Thread: A few questions about a GXP

ha. sorry bout that i just looked and saw your thread. ill post up.

thats one pretty ass exhaust

as far as snow they do ok if you keep your foot out of them. i drove my comp g up and down the mountain when i worked in park city for 2 years with blizzacks. thing rode like it was on rails

mine does fine in the snow. the stability control kept me in check.

you can do both and actually if you can afford it i would. the diablo tuning method only tunes the engines performance perameters. the over kill tune does the engine and transmission. but the diablo tuning method releases much more power. typically around 10 hp over the overkill tune. if there is a tuner near you that is reliable i would do the overkill tune for the trans tune and then have the local tuner dyno tune the car. with the overkill tune you can either order a ecm and tcm from him and you get a core refund when you send yours back. or you can send yours off to him to be tuned. with the diablo method you need to purchase a diablosport handheld tuner and then plug it into the car yourself.

Nope..the trans is ticking the second the car comes off the assembley line. If you don't plan on upgrading the trans, don't bother modding. Skip the k and n either way, make your own intake. Headers are mega pricey for the gxp. And all you need is one tune. Iirc gxps have pcm's just like the gtp. One computer controls both engine and trans. Find a competent tuner and get a solid tune after all your modss are installed.

[QUOTE=boostedcompg;658306]gxps have pcm's just like the gtp. QUOTE]
the gxp has an engine control module and a seperate transmission control module. and on top of that a body control module in the trunk. overkill is the only person out right now that tunes both. you cant "chip" these cars. you have to have the module re-tuned. i got the overkill tune. you send him both modules. they are the 2 that are inside your airbox. he changes shift points, line pressures, etc in the tcm.

this is copied over from gmls4.com

RickAKATed10
Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 14:07:57
http://www.getoverkilled.ca/LS4CompProg.html

Has anyone heard about this or have it done?

What are everyone's thoughts?
This seems like a very cost effective tuning option for us LS4 guys. One of my concerns however is this:
"Please be advised there are no returns on these computers for any reason. If you do not like a specific aspect of our calibration, email us within 30 days of recieving and we can provide a retune of the computers we sent you at no retune charge, just pay shipping back to us and we will pay the shipping back to you. The computer modules are warrantied for 90 days for replacement of the defective computer unit only with a similar unit."
I couldn't be without my car for any period of time, so I'd want to look into buying another PCM to ship to Canada in order to have this done.
Well, let's discuss!

GMLS4.com Chief Public Relations Officer

CarDomain / MCF Photo Gallery / MCF Garage



06MonteSS
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 14:21:26
User BlackGXP has the Overkill tune setup... saw it listed in his sig....
hopefully he'll chime in for ya...


2006 Monte Carlo SS - CAI, Poly mount, STB's, Super 40's, NGK TR6IX Iridium,
NGK Performance Wires, Custom DiabLew Tune!
Email: 06MonteSS@diablewtune.com



RickAKATed10
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 14:38:42
Quote: 06MonteSS 03-04-2011 12:21:26
User BlackGXP has the Overkill tune setup... saw it listed in his sig....
hopefully he'll chime in for ya...
I hope so too. Maybe I could email Will again and have him post some information here as well. No need to pay a crazy sponsor fee.

