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King Trashmouth
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21,886 Posts
Discussion Starter #1,241
Self tuning has been going pretty well. Got a free rev test in. Better than any Amazon tune I had. Made a few more tweaks to it and took it for a road test. Not perfect, but good enough the STFT could keep AFR in check. I got her up to 45mph and got some good data. Very happy with how fast it starts and how it comes to idle initially.

Only bit that is going to take some work is after tip out. It will go lean and come down to idle, but as it approaches idle it will drop down really low, surge back up to save itself, repeat that two more times, then it's solid as a rock again. Doesn't appear to be dashpot related, more likely idle or IAC. Nothing I can't fix.

Since it was covered in dust from sitting all winter, I took the opportunity to wash it before the road test. It doesn't clean up half bad for a dumpsterfire.
 

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Carving corners
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3,327 Posts
Self tuning has been going pretty well. Got a free rev test in. Better than any Amazon tune I had. Made a few more tweaks to it and took it for a road test. Not perfect, but good enough the STFT could keep AFR in check. I got her up to 45mph and got some good data. Very happy with how fast it starts and how it comes to idle initially.

Only bit that is going to take some work is after tip out. It will go lean and come down to idle, but as it approaches idle it will drop down really low, surge back up to save itself, repeat that two more times, then it's solid as a rock again. Doesn't appear to be dashpot related, more likely idle or IAC. Nothing I can't fix.

Since it was covered in dust from sitting all winter, I took the opportunity to wash it before the road test. It doesn't clean up half bad for a dumpsterfire.
That's awesome man in going to dive into self tuning this year, wasn't too fine tune my cold start with my cams etc. Glad to see the project is still going

Follow me on Instagram! Username: raj03130616jar
https://instagram.com/_u/raj03130616jar?r=sun1
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,243
Another day another test. I can watch STFT at idle switch +/-5%. That part seems to be dialed in. Transition region is operable. One of the things that needs work is as I walk higher and higher up the airflow it needs more work. Very rich (10 AFR) above a certain point, likely the result of adjusting a point and everything above it as you walk up the transfer function.

I think I've got the surges after tip out figured out. Dashpot is dialed in but the surge is likely due to ISC idle air. I logged the idle integrator and it needs more at that range. Fingers crossed that does the trick.

I made it all the way to the gas station, a first with this combination. I was going to get a picture to have proof the pile of garbage has actually left the driveway, but stupid me forgot my camera.
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,244
Took out the latest rev. Ran like ****. Previous datalog showed idle integrator of 0.30 at low RPM. Added 30% at that RPM range. It behaved awful and showed 0.40 at idle now. What the ****. That is the opposite of what should happen.

Good news is the idle and transition region transfer function seems dead on. Above a certain point it needs way more fuel pulled out. When I was driving I thought I was getting lean pops. Looking at the data it looks more like I was getting afterfire with how rich it was. Definitely wasn't lean pops.

Ultimately it drove so poorly I ended up flashing it to the previous cal to get back home. Greeeeeeeeeat. So I guess I'll roll back the ISC idle air table and adjust fueling accordingly, then deal with that pesky surge once fueling is dialed in.
 

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Do you think it's time to take it to a professional? I'm not judging your skills but for a very complicated setup as yours and you being a beginner tuner, I'm just wondering how long it's going to last before something major happens ( you give up or it blows up)
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,246
Do you think it's time to take it to a professional? I'm not judging your skills but for a very complicated setup as yours and you being a beginner tuner, I'm just wondering how long it's going to last before something major happens ( you give up or it blows up)


It was actually a pretty dumb mistake. Turns out the idle air integrator has units. So when it's showing a value, it's not a percentage deviation like fuel trims, it's actual lb/hr of air. Ergo you add the integrator to the table, not multiply.

Anyway, I reverted back to the original idle air table and fueling and took it for a few laps. Didn't drive great, but it drove. I kept having datalogging issues do I didn't get much for useful data. After reviewing it I realized my aforementioned mistake. I changed the idle air table accordingly and fired it up. Monitoring the data, it's way closer to in spec, and behaved pretty well. I hit the throttle several times and while I saw a little deviation, there's no multiple surges like there was before.

