Speed limiter??

[iCryWheniGoPoop]

Guys just wondering if the only way to get rid of my 98 mph top speed is a tune?? Watched a video of a denali on youtube with the american racing headers and corsa exhaust and his went way above 100. Thought I read in the comments on the video that he said it was untuned...

 

Sent from my SAMSUNG-SM-N900A using Tapatalk

Yes, needs a tune to bypass limiter.

 

By untuned he may have just meant that the tune is not optimized for the headers, or factory air/fuel/spark calibrations were still in place.

 

 

Sent from Off Driller Side

[Sierra Matt]

When I pull out to pass a semi and my truck cuts out at 98... well it's a SOL feeling until you get around... not good to be hanging out there with no where to go. And any tune will VOID engine warranty... correct?? Either way one could still be SOL!

[robvas]

You have to go 100+ to pass a semi?

[TxTruckMan]

if it's going 95...

[Sierra Matt]

No... but when he's doing 70 and passing zones are short... want to get around without any hesitation from my truck:) Just feels weird having it just stop accelerating when you really want it to just go.

[Essayons24]

First post, long time looker. Mine shuts down at 110-112. Weird how there are so many variances between trucks.

[BBRU]

I'm pretty sure it has to do with the gears. My truck cut off at 98 and it's a 6.2 max tow with 3.73's. My buddy has the same truck with 3.42's and his cut off at 112.

[Sierra Matt]

I'm pretty sure it has to do with the gears. My truck cut off at 98 and it's a 6.2 max tow with 3.73's. My buddy has the same truck with 3.42's and his cut off at 112.

 

Mine has the 8 speed and 3.23 gears. Cut off is 98 exactly

[07Softail]

I data (Flogged) my truck today and It went 112 MPH and had to get out of it pretty quickly.

 

RT

[Jonathan M3]

I don't understand why we keep pointing at an aluminum driveshaft as being the weak link. I have read this many times on this board. Is there something about these that is failing? I put 640hp to the ground in a 4400lb 96 impala that had an aluminum drive shaft and it would pull the front left wheel on a 200shot of nitrous out of the hole. I can probably dig up a video if I have to. This car withstood 6 years of solid abuse with ZERO driveshaft issues.

Bottom line... If our driveshaft is failing, it's not because it's aluminum. I'll buy poor material grade choice, too thin of wall (my driveshaft wall was .125), poor welds/craftsmanship etc.

And I certainly don't see how rotation speed is going to make it weaker... Applying 640hp from a dead stop is going to produce much more abuse.

 

As soon as I get some info on what ours is made of exactly, I'll try to do some calcs on it.

 

 

Sent from Off Driller Side

The one-piece aluminum driveshaft is definitely the biggest issue for ext. cab and crew cabs(especially the 3.73 geared 2WDs). They are well known to come apart on people that take these trucks to 100+mph, or guys that swap in 4.10s have had them blow out doing 85-90mph. Its not so much a matter of it being aluminum as it is the sheer length of it. On a 2WD, they can be almost 7' long. You simply can't spin a DS that length at a high speed.

 

On my truck I start getting a noticeable vibration from my DS from 105-110mph, and I have 3.42s. If you have shorter gears, the DS's critical speed will be even lower.

 

A two-piece DS conversion is needed if you plan to regularly take your truck over 100mph, otherwise the one-piece is a ticking time bomb.

[iCryWheniGoPoop]

Interesting, I have yet to have one come apart or known of one personally. Lots of boosted and big cam trucks on the Dyno and at the track. We may use drive shaft loops just in case but I can't recall ever actually needing it. I guess I need to research this a little more.

 

 

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[MikeNH]

I know it was a big issue on the 800-series trucks when I had my 03, back when the computer tuning was first taking off.

[Jonathan M3]

Interesting, I have yet to have one come apart or known of one personally. Lots of boosted and big cam trucks on the Dyno and at the track. We may use drive shaft loops just in case but I can't recall ever actually needing it. I guess I need to research this a little more.

 

 

Sent from Off Driller Side

I've only personally seen one go, and it was a RCSB on a dyno about 10yrs ago, but always heard stories about the longer wheelbase trucks grenading shafts after GM started putting one-pieces in them rather than the old steel two-pieces.

 

Heres just one thread of many discussing the topic: http://www.performancetrucks.net/forums/gm-drivetrain-suspension-22/aluminum-driveshaft-nnbs-466190/

[Badass69]

When a shaft grenades its a damn mess is what it is lol. I bounced off mine for the first time today.... 98 mph like many others here. 6.2/8L90E/3.23.

[fogarty]

2015 6.2l High Country with 8spd and 3.23's - 160km and she dies.