Moving the Top Speed Limiter

Husker_1911 · January 15, 2019

To preface this thread; I am not looking to go to Bonneville or the Autobahn. Now that that's out of the way... 98-99 MPH when it's still pulling hard, and is on T Speed Rated tires, is a bit of a let down. I don't go that fast all the time, but I have found myself hitting the nanny state leash a time or two on the toll roads not far from where I am. In the immediate future is a CAI cold air that I will need a DiabLew Tune update to get the best results from. My thinking is that when he does the update, he also moves the limiter. Here is my question: What is the max safe top speed we can set it to? I say max safe from the stand point of not exceeding the drive shaft's max rotational speed, what Complete Street Performance called "Critical Speed". The truck in question is a 2018 Silverado 1500 LT TX Edition, Crew Cab, Short Box, 2WD, 5.3L, 6L80, 3.42 G80 rear diff, one piece driveshaft, on a 265/65R-18 112T Tire. If going off the speed rating of the tires, one would say 118. The speed rating chart is common knowledge, but not the end all answer. Again, what I'm not sure about is the max speed of the truck vs rotation speed of the drive shaft with my combination of trans, rear diff, and tire size. I'm thinking... 110-115. Thank y'all in advance!

SS502 · January 15, 2019

6 minutes ago, Husker_1911 said:

To preface this thread; I am not looking to go to Bonneville or the Autobahn. Now that that's out of the way... 98-99 MPH when it's still pulling hard, and is on T Speed Rated tires, is a bit of a let down. I don't go that fast all the time, but I have found myself hitting the nanny state leash a time or two on the toll roads not far from where I am. In the immediate future is a CAI cold air that I will need a DiabLew Tune update to get the best results from. My thinking is that when he does the update, he also moves the limiter. Here is my question: What is the max safe top speed we can set it to? I say max safe from the stand point of not exceeding the drive shaft's max rotational speed, what Complete Street Performance called "Critical Speed". The truck in question is a 2018 Silverado 1500 LT TX Edition, Crew Cab, Short Box, 2WD, 5.3L, 6L80, 3.42 G80 rear diff, one piece driveshaft, on a 265/65R-18 112T Tire. If going off the speed rating of the tires, one would say 118. The speed rating chart is common knowledge, but not the end all answer. Again, what I'm not sure about is the max speed of the truck vs rotation speed of the drive shaft with my combination of trans, rear diff, and tire size. I'm thinking... 110-115. Thank y'all in advance!

You obviously don't suffer from the "Chevy Shake" so lets just say 110 is probably as fast as you should ever want to take a truck...I only say this because at 90mph, my truck feels rock solid but I personally wouldn't feel comfortable riding any faster for any length of time...tires are the biggest player in my opinion, aero is huge too.

TXGREEK · January 15, 2019

The Max Speed really depends on the level of education, life and street smarts. I’ve got a 6.2 with a small tune, no limiter [emoji6], that’s a beast but it’s not my Sports car which is designed to go really fast with zero handling worries.

Not saying that you can’t or shouldn’t go fast in a truck but they’re designed to tow and haul which is why it’s so much fun doing modifications to them that’ll either help improve towing or play in the dirt. If you’re looking to take it on a track, take it to a professional race shop but I’d go to the track itself and talk with the truck owners with experience and know how to get you where you’d wanna get to. I’d start off with high performance brakes, drive shaft, suspension “which will keep you down on the street due to spring ratio etc”. One thing I’m sure many of us would like to ask from you is to not be an A’Hole on the public street, it’s one thing to briefly speed but it’s another showing continuation of high speed cause trucks and truck owners are already targeted enough as it is, there’s a lot of really really stupid people doing really stupid things in trucks and we don’t need anymore of them giving truck owners a bad rap, just be SMART and think about others on the road too.

Sent from above

ShubiSnax · January 15, 2019

TXGREEK is on point here. Tires are a big factor, but you can't overlook suspension and brakes and most of us have seen videos or testimony of GM driveshafts exploding on a dyno between 100 and 110mph.

Husker_1911 · January 15, 2019

1 hour ago, SS502 said:

You obviously don't suffer from the "Chevy Shake" so lets just say 110 is probably as fast as you should ever want to take a truck...I only say this because at 90mph, my truck feels rock solid but I personally wouldn't feel comfortable riding any faster for any length of time...tires are the biggest player in my opinion, aero is huge too.

