Dyno tuning or not?
11-25-2003, 08:57 AM
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Dyno tuning or not? Gents,
I'm geting some LTs soon and want a performance tune. Is it practical to tune your LS1 yourself using LS1EDIT (in particular spark advance and fuel settings) or should it be taken to a professional tuner?
In other words spend the $$ on the tools and do-it-yourself or spend the money at the shop?
Thanks in advance!
I'm geting some LTs soon and want a performance tune. Is it practical to tune your LS1 yourself using LS1EDIT (in particular spark advance and fuel settings) or should it be taken to a professional tuner?
In other words spend the $$ on the tools and do-it-yourself or spend the money at the shop?
Thanks in advance!
11-25-2003, 11:40 AM
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Originally Posted by S2002S
Gents,
I'm geting some LTs soon and want a performance tune. Is it practical to tune your LS1 yourself using LS1EDIT (in particular spark advance and fuel settings) or should it be taken to a professional tuner?
In other words spend the $$ on the tools and do-it-yourself or spend the money at the shop?
Thanks in advance!
I'm geting some LTs soon and want a performance tune. Is it practical to tune your LS1 yourself using LS1EDIT (in particular spark advance and fuel settings) or should it be taken to a professional tuner?
In other words spend the $$ on the tools and do-it-yourself or spend the money at the shop?
Thanks in advance!
You have to get you ltrims negative first.
Now you need a good stretch of road where you can log a 4th gear blast. I run from 2000 to 6000 RPM, or about 40 to 120 MPH. If you don't have low gears, you will have to use 3rd or less. You want road and weather to be as consistent as possible, or else you will have to correct for weather.
Take your data and take the derivative of the RPM. What you want is acceleration, but RPM is less noisy than MPH (smoother curve). And forget EFIlive HP. I use awk or Python and bang out some quick code to do it, but you should be able to use Excel. What you have is acceleleration in RPM/sec.
Since F=MA and torque is force times distance (radius of the tire), you can get axle torque using your mass (weight / 32.2) and driveshaft torque with your know rear end ratio and converting RPM to MPH and and MPH to torque and finally torque to HP since HP = torque * RPM / 5252. However, if you plot RPM/s vs RPM, you will have a curve the same shape as your torque curve would be, just with different scaling. You can also get the shape of the HP curve by taking RPM/s * RPM and dividing by some constant to get the numbers to fit your graph.
Make your changes (ie, lean it down or bump the timing or whatever), repeat the above and compare to prior runs. I picked up about 12% (or a comuted 335 to computed 375HP) doing this.
If you want more details, I can expand here if this is of general interest or by e-mail or PM.
Disclaimer: This is typed off the top of my head. I _think_ it is correct, but don't bust my b*lls if not, please
11-25-2003, 06:55 PM
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Originally Posted by critter
Yes, it is practical and not real difficult, but it takes a bit of work and something good to log with. I have used LS1M and EFIlive for logging. Both work. I have an M6 but perhaps the technique would work with an M4. Maybe "a bit of work" makes it impractical for you
You have to get you ltrims negative first.
Now you need a good stretch of road where you can log a 4th gear blast. I run from 2000 to 6000 RPM, or about 40 to 120 MPH. If you don't have low gears, you will have to use 3rd or less. You want road and weather to be as consistent as possible, or else you will have to correct for weather.
Take your data and take the derivative of the RPM. What you want is acceleration, but RPM is less noisy than MPH (smoother curve). And forget EFIlive HP. I use awk or Python and bang out some quick code to do it, but you should be able to use Excel. What you have is acceleleration in RPM/sec.
Since F=MA and torque is force times distance (radius of the tire), you can get axle torque using your mass (weight / 32.2) and driveshaft torque with your know rear end ratio and converting RPM to MPH and and MPH to torque and finally torque to HP since HP = torque * RPM / 5252. However, if you plot RPM/s vs RPM, you will have a curve the same shape as your torque curve would be, just with different scaling. You can also get the shape of the HP curve by taking RPM/s * RPM and dividing by some constant to get the numbers to fit your graph.
