Sam Harris
Supporting Member
Are the PPV swaybars solid?
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
- Start date
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Factory bars are hollow, never heard of the ppv having a different sway bar than factory nor have I seen any different part numbers specifying PPV, the hellwigs are noticeably larger
But I’d be willing to bet your stock ones are hollow. I installed the solid DJM’s on my 02 Denali and they weighed a ton compared to the hollow OEM ones. Size isn’t all that matters. AFAIK GM didn’t offer solid ones, PPV or not.
ISTR that when I was ordering front sway bar bushings there were two size options for the OEM bar.
I don’t have any particular interest in stiffer suspension myself, (the opposite actually) but I’m always interested in technical discussions. My education on the topic of torsional rigidity was that most of the strength is in the outside of a tubular rod or shaft. And the stiffness will have as much to do with the metallurgy as with the physical dimensions.
It would be interesting to see some data on the deflection (AKA spring rates) of factory bars compared to aftermarket.
And of course the bar is only one element in a complex spring assembly, together with all the bushings and end link compressible bits.
Fascinating stuff.
Sam Harris
Supporting Member
With the upgraded suspension components for ppv’s I’d be surprised if they weren’t upgraded as part of the ppv package, but I have no knowledge one way or the other.
I am 99.99% sure there is no difference otherwise you would see people using them and parts places would denote "ppv" the factory ppv suspension is lowered like 1-2" with shorter springs and different shocks, brake calipers have heat resistant parts and slightly thicker rotors and semi-metallic pads, 1/8" thicker radiator, oil/trans cooler. dual battery option but that's about it other than weight reduction by means of no interior insulation. the only other differences are in the bcm programming and wiring for lights/radio, cluster and dic button delete, there's no secret sauce other than maybe some transmission shift programming so it will stay in a lower gear for pursuit purposes. oh and the "speed rated tires"
Stiffer sway bars won’t make the suspension stiffer. They keep the body from flexing on the suspension in relation to the frame, corner-to-corner, side-to-side and front-to-back. The result is it will stay more parallel to the roadway during hard cornering or braking. Less body roll during cornering and less porpoising during hard braking. You might be surprised how much better the handling is.
Yeah, that’s 100% true. Except I’m the guy with a 6” lift for off-road. I’d prefer the body not do what the tires are doing.
At some point I may remove mine and donate it for research.
Sparksalot
Supporting Member
The ends are very much a machined single piece. I can’t imagine how these would have been extruded with a hollow in them.
Carroll Smith was one of the lead engineers in Ford's Le Mans effort. He wrote a series of books on race car preparation and development. In his early books he covers the basics and some of that is chassis design, spring rates, motion ratios and their affect on wheel rate.
He also has a section on sway bars, why you want them and why a heat treated tubular sway bar is far superior to a solid one. Oh, and he did a lot of Baja race car development later in his career where in had to unwrite a lot of what he had written regarding suspension design.
All extremely interesting stuff.
PS - You can always tell someone who hasn't read his books when they proudly state they used Grade 8 bolts for something on a motor vehicle or aircraft...