It feels REALLY good at its current limiter, no shakes. I have "experimented" with setting the cruise at 90 on SH130 for a while (though not long enough to fly under one of the toll cameras moving along like that) and it felt fine, confidently planted is how I'd put it. I am very impressed with how the K2XX chassis feels full stop. It stops well. It corners well. It cruises (and super-cruises... to use a phrase that was a big selling point of the F-22) well. It's almost sedan (real sedan... engine in the front, drive wheels in the back, and a grinning piece of meat in the middle... Such as a Charger or a Caprice) like... certainly more so than any other truck I've had. Good tires are key. I like the Michelins that are on it, but I have seen a non-eco focused Michelin I like and the Conti's on The Boss' Suburban feel good too. They make both in a 265/65-18 and a 275/65-18 (a minute change that I reckon would look and perform great). My gut is still saying 110-115 is the answer... 110 being intelligently conservative.

Husker_1911 · January 15, 2019

4 minutes ago, ShubiSnax said:

TXGREEK is on point here. Tires are a big factor, but you can't overlook suspension and brakes and most of us have seen videos or testimony of GM driveshafts exploding on a dyno between 100 and 110mph.

The drive shaft is why I've solicited guidance from the masses. I took it down as a note after I saw GuitarmagedonZL1's 17' Silverado Z71 go on CSP's dyno and the Shop owner said he had to do his pulls in 3rd because it hit the limiter (approx. 110) in 4th before starting to tune, but he didn't want to yank the limiter because he wasn't sure how far he could push it before the driveshaft went kablowie. That's why I'm thinking 110... However that truck is on a 285/45-22. That's a lot of wheel and tire... a lot more than I want to deal with.

SS502 · January 15, 2019

1 hour ago, TXGREEK said:

The Max Speed really depends on the level of education, life and street smarts. I’ve got a 6.2 with a small tune, no limiter , that’s a beast but it’s not my Sports car which is designed to go really fast with zero handling worries.

Not saying that you can’t or shouldn’t go fast in a truck but they’re designed to tow and haul which is why it’s so much fun doing modifications to them that’ll either help improve towing or play in the dirt. If you’re looking to take it on a track, take it to a professional race shop but I’d go to the track itself and talk with the truck owners with experience and know how to get you where you’d wanna get to. I’d start off with high performance brakes, drive shaft, suspension “which will keep you down on the street due to spring ratio etc”. One thing I’m sure many of us would like to ask from you is to not be an A’Hole on the public street, it’s one thing to briefly speed but it’s another showing continuation of high speed cause trucks and truck owners are already targeted enough as it is, there’s a lot of really really stupid people doing really stupid things in trucks and we don’t need anymore of them giving truck owners a bad rap, just be SMART and think about others on the road too.

Sent from above

Exactly, and if it makes you feel any better our 2018 6.2's have a slightly larger aluminum driveshaft

SS502 · January 15, 2019

6 minutes ago, Husker_1911 said:

The drive shaft is why I've solicited guidance from the masses. I took it down as a note after I saw GuitarmagedonZL1's 17' Silverado Z71 go on CSP's dyno and the Shop owner said he had to do his pulls in 3rd because it hit the limiter (approx. 110) in 4th before starting to tune, but he didn't want to yank the limiter because he wasn't sure how far he could push it before the driveshaft went kablowie. That's why I'm thinking 110... However that truck is on a 285/45-22. That's a lot of wheel and tire... a lot more than I want to deal with.

I would not go any higher than 110 with your 3.42 gearing...if I was considering what you are I'd probably, well no I would just spring for a high performance driveshaft and never worry about it again.

Husker_1911 · January 15, 2019

1 hour ago, TXGREEK said:

The Max Speed really depends on the level of education, life and street smarts. I’ve got a 6.2 with a small tune, no limiter , that’s a beast but it’s not my Sports car which is designed to go really fast with zero handling worries.

Not saying that you can’t or shouldn’t go fast in a truck but they’re designed to tow and haul which is why it’s so much fun doing modifications to them that’ll either help improve towing or play in the dirt. If you’re looking to take it on a track, take it to a professional race shop but I’d go to the track itself and talk with the truck owners with experience and know how to get you where you’d wanna get to. I’d start off with high performance brakes, drive shaft, suspension “which will keep you down on the street due to spring ratio etc”. One thing I’m sure many of us would like to ask from you is to not be an A’Hole on the public street, it’s one thing to briefly speed but it’s another showing continuation of high speed cause trucks and truck owners are already targeted enough as it is, there’s a lot of really really stupid people doing really stupid things in trucks and we don’t need anymore of them giving truck owners a bad rap, just be SMART and think about others on the road too.

