Competition My Twins Got a Divorce

[Partyat33]

For the life of me I cannot figure out how I lost 25 PSI of boost and EGT's up 250 degrees. I have checked both turbos and they spin well with no play. I checked all the connections and they are tight. I put in a new spring in the external wastegate and cleaned and lubed the wastegate.



Behavior. When I first got them the made almost 70 psi right out of the box and the wastegate did a great job of controlling them. I could turn them down or up at will. Was running 50 psi towing with 900 degree temps.



Now I can make 55 psi max, but according to my guage in the cold pipe the big turbo only makes about 10 PSI.



I took the sping out completely and I could only make 1 psi, which is what I expected.



I put a weak spring in and I can make 30 psi, with the big making 15 psi. As I tighted the spring total boost goes up, but big turbo boost goes down.



I am at wits end. Any ideas.



Dennis

 

[Bandit1]

did you check for boost leaks? i had a hole rubbed in my turbo side intercooler boot and took me a lot of looking to find. or is your gauge ok? hole in the line from the guage.

 

[Summit]

"Home Made" twins in your sig doesnt give much info, what turbos? are both wastegated? or just the top one? pics would be more helpful.



sounds like the big charger is wastegated and is stuck or sticking open.



as mentioned earlier, have you checked for boost leaks? pressurize the system from the intake back to the inlet of the top turbo and pressurize to 70 or 80 psi and listen.

 

[getblown5.9]

check first for boost and exhaust leaks, if nothing is leaking i would start testing your VP44... have heard of them getting weak and power/boost dropping with lack of fuel but EGT's still going up since the timing gets messed up

 

[Partyat33]

Its a Piers HX-35/40 Hybrid with a 12 CM housing, wastegate bolted shut, bottom is a non divided HT3B 22 cm. One big wastegate on the manifold.

 

[Sled Puller]

Intercooler is rusted out.

 

[Partyat33]

Gene, would that explain why so little boost from the big turbo ? Have you ever measured the pressure in the cold pipe between the turbo's ?

 

[Summit]

i would check for exhaust leaks, then pull the wastegate off and make sure it's not sticking open a little,,, it doesnt take long if you make a ton of smoke for the soot to start to build up a little. it sounds like somthing is causing the drive pressure to drop and not spool the big turbo enough.

 

[JasonCzerak]

Intercooler is rusted out.

If one could manage that feat with aluminum, that would be impressive! If D/C would figure out how to paint an innercooler so that the paint doesn't peal off, that would be even more amazing (I've seen this on 12 year old CTD!)

 

[Sled Puller]

Ok, Jason how about the CRAP aluminum they use has corroded away!!!!!:-laf



Dennis,

I never did on mine, but you shouldn't have a lot of boost on the big one. More than 10 though.



I would say yes, if you have a hole in a tire, you can't get it to hold pressure, right?

 

[Partyat33]

All is well. After thinking I knew what the problem was I consulted an expert. JR Adkins. He gave me the clues I need to do some testing, and I found a huge leak on one of the boots of the cold pipe. Took a little run last night and got out of it at 64 psi. Big turbo was making way over 30.



Thank you Mr. Adkins.

 

[Sled Puller]

did you check for boost leaks? i had a hole rubbed in my turbo side intercooler boot and took me a lot of looking to find. or is your gauge ok? hole in the line from the guage.

First reply, and you had to call JR Adkins????:-laf



JR just read the thread and answered you, he is the turbo GURU!!!

 

[JReiley]

sounds like a fueling problem! what is the pressure the lift pump is supplying to the vp-44, and is it the factory pump?