Re: Thread for those of us who tune our own cars
 

why in the hell would you want to run stoic "14.65 A/F" at WOT you will run the car too lean and end up detonating it. And no the base fuel table is not used at WOT your maf transfer is what controls the amount of fuel being delivered to your motor. You can command whatever you want thru the base fuel table but it won't change a thing to the amount of fuel you motor will see at WOT. If you want to add or subtract fuel to get the a/f at your desired a/f ratio what ever that ratio might me for the type of fuel you are running it has to be done with the maf transfer funtion.

I was under the impression you tune the entire maf curve for stoich initially. Leave the base fuel table at lamba for all of the low load and low throttle position. Adjust the maf transfer function in open loop until its darn near 14.7 under all part throttle driving and project the trend to conditions you can't datalog at cruise. Then adjust base fuel table high load/ high throttle position to what you want at WOT then readjust the maf transfer until you see your commanded lamba. I guess you could just leave it all at lamba and just continually ramp up the maf but then the system is less adaptive/dynamic.

Re: Thread for those of us who tune our own cars
 

You are correct but the thing is the higher the load the more fuel you want so you do not want that at lambda across the load range of the motor and as you go higher in the load range your computer switches from closed loop using the basefuel table to open loop using only the commanded setpoint in the maftransfer function for the load the maf is seeing at that load range and as the load range increases you will need to add more thru the curve to insure your A/F stays at your desired ration thru out the whole cure at full load under WOT.

Re: Thread for those of us who tune our own cars
 

So your saying your base fuel table is set to stoic everywhere and u just skew the mtf to hit the AFR s u want?
Also where your say when it goes to open loop it only uses the MTF that is not entirely correct the Mtf Is measured air flow. You should be dialing in the MTF to hit your comanded fuel of the base fuel table. Not scewing the MTF to hit your desired AFR

Re: Thread for those of us who tune our own cars
 

No it is not set to stoic everywhere and you should dial the mtf to hit the commanded setpoint in closed loop but in high load in open loop it uses the mtf as to what you have commanded but i tune my car in open loop so once you get the mtf dialed in you can then switch it back to closed loop using the basefuel table and it should be dead on and your bft shouldn't have to adjust anything if you tune it correctly

Re: Thread for those of us who tune our own cars
 

Most tuners will tune in open loop first to get the car dialed in correctly thru the maf transfer function then set it back to open loop to let your o2's make small adjustments if needed at part throttle for the commanded A/F from the basefuel table at the desired load and rpm

Re: Thread for those of us who tune our own cars
 

And if you log your short term fuel trims you will see how much your o2's are adjusting what you have commanded in the basefuel vs what you have in the maf transfer function and if there is a lot of adjustment you need to make changes in your maf transfer function

Re: Thread for those of us who tune our own cars
 

I have a question:
I emailed Kurgan for an update on my tune. I have 4.10 gears and going to a 3.73 gear. Now, here in SE GA it gets hot and car runs around 200 degrees, doing track days I want to ask him to change temp of when lo fan and hi fan comes on, what temp should I give him for each?? Car has a stock thermostat.
Thanks !!!

Re: Thread for those of us who tune our own cars
 

Knowing I have a 190' thermostat, looking to do:

FAN 1 ON/OFF: 195/190
FAN 2 ON/OFF: 205/195

What do you guys think ??

Re: Thread for those of us who tune our own cars
 

Tell him to send you the tune with options. This will allow you to adjust the gear ratio and fan settings yourself on the handheld. I'd go 185 low and 195-200 high on the fan settings.

Re: Thread for those of us who tune our own cars
 

+1 and see what works best for you.

Re: Thread for those of us who tune our own cars
 

Thanks guys, he sent this to me concerning fans:

as far as the fans, I have them set to come on sooner then you have requested… that is the first thing I do on custom tunes..

I will ask about the options

Re: Thread for those of us who tune our own cars
 

If that is the case then you should get a cooler t-stat if you want to keep temps lower.

Re: Thread for those of us who tune our own cars
 

Where do you get value files from?