Sent from above

I have a little experience driving a vehicle way faster than the engineers intended... When you're in a M1114 or a (UPGRAYEDD!!!) M1151 on RTE TAMPA, briefed convoy speed goes out the window. Pushing those trucks to the limit of your skill and the vehicle's capes, and communicating to the rest of the convoy what you can or can't do, is one of many ways you avoid getting blown up by the 3 155 shells buried next to the road. Stateside, I tend to drive... fairly calm, confident. I don't tailgate or change lanes short after overtaking. I'll usually go a hair less than 10% over what's posted. If 75 is posted... I'm going 82 because I'm brainwashed. Much of I-10 is 80 in Texas... 82 because ALL AMERICAN. 90, 95, even 100 plus is a rare occurrence and usually only done semi-inadvertently while passing. I guess what I want is for me to dictate how fast I go for short bursts and not the computer. As to suspension, brakes, and propshaft... I'm poking around a few ideas. I'm tempted to go talk to my GM parts guy and pick his brain about what all the SSV variant has in it different than the Joe Schmoe Silverado, maybe ask him what from the Tahoe PPV is compatible with the Silverado. It's a running and continually refineable concept.

Edited January 15, 2019 by Husker_1911

Husker_1911 · January 15, 2019

15 minutes ago, SS502 said:

I would not go any higher than 110 with your 3.42 gearing...if I was considering what you are I'd probably, well no I would just spring for a high performance driveshaft and never worry about it again.

Maybe the Tahoe PPV driveshaft?

SS502 · January 15, 2019

2 minutes ago, Husker_1911 said:

Maybe the Tahoe PPV driveshaft?

Not to skirt the question, but I am no expert in driveshaft replacements and do not want to steer you down the wrong road. If I was going to do what you're considering I would do exactly what you're doing and ask for suggestions/help and then proceed after I made my choice. I am sure given enough time on the site, some members with much more knowledge on the subject will chime in, good people here.

Husker_1911 · January 15, 2019

23 minutes ago, SS502 said:

Exactly, and if it makes you feel any better our 2018 6.2's have a slightly larger aluminum driveshaft

Is the 5.3 drive shaft steel? I haven't crawled under and put a magnet to it.

Husker_1911 · January 15, 2019

2 minutes ago, SS502 said:

Not to skirt the question, but I am no expert in driveshaft replacements and do not want to steer you down the wrong road. If I was going to do what you're considering I would do exactly what you're doing and ask for suggestions/help and then proceed after I made my choice. I am sure given enough time on the site, some members with much more knowledge on the subject will chime in, good people here.

I'm in a very conceptual stage at this point. I'm going to gleen knowledge from the group here and the parts guy at my local dealer before replacing anything. I'm also going to engage DiabLew when the CAI Cold Air intake comes in and get his take on things.

KARNUT · January 15, 2019

All components have stress level of endurance. An engine for instance can go 5K in short burst. Living there for hours on end would shorted its life. That goes with most components. If GM produces drive shafts that can't handle 120 mph a few times in its lifespan, shame. If anyone's been out west where the limits are quite high. Cursing at higher speed is effortless in these trucks. If 100 mph is critical mass for a driveshaft, again shame.

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Husker_1911 · January 15, 2019

27 minutes ago, KARNUT said:

All components have stress level of endurance. An engine for instance can go 5K in short burst. Living there for hours on end would shorted its life. That goes with most components. If GM produces drive shafts that can't handle 120 mph a few times in its lifespan, shame. If anyone's been out west where the limits are quite high. Cursing at higher speed is effortless in these trucks. If 100 mph is critical mass for a driveshaft, again shame.

Sent from my iPad using Tapatalk

The chassis in the K2XX is very well sorted out. It's stability at speed and chops in corners are why I chose it over the Ford and the Ram. I am a firm believer in what you mentioned about stress levels and the endurance of various parts. I gun... a lot. The ammo I train with is often a lot "cooler" than what I carry with. Let's look at .45 and my TRP. I carry a 230gr Gold Dot that cooks along at 890FPS and will Qual with a 230gr ball goes just as fast. That said, I usually train with a 230gr ball that goes about 830-840 FPS because it's easier on the gun when I'm going to put a few hundred rounds through in a few scant hours. I can correlate this to my post by saying that what I do daily (or when I go to the range... I'd like to do that daily, but I'm not there yet. Stupid day job.) is less than what I or my "equipment" can handle, but a threshold that far exceeds what I or my equipment can handle under normal conditions is a nice thing to have in the back pocket.

Edited January 15, 2019 by Husker_1911