Z55 Delete planning

[R3cord303]

Howdy Ya’ll. I have a 2007 Tahoe LTZ 4x4 with the Z55 Autoride. Its got almost 220,000 miles on it with the OG front air struts and about 30,000 on its second set of rears. I want to put a list of part numbers together for when it kicks the bucket.

I know I want to run the Bilstein 5100s that have the adjustable height front shocks.

I have some questions:

1) What does ‘preload’ mean on struts? I keep seeing people talk about it but I don’t know what it means

2) for the Z71 NNBS vehicles what was the difference as far as the struts in front and the springs in the rear?

As of now what I think i want to do is get new front struts from rockauto and the set of the 5100 shocks from amazon, and have a shop install the Bilsteins set to the 2nd notch for ~3/4” of lift in the front, and order the non z71 non z55 rear coil spring for no ride height change in the back. That way I have a touch more clearance and travel in the front, and no change in the back. As far as resistors, What should I do?

Is there a way I can delete the air compressor so I’m not carrying it around?


Thanks in advance everyone!

 

[fireburban]

1.) Preload means the amount of pressure the strut spring is giving against the strut body itself. More preload will increase stiffness/height, and vice versa. On the bilstien design it will increase the lift by increasing preload.

2.) I'd use matching, front and rear shocks/struts if I was you. Difference is the rears are, shorter and softer in Z55/Autoride trucks, taller and stiffer on the Z71 (Non-Z55) models. Front strut springs I'm not sure are any different, but I could be wrong. You might want to swap them out at 200k+ miles. I kept the stock springs in the struts, but mine only have 75k miles on them.

You pretty much are wanting to do the same most of us have done or want to do. You'd level the front with the 5100 at 2nd notch, and put Z71 springs in the rear with a 5100 shock. Just remember the rear spring and shock setup is longer, so you'd get added travel. If I could it again I'd keep the front strut at factory setting and use the leveling kit strut spacer as the only lift, so I'd have no added preload in the front.

 

[R3cord303]

1.) Preload means the amount of pressure the strut spring is giving against the strut body itself. More preload will increase stiffness/height, and vice versa. On the bilstien design it will increase the lift by increasing preload.

2.) I'd use matching, front and rear shocks/struts if I was you. Difference is the rears are, shorter and softer in Z55/Autoride trucks, taller and stiffer on the Z71 (Non-Z55) models. Front strut springs I'm not sure are any different, but I could be wrong. You might want to swap them out at 200k+ miles. I kept the stock springs in the struts, but mine only have 75k miles on them.

You pretty much are wanting to do the same most of us have done or want to do. You'd level the front with the 5100 at 2nd notch, and put Z71 springs in the rear with a 5100 shock. Just remember the rear spring and shock setup is longer, so you'd get added travel. If I could it again I'd keep the front strut at factory setting and use the leveling kit strut spacer as the only lift, so I'd have no added preload in the front.

Thank you for the information! I have revised my plan. I want to get new front struts and do the bilsteins on the second notch in the front, and do the 5100s and the z71 spring in the back. I'm just a hair under 6 foot 5, and with shoes on i'm a little over and i friggen nailed my head on the lift gate twice this past weekend. Soooo I do want to keep a little bit of rake, but I do want to lift the vehicle up a little bit. Will the Z71 rear springs and the bilsteins on the second notch accomplish that?
I don't have a problem with a little bit harsher ride. I had an S10 before the tahoe with bilstein 4600 shocks and polyurethane LCA bushings. It handled great but it was pretty harsh. The tahoe feels like a lexus in comparison. I wouldn't mind stiffening up the front end to make it corner a little bit better.

 

[fireburban]

Yes that would accomplish it.

And I agree on stiffening up the front sway.

Good luck!

 

[R3cord303]

Yes that would accomplish it.

And I agree on stiffening up the front sway.

Good luck!

Thank you for your information! Very helpful!

 

[R3cord303]

@fireburban out of curiosity, would there be any downside to running the z71 coils front and back?

As far as I can tell on rockauto.com the part numbers are:
45H0426 front z71 coil

45H2164 rear Z71 coil

Is this correct?

 

[R3cord303]

Yes that would accomplish it.

And I agree on stiffening up the front sway.

Good luck!

Sorry to keep bugging you- for the ebay resistors you bought when you were doing your delete, do you just cut the plug off that went to the air shock, and crimp the resistor pack onto the harness and heatshrink it to keep water out? For the height sensor do you then just zip tie that off somewhere or what? I found that Arnott and Strutmasters both have bypass modules that hook into the z55 harness in the cargo area inside the vehicle, and you leave everything alone under the truck, but strutmasters wants $400 for theirs, and Arnott doesn't even have theirs listed by itself on their site...

 

[fireburban]

@fireburban out of curiosity, would there be any downside to running the z71 coils front and back?

As far as I can tell on rockauto.com the part numbers are:
45H0426 front z71 coil

45H2164 rear Z71 coil

Is this correct?

I would buy stock front strut springs, and the Z71 rear springs. I have all the part numbers I used listed here. Post #15

Only because I don't know the difference between the Non-Z55 and the Z55 Strut springs.

 

[fireburban]

Sorry to keep bugging you- for the ebay resistors you bought when you were doing your delete, do you just cut the plug off that went to the air shock, and crimp the resistor pack onto the harness and heatshrink it to keep water out? For the height sensor do you then just zip tie that off somewhere or what? I found that Arnott and Strutmasters both have bypass modules that hook into the z55 harness in the cargo area inside the vehicle, and you leave everything alone under the truck, but strutmasters wants $400 for theirs, and Arnott doesn't even have theirs listed by itself on their site...

I never installed the resistors. So I can't help you, I just reset my service light every time I start it up. I left everything unplugged and zip tied out of the way. I would think going the Ebay route would be better cost wise, even if they fail after a year or 2, cheaper then the bypass harness. My 2 cents!

 

[R3cord303]

I never installed the resistors. So I can't help you, I just reset my service light every time I start it up. I left everything unplugged and zip tied out of the way. I would think going the Ebay route would be better cost wise, even if they fail after a year or 2, cheaper then the bypass harness. My 2 cents!

Thank you again!!!