RE: My PCM tuning with PCMforLess.com - Process and Results
Login  | |
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/10/2006 12:50:46 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
Ah ok. That makes more sense. I kinda figured that but wasn't sure. I should have remembered that whole discussion we had on here about that.
|
|
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/12/2006 1:49:18 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
Alvin called me this morning to ask me a couple of things about my preferences. He is a very nice and friendly guy. It's nice to have that personalized attention to detail. I was impressed 
He's also shipping it back to me today. It's already been picked up. MAYBE it will be here by the weekend, but I doubt it. If I get it Saturday, I probably wont be around to post the results until Sunday, because I have my #@$#@ sister in law B-day thing to go to (no I don't like her very much) 
< Message edited by HummerGuy -- 10/12/2006 1:53:48 PM >
|
|
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/12/2006 3:51:46 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
She's not smart enough to to figure out how to email you, so right there I know you are lieing
And she has her own tax office. I'll just end it at that 
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/12/2006 6:29:07 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
Here are pictures of the piece of the clip that broke off inside one of the three PCM wire harness plugs:
|
|
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/12/2006 11:02:46 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
That's great news. He is also anxious to hear how I like it and wanted some feedback. I told him I'd give him a call and let him know how things feel. The Idle is definitely a good thing.
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/13/2006 5:11:45 PM
|
|
|
jn1300r
Posts: 15
Joined: 8/6/2006
Status: offline
|
I had mine did and love it.
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/13/2006 7:41:59 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
quote:
ORIGINAL: jn1300r
I had mine did and love it.
So, YOU are the mystery man/woman! What kind of a increase did you notice? Are you getting metter gas mileage? Please share with us 
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/13/2006 9:45:51 PM
|
|
|
ChevyHighPerformance
Posts: 159
Joined: 7/5/2006
Status: offline
|
Here is some new fuel economy test data.
First, the goal was to test my modified tranny shift table versus the one supplied from Alvin in his tune.
There are two elements to fuel economy: acceleration efficiency and cruise efficiency.
CRUISE EFFICIENCY
For highway traveling, the goal is to maximize the cruise efficiency. For example, for a typical vehicle the amount of gas it takes to accelerate from 0 to 60 MPH is about the same amount required to keep the vehicle traveling 60 MPH for about a mile. So you can see that when you are traveling many miles the amount of gas used to accelerate you is very small compared the amount of gas you’ll use to keep you at speed for many miles. This sets up my first test for which everyone probably already knows the results. I ran the H3 at two fixed speeds (40 MPH and 44 MPH) in both 3rd and 4th gear and measured the rate at which the gas is consumed. (The gas volume was measured and since the temperature was constant for all tests the volume is reflective of the mass of gas used.)
3rd gear:
40 MPH - fuel utilization rate = 3.38u/s
44 MPH - fuel utilization rate = 3.92u/s
4th gear:
40 MPH - fuel utilization rate = 2.90u/s
44 MPH - fuel utilization rate = 3.05u/s
u/s is a scaled volume of gas used per second
The conclusion here is that if you are cruising you want to be in the highest gear with the torque converter locked. My guess is that even though the drivetrain efficiency is higher in 3rd than 4th gear, the higher engine parasitic losses associated with the higher RPMs in 3rd than 4th gear dominated the fuel rate utilization.
ACCELERATION EFFICIENCY
For city traveling, the goal is to maximize the acceleration efficiency. If you are starting and stopping every block then the amount of gas used to accelerate the vehicle will dominate the fuel consumption and MPG. The trick the hybrids do is absorb energy and store it during braking; then use this stored energy to accelerate the hybrid. This is why the hybrids do proportionally better in the city than the highway.
I ran the H3 at three different constant throttle positions (35%, 45%, and 55%) and measured the total fuel volume used when going from 20 to 50 MPH. (The gas volume was measured and since the temperature was constant for all tests the volume is reflective of the mass of gas used.) I ran this test for both my tranny shift tables and Alvin’s tranny shift tables.
