a City Diesel Tech before I did it, and got the plan blessed off.



Well... .



I removed my electric set up, and connected the boost elbow that came with the turbo. I believe, that it was set for 40 psi. I did bark it again, but only once after coming off of WOT with the TST set at 9. So I loosened up on the boost elbow 1/2 turn and tried it again. NO BARKING AT ALL?



I don't know much about how all this "orkestrates" together and it has me confused. Other than the initial problems, the turbo performs very well. Runs a little hotter when it is loafing, but cools everything right down. Currently, my maximum boost is about 38 psi (at the manifold) and it does not bark.



Anyone have a good idea what goes on for me?



Thanks;

Jim

 

[NoSeeUm]

More testing... .



I can hammer the throttle almost like I could with the stock HX35. I have not barked it since I set the waste gate lower. I am a bit more careful letting off now though.



I still have no clue why it was barking so bad, but it seems that in my case the DZ likes a little bit of waste gate creep to keep it on the MAP. Pretty close to the HX35, with the Smarty and the Helix 2 the spool up is very quick. However, the drive pressure is noticeably lower until I get up to the around 35 psi of boost then it shoots up to 55 psi. Which is still lower than the HX35, where I could peg my 60 psi gauge. I am guessing that is when I the waste gate opens. With the restriction in the exhaust brake elbow I expected the higher drive pressure after the waste gate opened.



Back to the barking. Maybe I was just building pressure in the piping and the intercooler so fast that it was quite a bit higher than the pressure in manifold. The manifold is where my boost gauge is connected. I can see how this might cause the bark when the manifold pressure is still relatively low. Unfortunately, I did not have a gauge connected to the compressor discharge to verify this and I don't want to back to backing the heck out of it just to test the theory.



At any rate problem solved and I am back to re-calibrating my brain to try and follow the first rule. Wonder how that will last?



Jim

 

[BTowler]

Jim,



How did you get 60psi out of an HX35?!?!?!? :--) I thought they dropped off at about 37psi.



Bruce

 

[NoSeeUm]

Jim,



How did you get 60psi out of an HX35?!?!?!? :--) I thought they dropped off at about 37psi.



Bruce

LOL

Only if you are really good Bruce.....



Actually, I might have presented it in a confusing way. The 60 psi I was talking about was DRIVE pressure not BOOST pressure. For my set up with the HX35, with the TST on kill I got 35 psi boost at 60+ psi drive. Kind of scary, one reason I bought the Dodgezilla.



Jim