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Top Speed?

Daubs

By Daubs
in 2000-2014 Silverado HD & Sierra HD

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Daubs Enthusiast

Daubs

Posted
Posted

I'm driving on a remote stretch of highway in central Nebraska and thinking to myself, "self, I wonder just how much giddy-up this 8.1L has...let's see what she's got." So I pick out a nice long straight away, check the GPS is working and punch it...

 

Doing about 60 and the Allison drops down in to third gear as the mighty Big Block revs up...It's pulling hard and the spedo is climbing.

 

At ~75 MPH she kicks in to fourth gear and is still pulling hard. I smile.

 

At ~93-94 MPH she kicks from fourth in to fifth, and is now pulling 3,000 RPM's...the spedo continues to climb.

 

The computer speed limiter kicks in somewhere above 100 MPH and I begin to slow. Felt like the truck had a lotta-mo left go go.

 

I coast down to the speed limit and glance at the GPS. I've got it set to record maximum speed. I'm impressed that it reads 106 MPH. My CC is very stock, save the Volant intake and 285 Revo's. I've got this big $h!ty grin on my face the rest of the trip.

N900WM Enthusiast

N900WM

Posted
Posted

Add the Westers computer and your smile will increase in size 10 fold!

I have had my truck to an indicated 125+ (with GPS, speedo only goes to 120mph)

If you hold the go pedal down, it won't shift into 5th. If you let up a bit and let her shift into 5th, she'll go like the :banghead:

vhato Enthusiast

vhato

Posted
Posted

106 MPH!!!. Wow!!! EIther that is just with the Big Block option or your PCM is not correctly Calibrated for the 285's. 285's are roughly 30.5-31" tall.

 

 

On the 03-05's 6 Liter V-8 at 95 MPH the computer closes the throttle blade to 45-50% and advances timing enough to maintain 99 MPH.

 

Congrats!!

4x4chevyman Enthusiast

4x4chevyman

Posted
Posted
106 MPH!!!.  Wow!!!  EIther that is just with the Big Block option or your PCM is not correctly Calibrated for the 285's.  285's are roughly 30.5-31" tall.

 

 

On the 03-05's 6 Liter V-8 at 95 MPH the computer closes the throttle blade to 45-50% and advances timing enough to maintain 99 MPH.

 

Congrats!!

 

 

 

actually most 285's are 32.5-33 inches tall

it sounds like you are talking about 245's or 265's

vhato Enthusiast

vhato

Posted
Posted

285 are are 32.5" tall when measured from thr ground up, but that is not an accurrat way of measuring diameter. When doing the rolling method you get a perfectly true measurement that is usually 2" smaller than advertised. For instance a rolling measurement of a 37" Swamper comes to 111.5" and you divide by PI (3.14159) that comes to 35.49". A 315/75r16 is around 104" and that comes to 33".

 

Just mark the tire and mark the pavement, make one full rotation and mark the pavement again. Measure the distance from mark to mark in inches and divide by PI. That is how you measure when adjusting for tire size when reprogramming.

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