Having EGT problems with twins

C

CrashCade

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Mar 28, 2007
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142
I have this posted a couple of places. I really need some help and ideas...

OK, so I have a 62/65/12 over an HT3b. I finally was able to put a boost gauge on the bottom turbo. I was only seeing about 10-12 psi @ 50psi overall. Well, I found the problem and it was a bearing on the the HT3b, so I swapped out bearing housings and compressor housing with a new turbo today and now I am having high egt problems. I opened my waste-gate up so I am only hitting maybe 45psi. However, my EGT's are through the roof.

On stock programming I am seeing 1100*-1200*. Before this problem I was barely able to hit 1200* with electronics on Kill. I cannot find a boost leak, my overall boost is still 45. My bottom turbo boost is only like 10 or so.

What should I be looking for. I have to get this figured out first thing in the morning as I am supposed to be on the road. Any ideas would be great. I am pulling it back into the shop in the AM. New turbo parts were very tight and looked great. I am going to drop the intake off in the morning and make sure the compressor wheel isn't hitting anything. But, I am at a loss with this one.

If my top turbo isn't being fed air will it run hot like that? Is there some reason the bottom turbo wouldn't spool and feed the top?

Thanks For the Help Guys. I am Stressed!
 
What size exhaust housing on the 3b? I had a 3b with a 22 cm housing and when total boost was 10 lbs. the 3b was making 3 lbs. Instant boost out of them. Is your wastegate opening up? Sounds like not and not letting the big turbo take over.
 
I am not really sure on the Exh housing size. I am testing the WG and making sure everything spins freely.
 
You should see alot more than 10 psi out of the primary. I would guess the turbine housing is too big.
 
Ok, everything looks and spins and moves great! I am at a loss. Nothing a match and gas couldn't fix... J/K!
 
Jason, bring your truck down here, im home today and only 20min from you and we'll figure it out. could be a couple things
 
Al, I have tried everything with this truck. I am ready to go trade it in. I have adjusted the WG to start opening at everything from 8-20 PSI. Completely shut it off with a ball valve. Nothing makes a difference on that bottom turbo. PM your number. I might be able to come down that way.
 
Do you guys think that if my fueling was insufficient or had a problem that this could be my problem? Would that cause the high Egts and not being able to light the bottom turbo?
 
id come up there but im waiting for a delivery that i have to sign for. if you can come down id sure do what i can to figure it out.
my truck did similar thing 2 months ago, wastegate for big charger was stuck open and boost was only 18lbs, egts went to 1975*:charger:
 
Well, I have backed my wastegate all the way out. I am swapping boost gauges to see if that is my problem other than that I am at a loss. My egts will just continue to climb until I lift and it gets hot. . . way hot. Before I started having problems I could get this thing over like 1375 or so. I still only see a max of 10psi out of the bottom turbo and if I let of the gas it will surge up to 15-20psi or so.

If I cannot maintain Rail pressure would that be causing a problem like this? Thanks Guys
 
Set your progamming to mild...this will help eliminate rail problems.
How tight is your top wastegate? The tighter this is the less the bottom charger will work...less top end power.
If you are 50psi overall and 10 on the bottom, loosen the top wastegate some to see if this improves.
EGTS should reduce by bettering your splits.

Rob
 
WG is very loose.I need to put some air on it and see what it is really set at. I am having the same problems on stock settings as well.
 
OK so based on your first post. You installed new housings due to poor performance ie low boost. How did the cartridge feel and look.
 
onetun said:
OK so based on your first post. You installed new housings due to poor performance ie low boost. How did the cartridge feel and look.
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I left the exh housing on the truck and changed out the bearing housing with new cartridge and new compressor housing. The reason for changing them was poor performance. When I got the hose off of the inlet on the secondary I saw that the compressor whell was damaged and making contact with the housing. Swapped everything out and now hear I am.
 
Are you sure the turbo's are the same part number or have the same turbine wheel? It almost sounds like a clearance issue on the turbine wheel. I would try taking the turbine housing out from the old turbo and put the one in that came on the turbo you are trying to use unless you know (by measuring) that the turbine wheel is the same size.

In the first post you stated you swaped the HT3B (primary turbo) but later said you swapped the secondary. Assuming it was the 3B I would check the 62/65/12 for compressor wheel damage too if the 3B compressor scrubbed the housing. It can send parts of the wheel into the 62 and cause problems as well.

Short of that, pressure testing the system to make sure there wasn't a leak would be a high priority. It doesn't take a very big hole to lose a lot of boost.
 
Idaho CTD said:
Are you sure the turbo's are the same part number or have the same turbine wheel?
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They are the same part number and the wheels looked to be identical.

In the first post you stated you swaped the HT3B (primary turbo) but later said you swapped the secondary.
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Sorry I meant the 3B. I will pressurize the whole system and see if I am leaking somewhere.

I will pull the 62 back apart and make sure everything is good.
 
When I set the wastegate on the first twins I took the cold pipe off and let the big turbo blow into air. When set right it wouldn't go over 25 psi no matter how much fuel I put to it.
 
gwhammy said:
When I set the wastegate on the first twins I took the cold pipe off and let the big turbo blow into air. When set right it wouldn't go over 25 psi no matter how much fuel I put to it.
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Do you mean the top turbo wouldn't go over 25psi?
 
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