GMLS4.com Chief Public Relations Officer

CarDomain / MCF Photo Gallery / MCF Garage



Overkill
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 16:56:22
Thanks for the email Rick!
I'm sorry to have heard about what happened on the "other forum". I believe there's enough emerging LS4 enthusiast owners to support its own community!
The link provides a lot of information on my LS4 tuning (don't forget to click the popup window links mid-way through the page). I've been tuning W-Body vehicles for about 7-8 years now, specializing in the 3400s and 3800s and now doing more and more LS4 computer tunes as more enthusiasts being to mod them.
My specialty is the transmission settings in my computer tunes. I've spent years of R&D with my own vehicles and other high horsepower W-Bodies with the same transmissions as LS4s on how the computer tuning can help increase the lifespan of the transmission and how to retune it to perform its best.
There are 17 jumbled tables that control transmission fluid pressures, 2 reference tables for those 17 tables, and 9 shift time duration tables in the factory computer which affect how the transmission shifts; all have been proprietarily recoded to make the transmission shift better more consistently and aim to improve its life expectancy. Thusfar I have had consistent reports of reduced or cured off-line shuddering, and 1-2 gearchange slip.
Transmission shift points are completely remapped at all throttle positions in every gear, including when the torque converter or "overdrive" kicks in and out. 1st gear kickdowns occur up to 41mph. 2nd gear kickdowns on the highway occur up to 85mph, while the 2-3 gearchange occurs at the same 6000rpm as the 1-2 gearchange, no more short-shifting. For those with GXPs, TapShift is retuned for quicker shifting, no torque converter lockup so you have complete control over what the transmission does with the exception of a built-in an anti-abuse feature that downshifts into an appropriate gear under hard throttle if you're not in a low enough gear based on road speed (this removes the opportunity to drag the transmission in a high gear at low speeds under heavy throttle).
Engine tuning for more power is accomplished through fuel and spark revisions. Hard throttle fueling has been remapped to provide a lean and linear air/fuel ratio and lags/delays have been removed. Spark timing advanced has been remapped over its considerable variety of adder/subtractor tables to promote more consistent performance as ambient temperature changes, and removes the need for these HSRK (Heat Soak Reduction kits) which relocate the intake temperature sensor.
Fuel economy tweaks are performed through the ignition timing tables but more importantly the fuel and DoD tables. DoD kicks in more at higher road speeds on the highway and holds longer into the throttle. Its maximum run time is increased from 8 minutes to 10 minutes. The ethanol guessing game (as I like to call it) is reconfigured: Part throttle air/fuel ratios are configured to be more consistent with pump gas containing up to 10% ethanol.
And there are lots of additional features. Speed limiter removed. Trouble codes for high flow cat converters, loose gas caps and removed rear O2 sensors are disabled. The air condition system will switch off above 4000rpm or 40% throttle to free up the lost horsepower running the air compressor, then kick back on when rpms or throttle input is lowered. Cooling fan turn ons are remapped to bring the low speeds and high speeds earlier and keep the engine cooler, plus the fans will remain on for 60 seconds when shutting the car off, if the temperature is high enough, to continue to cool the engine while it's at a standstill. And yes I can turn off DoD if you desire.
I reprogram spare engine and transmission modules to ship to you, and you ship your old ones back or choose to keep both per your desire. Programming is $199, and the core charge on your original computers is $145 which you'll receive back when/if you send back your existing modules. This provides the opportunity to lower costs versus a handheld programmer, keep your original computers completely intact should you be worried about going back to how the car originally was, and provides me the opportunity to make the most revisions possible as I use several tuning softwares to create the tunes.
I typically have computer modules instock to reprogram. I offer a special for 05-06s which you can read about on my website. Should you wish to send in your factory computers to be reprogrammed and avoid the $145 core charge, you can do so. Should you wish to send in other computers you've obtained to be reprogrammed, you can do so as well, but email first to ensure that you get the proper modules for your year/model.
To answer the above, they are non-returnable as I leave the computer unlocked so you can have the car retuned more locally if you modify further should you desire to do so. For this ability for the end consumer, a request I had for many years, I cannot accept any tunes back for refunds for any reason. Should you desire a return policy, I can lock the computers and provide you with a 60 day fully refundable guarantee, keeping in mind that no local tuner will be able to read, edit or overwrite the modules that I send to you. I do provide retuning, cost is $50 for unlimited revisions, and update to my latest coding, and $25 shipping.
Thanks for the opportunity to share info on my computer tunes. Email willoverkill@gmail.com or post if you have any questions.

Overkill LS4 Computer Tunes available @ www.getoverkilled.ca

Former Pontiacs: 1998 GTP, 1997 GTP, 1997 GTP, 2004 GTP CompG and 2009 G8 GT
This post was edited by Overkill at 03-04-2011 16:57:19.



06MonteSS
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 17:29:42
Welcome man!!!


2006 Monte Carlo SS - CAI, Poly mount, STB's, Super 40's, NGK TR6IX Iridium,
NGK Performance Wires, Custom DiabLew Tune!
Email: 06MonteSS@diablewtune.com



Ill_Born_ss
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 17:39:52
Hey Will welcome, thanks for the info and find a spot or the whole site. Aiming for a great experience for all.



RickAKATed10
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 18:49:15
Hey Will, I'm really glad you came over here and that you're hear to answer our questions. Hopefully this forum will bring some business for you.
It's interesting to read about the DOD maximum run time. I had no idea that there was a max time set in the ECU. I figured if set at a low enough speed and you turned on cruise control or just maintained speed it would stay engadged for as long as it can. Good to know.
I really want to try and take advantage of this tune. I'm in the process of trying to find a local junk yard or retailer that would sell me both computers at a good price so I can send them to you and have stock and the reprogrammed one at my disposal.
Thanks again!

