Am I missing a lot of potential in my tune?
Am I missing a lot of potential in my tune? Mods in sig. Car just ran a 12.8 at 111mph tonight with clutch slipping on the launch in 70 degree weather, 60% humidity, sea level.
My tuning process has been as follows (other than the little tweaks) over the last 2 years:
Adjusted IFR until LTFT were at -3 or so.
Adjusted PE until O2s were around 900, and there's no knock (more knock if leaner).
Adjusted timing everywhere so that 1 degree more basically anywhere gets KR. (24-25 at WOT). I have about 11.3:1 compression.
Adjusted the heck out idle crap for multiple months to get it right. Now it idles fine, and doesn't float.
BUT, one thing that I didn't do was to redo the IFR after heads/cam because the LTFT are still barely negative (except for the last week they average -2 and -10).
I've got a stock MAF and stock throttle body. I've never recalibrated the MAF or done anything more than the above for WOT tuning.
Your thoughts? I should note that I don't plan on removing the MAF.
My tuning process has been as follows (other than the little tweaks) over the last 2 years:
Adjusted IFR until LTFT were at -3 or so.
Adjusted PE until O2s were around 900, and there's no knock (more knock if leaner).
Adjusted timing everywhere so that 1 degree more basically anywhere gets KR. (24-25 at WOT). I have about 11.3:1 compression.
Adjusted the heck out idle crap for multiple months to get it right. Now it idles fine, and doesn't float.
BUT, one thing that I didn't do was to redo the IFR after heads/cam because the LTFT are still barely negative (except for the last week they average -2 and -10).
I've got a stock MAF and stock throttle body. I've never recalibrated the MAF or done anything more than the above for WOT tuning.
Your thoughts? I should note that I don't plan on removing the MAF.
1. Don't use the IFR to get your trims in line.
2. Don't use the narrowband O2 sensors to tune WOT.
Yes, you are leaving a good amount on the table IMO. Get a wideband, and go from there.
2. Don't use the narrowband O2 sensors to tune WOT.
Yes, you are leaving a good amount on the table IMO. Get a wideband, and go from there.
Will 3 passes on a dyno with a wideband be enough?
Or, would I be better off buying a wideband?
Should I use my VE table to change my LTFTs? The only thing I've used VE for so far is getting my idle in line.
Or, would I be better off buying a wideband?
Should I use my VE table to change my LTFTs? The only thing I've used VE for so far is getting my idle in line.
WOT is a sideeffect. having IFR reflect the flow of your injectors and having VE reflect the flowing characteristic of the motor is usually enough to get your fueling right. PE mode is a derivative of the normal closed loop mode, that's why PE table is filled with a division ratios. you do not need a wideband or a dyno to get your IFR or VE right. if they're done right, and PE and timing is set to something sensible, your effective AFR will be close to the desired AFR.
dyno and wideband is to account only for these tiny little differences in the end. nothing else. use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be. do NOT alter IFR/VE for that, they have nothing to do with WOT!
dyno and wideband is to account only for these tiny little differences in the end. nothing else. use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be. do NOT alter IFR/VE for that, they have nothing to do with WOT!
"use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be."
I'm not familiar with the AFR/rpm graph. What is it?
I've also read a bit about VE tuning, and I still don't really understand what needs to be done.
Also, with my LTFTs, what does it mean if bank 1 is -2 and bank 2 is -10?
I'm not familiar with the AFR/rpm graph. What is it?
I've also read a bit about VE tuning, and I still don't really understand what needs to be done.
Also, with my LTFTs, what does it mean if bank 1 is -2 and bank 2 is -10?
Originally Posted by silverTA2002
"use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be."
I'm not familiar with the AFR/rpm graph. What is it?
I've also read a bit about VE tuning, and I still don't really understand what needs to be done.
Also, with my LTFTs, what does it mean if bank 1 is -2 and bank 2 is -10?
I'm not familiar with the AFR/rpm graph. What is it?
I've also read a bit about VE tuning, and I still don't really understand what needs to be done.
Also, with my LTFTs, what does it mean if bank 1 is -2 and bank 2 is -10?
My guess is it means that you may have a header leak on bank one. I don't know for sure on that one though. It would take some troubleshooting.
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Originally Posted by white2001s10
He means the PE vs RPM table.
My guess is it means that you may have a header leak on bank one. I don't know for sure on that one though. It would take some troubleshooting.
My guess is it means that you may have a header leak on bank one. I don't know for sure on that one though. It would take some troubleshooting.
I've got the Jet hot catted Y pipe. It has like 7 pieces that each fit together with band clamps.
There's ALWAYS a freakin leak popping up somewhere. So frustrating.
My "solution" is using sensor safe high temp RTV on every connection, covered that with high temp muffler tape, covered with stainless steel band clamps tightened as tight as they go.
