What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Sam Harris]

Okay, with all this Hellwig chat, I finally looked them up.

Bar for the front is 1-1/2”. Rear is 1-1/4”. Which is exactly what my PPV already has. Hmmm.

View attachment 277933

Are the PPV swaybars solid?

 

[Doubeleive]

Okay, with all this Hellwig chat, I finally looked them up.

Bar for the front is 1-1/2”. Rear is 1-1/4”. Which is exactly what my PPV already has. Hmmm.

View attachment 277933

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

 

[Rocket Man]

Okay, with all this Hellwig chat, I finally looked them up.

Bar for the front is 1-1/2”. Rear is 1-1/4”. Which is exactly what my PPV already has. Hmmm.

View attachment 277933

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.

 

[Bill 1960]

Okay, with all this Hellwig chat, I finally looked them up.

Bar for the front is 1-1/2”. Rear is 1-1/4”. Which is exactly what my PPV already has. Hmmm.

View attachment 277933

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]

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

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.

 

[Doubeleive]

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"

 

[Rocket Man]

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.

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.

 

[Bill 1960]

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]

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.

The ends are very much a machined single piece. I can’t imagine how these would have been extruded with a hollow in them.

 

[wsteele]

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.

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...

 

[Rocket Man]

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.

Sway bars work even better for lifted vehicles. There’s nothing worse than body sway when you’re way up in the air. My buddy has a ‘18 3500 HD Silverado with a 10” lift and 42” tires and big sway bars were part of the deal when he had a shop install everything. It stays pretty damn flat during cornering or braking. I
And when you’re off roading gravity is at work so more sway definitely isn’t better, it just means you’ll lean more.

 

[Rocket Man]

The ends are very much a machined single piece. I can’t imagine how these would have been extruded with a hollow in them.

Well....they are. My stock ones had the same solid ends. They’re still hollow tubes.

 

[wsteele]

Sway bars work even better for lifted vehicles. There’s nothing worse than body sway when you’re way up in the air. My buddy has a ‘18 3500 HD Silverado with a 10” lift and 42” tires and big sway bars were part of the deal when he had a shop install everything. It stays pretty damn flat during cornering or braking. I
And when you’re off roading gravity is at work so more sway definitely isn’t better, it just means you’ll lean more.

I think he was alluding to when he is waaaay off-road and wants the sway bars not there so he gets the most wheel articulation, trying to keep all four in contact as much as possible.

 

[iamdub]

Well....they are. My stock ones had the same solid ends. They’re still hollow tubes.

Ends are stamped flat on the stock ones. The thick paint makes them look solid. It's just a bent tube with the ends squashed shut.

 

[iamdub]

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.

I'd advise against removing them for any street duty. One abrupt emergency swerve or lane change could very easily start an oscillation and likely roll it. You could get sway bar disconnects for when you're on the trails.

 

[Rocket Man]

I think he was alluding to when he is waaaay off-road and wants the sway bars not there so he gets the most wheel articulation, trying to keep all four in contact as much as possible.

Oh yeah. Duh.

 

[RooTBeeRthe1st]

Here are my averages after 145 refuelings:
View attachment 277930

Note: E0 and E10 are always 93 octane. The only time this motor sees 87 is when mixed with E85.

Bill, there are lots of stations that sell ethanol in Florida but it does depend on where you live. There's but two in the Daytona area, 8 or 9 in my county, dozens in and around Orlando, about a half dozen in the Tallahassee area. Don't you live near Roger in the Naples/Fort Myers area? There's about six or seven Marathons, Racetracs and Union 76s and some are real proud of it!

I run it for three reasons, for the fun of it, for its cleaning properties and when mixed and or when the price is right, because of cost.

If you look at the chart posted above, when we mix E85 and gasoline to get an alcohol content of E15 or E20, my motor at least, gets it best gas mileage. At four cents a mile difference, it adds up to twelve dollars less spent on fuel over 300 miles.

Of course, those who burn 87 will have completely different numbers and experiences. Since getting my license at 16, I've endeavored to stay away from low test gas whenever possible, it's just not good enough for these old fashioned motors. DI motors? Different story as Gary taught me.

I have a giant Lead shoe I wear while driving, but with the border patrol style front bumper cut, tow mirrors, 33" tires, and front end lifted 3"s(rear only 1"), I average about 8.5mpg on corn and 10.5ish(I haven't run it in a long time to do any numbers comparisons) on 87.
All highway is maybe only one or one and a half MPG higher for each.

 

[Doubeleive]

The ends are very much a machined single piece. I can’t imagine how these would have been extruded with a hollow in them.

what color are they? solid flat black or a different finish?

 

[RooTBeeRthe1st]

On another note.

Took a while, but it finally doesn't like the Corsa.
Guess I should actually put my wide band in that I've had laying around for at least 2 years.
Time to relearn HPtuners and do some maf fixing to correct the lean fuel trims.

 

[Sparksalot]

what color are they? solid flat black or a different finish?

Front is a matte, phosphate like, finish. Rear is flat black. @Rocket Man the ends of the rear are pinched closed if i look hard. I've never heard of spring steel in a tube before.