Proper LS4 dyno pulls, practice
07-05-2011, 10:15 AM
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Proper LS4 dyno pulls, practice Alright, I've looked around and I haven't found a comprehensive dyno prep, procedure for the LS4. Being new to the forum and to the world of the LS4 I want to hear from you more experienced people....I'm curious what is the best dyno prep and procedure for the LS4? The local performance shop isn't really keen on FWD, LS4 cars and I don't want my trans or engine blown up due to their ignorance. I dynoed my car last week and my tires took a serious beating but I'll take the hit on that considering my wifes mother put T rated tires on the car before we were married and I didn't bother to check before hand. Yeah...I know, feel free to skewer me. 
Anyways, the car has been Overkill tuned so the top speed limiter has been removed and I do believe the fuel cutout at redline in 2nd and 3rd has been extended a bit. We did pulls last week to 160MPH before it cutout.
1. Why go that far? What's gained by pushing through 160 MPH when you've already reached peak HP long before this?
2. Would it be better for the car for me to reset the stock fuel cutout points and reinsert the top speed limiter? Pulling 160 mph for multiple pulls can't be healthy.
3. What settings should be disabled, limited etc using HP Tuners? Last pulls TC/SC, torque management were disabled, DOD was not.
4. This guy is meticulous and strives to pull as much performance and gain he can, problem is this can mean multiple pulls. Is there a max amount of pulls that should be done per dyno session? I'm guessing heat is a factor and it averages 90+ during the summer months here and the shop doesn't have the best ventilation.
At a minimum maybe this post and my tire f***-up can help other LS4 owners down the road.
Anyways, the car has been Overkill tuned so the top speed limiter has been removed and I do believe the fuel cutout at redline in 2nd and 3rd has been extended a bit. We did pulls last week to 160MPH before it cutout.
1. Why go that far? What's gained by pushing through 160 MPH when you've already reached peak HP long before this?
2. Would it be better for the car for me to reset the stock fuel cutout points and reinsert the top speed limiter? Pulling 160 mph for multiple pulls can't be healthy.
3. What settings should be disabled, limited etc using HP Tuners? Last pulls TC/SC, torque management were disabled, DOD was not.
4. This guy is meticulous and strives to pull as much performance and gain he can, problem is this can mean multiple pulls. Is there a max amount of pulls that should be done per dyno session? I'm guessing heat is a factor and it averages 90+ during the summer months here and the shop doesn't have the best ventilation.
At a minimum maybe this post and my tire f***-up can help other LS4 owners down the road.
07-06-2011, 10:43 AM
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Did you ask him why he would go to 160? Personally, if a shop would have done a dyno pull to 160 in my car more than once while I was watching them I would have pulled the guy from my car and back handed him numerous times.
07-06-2011, 11:47 AM
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Dyno in 3rd gear and make sure the engine is cool to touch before starting the pull's.
Run the engine up to 5900 rpm in 3rd and let off of the throttle to slow the wheels down to a stop.
PM JCM5, he dyno tunes and has a bunch of experience with LS4's.
Run the engine up to 5900 rpm in 3rd and let off of the throttle to slow the wheels down to a stop.
PM JCM5, he dyno tunes and has a bunch of experience with LS4's.
07-06-2011, 11:47 AM
#4
The reason he did that is because it was 3rd gear. 3rd gear is a 1-1 ratio. Meaning it shows true power. The problem with our cars though is that it goes to 160 mph lol. I usually do a 2nd gear pull because i dont want to drive my car that fast on some barrels. However people say this isnt proper power ratings..
Also you can raise the fuel cutouts over stock and take the top speed limiter off and be safe. Just dont run it above 7200 rpms without supporting mods.
Also you can raise the fuel cutouts over stock and take the top speed limiter off and be safe. Just dont run it above 7200 rpms without supporting mods.
07-06-2011, 04:14 PM
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I'm guessing your car is pretty well tweaked any advice for tweaking to maximize gains? I've been reading around and ideal AFR @ WOT for these LS4s in order to maximize power seems to be debatable I heard anywhere from 12.4-13.0. Hoping to add quite a bit of timing too since I'm at altitude and on 91 Octane. I guess we'll see though.
EDIT: Is there an easy way to tell if the TC is locked-up using HP tuners, I'm guessing it can be manually locked?
