I own a 99 F350 psd and was wondering if anyone has played with the vacuum on the wastegate to hold boost longer. If you have please let me know how high you went before problems, if any?

 

I work in the engine test area at the Navistar plant where the Powerstroke engine is manufactured. I have "played" with these engines on the dyno and there is no advantage to modifying the waste gate actuation as far as horsepower/torque is concerned. And, since the entire system (including the waste gate actuation solenoid) is controlled by Ford's EEC 5 computer, if the intake manifold pressure isn't within the specified parameters, you'll get a check engine light throwing the computer into "open loop". My advice: Don't do it. There are better ways of getting more power. You need more fuel not more air. There are several companies engaged in diesel preformance (Hypertech is one). Most offer a "chip" upgrade among other things. That is the way to go.

 

I own a 99 F-350 7.3 When new , the waste gate did not seem to "work" as hard as it does now (in cold temps...below 30 degrees F) Even after my temp. gauge is in the normal range, the vacuum sound continues for another 10 mins. is this normal?
Greg

 

Just for your information, the wastegate actuates under boost pressure, not vacuum.

 

g2times I think you are confusing the wastegate operation with the EBPV operation. When cold the exhaust back pressure valve ( the EBPV ) closes a valve on the exhaust side of the turbo helping the engine to warm up faster.this is what I think you are hearing and when it is cold is normal.

The wastegate opens to bleed off excessive boost pressure.

 

The wastegate opens to bleed off excessive exhaust pressure.

Peak horsepower/torque isn't really affected. However, holding the wastegate closed longer does affect lower RPM power. Bleeding off exhaust through the wastegate is technically wasted energy. The Ford PCM is set to begin opening the wastegate at only 5 psi of boost. Hold the wastegate closed longer under lower boost situations, and you have better power down low.

Just about any chip or tuner will allow you to throw that overboost code. Depending on which PCM you have, you can overboost at either 22 psi or 24 psi. There are MAP line foolers to deal with that problem and allow you to go beyond that 22-24 psi range without setting a code. However, at those higher boost pressures (beyond 25 psi), the stock turbo isn't going to live long.

 

Thank you Pocket I stand corrected not enough coffee yet.

 

Thanks for the quick reply 1996pwrstrk. I now have one less worry in life ...and between you and me, I still think it sounds like a vacuum, even though it's the "wastegate actuating under boost pressure".