bshiosaki

I just got back from the dyno and I'm trying to understand a few things about the tune and why they had to make the adjustments they did. So if anyone has suggestions or recommendations, I'd appreciate the help.

Only mods so far are: JLT II CAI, tune provided by SCT Excalibator2 SF, and the GMS coil-over connectors (a friend had recommended them). Was testing the 93 tune

And here's the story: On the way to the dyno, I had just tanked up with premium at a local Chevron, 92 oct is all we get in Or. and I'm not sure if it's a blend. I noticed some pretty heavy pinging during one "more spirited" run. I've never been able to say that "it's a whole different car" after I put in the CAI and tune, so I've always wondered about the tune. They had a tough time on the dyno, they were getting serious pinging above 4k and actually had to back out of the first few pulls.

They eventually got her running well, but they had to pull 5 deg. out of the timing and add 4% to the A/F mixture. They're still suspecting the gas may have been a big part of the problem, and I've got a game plan once the gas has been run thru, but I'm looking for ideas on what else I could look into. I read somewhere that the canned tunes for the JLT's ran lean from start, but I'm wondering how the timing plays in. I'm down a little power due to these settings, which is why I'm trying to make sure everything is right.

Could the coil-over connectors be an issue, (jr mechanic at best here) so I'm looking at what's changed as possible problems. Would the 91 tune be a much better combo for the 92 oct gas that available?

Thanks in advance.

sook

I've only started to play around with HP tuners (mostly just staring at the screen), but it seems to me that either the canned tune was running way too much timing by mistake or your gas was crap. Having to pull 5 degrees even from a canned tune seems like alot. I know you said you are using JLT II and Xcal2 but who wrote your tunes? Or are you using the SCT tunes? What were your A/F numbers like from the dyno? You said they richened up the mixture, but what was the actual number?

Try running a different brand of gas for the next fill up. NO OCTANE BOOSTER You can add timing slowly via the XCal. If you can get back a few degrees of timing without detonating, then it was your gas.

theedge67

Yes, if you had 87 in your tank before you filled up with 92, chances are you still had at LEAST 2 gallons left in the tank. Combine that with the 92 and you have about 91.5 octane in your tank. You said your tune was for 93 octane. There's your problem. Also, the canned tunes from SCT are marginal at best according to many on this site. Tweaking them with a dyno on 3 runs is tough because there is only so much they can change at one time. Tweaking a marginal tune will yield a decent tune. Tweaking a good tune will yield an awesome tune. Make sense? Most guys here would recommend www.bamachips.com or www.brenspeed.com. I've never heard anyone say anything but GREAT things about both tuners.

Also, if you have 92 gas available, do NOT run a 93 tune, you will get pinging. Run a custom 92 tune, or a 91 tune. Always run a tune for the same or less octane fuel than what is in your tank.

theedge67

Also ethanol blends will make a difference on the tunes.

bshiosaki

I believe the tune was a canned tune straight from SCT, least I have no idea who actually put it together. I have been using premium gas all along, no reg ever, but I usually fill up at a Shell station near where I live. The Chevron was close to where I was meeting a friend I was heading up with, and not where I normally fill up.

My friend has a GT vert with the same mods but an older tuner from SCT, and he had no problems what-so-ever. I had been running the 91 tune till a couple days ago, but it didn't feel like it ran any better. I'm not sure about post 4k since I don't see too much of that. BTW, friend was running the 91 tune, his didn't come with a 93 tune.

Now for the numbers; looks what I wrote down were timing is at 24 deg. and AFR is 12.6 Unfortunately the mech was talking a bit over my head. I haven't figured out the tuner well enough to be able to go in and check the settings, that's something I'm working on, if only my comp liked my tuner.

I have the printout from the dyno, which was a mustang dyno, for the good run. She's averaging 12.9 for AFR and making good power (295hp and 301trq). I'll try to scan the printout from work and post it. The numbers seem high compared to what I see most posting, even on a mustang dyno, but I'm quite happy with how the car feels and can now say WOW what a difference. The car has significantly more power and throttle response.

