Quote:
Originally Posted by wood4heat
Dropping it down to third seemed to take care of it but who wants to down shift when there is ample power to pull the higher gear? Who wants to downshift, right? I mean, it's a TON easier on the engine and transmission when you run 3000 RPM in 3rd than it is to run 2000 RPM with a load behind the truck. Seriously. These engines will run 3300 RPM 24/7 and it's a lot easier on the engine and transmission to run a lower gear. I don't even try towing that kind of load in 4th gear if there's any chance I'll be in the surge area of the compressor map.
With all of that in mind what are the pros and cons of the various things people do to cure turbo surge? At the moment I'm leaning towards an ATS ported housing with my factory impeller. Anyone run this setup? Did it work, add noise, any change in performance, what can you tell me? The ported compressor housing is the more efficient way to cure surge...and it's almost 100% effective. The stock compressor wheel moves more air and it's quieter (more of a whine than a whistle) than the stepped-blade compressor wheel. The whole idea of the ported housing and/or stepped blade compressor wheel is to slightly lower the airflow.
I've also read a lot about the Wicked Wheel making a lot of noise. Any truth to this or have people blown the issue out of proportion? How well does the WW alone work in terms of surge? It depends on the filter setup you're using. With the AFE, you'll definitely hear it. Another thing to consider is that changing the compressor wheel is more involved than just changing the compressor housing. To me, it's worth every penny to have to disassemble less to gain more.
Last I've read an adjustment to the waste gate will eliminate surge. Seems like you would also be giving up boost, is that correct? I don't agree with this method as the factory wastegate is a horrible design and only bleeds exhaust drive pressure from the passenger-side of the engine.
Any other advice short of going back to stock or quitting towing is welcomed. 
As always thanks for your input!  |
What we're trying to do is keep the compressor from moving a certain amount of air in the operational range where there is insufficient drive pressure on the turbine side to maintain the airflow that the compressor is trying to make under certain operational conditions. When the airflow of the compressor is above what can be supported by the turbine, we get surge. This occurs with a "chipped" 7.3L very easily as the added fuel and heat driving the turbine causes the compressor to spin faster under load than stock in the mid-RPM range. Surge is compressor map related, which is why it can be solved by a few different methods. One of which is a less restrictive turbine housing. By reducing the drive pressure of the turbine, it is going to spin the turbocharger shaft slower under all driving conditions should all else remain the same, thus reducing airflow.
In lieu of spending any money on hard parts, it's just easier to downshift and let the engine be happier.