Last edited by redlightrampage; 07-06-2011 at 04:41 PM.
07-06-2011, 05:09 PM
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I'll pass this on thanks for the info. He was unloading the transmission by dropping it into neutral, seems like this would be safer than just backing off especially in an auto? The "dyno disaster" post was kind
I'm guessing your car is pretty well tweaked any advice for tweaking to maximize gains? I've been reading around and ideal AFR @ WOT for these LS4s in order to maximize power seems to be debatable I heard anywhere from 12.4-13.0. Hoping to add quite a bit of timing too since I'm at altitude and on 91 Octane. I guess we'll see though.
EDIT: Is there an easy way to tell if the TC is locked-up using HP tuners, I'm guessing it can be manually locked?
I'm guessing your car is pretty well tweaked any advice for tweaking to maximize gains? I've been reading around and ideal AFR @ WOT for these LS4s in order to maximize power seems to be debatable I heard anywhere from 12.4-13.0. Hoping to add quite a bit of timing too since I'm at altitude and on 91 Octane. I guess we'll see though.
EDIT: Is there an easy way to tell if the TC is locked-up using HP tuners, I'm guessing it can be manually locked?
13.1:1 AFR is a good place to start. It all depends on what meter you are using and where it is placed. Don't get too hung up on dyno numbers, since these cars are not known to do too well. Keep in mind that once you get your AFR dialed in on the dyno, you'll want to have the tuner richen it up a little for the road. Same holds true for timing. You don't want to get too aggressive or else you'll get spark knock once you hit the road. I'm sure your tuner knows this stuff.
Leave your converter unlocked!!! On the highway I can tell when it locks and unlocks with my exhaust. The engines rev's super quick when it's unlocked. Just tap the brake (locked) and it will unlock.
We only have single clutch converter (Heavy as hell) so it doesn't take much to ruin it. My PI converter use a single clutch too, and I was told not to lock it up for max power.
When I was dyno tune by Vince, he dialed in the AFR and then adjusted the timing.
For the trans he moved the tap shift tables to the Drive tables and added a little more line pressure in tap mode. The 2nd to 3rd shift points were set to 5900 in drive since the stock shifts occurred at 5200 or so.
I was happy with the tune but this was done when I was mostly stock, back in 2007.
What I don't like about dyno tuning is that we are only tuning for WOT.
Lewis re-tuned my engine by using data logs that were recorded under real life driving situations. Part throttle and full throttle logs were used.
As far as my car being tweaked for max gains? I would say no... very close though. I am not happy with my stock dinky tiny intake tubing and MAF. I am also not happy with the summer heat heating the heck out of the engine. IAT's are up to 145, oil temp is around 225 and water is at 210-215. Shutting the engine down really cooks the S word out of everything and power goes away real quick.
Last edited by DavidGXP; 07-08-2011 at 01:23 AM.
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07-06-2011, 05:37 PM
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13.1:1 AFR is a good place to start. It all depends on what meter you are using and where it is placed. Don't get too hung up on dyno numbers since these cars are not known to do too well. I blame it on the engine bay heat. Keep in mind that once you get your AFR dialed in on the dyno, you'll want to have the tuner richen it up a little for the road. Same holds true for timing. You don't wanna get to aggessive or else you'll get spark knock once you hit the road. I'm sure your tuner knows this stuff.
Leave your converter unlocked!!! On the highway I can tell when it locks and unlocks with my exhaust. The engines rev's super quick when it's unlocked. Just tap the brake and it will unlock.
We only have single clutch converter (Heavy as hell) so it doesn't take much to run it. My PI converter use a single clutch too and I ws told not to lock it up for max power.
When I was dyno tune by Vince at Trifecta, he dialed in the AFR and then adjusted the timing.
For the trans he moved the tapshift tables to the Drive tables and added a little more line pressure in tap mode. The 2nd to 3rd shift points were set to 5900 in drive since the stock shifts occured at 5200 or so.
I was happy with the tune but this was done when I was mostly stock, back in 2007.
What I don't like about dyno tuning is that we are only tuning for WOT.
Lewis re-tuned my engine by using data logs that were recorded under real life driving situations. Part throttle and full throttle logs were used.
As far as my car being tweaked for max gains? I would say no... very close though. I am not happy with my stock dinky tiny intake tubing and MAF. I am also not happy with the summer heat heating the heck out of the engine. IAT's are up to 145, oil temp is around 225 and water is at 210-215. Shutting the engine down really cooks the S word out of everything and power goes away real quick.
