pros and cons of options to remedy turbo surge?

wood4heat · #1 Tue, July 26th, 2011, 02:50 AM

I'm running an '03 7.3 4X4 auto with 4" turbo back exhaust, an AFE stage II intake and Phoenix chip. Running the 80hp DD tune without a load it runs great with no surge. Towing light (around 6500lbs) it begins to surge only if I try pulling a hill at low RPM with lots of throttle. This past weekend I was pulling between 10,000 and 11,000lbs still on the 80hp DD tune. The exhaust temps hit 1200° a handfull of times but only for 10 seconds or less before I backed out of the throttle. With this load turbo surge was more of an issue. 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?

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?

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?

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?

Any other advice short of going back to stock or quitting towing is welcomed.

As always thanks for your input!

***cleatus12r*** · #2 Tue, July 26th, 2011, 09:11 AM

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.

rammertide07 · #3 Tue, July 26th, 2011, 09:23 AM

I agree 100% with Cody.

I went with the x-wheel because its more cost effective. It also does whistle a lot louder and flows less air. I can hit about 20-22psi when I could hit 29 with the factory wheel. I hear going over 24 is bad for the turbo but I'm not sure what is safe reccomendation for the x-wheel sense it does flow less air. I didn't really see a power loss. Instead I found smoother power/acceleration and no more surge.

I've also thought I might be seeing less boost because I attempted, and suceeded, in taking the housing off without disconnecting the E clip on the waste gate rod. It took a good bit of tugging and pulling but I slipped the waste gate and bolts off of the housing by taking the housing off first. Probably not the safest way to do things but after laying on top of my engine for 4hrs I was wanting to get the job done. After I got the housing out, I slotted the holes used to secure the waste gate so it would slide right off if there is ever a next time.

wood4heat · #4 Tue, July 26th, 2011, 11:50 AM

Would it be recomended to tow in third rather than fourth or just to downshift on the hills?

Would towing in third have a substantial impact on my mileage?

Love the way it tows with your tunes by the way! Seems effortless!

Thanks again.

***Power Hungry*** · #5 Tue, July 26th, 2011, 01:15 PM

Ford's recommendation is to always pull out of O/D. I tend to recommend pulling in whichever gear is going to let you pull comfortably without excessive EGTs or Trans temps. When pulling modest to heavy grades, it is still recommended to downshift or drop O/D as this provides a 1:1 through the transmission. This is less stressful on the transmission components and provide good pulling power to get through the grades.

Yes, driving without O/D will absolutely have an impact on your fuel economy, so use O/D when you can.

wood4heat · #6 Tue, July 26th, 2011, 02:24 PM

Got it, thanks!

I kept a close eye on my gauges throughout the trip. Averaging 65mph in 4th with outdoor temps between 90° and 94° my trans ran 177°-181° and EGT's were mostly between 700° and 1000°. For what I was pulling I felt like it was doing pretty good in terms of temps.

rammertide07 · #7 Tue, July 26th, 2011, 02:41 PM

The way I did it, is if my transmission is searching gears a lot (in and out of OD) I'll just turn the OD off.The transmission knows when to give you more "umph" if you are needing it, so if its not changing in and out you are good with leaving OD on IMO.

muns53 · #8 Mon, August 1st, 2011, 12:34 PM

I put a Wicked/Whistlin' Wheel and a Turbomaster on my turbo (and also rebuilt the guts with a kit from Guzzy at the same time). The WW provides lower power, is much louder (and I just have the 6637 air filter), but seems to spool quicker and does not surge. The Turbomaster allowed me to adjust the performance back up to the stock wheel and it holds boost right where I want it much better than the stock blow-off valve. So, it was a good mod overall for me to eliminate the surge in my truck. However, I'm sure there are other/better ways to go about it.