| Author | Message | ||
| Ron Walker (Prevost82)
Registered Member Username: Prevost82 Post Number: 390 Registered: 11-2003 Posted From: 208.181.210.47  Rating: N/A |
Hi guys I've got an 8V92ta with around 120K miles on it. I've lost some power and tubro boost this year, all I can get is around 13 lbs boost. I was wondering if it could be the blower bypass valve. The turbo was rebuilt 20K miles ago ... I've change air filter and check the exhaust for restrictions and it all looks good. Any thoughts? Thanks Ron | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 250 Registered: 2-2007 Posted From: 205.188.116.203 Rating: N/A |
Exhaust manifold gaskets and pipes to the turbo. Clamps tight from turbo to engine? Due for a tune up? Hitting on all 8? Low fuel pressure, fuel in oil? #1 fuel instead of #2? | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 738 Registered: 8-2006 Posted From: 74.33.54.207 Rating: N/A |
If you want more boost pressure you will need to change the hot housing.13 to 17# is ok for 8v92 I get 15# from my 8v92 and when you use 20# and above the oil leaks will start good luck (Message edited by luvrbus on July 16, 2009) | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 251 Registered: 2-2007 Posted From: 205.188.116.203 Rating: N/A |
Cliff may be on to something, maybe your rebuilder kept your good parts.... | ||
| Ron Walker (Prevost82)
Registered Member Username: Prevost82 Post Number: 391 Registered: 11-2003 Posted From: 208.181.210.47 Rating: N/A |
No exhaust leaks, no fuel in oil, all clamps are tight. I think my fuel pressure is good. Could be ready for a tune up. I was getting around 17 to 20 lbs boost before and I had no oil leaks. I was at the rebuilder and watched them rebuilt the turbo ... and it's been putting out good boost until this year. What affect does the blower bypass valve have if it's not working properly? Would it not have the same result and I describe? Thanks Ron (Message edited by prevost82 on July 16, 2009) | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 252 Registered: 2-2007 Posted From: 64.12.116.203 Rating: N/A |
Ron, Pull it out and test it. The valve piston should move open with hand pressure and the internal spring will return the piston to closed if its OK. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 910 Registered: 8-2006 Posted From: 76.171.79.185 Rating: N/A |
Ron, Probably not the bypass valve. Turbos are exhaust driven, and to get boost, you must have exhaust. To get sufficient exhaust, you must have sufficient fuel to burn to make that exhaust. "I think my fuel pressure is good" ? ? If you haven't changed your fuel filter in a year, start there. To get full boost, you must have full fuel rack, and fairly high engine rpm. You won't get full boost when you are against the governor at 2100 rpm, because the gov has moved the rack away from full fuel to keep from over-revving the eng. Check your air filter, and make sure your throttle linkage is moving the gov speed lever to the full speed position with the throttle fully depressed. Smoke, as in black, as in unburned fuel? You don't mention it, so I would really look at throttle linkage and the fuel filter! G | ||
| Jack Campbell (Blue_goose)
Registered Member Username: Blue_goose Post Number: 133 Registered: 5-2007 Posted From: 71.100.201.35  Rating: N/A |
You should get no less than 21 lbs of turbo boost. If everything is good on a hard pull in third gear at about 1700 to 2000 rpm you should get over 25 lbs. If you arn't getting this you have a problem or too small of a turbo. Jack | ||
| Ron Walker (Prevost82)
Registered Member Username: Prevost82 Post Number: 392 Registered: 11-2003 Posted From: 208.181.210.47 Rating: N/A |
Well .. I don't think the turbo is to small because I was getting 20 lbs on a hard pull @ 1700 to 1800 ... now I'm not. I never run I over 1900 RPM on a hard pull I would say the throttle linkage is fine as it moves the gov speed lever to full position. I have put in a new air filter and have 2 filter minders (1 on the dash and 1 on the filter) and they are not indicating any filter restriction. I will change my fuel filters and see if that makes a difference. |