Max Speed

Visegrip117 · January 16, 2010

Anyone know what the 5.3's are running on the top end, with out the speed limiter?

I know weight, tires, and gears all factor in , but I was looking for a round about answer.

I have an ext cab with 3.42's

pj5454302 · January 16, 2010

Well i know if you have any type of programer they limit you to 128mph or 130mph not sure with a custom tune. With your mods prob 130-135. But carefull becuse your tires are pobly rated for 110.

C. Charles Hahn · January 16, 2010

Well i know if you have any type of programer they limit you to 128mph or 130mph not sure with a custom tune. With your mods prob 130-135. But carefull becuse your tires are pobly rated for 110.

The point of a programmer is that you can remove the speed limiter in the computer. Hypertech units at least let you go to 155, and with a custom tune there's literally no limit. FWIW, I have the parameter in my truck set to 216, even though it would never actually hit that speed.

Visegrip117 · January 16, 2010

Thanks for the info guys.

I 'm getting my Blackbear tune in Februaury.

I'll probably never hit the top speed, I was just curious.

Wife has threatened to strangle me if I get any more tickets.

bigredmariner · January 16, 2010

Just set the limit up about 10 mph more than what your speedometer reads. You will never know the difference once the needle gets off the scale anyway. Tires though are your biggest limiting factor. Have fun with it and enjoy the tune.

Nytemare · January 16, 2010

You can fully remove the limit.

You can peg it with a nearly stock engine. I left mine alone...and the one time I did try and hit the limit...I was at ~3300 rpm and I was pulling hard at 180km/h (thats the cut out)

I have a 3.42 ratio and a 4.8L

thearborbarber · January 16, 2010

HPtuners requires a number to be in the top speed field. The highest number is 256mph

pj5454302 · January 16, 2010

I said 128 becuse a guy i know has a hypertech programmer on an older s10 says he ran up to 128 and it cut him off. The only way he could tell is his aftermarket gps has a spedometer built in.

Nytemare · January 16, 2010

HPtuners requires a number to be in the top speed field. The highest number is 256mph

Ain't too many trucks going that fast.

I seen no reason to remove mine...I have no need to go over 110 MPH

ybsane · January 17, 2010

More to the question would be sustained speed for an extended period of time or just pegging the gas pedal for shit and giggles, just to see what she will do.?

Where are the Montana people? is there still a reasonable and prudent daytime speed out there?

Rob

thearborbarber · January 17, 2010

HPtuners requires a number to be in the top speed field. The highest number is 256mph

Ain't too many trucks going that fast.

I seen no reason to remove mine...I have no need to go over 110 MPH

Since GM is tracking PCM changes, I am not messing with mine............for now.

502ci · January 17, 2010

I have the Hypertech programmer and set my limit as high as it was possible...I think it was 255mph...basically removing the limit.

If the time ever came for me to go as fast as the truck was capable it must be a pretty good reason (life or death)...given that I did not want a stupid limiter slowing me down.

GPSilverado · January 17, 2010

I had created an Excel speadsheet that allowed me to calculate mph based off of rpm, gear ratio, trans ratio, and tire diameter so that I could compare the differences in RPM if I decided to switch from my 3.42 gears to something else.

With a 3.42 gear, 31.8" tires (approx size of 275/55R20 I think), on a 4l60e, IF I had the horsepower, the truck would run 138mph at 5000rpm in 3rd gear, or 198mph at 5000rpm in OD.

I have no idea how far the stock 5.3 would push it, btu I am certain I couldn't turn 5000 rpm in OD, and probably not in 3rd. I personally haven't been past 90 in this truck, which is a sign that I must be getting too old (45). I had a 2000 Ford F-350 4 dr 4x4 powerstroke, and I found out on my trip to Daytona one year that the speed limiter would prevent you from keeping up with the traffic on I-95 between Jacksonville and Daytona. I think it was limited to 92 or 98 one, can't remember which. I installed a stage 2 chip in that truck, with no limiter, and I saw it to 120 but let off due to safety (tires not built for it) but it still had me pressed back into the seat pretty good at that speed. No telling where it would quit pulling. That thing had about 750 - 800 lb/ft of torque.