Leave your converter unlocked!!! On the highway I can tell when it locks and unlocks with my exhaust. The engines rev's super quick when it's unlocked. Just tap the brake and it will unlock.
We only have single clutch converter (Heavy as hell) so it doesn't take much to run it. My PI converter use a single clutch too and I ws told not to lock it up for max power.
When I was dyno tune by Vince at Trifecta, he dialed in the AFR and then adjusted the timing.
For the trans he moved the tapshift tables to the Drive tables and added a little more line pressure in tap mode. The 2nd to 3rd shift points were set to 5900 in drive since the stock shifts occured at 5200 or so.
I was happy with the tune but this was done when I was mostly stock, back in 2007.
What I don't like about dyno tuning is that we are only tuning for WOT.
Lewis re-tuned my engine by using data logs that were recorded under real life driving situations. Part throttle and full throttle logs were used.
As far as my car being tweaked for max gains? I would say no... very close though. I am not happy with my stock dinky tiny intake tubing and MAF. I am also not happy with the summer heat heating the heck out of the engine. IAT's are up to 145, oil temp is around 225 and water is at 210-215. Shutting the engine down really cooks the S word out of everything and power goes away real quick.
One thing I've just realized is that my first pull last time was 233/266, my 2nd pull was 246/27* I believe. Problem here is I'm fairly certain 1st run was 3rd gear and 2nd run was 2nd, this is kind of concerning because the 2nd pull wasn't anywhere near 1.56 X the torque seen in 3rd. I'm thinking either both runs were done in 3rd or something is seriously wrong here. He runs a Dynojet 248X. I'm hoping either his gear adjustment is off or something, I'm going to stop by there today and grab those dyno results.
07-07-2011, 08:41 AM
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Turn off your TC and Stab. Trac. with your cockpit button, pull that daddy up on the drums...mostly just behind the drum...almost on top to keep some of the rock back off the tranny while strapping it down...put the emergency brake on and put it in N...X strap it in front on subframe, and straight strap in back around wheels to anchors...you can keep your emergency brake on if you want, or just let it off if your chalking the back wheels...in HPT: No DOD, your fuel cut off to unlimited or at 6300 and just stay under that, and let her eat!!!
As far as running up to 160 over and over again...you shouldn't need to go up to that speed on dyno to get the max power out of it...redline, or where you set your fuel cut out, or just under is your rpm range and is how I would say is what you look at to determin your "power band"...that tachometer is your power band gauge...think of it that way...0-6300 give or take depending on your habbits and the tuners' settings. The power you get is determined by Xrpm not Xmph...MPH is only telling you how fast your going in your "power band" so to speak...MPH for these cars, with the 3rd gear being a really tall 1:1, is not a deciding factor...you will have same power at 130's as you would at 160's most likely...depending on set up...you said it yourself though...shouldn't have to go 160 for NO MORE than 2 runs max...or 3 with a good cool down....DONT DO THAT...just no need...ive been to 172 on the dyno...that was early days and I was trying to set dyno speed records...LMAO...no i wasnt, jk! LOL remember...RPM max, not MPH max...dyno the car using your tach...not your speedo....not the swimming kind either! You guys are sick! LOL
Your probably going to notice how low on the power band the converter locks up...especially with the DOD off...you will work your way up into 3rd just fine...and then...there is a spot where it will seem like it shifts again while in third...it will dip under 3k rpm and seem like a slug....dont puch it from there to do your pull...just snap the throttle a bit and get it back over 3k rpms and get her peppy again...that gets you back in power band with some rpm behind you...then go to town to RED LINE ON TACH...thats it...no need to go any more...no more gained more than likely
As far as popping the car into N after a WOT 3rd gear pull...that's ok...but it would be easier to just pop it in D after the pull and YOU HAVE LET OFF THE THROTTLE...the car will shift into 4th on dyno WITHOUT LOAD just fine, nice and smooth...NEVER SHIFT ON THE DYNO UNDER POWER OR BUILDING POWER....things can break! And for God sake...dont down shift! Ol Ken can tell ya about that...he recently lost some expensive parts for that happening...Sorry Ken...but he is getting it buttoned up as far as I know...The 4th shift isnt under power so you will be fine...hell, you don't even want to shift into 4th on the street under a load...LOL its that bad for 4th...just lift before you drop into D and let the tranny brind the motor and itself down on the rollers...NO LOAD WHEN YOU DO, THIS IS THE KEY HERE!!