My tranny table
35% throttle: time=28.8 sec, total gas used = 3583u total
45% throttle: time=15.8 sec, total gas used = 2945u total
55%+ throttle: time=13.1 sec, total gas used = 2567u total
Alvin’s tranny table
35% throttle: time=29.3 sec, total gas used = 3803u total
45% throttle: time=12.0 sec, total gas used = 2473u total
55% throttle: time=11.1 sec, total gas used = 2508u total
u total is a scaled amount that represents the total gas volume used
Because it was difficult to precisely hold the throttle in a fixed position there is some variance (maybe +/- 5%) about each time and total fuel used data point. There are two conclusions from this test: 1) Alvin’s table resulted in less fuel consumption than mine and 2) the more throttle you use to accelerate (within reason) the less fuel you use. This goes against the EPA’s advice to not accelerate fast when pulling out because you’ll waste gas. I think the reason why the higher throttle resulted in less total fuel being used is due to the lower pumping losses associated with larger throttle positions thereby increasing the engine’s overall efficiency. Basically, your engine doesn’t have to work as hard to suck air into the engine when the throttle body is open more.
I think the key is learning how to drive based on how the tranny tables are set up. I think my tables are better for cruise (highway) and Alvin's are better for acceleration (city).
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/13/2006 9:59:01 PM
|
|
|
HummerGuy
Posts: 6650
Status: offline
|
I'm completely impressed right now. I love learning these new things. I'm like a black hole for this kinda stuff.
I think it's very interesting that you disproved an EPA theory, at least for this vehicle.
Secondly though, This really wouldn't apply to a manual transmission, would it? You would be controlling everything. Do you know what the odd thing is? I noticed these results with my manual and could never figure it out. Whenever I would give it more gas and shift at higher RPMs while accelerating to my final speed, I would get better MPG. I intentionally used a tank of gas and accelerated shifting on or below 2500 rpms, and got worse MPG, I'm assuming because it wasn't really producing enough torque at those lower RPMs to make the thing move very well. What you are saying makes perfect sense. I'm interested in finding out more of what you find with normal day to day driving.
I should have Alvin's PCM back hopefully tomorrow. You guys are getting me all geeked up about this stuff
|
|
|
|
|
|
|
|
|
RE: My PCM tuning with PCMforLess.com - Process and Res... - 10/13/2006 11:48:17 PM
|
|
|
lotus4s
Posts: 48
Joined: 8/21/2006
Status: offline
|
I've had mine in for a couple of weeks now and overall am pleased. Noticeable difference in low end torque and upper end when you kick it into passing gear. It doesn't seem to labor as much as it used to when taking off from a standstill.
Haven't noticed much of an improvement in mpg, I'm still getting 12 in town and 14 on the highway driving 80-85. It was nice last weekend being able to hit 110mph on the interstate though, no more speed limiter and the truck was very stable. This was on the factory 33" Bridgestones, not my 35" mudders. It doesn't downshift as much trying to maintain higher speeds either.
So that's my SOP opinions and I think it's worth the $ for the improvements.
Jim Knowles
_____________________________
06 H3 Superior Blue, lux/adventure, sunroof, oem ucp & rock rails, 35" Cooper STT's, DOI winch bumper, gobi stealth rack and PIAA 1500xt's, dvd
|
|
|
|
 Today's Posts
Most Active Topics
Make A Donation
Forum Rules & FAQ
RSS Feeds
Hummer Prices
Hummers
Hummer H1
Hummer H2
Hummer H3
Advertising Info
|
Contact Us |
Advertising |
Automotive Directory |
About Us |
Link To Us |
Archive |
Hummer Links |
Legal |
Privacy Policy |
© Hummer Forums.com
Hummer Forums .com is not affiliated with or endorsed by General Motors Corporation.
|
Printable Version
