Tuning difficulties?
08-22-2006, 01:50 PM
#1
Staging Lane
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Tuning difficulties? Right now, I'm working on a motor build with flat top Mahle pistons with 2 cc valve reliefs, Scat H-beam rods, PRC stage 1 6.0 L heads with the CNC valve job and Comp 918 valve springs, and a TSP 224/228, .581"/.588", 115+4 LSA cam. I inquired about tuning services and received this reply:
If you are doing a whole engine, we will need to spend time on the drivability tuning- that needs to be done before anything else (and can take 1-2 days just for drivability) if the drivability isn't correct, it will adapt over time and cause issues that will come up later on. This is the PROPER way to do things and for what you have is the only way I will involve myself in the project (i don't want to be buying parts!!)
Is this pretty much standard operating procedure for buillt FI motors? Thanks.
If you are doing a whole engine, we will need to spend time on the drivability tuning- that needs to be done before anything else (and can take 1-2 days just for drivability) if the drivability isn't correct, it will adapt over time and cause issues that will come up later on. This is the PROPER way to do things and for what you have is the only way I will involve myself in the project (i don't want to be buying parts!!)
Is this pretty much standard operating procedure for buillt FI motors? Thanks.
08-22-2006, 01:53 PM
#2
The drivability needs to be done first, yes. With a FI car, you have to rebuild the whole VE table first and then start with WOT tuning. It can be time consuming. 99% of the tuners in shops, just tune for WOT on a dyno because drivability takes forever to do.
08-22-2006, 08:14 PM
#4
start with hardware setup, injectors, cylinder volume, stuff like that.
get drivability right. this is tricky, because you will need to interchange RAF/VE tuning here. to drive around to gather VE data, you will want a decent RAF. to get it to idle, you will need a decent VE. it's basically a chicken and egg problem, and unless you eyeball them into a reasonable (read: doesn't die, and it's tunable) range, you're never gonna get it done.
FI is tricky, boost can come on early and hit hard, so adjust your PE triggers accordingly. move slowly. do everything up to 2500rpm, if it drives fine, then move onto another 600rpm, do that, move on another 600... rinse repeat, and verify your previous range every time you move on.
wideband for FI is not an option but a must. 2 or 3 bar MAP coupled with a 2 or 3bar SD tune is the preferred way to go on FI setups with stock PCM. check that your fuel can support the power you're making at all rpm, not just peak.
once your VE is dialed in perfect, work on PE(AFR) and spark. start from the low side, and remember that in FI torque isn't related to rpm, so watch where you have load, and adjust timing accordingly in all the right places. PE and spark will affect each other, so you have to just play with it until you arrive at a good steady, repeatable combo that yields a decent result. best to be tested at the track with a good TIME based device. another way of doing it is to find a real dyno (not a mustang or dynojet) and find the proper PE/spark time that way.
get drivability right. this is tricky, because you will need to interchange RAF/VE tuning here. to drive around to gather VE data, you will want a decent RAF. to get it to idle, you will need a decent VE. it's basically a chicken and egg problem, and unless you eyeball them into a reasonable (read: doesn't die, and it's tunable) range, you're never gonna get it done.
FI is tricky, boost can come on early and hit hard, so adjust your PE triggers accordingly. move slowly. do everything up to 2500rpm, if it drives fine, then move onto another 600rpm, do that, move on another 600... rinse repeat, and verify your previous range every time you move on.
wideband for FI is not an option but a must. 2 or 3 bar MAP coupled with a 2 or 3bar SD tune is the preferred way to go on FI setups with stock PCM. check that your fuel can support the power you're making at all rpm, not just peak.
once your VE is dialed in perfect, work on PE(AFR) and spark. start from the low side, and remember that in FI torque isn't related to rpm, so watch where you have load, and adjust timing accordingly in all the right places. PE and spark will affect each other, so you have to just play with it until you arrive at a good steady, repeatable combo that yields a decent result. best to be tested at the track with a good TIME based device. another way of doing it is to find a real dyno (not a mustang or dynojet) and find the proper PE/spark time that way.
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08-25-2006, 07:10 AM
#8
Originally Posted by studentdriver
Right now, I'm working on a motor build with flat top Mahle pistons with 2 cc valve reliefs, Scat H-beam rods, PRC stage 1 6.0 L heads with the CNC valve job and Comp 918 valve springs, and a TSP 224/228, .581"/.588", 115+4 LSA cam. I inquired about tuning services and received this reply:
If you are doing a whole engine, we will need to spend time on the drivability tuning- that needs to be done before anything else (and can take 1-2 days just for drivability) if the drivability isn't correct, it will adapt over time and cause issues that will come up later on. This is the PROPER way to do things and for what you have is the only way I will involve myself in the project (i don't want to be buying parts!!)
Is this pretty much standard operating procedure for buillt FI motors? Thanks.
If you are doing a whole engine, we will need to spend time on the drivability tuning- that needs to be done before anything else (and can take 1-2 days just for drivability) if the drivability isn't correct, it will adapt over time and cause issues that will come up later on. This is the PROPER way to do things and for what you have is the only way I will involve myself in the project (i don't want to be buying parts!!)
Is this pretty much standard operating procedure for buillt FI motors? Thanks.
08-28-2006, 11:17 PM
#9
Staging Lane
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Well, going from the stock 66.67cc combustion chamber to the 71.06 cc chambers should drop compression to about 9:1. I'm hoping that will be sufficient; most people seem to have success with similar ratios.