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Speed Governed?

Chasman

Charter Member
SM 2003
Full Member
Joined
Apr 8, 2002
Messages
550
Location
Edmonton, Alberta, Canada
My buddy just got back from Whistler and said he couldn't keep up in his 97 Suburban with an Av that passed him at somewhere over 150 km per hour (approx. 90 m per hour). His Suburban is governed at that speed. As I do not wish to speed myself ;), has anyone found out if our vehicles are governed, and at what speed?
 
I had an opportunity two weeks ago to lay the needle over on a remote country road straight away. I was already travelling at 70 mph and just punched it on over to 98. ;D ;D ;D It took no time at all to go from 70 to 98, but that's where it stopped. (of course my stock guage only goes to 100 anyway.)
The engine sounded like it was cruising. I could tell there is plenty of room above 98. I'm pretty certain that 98 is what the stock limiter is set at. I'd be willing to bet you could punch it on up to 120-130 and still not be redlining. :cool: :cool:
I pushed my old Dodge Ram up to 110 once, and it sounded like the engine was about to blow up. :p Not so with the AV.

helmet
 
I haven't punched it over 80 yet only because the goodyear's at/s aren't rated too much above 100.....if I had a set of pirelli scorpion zero's or something along those lines I would give it a go no problem......
 
It's governed at 100 . . . though with an appropriate programmer (HPP3 or similar) I'm told that it can be bumped up to 128 - see other threads.

Or course you then need higher speed rated tires and a guage cluster swap to a 120 MPH speedo!
 
With the HPP3 or SCU2000 you can remove the soft limit, at your peril or discretion and consideration for tires, etc. There is, I believe, a hard limit of 128 that you can not change with an off the shelf programmer. ;D
 
And again Gandolph is right, the speed limiter is set right at the 98-100 mark. The HPP3 will allow you to get the 128mph out of it, but that is it.
I had a talk over the last few years with the guys i do business with tires, as i had a 96 impala SS and he told me the speed rating was for sustained speeds. Like a tire rated for 110 was rated at that speed for a sustained distance. He also mentioned if i was just checking top end, hitting it and coming back down i was alright with the michelin cross terrains, but not to be cruising for 15-20 minutes at the high speeds. Just my knowledge of that subject, from what i have been told.
zeeya
 
I am definitely getting old - I remember when there was no speed or rev limiter except when the cylinders came through the hood - not considered a good thing. I owned a '67 GTO that would cruise all day at 140 mph on the interstates with Michlen tires, and a Plymouth RoadRunner [bright yellow with black stripe] that was right up there. ?;D
 
I got my Avy up to about 95 once trying to pass a moron. (See Road Rage Posting). I was very impressed with how smooth the engine was running despite such a heavy vehicle going so fast. Without the limiter I would be shocked to see the engine put out over 120 mph.
I would like to make an observation. I noticed that I can maintain 70 MPH while keeping the RPM needle ever so slightly above 2000 RPM's. I suppose everyone else is the same. Isn't that low though? How can this engine ever die if it appears to never exert itself?
 
Powersurge said:
I got my Avy up to about 95 once trying to pass a moron. (See Road Rage Posting). I was very impressed with how smooth the engine was running despite such a heavy vehicle going so fast. Without the limiter I would be shocked to see the engine put out over 120 mph.
I would like to make an observation. I noticed that I can maintain 70 MPH while keeping the RPM needle ever so slightly above 2000 RPM's. I suppose everyone else is the same. Isn't that low though? How can this engine ever die if it appears to never exert itself?
I did that eval of RPM/Speed also, so I can compare it to the RPM numbers after my conversion to Synthetic oil. ( My 1997 Suburban lowered it's RPMs after synth conversion - looking for the AV to do the same.)

Here's what I got from my AV when it had about 800 miles on it:

45 mph = 1325 RPM
55 mph = 1500 RPM
60 mph = 1625 RPM
65 mph = 1750 RPM
70 mph = 1900 RPM
75 mph = 2000 RPM

Some of you shade-tree mechanics can correct me if I'm wrong, but I believe those low RPMs at speed are indicative of an engine that makes most of it's power and torque at the low end. ???
Laterz......
 
Why would the RPM vs speed points change with a synthetic conversion? For a given gear with the converter locked, speed vs RPM should be pretty well fixed.

Even with a non-locking convertor, I don't see why this would happen - unless you put the synth oil in the tranny!

Am I missing something?
 
I assumed these things kept going until you start launching pistons and rods from under the hood... ;D There's one way to gear it....
 
From what I have read the current engines have lots of high end power - thats why the heavy tow choice is the 4.10 rear end. The performance issue is mostly concerned with the low end torque. ;D
 
lars-ss said:
I did that eval of RPM/Speed also, so I can compare it to the RPM numbers after my conversion to Synthetic oil. ?( ?My 1997 Suburban lowered it's RPMs after synth conversion - looking for the AV to do the same.)

I use Mobile 1 in my truck and have been doing so since the first oil change. I am using it because I hate changing oil every 3000 miles and I hear your engine will run and sound better longer than regular oils. I am surprised your getting 75 MPH out of 2000 RPM's. That is higher than what I am getting.

 
Here, here... I also have the 4.10's, and cruise around 75 mph hugging the 2000 rpm's using Mobile 1. I have a few other mods that might contribute to this.
I hate to admit it, but 90 mph on cruise control only bumps it up to 2400 rpm's.
(I sense the Texas Department of Public Safety looking for me as I post this. :eek:)

helmet
 
wrchism said:
Why would the RPM vs speed points change with a synthetic conversion? ?For a given gear with the converter locked, speed vs RPM should be pretty well fixed. ?
Even with a non-locking convertor, I don't see why this would happen - unless you put the synth oil in the tranny!
Am I missing something?
I figured when it happened to my Suburban that the engine, because of the now superior synthetic lubrication, gets more work done at lower "effort," thus the lower RPMS can create the same amount of speed.

It's like if you are turning a rusty screw - takes a lot of effort. But if you lubricate it, you can get a lot more done with less effort.

Make any sense to anyone but me? ;D

I will know FOR SURE the effect of the oil in three weeks when I convert to Amsoil Series 2000 0W-30. :D
 
I dunno....

From my memory when the torque convertor is locked up the engine speed is directly proportional to MPH. I do not believe the tranny has any slip in it so the engine speed for a given MPH will remain constant for a given truck unless you change tire diameter or rear end gearing.


 
from the engine, through a locked torque converter, through the tranmission gears, down the drive shaft, through the rear end, along the axles to the wheels and finally to the pavement....

those are all solid surface to solid surface connections. there is NOOOO way that changing to ANY kind of oil will change the GEARING and therefore the RPMs at an indicated speed. PERIOD!!!!

what you may get if the engine is indeed putting out less effort to maintain cruising speed is better fuel economy. That it.
 
I just recently purchased my av in wasilla alaska and drove it all the way back to fairbanks alaska in the same day and I have never enjoyed driving as much I did that day. My average speed was between 70-80 mph for over 300 miles, at one time the limiter came on at 100mph. I drove a 99 cougar down to trade in for my AV and the ride was okay but couldn't compare to the ride back.I love my AV! >:D
 
Helmet, That is close on the MPH and RPM range that i am running with the 373's.
75mph=2000rpms
90mph=2350-2400rpms, so close it is hard to tell.
And to think i did not want to get the 410's because I thought they would kill me on highway speeds. Just came through Mississippi with it on cruise ,,, 95% of Mississippi at 2500rpms >:D
 
I have had mine up to 128 mph that is the hpp3 governor . i also have the beefy hotchkis setup and the truck seems really tight to me with the big sway bars very little body roll now. The only problem is my tires could not take a long speed run but a quick blast once and a while is ok. if i want speed i just take my 95 impala ss out and i can run 140 all day long he he he. but if setup right these trucks can be made to handle better and be quick l8tr all. :cool:
 
With my 3.73s, I don't tip 2000 til just shy of 80. Around 78 - 80 is where I hit 2000. 75 is right around 1900 RPM.

Jamie
 
All I can say is that I am glad these things are governed.. Sometimes on I-285 in Atlanta, GA, I get up to 90+ (yes... traffic in Atlanta *CAN* go that fast at times.. when it is moving... it is MOVING!!!) I really don't want to get that much metal moving too quick... That could equal OUCH!!!

 
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