PPE Boost Valve vs. Kennedy Boost Valve

[paoutdoorsman]

I'm assuming these two products do the same thing...

Does either have an advantage over the other that I would notice with a stock LB7. I do have a Kennedy UNI Filter, and a full Flowmaster exhaust.

[More Power]

I haven't seen PPE's unit. I've used JK's for nearly a year. Works well. We'll have to ask Joe at PPE to keep us in the loop. :)

Jim

[Mark Rinker]

They do essentially the same thing, but are different when it comes to adjustability and how they signal the wastegate actuator to do its job. I have run both (not at the same time, of course) on my '01 to compensate for additional fuel rates in the form of Predator tunes and/or propane.

The Boost Valve allows you to turn up boost in a linear fashion, and is adjustable. The PPV valve is fixed at one setting. Both work by delaying the wastegate from opening, increasing boost, but do it in two different methods.

The PPE unit is a small restrictor to the boost pressure 'feedback hose' that acts on the wastegate actuator. The KD unit uses a two peice, threaded and machined housing enclosing a spring and ball valve, making it adjustable. I think you can envision the two very different boost curves created by the two approaches.

The Boost Valve allows the turbo to spool up, and releases pressure quickly once you have hit the boost threshold you've dialed in. The PPE delays the opening of the wastegate in a problematic way (incorrect boost information at the wastegate actuator), and under high fuel / high loads / heavy foot can let boost thresholds get out of range. In comparison, the KD design bleeds off boost more predictably in my experiences and use.

If you use the PPE, you could take the approach of adding fuel to match the new boost curve. If you use the KD valve, you can adjust your boost to match your fuel. Are you planning to run a tuner, box or secondary fuel?

Search this forum for more information and opinions.

[paoutdoorsman]

There are so many different opinions out there on tuners I'm not certain what I will ultimately run. I'll probably end up buy several before I find what does what I need well. My new Predator just arrived a couple days ago, and I've talked with Edge about the Juice/Attitude, and the possibility of the release of an "Evolution" for the LB7. I called Kennedy to discuss boxes and custom but he's a very busy man and I was referred to his web site for information. It gives good info on the theory of each of the options out there, but no real world results in terms of which is best for my application.

I don't hot rod, smoke my tires, race, or enter pulling competition. I let the truck shift short most of the time so I rarely see anything over 2500 rpms... The reason I was thinking a boost valve would be an advantage. I basically use the truck for a toy hauler and am looking for the best combination of pulling torque and fuel economy.

I just tuned with the Predator to the tow tune, but have not towed with it yet. I'll probably buy an Edge Juice as well for comparison to see which works the best for my needs and driving style - unless someone that has experience with both can chime in and share their experience. :)

Bottom line; I'll probably be tuning with something in the end, but nothing close extreme.

[Mark Rinker]

I am familiar with Predator tunes, but suspect the programmer I bought last year was probably reflashed to a version from from '03 or '04 and may need updating. The tow tune is a nice improvement over stock, but the higher settings are 'choppy', noticeable new diesel rattle, and black smoke (overfueling).

The KD switchable tune on my 2002 is smoother than OEM and makes 20+ empty MPG on the economy/tow setting, which is noticeably stronger than OEM stock when towing. I never saw that kind of empty mileage stock or with the Predator tune. The truck has very little diesel rattle and is very smooth through all RPM transitions and shifts.

I run about 8-10psi boost on the '01 with the BV at 60-65mph unloaded, and about 12-15psi at 60mph with trailer and cargo averaging 10K. I will see max boost peaks of 25psi, and average about 12 mpg towing most loads, running about 20% propane when loaded, straight #2 when unloaded.

Since our trucks need to be 99% available for my business, I have avoided power adders using other 'boxes' (Edge, Banks, etc.) that can fail and cause the truck to be stranded. I like tuners (Predator) for a selection of tunes, pulling codes, etc. and KD's replacement ECMs even more for reliability and simplicity. Seriously, who needs 5 settings?

At the risk of sounding like a commercial, KD is selling a tune that is better than factory OEM. My driver even noticed it after the ECM' was swapped without his knowledge.

He remarked..."Have you noticed how well the '02 is pulling? It is so smooth and quiet compared to the '01."

I don't know much about the tuning process, but tow daily and have seen big differences between the products mentioned in this thread.

[paoutdoorsman]

Thanks Mark. I've read another post or two where you praise the John K's custom tune. I seriously considered it for a while but there are so many unknowns and at $1,250 ($700 custom tune, $300 ECM, $250 gauges), the cost is something I'm just not sure I can justify. The boxes and programmers will return a large portion of my investment for the ones I choose not to keep, but a custom ECM? Not likely.

I also question the need for 5 settings for my situation. I really need one good all around tune that has excellent driving/towing manners and gives me the fuel mileage I bought the truck for. But I have heard guys mention the need to tune back to stock for icy or certain snow conditions to keep from breaking traction so easily - so that is an advantage that the tuners offer.

Back to the differences in those two boost valves; The adjustability sounds like it could be a benefit, but could it also be a detriment if incorrectly adjusted for a particular setup? If I understand correctly, with the spring and ball setup of the KV, shortening overall length would increase spring/ball seat pressure and allow more boost to build before actuating the wastegate? And lengthening would decrease ball seat pressure and lower maximum boost? I'm not sure I've ever had the wastegate actuate running in stock form. How would I know?

[paoutdoorsman]

Ooops, just realized I started this thread in the Performance Shop!! Sorry! Looking more for economy/tow performance rather than making big power. Meant for this to be in the Duramax 6600 forum.:o :o

[DmaxMaverick]

Ooops, just realized I started this thread in the Performance Shop!! Sorry! Looking more for economy/tow performance rather than making big power. Meant for this to be in the Duramax 6600 forum.:o :o

You did start it in the Duramax Forum. I moved it. Even though you are not looking for high performance, you are discussing a performance upgrade, which is appropriate in this forum. The Duramax Forum is primarily for common issues and discussions. This would also be appropriate in the Accessories Forum. The feedback you are seeking will likely be inline with discussions here. I can move it back, if you like. But, I think it is best served here.

[Mark Rinker]

Back to the differences in those two boost valves; The adjustability sounds like it could be a benefit, but could it also be a detriment if incorrectly adjusted for a particular setup? If I understand correctly, with the spring and ball setup of the KV, shortening overall length would increase spring/ball seat pressure and allow more boost to build before actuating the wastegate? And lengthening would decrease ball seat pressure and lower maximum boost? I'm not sure I've ever had the wastegate actuate running in stock form. How would I know?

Q1) The worst you could manage would be to set an overboost code, which illuminates the SES light and resets with the next key cycle. I haven't tried cranking up boost to the MAX, but have rarely heard of people driving the turbo into a 'bark' due to overboost, and never with the PPE or the Boost Valve. I purposely set mine very conservatively as I don't want to stress engine internals.

Q2, Q3) Exactly. Exactly.

Q4) You wouldn't with the DMax. Its not audible. You can 'see' it actuate with gauges when the boost peaks. Then you make a setting change, go for another run, and the boost peak changes. Thats the wastegate opening, and bleeding off excess turbocharger pressure.

I wish the DMax turbos were LOUDER! My 6.5 is fun to listen to and personally, I never tire of it. Back on the farm, the 4630 John Deere wasn't that noticeable when working, but would still be spooling down as you stepped out of the cab, engine off, after a long day plowing. It was a great sound...