Shifting Avalanche

[havalanche]

I removed approximately 95% of the torque management on my AV, which has helped a little on takeoff (getting 5700 lbs off the line ain't easy). I know a new torque converter could definitely help (2500 stall is what I'm looking at for the future).

However, until that time, I'm trying to firm up the shifts. At WOT, the transmission feels like it just wants to "slide" into gear. At part throttle, it feels a little firmer.

What do I need to look at for enhancing shift firmness, and what would I need to log?

Also, although not a recommended practice, when I try to power-brake, all the engine will rev up to is 1600 rpm. Any way to change this? I would like to get the truck to spin off the line, but I know it's an uphill battle with the truck weight, tires, and gears, etc.....I already know the FI, gears, etc changes to make, but ye ole wallet is dictating this schedule of upgrades.

Any ideas are appreciated.....

[Russ K]

Post your bin or htp file and I'll take a look at the shift pressures. I would only take out 50% of torque reduction with stock trans internals. With those tall tires and 3.42 gears, you wont be getting any tire spin. A 1600 rpm stall speed sounds about right for a stock torque convertor.

Russ Kemp

[Zick]

A higher TQ will cure that 1600rpm power stand problem.

Also, with those big tires I would think about more gearing.

[havalanche]

The current tune I'm running is attached (I've just started with dialing in the MAF, hence the DFCO and PE being disabled).

As far as the gearing, FI upgrades, etc, dont rush me.....Remember that the new truck IS PAID FOR. I paid it off in 3 months, hence NO MONEY.....So, upgrades will have to wait a little while.

Now, any ideas for firming the transmission shifting is appreciated.....

Now, another question regarding the 1600 stock stall.....I can understand the converter stalling up to that RPM, but why won't the engine rev higher with the brake depressed? Is there a way to change that? You can't tell me that 300hp won't powerbrake this truck. Other GM trucks ('03, '04) will do it, and don't know what the difference is in the setup of the Avalanche.

[Russ K]

You had your pe enable map set to 640 which won't allow pe. Also your pe delay was at 5000 rpm = delay untill 5000 rpm. Then the pe enrich rate was at .0195 = very slow pe enrichment. Why was the tps enrich threshold at 98%?
I increased your shift pressures and set the tables I just mentioned. I would just reduce the upshift torque reduction by 50%. Did you want your 2-3 shift at 4952 rpm? Are you using a wide band O2 to check the AFR?
Hope this will work for you.

Russ Kemp

[havalanche]

Thanks Russ.....

The PE was set to 640 because I'm starting to dial in the MAF. Same with the threshold. I didn't want to go into PE mode when I dialing the VE table.

The shift pressures/RPM should have been the stock settings. The only other thing was eliminating most of the torque management.

I don't have a wideband as of yet to tune the AFR.....Still recouperating from paying the truck off in 3 months.....

[Mongoose]

Now, another question regarding the 1600 stock stall.....I can understand the converter stalling up to that RPM, but why won't the engine rev higher with the brake depressed? Is there a way to change that? You can't tell me that 300hp won't powerbrake this truck. Other GM trucks ('03, '04) will do it, and don't know what the difference is in the setup of the Avalanche.

My 05 Silverado 5.3 will rev to 2000 rpm in OD but if I drop in 3rd it powerbrakes no problem. I can't seem to find out how to change it and a few others with HP haven't found it either.

Brian

[98A4LS1]

Post your bin or htp file and I'll take a look at the shift pressures. I would only take out 50% of torque reduction with stock trans internals. With those tall tires and 3.42 gears, you wont be getting any tire spin. A 1600 rpm stall speed sounds about right for a stock torque convertor.

Russ Kemp

Are you guys talking about trans->torque management->
"torque reduction vs rpm"
or
"torque reduction vs torque vs shift - normal" when taking out 50% torque management?

Thanks

[FlaBouy]

Hav

My 2004 used to have the same problem and even when I disabled 100% torque management I could not turn over the 265/70/17's that came on the AV. I added exhaust and CAI and still no dice. Like you said it would run up to 1600 under power break and just sit there and build heat. Then I added the Vortec and stock pulley. I was dynoing 383 rwhp and guess what...On new asphalt on launch I could just barely turn them over. Granted I am running 3.73 gears but I was kinda disapointed in the S/C at 6 psi. That was back in September. (BTW my truck was paid in full also).
To make a long story short, you can look in my sig and see what I have installed since then. I now have went to the other extreme on the 17 rubber. I am looking to add 20" rims and 305/45/20 rubber to help with this issue. But as soon as I do the G80 is going to break. All my buddy's in the Avalanche club are breaking rear gears with 4,10 or lower gearing and 33" and larger tires and FI.
Half of your issue with the power break is the Antilock Braking system. Think of what you are doing, foot fully depressed on brake while trying to build RPMs.......
Without FI, or cam and heads, the only way to get what you want is a stall convertor. I run a loose 2600 Edge Racing convertor....Bye Bye 1600 RPM...

[jimmyblue]

Torque management - I had some bad luck with trying
to finesse the commanded torque reduction, myself;
tried to make it a plateau (constant torque above
300 lb-ft) but only got myself into a sort of shift-
hang mode that seemed to pop up whenever the
throttle was on-off-on (as happens on the street
sometimes, like you get cut off right when you were
fixed to go for the hole). Anyway, I have had better
luck with leaving the commanded reduction alone
but cutting the retard values in the spark retard vs
torque reduction table - despite this being a case of
lying to the PCM.

Burnouts - look to the traction control stuff under the
DFCO tab, if this is an electric throttle truck. If you
see TPS being held back when you have the pedal
matted, this (or somebody) is busting your balls.

Having no PE means you are also suffering from way
low spark advance and just in a factory-dismal power
tune state of affairs. If this is a truck that doesn't
care about towing fuel economy, I'd look to the
'vette and F-body tunes for some more sporty
settings; PE and spark.

[jimmyblue]

The other thing that hold trucks back, is burst knock
enable delta-CylAir values which are less than the
CylAir runup rate, in normal WOT RPM run-up. The
CylAir you would expect to be constant but where the
VE changes a lot w/ RPM (like the lower side of the
VE table does) so does the CylAir, and you may see
burst knock retard applied during acceleration (bleh).
Check for this if you see a lack of spark advance,
without obvious KR, relative to main table settings.