Make your changes (ie, lean it down or bump the timing or whatever), repeat the above and compare to prior runs. I picked up about 12% (or a comuted 335 to computed 375HP) doing this.
If you want more details, I can expand here if this is of general interest or by e-mail or PM.
Disclaimer: This is typed off the top of my head. I _think_ it is correct, but don't bust my b*lls if not, please
You have to get you ltrims negative first.
Now you need a good stretch of road where you can log a 4th gear blast. I run from 2000 to 6000 RPM, or about 40 to 120 MPH. If you don't have low gears, you will have to use 3rd or less. You want road and weather to be as consistent as possible, or else you will have to correct for weather.
Take your data and take the derivative of the RPM. What you want is acceleration, but RPM is less noisy than MPH (smoother curve). And forget EFIlive HP. I use awk or Python and bang out some quick code to do it, but you should be able to use Excel. What you have is acceleleration in RPM/sec.
Since F=MA and torque is force times distance (radius of the tire), you can get axle torque using your mass (weight / 32.2) and driveshaft torque with your know rear end ratio and converting RPM to MPH and and MPH to torque and finally torque to HP since HP = torque * RPM / 5252. However, if you plot RPM/s vs RPM, you will have a curve the same shape as your torque curve would be, just with different scaling. You can also get the shape of the HP curve by taking RPM/s * RPM and dividing by some constant to get the numbers to fit your graph.
Make your changes (ie, lean it down or bump the timing or whatever), repeat the above and compare to prior runs. I picked up about 12% (or a comuted 335 to computed 375HP) doing this.
If you want more details, I can expand here if this is of general interest or by e-mail or PM.
Disclaimer: This is typed off the top of my head. I _think_ it is correct, but don't bust my b*lls if not, please
Thanks for the overview. How much time to do this is needed? If I rent a dyno, can it be done in a single 1 hour session or several sessions, leaving time between runs for analysis?
11-25-2003, 08:03 PM
#4
Originally Posted by S2002S
Thanks for the overview. How much time to do this is needed? If I rent a dyno, can it be done in a single 1 hour session or several sessions, leaving time between runs for analysis?
I use A-tap and LS1Edit.You do not need a dyno to tune it in,but it comes in handy to find out what hp gain you get.
Take some time and read some threads on this board about tuning to get an idea.There are many people here that will help you out when you start Editting.
11-25-2003, 08:07 PM
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Originally Posted by S2002S
Thanks for the overview. How much time to do this is needed? If I rent a dyno, can it be done in a single 1 hour session or several sessions, leaving time between runs for analysis?
11-25-2003, 10:14 PM
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Originally Posted by critter
I'd log on the way home from work and then make changes with LS1Edit. Well, actually I'd make a couple runs on each change to make sure it was consistent. That way it took a couple weeks. If you had access to clear road, it could probably be done in an hour or so. I think most dyno tuners figure on four or five runs which is about what it took me. I'd guess you could get a lot done in an hour of dyno time if you can find someone that will let you do your own tuning. You are right, you can get LS1Edit for the cost of a dyno tune. You can do other things if you have edit - disable rear O2s if you leave the cats off, disable AIR and EGR if you leave them off, change A4 shift points, raise RPM limiter, ad nauseum. Yeah, I spent the money on edit and do not regret it.
Thanks again for the advice!
Brad
11-26-2003, 09:17 AM
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Originally Posted by Slowhawk
It's actually alot easier than posted above for basic tunning of your car.
I use A-tap and LS1Edit.You do not need a dyno to tune it in,but it comes in handy to find out what hp gain you get.
I use A-tap and LS1Edit.You do not need a dyno to tune it in,but it comes in handy to find out what hp gain you get.
I think the simple way would be a WB O2, but I haven't gotten off my wallet for that yet. Hence I need another way to measure the effect of the changes and thus my method.