The game plan was run the gas out, fill up with good gas and add 2 deg back to spark and decrease richness by 2% and look for any pinging. I'm thinking of having the same shop do cat-back exhaust and my Steeda UD pullies, maybe even an x-pipe. If so, any recommendations on how to proceed with tuning. Keep what's probably a highly modified 93 tune or retune based on the 91? Would that help with the timing and richness settings. The guy who did the tune said they generally see about 10 more horsepower and torqe than what I was making with the more optimal settings. Is this bull or would it be worth it to retune?

Thanks again

sook

I think I understand what you are saying. First off, if you are already making 294 at the wheels on a mustang dyno with only a CAI and tune, I have no clue how your tuner expects to make 10 more by tweaking the tune. Hell, if he can get you over 300 with a CAI and tune, I'll bring my car to him myself. Anyways, if you are a manual, you are probably making about 265ish stock. A 30 hp gain is a good return on your investment. If your A/F ratio and dyno numbers were taken after the tuner removed 5 degrees and added fuel, they you seem to be right where you want to be for this mod.

If you do decide you want to add spark using a different fuel, the datalog the car with the xcal2. And maybe go one degree at a time instead of two. Most will probably say go for it, but I am a cautious guy.

Lastly, I wouldn't run 92 octane in a car that calls for 87. Certainly, its not a stupid as running 87 in a car that calls for 92, you may be hurting your engine more than helping.

theedge67

The main reason the owners manual calls for 87 is because that is what it is tuned for. When you change the tune, you can change the octane the computer is set up for. Now, compression ratio is also very important in octane ratings, but there is nothing we can do about that short of new heads. = $$$$

Stang281

You shouldn't be getting any pinging, most ECUs today use their knock sensor to detect any abnormal noise (above a certain db) and will adjust the ignition timing and/or AFR to compensate.

Mostly for those that live in different climates, so that the ECU can manage the engine regardless of the enviroment it is in.

m05fastbackGT

That's true providing of course it's within the knock sensor's +5 and -5 adjustability range ? if at anytime it goes beyond +5 degrees of timing you end up with an A/F mixture of being too rich..if on the other hand it should go beyond -5 degrees of timing ? you'll end up with an A/F mixture of being too lean which can then result in knock and pinging from detonation..when I first started out with an SCT canned tuner, my A/F was 13.5 at WOT on the dyno and although I didn't notice any knocks or pings ? the dyno technician claimed that my air/fuel was running lean and recommended adding 6% more fuel to bring it down to a more suitable 13.1 level..

bshiosaki

Thanks all for the input. I had always wondered about the my canned tunes since I didn't see the big difference others were seeing with some of the tunes from Bamachips or Brenspeed. Also I feel like I opened myself up from some troubles due to the way the car was running when I took it in. So I was looking to learn a little and not make any major mistakes as I continued to play with what the car can do.

I do plan on heading to the track this spring, but my main plan is to have the car running and looking tip-top. She is my baby as well as my daily driver, but if I can squeeze a little more "grin-factor" along the way, all the better .

Thanks again

metroplex

And we come full circle back to our friend, the air transfer function. When your tuner said he will add "6% more fuel", he is tweaking the air transfer function at the MAF voltage/counts where you are running lean. It's important to get the AFR data while on the dyno rollers, and some tuners want to drill holes and weld an O2 bung in your exhaust for their wideband sensor so it is located in the right spot. If it is too far downstream, it will read too lean. There are also other things to do to the tune before your car can be tuned properly.

I believe the full range is +/- 8 degrees of timing pulled/added through the stock calibration and knock sensors. However you should not rely on the knock sensors for a solid baseline tune.