Just my .02 though...have had lots of dyno time and experiences with my car...LOL...and those who have commented in this thread...David and mongoose...well, lets just say we've been around these motors a bit, and have seen and done some things...LOL and good comment by Impalass07...smack that guy! LOL
As far as running up to 160 over and over again...you shouldn't need to go up to that speed on dyno to get the max power out of it...redline, or where you set your fuel cut out, or just under is your rpm range and is how I would say is what you look at to determin your "power band"...that tachometer is your power band gauge...think of it that way...0-6300 give or take depending on your habbits and the tuners' settings. The power you get is determined by Xrpm not Xmph...MPH is only telling you how fast your going in your "power band" so to speak...MPH for these cars, with the 3rd gear being a really tall 1:1, is not a deciding factor...you will have same power at 130's as you would at 160's most likely...depending on set up...you said it yourself though...shouldn't have to go 160 for NO MORE than 2 runs max...or 3 with a good cool down....DONT DO THAT...just no need...ive been to 172 on the dyno...that was early days and I was trying to set dyno speed records...LMAO...no i wasnt, jk! LOL remember...RPM max, not MPH max...dyno the car using your tach...not your speedo....not the swimming kind either! You guys are sick! LOL
Your probably going to notice how low on the power band the converter locks up...especially with the DOD off...you will work your way up into 3rd just fine...and then...there is a spot where it will seem like it shifts again while in third...it will dip under 3k rpm and seem like a slug....dont puch it from there to do your pull...just snap the throttle a bit and get it back over 3k rpms and get her peppy again...that gets you back in power band with some rpm behind you...then go to town to RED LINE ON TACH...thats it...no need to go any more...no more gained more than likely
As far as popping the car into N after a WOT 3rd gear pull...that's ok...but it would be easier to just pop it in D after the pull and YOU HAVE LET OFF THE THROTTLE...the car will shift into 4th on dyno WITHOUT LOAD just fine, nice and smooth...NEVER SHIFT ON THE DYNO UNDER POWER OR BUILDING POWER....things can break! And for God sake...dont down shift! Ol Ken can tell ya about that...he recently lost some expensive parts for that happening...Sorry Ken...but he is getting it buttoned up as far as I know...The 4th shift isnt under power so you will be fine...hell, you don't even want to shift into 4th on the street under a load...LOL its that bad for 4th...just lift before you drop into D and let the tranny brind the motor and itself down on the rollers...NO LOAD WHEN YOU DO, THIS IS THE KEY HERE!!
Just my .02 though...have had lots of dyno time and experiences with my car...LOL...and those who have commented in this thread...David and mongoose...well, lets just say we've been around these motors a bit, and have seen and done some things...LOL and good comment by Impalass07...smack that guy! LOL
Last edited by Rossko85; 07-07-2011 at 08:46 AM.
07-08-2011, 12:53 AM
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Yeah...most likely...just need different springs and pushrods for sure though...but they will get a bit weak around those numbers...beware! LOL somebody on here did it...i cant remember...they took the RPMs up up and away on factory lifters...who knows LOL I think they can go up there though...
07-08-2011, 01:28 AM
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Turn off your TC and Stab. Trac. with your cockpit button, pull that daddy up on the drums...mostly just behind the drum...almost on top to keep some of the rock back off the tranny while strapping it down...put the emergency brake on and put it in N...X strap it in front on subframe, and straight strap in back around wheels to anchors...you can keep your emergency brake on if you want, or just let it off if your chalking the back wheels...in HPT: No DOD, your fuel cut off to unlimited or at 6300 and just stay under that, and let her eat!!!