GMLS4.com Chief Public Relations Officer

CarDomain / MCF Photo Gallery / MCF Garage



06MonteSS
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 18:54:34
Quote: RickAKATed10 03-04-2011 17:49:15
....Hopefully this forum will bring some business for you....
but not TOO much hahahaha... j/k...
yeah, similar DOD parameters are available via the diablo custom tuning as well, to have the dod stay on longer, etc...
but most prefer to just have it disabled, unless you do a LOT of highway driving, there's really no benefit... and people actually usually gain mpg with it off - like I say tho unless they do a LOT of highway driving, then the dod is beneficial... but then there's the oil consumption issue because of DOD, heh...


2006 Monte Carlo SS - CAI, Poly mount, STB's, Super 40's, NGK TR6IX Iridium,
NGK Performance Wires, Custom DiabLew Tune!
Email: 06MonteSS@diablewtune.com
This post was edited by 06MonteSS at 03-04-2011 18:55:46.



Overkill
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 19:27:39
Thanks guys and don't worry Lew I know we're "competitors" but I think different people will buy our individual tunes for different reasons and there's plenty of LS4 enthusiasts for both of us!
I will agree and disagree with you, however, on the DoD. I agree that most customers want rid of it because of the sound through the exhaust and the feel of it, but it definitely saves gas. My Pontiac G8 was fantastic on gas with DoD for a 6L V8, and that's coming from a supercharged V6 that by comparison quite simply drank fuel if you used the boost; former GTP customers upgrading to GXPs comment on how much less fuel the V8 uses.
I actually like the DoD in the LS4s better because there's less vibration, smaller V8, less weight (about 375lbs), it stays active longer.
Its a shame that the technology isn't a bigger hit with enthusiasts but we're filling up at $1.23/L here now for regular 87 octane ($4.79US/gallon with volume and currency conversion), so that may change everyone's mind!

Overkill LS4 Computer Tunes available @ www.getoverkilled.ca

Former Pontiacs: 1998 GTP, 1997 GTP, 1997 GTP, 2004 GTP CompG and 2009 G8 GT


06MonteSS
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 21:08:45
hahaha... yeah, no worries man... we have different offerings... no biggie... the whole point of this new forum was to allow stuff like this.. the more information out there and available for all of us, the better... instead of it getting squashed and subdued elsewhere and we're left with limited information...
as for the DOD... I agree that it does help, but it's been MY experience with these LS4's, as well as a lot of others, that it only really helps if you do a LOT of highway driving... other than that, say if you do 50/50 town/highway driving, it doesn't really help on these cars... maybe on the G8 it's a different story though, I don't know, don't have one haha...
but using my own personal experience as an example, I gained 2 - 2.5 mpg just by disabling the DOD... again, it depends on the persons driving habits... mine are 80 miles a day just for my work commute, and that's 50/50 town/highway driving... others have had similar gains/experiences as well... and of course, it helps having the custom tune as well, so that fueling is adjusted, etc etc... but all things being equal, if I just enable / disable the DOD, and only do that change, I lose mileage with it on...


2006 Monte Carlo SS - CAI, Poly mount, STB's, Super 40's, NGK TR6IX Iridium,
NGK Performance Wires, Custom DiabLew Tune!
Email: 06MonteSS@diablewtune.com
This post was edited by 06MonteSS at 03-04-2011 21:10:42.




Overkill 5.3 LS4 V8 Computer Reprogramming
Overkill
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-04-2011 21:18:37
That's true, most of the gains are on the highway and constant cruising. Stoplight to stoplight, DoD doesn't help much at all. Best for that is open loop tuning and some fancy AFR programming but I only do those in-car and by request, and even still it'll only get so good.

Overkill LS4 Computer Tunes available @ www.getoverkilled.ca

Former Pontiacs: 1998 GTP, 1997 GTP, 1997 GTP, 2004 GTP CompG and 2009 G8 GT


D J Real
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-05-2011 02:52:19
Will, If someone like me who lives in Michigan, (metro detroit) were able to drive the car to you to save shipping charges would you be willing to tune it at your shop (by appointment of course)?