TillmanSpeed

Bingo!

m05fastbackGT

That's why I don't put faith in the knock sensors and highly recommend to anybody who's re-flashing their Stang, seek out a reputable tuner and at least get you're air/fuel ratio checked for this reason ? each vehicle responds to modifications differently and are not calibrated the same even if they happen to be identical cars..When I first started out with the SCT canned X-CAL the first thing I did was set up an appointment to get my air/fuel tested and it was a good thing I did because I found out that my air/fuel was 13.5 lean at WOT and despite running the base SCT 93 octane tune ? I still had to add 6% more fuel in order to bring the A/F down to a more suitable 13.1 ratio.. Although I've since upgraded to Doug's 93 Race/Torque tunes ? I still plan on getting tested once again just to be sure my air/fuel remains right where it's supposed to be..

bshiosaki

Ok, so at this point I've got no concerns about richening up the mix to compensate for the additional air provided by the CAI or a lean canned tune. But I'm still curious about the timing, and why it was neccessary to pull 5 degrees out to get her running well, particularly if there's something I need to be looking into other than possible bad fuel. It makes me a little nervous to think that it could have been so far off that the ECU/sensors couldn't compensate. I've never seen any codes or trouble lights. The dyno shop claims to have done numerous 05+ Mustangs, and mine was unique in what was needed to get a good tune.

I guess I'm just wondering why mine was different. This is my first new car and I'm not as savy on tuning as I'd like to be. Would it be worth checking the plugs and connectors?

thanks again all.

sook

Without seeing a datalog from your car with wideband numbers, it could be anything. You may have gotten a bad tune from SCT. Your injectors could be flowing well below normal and you aren't getting enough fuel. It may just be the gas in your area. I'm assuming you are running 92 octane by the R+M/2 method. (I have never seen a gas station in america sell gas by just the R or M method) I'm no tuning expert, but I haven't a clue why your original tune was 5 degrees over.

Why did the dyno shop say your car was unique? in what way?

bshiosaki

I just got the impression they have a proven tune that they use as a basline, then they make small adjustments for the individual cars. Mine required substantial changes to this baseline tune to get it running well, in other words: no pinging. They couldn't even get a good safe pull out of it as the car was. Maybe I don't understand the process well enough, maybe there's absolutely nothing wrong with the car. That's what I'm hoping, but if there's something that caused a difference in how my car tune, I'd like to figure it out.

I also got the impression that while the car is running well now, it could run better if we could bring the timing and AFR back in a little. Maybe I started off on the wrong foot by having the 93 tune in the car in the first place, or maybe it is just as issue of some bad fuel. I guess I'm just fishing for some ideas on what I did wrong here.

Also, what could octane boost or fuel injector cleaner like the one from STP possibly do to the plugs and could that have been an issue if I had run some cleaner thru a tank or two ago, not knowing it was a no-no. Would it be worth pulling the plugs for a look?

Thanks again,

m05fastbackGT

The reason why you're car is unique ? was just as I previously mentioned every car responds to tuning mod's differently and no two vehicles are calibrated the same even if they happen to be identical cars..However it may also be very possible that your tuner's wideband sensor along with his dynojet equipment could of had a calibration issue that may have been the cause as well..If you continue having the same problem ? I would recommend trying out a different shop and get a second opinion..

sook

Sorry, just the way you phrased that made me think that the dyno shop said your car was really unique. I know ever car is unique and will respond to the same mods differently, but I was just curious if they meant something specific by unique.

I don't think anything is wrong with your car. m05fastbackGT is right. If you are really that concerned, get a second opinion from another shop. Get a full custom tune from them or tell them you just want special attention paid to A/F ratio and your timing. I really don't think you will be able to squeeze much more out of the tune than you have already. (Assuming that the dyno numbers reported by the first shop were accurate) In the end, its your motor. Personally, I woul rather be safe with my new car than squeeze 5 more horse out of it.

theedge67

Check your plugs, the fuel system cleaner junk is TERRIBLE on plugs. I tried some on my 89 mustang one time and it started running like crap a few weeks later. It was missing on several cylinders and had NO power. I pulled the plugs and they were RED. Not only red, but half the plugs were all chewed up looking, like they had been put into a blast furnace, the electrodes were all burt away and the arc was making a jump like 1/4" long to the side of the porcelan. They were platinum plugs too with 25K miles on them. After that, put new platnums in and they were fine for 50K miles, then I sold it.

TillmanSpeed

The only fuel cleaner additive I trust is the Lucas fuel treatment. That stuff I can swear by... no harmful affects. Great in diesels too, helps with the low sulfur fuel, etc. The reason it outperforms the others is because it doesn't contain any solvents.

CR
Tillman Speed