It probably would have been easier to start with a value file on my Mach 1 instead of starting from scratch. The stock MTF was not even remotely close. Took a while to get it to idle.

I think one of my o2s is trashed, because my STFT are about 8% off from each other. It is also pulling spark to 5 degrees at idle in order to stabilize.

Re: Thread for those of us who tune our own cars
 

I would use the the stock mtf file for your maf. What maf are you running?

Its the hpx with vmp housing 3" blow through. Signal is really clean it is easy to tune. It will be a while before I'm brave enough for WOT tuning but its cruises nicely.

You should have a bunch of value files on your computer. Go under File and Load All Values. Then select the MAF you're using. It's been awhile but I think it's base tune (N/A or blown), injectors, then MAF. That should get you close. You'll still have to tweak the MTF.

Re: Thread for those of us who tune our own cars
 

I had been having hanging idle issues ever since I swapped to a smaller blower pulley. Did some reading and learned about adjusting the IAC duty cycle and dashpot settings. I just decreased the air flow requirements for IAC at drive and neutral until it datalogged ~45% DC, increased the decay rate in dashpot, and reduced the IAC multiplier based on ECT. Seems to have fixed my problem but I'll need to drive it more to be sure. Any other idle tricks? Seems like most people have problems with not getting enough air in to have a stable idle vs. having too much.

Re: Thread for those of us who tune our own cars
 

If you adjust your base timing in the idle rpm and load range down it will clean up the idle and help keep it from surging. If you data log you timing you will most likely see it running around 15* or so at idle and your scale is probably stock setting at around 35-40* max. You can lower that setting down to 10* it will increase torque and steady the timing out from jumping around and that is what will cause a lot of surging issues with FI cars.

Unless I have put larger cams in I don't even mess with the IAC settings. Stock setting are normally just fine. Even with my powerglide auto and big stall I don't need to mess with the IAC controls.

Re: Thread for those of us who tune our own cars
 

WOT tuning is pretty easy. It is the ramping up to WOT that is the hard part. Just datalog and use a good wideband and slow start ramping up to higher load ranges and maf counts. With a turbo car like mine I can adjust WOT very easy. Once full boost kicks in the maf counts will stay the same so you know about how much fuel you need to add/subtract with a blower car it is a little different mainly on centrifical blowers because the boost increases as rpms do which increases maf counts and load.

Re: Thread for those of us who tune our own cars
 

Starting from a basic tune (or building from scratch) seems kinda complicated. :surprise:

Re: Thread for those of us who tune our own cars
 

Depends on your mods. I am so far from stock that the base file for a stock car isn't even close to being accurate. If you just had a few bolt ons it would be easier, and it would be easier if you updated the tune yourself as you continued to progress in mods.

My mach is already driving better than it did with the dyno tune from the best tuner in our state. And I've only been tuning a month. Its not that I am a better tuner, because I'm not even close. I just don't think you can dial a tune in after a few hours. Being able to datalog on the road with real conditions and make small changes makes a big difference.

Thanks for all the help M1R members. The SCT Flash forum is dead, so this is about the best resource I have to ask new questions.

Re: Thread for those of us who tune our own cars
 

Probably depends on your definition of from scratch. I've never had a base tune given to me. I've always had to load everything myself. Most of the injector and MAF values are decent. There's a couple things that usually need to be scaled. Especially with set ups like I had or what Mach828 runs. But the main thing is we'll put the time in that tuners won't or can't. Just because it's our car.

Re: Thread for those of us who tune our own cars
 

I like this forum for tuning and modding help too. This thread is fantastic lol. I'm really wanting to buy the software since doing some reading here. I'm a bit overwhelmed with it, but I don't have the software to look at settings that have been discussed and I don't have the books mentioned either. I'm sure that would help me follow along better.

Re: Thread for those of us who tune our own cars
 

Before this I was adjusting carbs and points. Well, not so much on the points anymore since I had swapped to electronic ignition. I was nervous when I started. But asking questions and lots of reading helped a lot. Now I enjoy tuning. For the most part at least. Every once in a while there's a problem that makes me want to pull my hair out.