Overkill
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-05-2011 15:05:21
Quote: D J Real 03-05-2011 01:52:19
Will, If someone like me who lives in Michigan, (metro detroit) were able to drive the car to you to save shipping charges would you be willing to tune it at your shop (by appointment of course)?
Yes absolutely, I prefer doing in-vehicle tuning whenever possible to get the best results.
I don't do any dyno tuning, I prefer to tune on the road to get a proper load on the engine. For $300 ($100 more than a mail-order tune), I'll read and modify your factory file to one of my codes and upload it back, then spend up to 2 hours and as many revisions as necessary to fine tune the computer to your vehicle with a diagnostic scanner connected and a wideband air/fuel meter in the tailpipe. This is particularly best if you modify your air intake, as the filter placement changes how the air flows over your MAF sensor and each intake system can do this a little differently; in-car tuning will bring the part throttle fuel trims and full throttle air/fuel mixture back in-line.
If you're coming from Michigan or anyone from New York, I don't mind meeting you on the west end of Toronto and saving you an hour off your trip.

Overkill LS4 Computer Tunes available @ www.getoverkilled.ca

Former Pontiacs: 1998 GTP, 1997 GTP, 1997 GTP, 2004 GTP CompG and 2009 G8 GT


D J Real
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-06-2011 15:54:16
Ahhh Great just e mail you to set something up?




06MonteSS
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-06-2011 21:49:15
yeah.. shoot him an email... he'll get back to ya and hook you up...



2006 Monte Carlo SS - CAI, Poly mount, STB's, Super 40's, NGK TR6IX Iridium,
NGK Performance Wires, Custom DiabLew Tune!
Email: 06MonteSS@diablewtune.com



JC05GXP
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-06-2011 23:40:04
I sent Will my spare ECM and TCM and requested to have DOD off and the 91 tune. Once I get them back I will post results.



06MonteSS
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-07-2011 01:35:52
cool... let us know...


2006 Monte Carlo SS - CAI, Poly mount, STB's, Super 40's, NGK TR6IX Iridium,
NGK Performance Wires, Custom DiabLew Tune!
Email: 06MonteSS@diablewtune.com



RickAKATed10
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-07-2011 18:52:55
Quote: JC05GXP 03-06-2011 21:40:04
I sent Will my spare ECM and TCM and requested to have DOD off and the 91 tune. Once I get them back I will post results.
I can't wait to hear how this goes. If possible, could you tell me where you were able to find a spare ECM/TCM? Thank you!

GMLS4.com Chief Public Relations Officer

CarDomain / MCF Photo Gallery / MCF Garage



Overkill
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-08-2011 21:43:10
Quote: D J Real 03-06-2011 14:54:16
Ahhh Great just e mail you to set something up?
Yes sir, that would be great. I'm available a couple days per week for tuning and can accomodate a weekend with advanced notice, so just let me know your schedule when ready!
If you're looking for spare computers, car-part.com is a great resource to search wrecking yards in your area.

Overkill LS4 Computer Tunes available @ www.getoverkilled.ca

Former Pontiacs: 1998 GTP, 1997 GTP, 1997 GTP, 2004 GTP CompG and 2009 G8 GT


RickAKATed10
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-09-2011 16:18:39
Thank you for the tip on www.car-part.com, I've looked there in the past, but wasn't able to find anything for a price I was willing to spend.

GMLS4.com Chief Public Relations Officer

CarDomain / MCF Photo Gallery / MCF Garage





Overkill 5.3 LS4 V8 Computer Reprogramming
Overkill
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-09-2011 21:15:18
There are 05-06 ECMs for $50.
Much much cheaper than what I have access to here in Canada; US wreckers won't ship to Canada. Infact I'd give someone a deal to send in a few E40 (05-06) cores.

Overkill LS4 Computer Tunes available @ www.getoverkilled.ca

Former Pontiacs: 1998 GTP, 1997 GTP, 1997 GTP, 2004 GTP CompG and 2009 G8 GT


RickAKATed10
Re:Overkill 5.3 LS4 V8 Computer Reprogramming
Posted: 03-10-2011 16:46:15
Hm... What kind of deal?
Let's say I've decided to go with your tune, I'm just waiting for funds. Since I can not be with out my car for any period of time, and I do own a 2006 LS4, what would we be able to work out? Perhaps we should have this discussion over email?

GMLS4.com Chief Public Relations Officer

CarDomain / MCF Photo Gallery / MCF Garage

I stand corrected on the pcm/tcm. Just about everything has a bcm so that's moot. I don't have the time to read through all that but is will the only one activly tuning the tcm or is he flat out the only one doing it? Seems any competent tuner could do it as well

only one actively doing it.