It left me sitting there like-


With it behaving itself I decided to take another crack at it. Livelink wasn't cooperating again so I said **** it and just took it for a romp. I would actually call it driveable now. It needs a little better blend at one spot, but it was actually surprisingly tolerable overall.

Hopefully that means I can finally take it out to some country roads and get to stretch its legs a bit.
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,247
After having some issues getting the datalogger to stay connected, I got some good weather and made a couple laps. It's not perfect, but I got good data. AFR stayed between 12-17.

The best part?

Getting into it some I heard a loud rushing noise below 3000 RPM. I couldn't believe I heard turbo noise- and that early with that little throttle!



The one thing I do wonder about is it likes to stumble at tip in when the engine is cold. Once it's warmed up you can rev it all you want smoothly. Not sure what's going on there...
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,248
Made use of the last datalog and made a few adjustments. Feeling confident I got a fresh tank of 93 and made the longest lap yet. The verdict? Pretty much dialed in up to 50mph. Temperature and everything is under control. Now we just need a chance to open it up.

I'm going to try and fix the hood latch first. Part of the reason I think it's such a bitch to get it to latch is the strut that goes from the core support to the latch is bent, likely from slamming it so much. Of course being the pain in the ass it is, the lower stud is spinning the insert, and the top bolt is a weird torx size.

Just to prove it's actually left the driveway:


...or maybe I pushed it down the street to the gas station. YOU DON'T KNOW. :shiftyeyes
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,250
Hey, can you do us all a favor and remove those wheels? kthxbai


The nice staggered, machined 03 Cobras with drag radials will go on with the next overhaul period. Then I'll do the hood latch, snug up a few fittings, and tuck the exhaust a little higher.
 

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Still slow.
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8,738 Posts
What are you using to tune again? I have the exact same idle issue and haven't been able to get it sorted ever since I installed cams.
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,252
What are you using to tune again? I have the exact same idle issue and haven't been able to get it sorted ever since I installed cams.
I'm using SCT Pro Racer Package (PRP.)

Got her out for a 30min romp today. I need to revisit my intercooler reservoir setup. Great for hiding, pain in the ass to monitor/service.

It drove pretty damn well, and I got some good data. I'll need to look at some of the load/throttle position values to see if the AFR is right, but it's all in the box.

The only issue I had was really light throttle modulation in traffic. If you were on the throttle or off, perfect. But if you're on and off, really light, it wants to buck and pop. You keep going from cutting fuel when you let out, to adding lots of fuel at tip in and it just wants to pop and buck. It's worse in lower gears and the manual only makes it worse. It should be a matter of adjusting how fuel is cut while motoring.

On the upside, it sounds nasty getting into the throttle; exhaust growls, blower whines, then the turbo spools by 3000 RPM, and the blowoff definitely works. It sounds like one bad motherfucker.


Of course being ever paranoid, didn't like the exhaust sound at idle when I got back, and the oil pressure still makes me nervous. The exhaust sound is probably more of an exhaust leak; and I can see where it's leaking at the slip joints. If it was a misfire I'd expect a leaner AFR, unless of course I ****ed up tuning it. And oil pressure is still technically within spec; 25psi @ 1500 RPM hot, but 10psi at hot idle.

With all that nonsense it's probably about time to take it down for a week or two. Fix some of the little stuff like exhaust height, get the Cobra wheels on, fix the hood latch, tighten some fittings, change the oil, cut open the filter, and check the plugs. Fingers crossed I don't see anything too bad. It definitely is showing some potential.
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,253
Did a bunch of little **** all week to get it in better shape. Sealed up some fittings, installed the restrictors, replaced the hideous drywall screws on the bumper, tucked the exhaust up, and washed it. It's still a depressingly ugly pile of trash.

As such, taking it to a car show they put me where I belong, next to the trash.


It didn't get near as much negative attention as I expected; only three people pointed and laughed. It did turn a few heads though, and I'm surprised at the number of people who think a supercharger and turbochargers are not compatible. One even went so far as to accuse me of having a fake supercharger. That's a new one.
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,256
Way late on this one.

I got a lot done. I had some trouble with return to idle. I tried dumping a ton more in the ISC neutral idle air table. