• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Newbie Acceleration Questions

A

Allen42

Full Member
Joined
Aug 27, 2002
Messages
70
Location
Dallas, TX
OK, as will be made clear by my questions, I am not a educated about performance issues at all, so please use little words when you flame me.

I had an F150 extended cab a few years back, and if I wasn't careful, the tires would break loose when I accelerated hard from a standstill. (Not racing, just trying to beat cross traffic for example.)

Now, don't get me wrong, I LOVE my Av. But it sure seems sluggish "off the line". I would think all that HP and torque would be able to break the tires loose, even if it is a heavier truck. I have a 17" Z66 5.3. I have stomped on it with & without the traction control enabled, and nothing.

Is there a simple (cheap) way to improve this a bit? I have read some posts about reprogramming, etc.

On an barely related topic, my first tank's MPG is about 14.5. This sucks. Will this get better with break-in? Why isn't it closer to the 16/18 on the sticker? (My driving is about 75% highway.)

Thanks,
-Allen
 
Did your F150 have lower gears, maybe for towing? I'm guessing your Av has the standard higher gear ratio. Getting the 4.11 gears makes it considerably snappier, I hear. I have the higher gears, and off the line isn't that great. My old S-10 pickup had the low gears, and it was great off the line, but started to peter out at highway speeds. Then I traded it in on a Blazer with the same engine, slightly more weight, and the higher gears. While still peppy, it was a dog compared to the pickup.

As for mileage, I think you're doing OK with 14.5, that's a hair better than what I'm getting with the 5.3. Did they change the ratings on the window stickers? I'm pretty sure mine said 13/16? 16/18 sounds more like what was on my Blazer.

-- SS
 
I agree with the accelration comment. It seems the easiest way to help this one out is to open the intake and exhaust. Do keep in mind though that there's a bit more weight on the rear of an Av compared to a pickup given it's frame design and continuous body line. Still, I'd expect to be able to chrip the tires whenever I want as well.

Depending on where you are in your miles, it should get better after the break-in period and some have even said a little better after that. I have 8365 miles. My normal MPG in city driving is 13.5-14.25 and highway is around 17.75-18.25. Hit 19MPG on one tank once but have been unable to duplicate that.

Jamie
 
I'm in the same boat as performance, I belive it is lacking. I am more interested in mods to keep the AV running till the wheel fall off and then more but performance is under par. My wife's Odyssey can blow the doors of it, especially from a dead stop.

I see many posts on this site about the performance of the AV and the associated 'kills' but I do not see or feel it. I was planning on taking it to a 1/4 track to see what it does this evening in Gulfport, MS but plans changed.

My mpg was 14 but now it is around 16 with mixed driving (2000 miles now). Running 80 on a country 4 lane last week I had almost 17mpg (Jackson, MS to Mobile, AL) so 18mpg is probably achievable on the interstate.

Perhaps the AV has too much weight over the rear tires to break'm loose. Me, spinning the tires only cost money. However, I am thinking I should have gotten 4.10 rear end which would probably help the short sprints as mpg cannot get much worse.

Anyone know of a code to look for on a wrecked AV to see if it has a 4.10 and a limited slip?


 
Allen42 said:
On an barely related topic, my first tank's MPG is about 14.5. ?This sucks. ?Will this get better with break-in? ?Why isn't it closer to the 16/18 on the sticker? ?(My driving is about 75% highway.)

Thanks,
-Allen
Click to expand...

Allen - I have 22K on my Z71 AV.

Over the last 5K miles which include hours of slow grinding 4x4, city driving and highway driving I have an average of 16.66 mpg. ?I have been told I drive heavy on the gas in the city - I thought I was driving normal ?>:D

I have changed the following items from stock on my AV - UPD intake, K&N filter, TB bypass, better flowing muffler and Mobile 1.

Last weekned doing pure Interstate miles with the AC going and rolling through some smaller mtns I was getting 17.5-18mpg. That is rolling at 85mph most of the time.

The AV is heavy and not fast off the line - if you want real fast off the line hook up with Ganx or Butch :)
 
I know what you mean about the tires breaking loose on acceleration. My '00 Silverado would always do that and my Av never does that. I see this as a good thing. The fact is that the Av is 1000 lbs heavier that my Silverado was and there is more weight distributed over the rear tires than there was in my Silverado. I do not know the weights of the F150 but I would bet it's the same reason.

-Mark
 
Your AV is set up to not spin from a start. It is all in the computer controled throtle, the Traction Assist, and the Limited slip differential. (help me out gear heads, did I get that right)

You can even try to do a brake stand and the computer will notice the brakes applied and it will stop the throtle from opening all the way!

New air intake and exhaust will help with get up and go, but squeeling off the line ..... well that will take alot of modding to get that on a 5.3!

 
Is there a simple (cheap) way to improve this a bit?
Click to expand...

Get the Superchip with our club discount price - That outa break em loose from a standstill >:D
BTW - If you haven't messed with it much, the Tow/Haul button will give her a little more get up, by shifting a little higher.
A TBS is also a cheap mod ($110) for a noticeable power gain.
 
ShapeShifter said:
Did your F150 have lower gears, maybe for towing? ...
As for mileage, I think you're doing OK with 14.5, that's a hair better than what I'm getting with the 5.3. Did they change the ratings on the window stickers? I'm pretty sure mine said 13/16? 16/18 sounds more like what was on my Blazer.
-- SS
Click to expand...

I have no ideas what the gearing was on the F150, but I do have the higher gears on the Av--supposed to be better for MPG, right?

13/17 is sticker MPG on 4wd, and 14/18 (my mistake) is sticker on 2wd, so 14.5 isn't unreasonable, I guess.

Wiki, thanks for the info. So a computer is killing off the line acceleration? It seems then that the chip could be reprogrammed to fix this pretty easy. My thoughts are the heavier the vehicle, the *easier* it would be to "squeal". (More weight=more inertia, meaning more force needed to make truck body move, thus the wheels would spin under the body. I guess we'd have to factor in the increased friction caused by the extra weight over the wheels, though. Hmmm...)
 
On the positive side though, once you are rolling at about 5MPH, it really launches from there. It just seems the take-off is bad. The flying is good ;D

Jamie
 
The reason I was thinking the weight was the factor is because my Silverado and my Av are both very similar configurations. Both have 3.73 gears, both Limited slip, both 5.3, both 4wd (not that it matters). The 2 differences that are easily noticable are the weight difference and the tires (Goodyear on the Av and :D: Firestone on the Silverado)

Wiki, what is the traction assist, is that something different than the Auto 4WD?

-Mark
 
Allen42 said:
I have no ideas what the gearing was on the F150, but I do have the higher gears on the Av--supposed to be better for MPG, right?
Click to expand...
Yes, supposedly better for mileage. Dealer (and wife) talked me out of lower gears based on mileage issues. However, from comments on this board, it sounds like it doesn't make that much difference. Wish I had a chance to do that dicision over again. :6:

13/17 is sticker MPG on 4wd, and 14/18 (my mistake) is sticker on 2wd, so 14.5 isn't unreasonable, I guess.
Click to expand...
My first few tankfulls, in dead of winter (usually lower due to slipping on snow, and colder air temps) and no highway driving was in the 11.3 to 11.8 range. Since then, I'm getting more like 13.8 to 16.2 with mixed summer driving. High (almost all highway) has been 17.3. It does get better with time.

My thoughts are the heavier the vehicle, the *easier* it would be to "squeal". ?(More weight=more inertia, meaning more force needed to make truck body move, thus the wheels would spin under the body. ?I guess we'd have to factor in the increased friction caused by the extra weight over the wheels, though. ?Hmmm...)
Click to expand...
Weight over the wheels will give added traction, contering the increased inertia. As stated by others, our Av's are a bit heavier in back than other trucks. If you want to spin your wheels, the ideal situation is a standard full size pickup: heavy overall weight, but relatively light rear end. Hmmm... something like an F150? :9: Or better yet, a Silverado? :B: :love:

(just kidding on the F150 cheap shot) >:D

-- SS
 
Allen,

You came to the right place for information to pep up your 5.3. ?On this site (it's great ?:love: ) you?ll find lots of ideas on upgrades, some are low dollars items. ? ?

If you had a chance to get a Z66 with the 4:10 that?s rare. ?In Sept of last year I checked dealer stock on the net and of the 600 AVs I found in Texas none were Z66s with the 4:10. ?
?
We have the same power train set up, with all the mods I have installed (some not listed below) my 5.3 is now around 335HP and 380LB-FT of Torque. ?Its no speed racer but it feels quicker off the line and through out the power band. ?And there are supercharger dreams dancing in my head! ?So if you want to get some more muscle in you AV check out what some of the other members have done and have fun.
 
Allen42 said:
...I have stomped on it with & without the traction control enabled, and nothing...On an barely related topic, my first tank's MPG is about 14.5. ?This sucks...
Click to expand...

They sure seem related to me! ;) ;D
 
nh_mark said:
...
Wiki, what is the traction assist, is that something different than the Auto 4WD?

-Mark
Click to expand...

I think it is only on the Z66. It takes away your acceleration if it senses wheel slip. This ussualy only happens from 2nd gear up. Great for wet roads and snow.
 
Mileage....

Thus far I have purchase three tanks of gas.

Tank 1 - 13.2 MPG
Tank 2 - 15.3 MPG
Tank 3 - 16.4 MPG

At this rate, it won't be long before I have to siphon out gas just to keep from spilling!
 
Great topic, Allen. I'm new as well and tried to start a new owner performance thread but I guess nobody loves us yet :cry:. Maybe yours will stick.

Danny.....you said you were getting 335 ponys out of your truck. Have you re-chipped yet? Also, what were your reasons to go with the volant intake as opposed to the others (K&N, AIRAID, etc.)

And hey folks, us new guys really appreciate your advice.

Harry
 
hshawiii said:
Danny.....you said you were getting 335 ponys out of your truck. ?Have you re-chipped yet? ?Also, what were your reasons to go with the volant intake as opposed to the others (K&N, AIRAID, etc.)

And hey folks, us new guys really appreciate your advice.

Harry
Click to expand...

Who's Danny?? ???
Yes the tuner was the last mod. Went we the Volant as I liked the reviews I've read on it and it looked like a little cleaner install. Volant rates the increase for the 5.3 at 15HP & 22FT-LB. That may be puffing. Do notice more pickup with the Volant at 3,000 RPM and up, seams to team up well with the cat back duals.

If you really want to see so HP increases check Butch's SC thread. >:D
 
BigGreen said:
Mileage....

Thus far I have purchase three tanks of gas.

Tank 1 - 13.2 MPG
Tank 2 - 15.3 MPG
Tank 3 - 16.4 MPG

At this rate, it won't be long before I have to siphon out gas just to keep from spilling!
Click to expand...

Six tanks so far

Tank 1 - 10.7
Tank 2 - 15.0 (all highway)
Tank 3 - 11.2
Tank 4 - 10.0
Tank 5 - 11.7
Tank 6 - 12.0

All but tank 2 are Houston I-10 bumper to bumper traffic, 1-1.5 hours to do 27 miles. Ooooh avg speed of 20 per.
 
Bruno said:
Six tanks so far

Tank 1 - 10.7
Tank 2 - 15.0 ?(all highway)
Tank 3 - 11.2
Tank 4 - 10.0
Tank 5 - 11.7
Tank 6 - 12.0

All but tank 2 are Houston I-10 bumper to bumper traffic, 1-1.5 hours to do 27 miles. ?Ooooh avg speed of 20 per.
Click to expand...

Here are my #'s ?This is for about 5K miles - I started tracking when the AV had 18K miles on it. This is a mix of city, hwy and off roading

Tank 1 ? ? ? ? ?18.31
Tank 2 ? ? ? ? ?14.78
Tank 3 ? ? ? ?? 14.67
Tank 4 ? ? ? ? ?15.43
Tank 6 ? ? ? ? ?15.29
Tank 7 ? ?? ? ??17.55
Tank 8 ? ? ? ? ?17.10
Tank 9 ? ? ? ? ?16.22
Tank 10 ? ? ?? ?16.37
Tank 11 ? ? ? ??15.94
Tank 12 ? ? ?? ?16.94
Tank 14 ? ? ?? ?17.27
Tank 15 ? ? ?? ?14.42
Tank 16 ? ?? ? ?17.97
Tank 17 ? ?? ? ?16.20
Tank 18 ? ? ?? ?19.07
Tank 19 ? ? ?? ?16.59
Tank 20 ? ?? ? ?17.60
Tank 21 ? ?? ? ?16.38
 
You must log in or register to reply here.
Back
Top