As far as running up to 160 over and over again...you shouldn't need to go up to that speed on dyno to get the max power out of it...redline, or where you set your fuel cut out, or just under is your rpm range and is how I would say is what you look at to determin your "power band"...that tachometer is your power band gauge...think of it that way...0-6300 give or take depending on your habbits and the tuners' settings. The power you get is determined by Xrpm not Xmph...MPH is only telling you how fast your going in your "power band" so to speak...MPH for these cars, with the 3rd gear being a really tall 1:1, is not a deciding factor...you will have same power at 130's as you would at 160's most likely...depending on set up...you said it yourself though...shouldn't have to go 160 for NO MORE than 2 runs max...or 3 with a good cool down....DONT DO THAT...just no need...ive been to 172 on the dyno...that was early days and I was trying to set dyno speed records...LMAO...no i wasnt, jk! LOL remember...RPM max, not MPH max...dyno the car using your tach...not your speedo....not the swimming kind either! You guys are sick! LOL
Your probably going to notice how low on the power band the converter locks up...especially with the DOD off...you will work your way up into 3rd just fine...and then...there is a spot where it will seem like it shifts again while in third...it will dip under 3k rpm and seem like a slug....dont puch it from there to do your pull...just snap the throttle a bit and get it back over 3k rpms and get her peppy again...that gets you back in power band with some rpm behind you...then go to town to RED LINE ON TACH...thats it...no need to go any more...no more gained more than likely
As far as popping the car into N after a WOT 3rd gear pull...that's ok...but it would be easier to just pop it in D after the pull and YOU HAVE LET OFF THE THROTTLE...the car will shift into 4th on dyno WITHOUT LOAD just fine, nice and smooth...NEVER SHIFT ON THE DYNO UNDER POWER OR BUILDING POWER....things can break! And for God sake...dont down shift! The 4th shift isnt under power so you will be fine...hell, you don't even want to shift into 4th on the street under a load...LOL its that bad for 4th...just lift before you drop into D and let the tranny brind the motor and itself down on the rollers...NO LOAD WHEN YOU DO, THIS IS THE KEY HERE!!!
As far as running up to 160 over and over again...you shouldn't need to go up to that speed on dyno to get the max power out of it...redline, or where you set your fuel cut out, or just under is your rpm range and is how I would say is what you look at to determin your "power band"...that tachometer is your power band gauge...think of it that way...0-6300 give or take depending on your habbits and the tuners' settings. The power you get is determined by Xrpm not Xmph...MPH is only telling you how fast your going in your "power band" so to speak...MPH for these cars, with the 3rd gear being a really tall 1:1, is not a deciding factor...you will have same power at 130's as you would at 160's most likely...depending on set up...you said it yourself though...shouldn't have to go 160 for NO MORE than 2 runs max...or 3 with a good cool down....DONT DO THAT...just no need...ive been to 172 on the dyno...that was early days and I was trying to set dyno speed records...LMAO...no i wasnt, jk! LOL remember...RPM max, not MPH max...dyno the car using your tach...not your speedo....not the swimming kind either! You guys are sick! LOL
Your probably going to notice how low on the power band the converter locks up...especially with the DOD off...you will work your way up into 3rd just fine...and then...there is a spot where it will seem like it shifts again while in third...it will dip under 3k rpm and seem like a slug....dont puch it from there to do your pull...just snap the throttle a bit and get it back over 3k rpms and get her peppy again...that gets you back in power band with some rpm behind you...then go to town to RED LINE ON TACH...thats it...no need to go any more...no more gained more than likely
As far as popping the car into N after a WOT 3rd gear pull...that's ok...but it would be easier to just pop it in D after the pull and YOU HAVE LET OFF THE THROTTLE...the car will shift into 4th on dyno WITHOUT LOAD just fine, nice and smooth...NEVER SHIFT ON THE DYNO UNDER POWER OR BUILDING POWER....things can break! And for God sake...dont down shift! The 4th shift isnt under power so you will be fine...hell, you don't even want to shift into 4th on the street under a load...LOL its that bad for 4th...just lift before you drop into D and let the tranny brind the motor and itself down on the rollers...NO LOAD WHEN YOU DO, THIS IS THE KEY HERE!!!
Gotta love that sig
07-08-2011, 10:31 AM
#13
Yeah...most likely...just need different springs and pushrods for sure though...but they will get a bit weak around those numbers...beware! LOL somebody on here did it...i cant remember...they took the RPMs up up and away on factory lifters...who knows LOL I think they can go up there though...
07-12-2011, 03:25 PM
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So is TC lock-up a no no on these cars or what? I'm going back to the dyno tomorrow. Trans is brand new, less than 6k miles on it, would prefer to not damage if it's that great of a risk. I've seen two different arguments on this...