And STILL every few months a clamp will slide around a bit and cause another leak.
I don't want to weld. If I had originally, the heads/cam swap would've been a bit more difficult.
Long story short, I did fix another leak. So, I'd bet if I logged right now, I'd be right at -2 and -4 LTFT just like always.
So........ Should I "recalibrate my MAF?" Or does that really make a difference in power?
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Verdad Gallardo recalibrate MAF only if your VE is done properly. and yes, it will give you a huge difference. i can send you some dyno charts/logs demonstrating what happens when your maf is off. sneak peak: scary!
Originally Posted by silverTA2002
"use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be."
I'm not familiar with the AFR/rpm graph. What is it?
I've also read a bit about VE tuning, and I still don't really understand what needs to be done.
Also, with my LTFTs, what does it mean if bank 1 is -2 and bank 2 is -10?
I'm not familiar with the AFR/rpm graph. What is it?
I've also read a bit about VE tuning, and I still don't really understand what needs to be done.
Also, with my LTFTs, what does it mean if bank 1 is -2 and bank 2 is -10?
Rinse and repeat. You want all values to be from 0 to -4 in the histogram once you are done. Sometimes you have to use a slightly lower value than the one shown. For instance, you make the change above and then the next histogram that you log may show (+)4 in the same cell. What I do here is that I split the number in 1/2 and add it to the cell in the VE table basically adding 2 into the number instead of the 4 value that the histo gave you. When VE tuning, the MAF should be unplugged. I am new to this also so that is why I added so much detail. I think that some of the more knowledgeable guys on here dont remember what it was like to be a noob at this (like me).
Also, the VE table is not idle tuning. You have to look at LTIT and STIT and add the values together in order to get your idle at it's best.
I am just getting past this part of the tuning process on my 402 (talk about starting on the tuning in the deep end). PE tuning and spark advance tuning are next for me.
Originally Posted by RedHardSupra
WOT is a sideeffect. having IFR reflect the flow of your injectors and having VE reflect the flowing characteristic of the motor is usually enough to get your fueling right. PE mode is a derivative of the normal closed loop mode, that's why PE table is filled with a division ratios. you do not need a wideband or a dyno to get your IFR or VE right. if they're done right, and PE and timing is set to something sensible, your effective AFR will be close to the desired AFR.
dyno and wideband is to account only for these tiny little differences in the end. nothing else. use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be. do NOT alter IFR/VE for that, they have nothing to do with WOT!
dyno and wideband is to account only for these tiny little differences in the end. nothing else. use the AFR/rpm graph to alter your PE divisors so your effective AFR is closer to what you want it to be. do NOT alter IFR/VE for that, they have nothing to do with WOT!
I am just getting to this point on the tuning of my 402. I am a little confused about the conflicting information that I have seen with regards to WOT tuning. I don't want to blow my new motor. Alot of experienced guys on here and the HPT forum say that you cannot tune the PE table w/o a WBO2 sensor. Because I am not working on a stock cube motor, should I trust the Stoich value that is in my tune? How does the computer know? I guess what I am asking for is a basic lesson in Stoich. Based on what I took from your quote above, pretty much all cars should have the same values in the PE vs RPM table and the WB02 is just to check and make sure that it is correct in the real world and that the narrow band O2's are reporting properly. Is this correct or did I misunderstand. The only 2 reasons why I am lending any weight to this is because 1) all of the so called experts say that you are one of the more knowledgeable people and 2) because I dont have a WB02 or a dyno handy
Also, should you tune the spark or the PE first?
Thanks in advance.
Originally Posted by chrisj6
When tuning the VE table, that is a percentage. You want to multiply by % - half instead of adding or subtracting from the table. Multiplying by 1/2 percentage avoids overshooting.
Chris
Chris
So if you have a value of -10 LTFT in cell X, what percentage to you multiply that particular VE cell # by?
From what I've read so far, people are adding and subtracting the LTFT from VE.
What's kinda interesting is that tuning VE sounds a lot like tuning Base airflow for you idle. You log, make changes, log again, make changes......... Until the STIT and LTIT don't move much.
So, for VE you log, make changes, log, make changes until your STIT and LTIT don't move much.
OR, are you saying that if cell X is -10 then subtract 5 from VE?
That's what I ended up doing with my base running airflow changes. Everytime I'd only change them by HALF of what the "formula" told me to. That way I wouldn't overshoot, undershoot, overshoot........
Originally Posted by chrisj6
When tuning the VE table, that is a percentage. You want to multiply by % - half instead of adding or subtracting from the table. Multiplying by 1/2 percentage avoids overshooting.
Chris
Chris
Chrisj, you may be using a dfiferent method that logs different values which may require multiplication but none of the methods that I have seen (using narrowband O2's) require multiplication. Once I get close on the VE table and I start to overshoot, then I split the value in half but I still add the value (whether negative or positive).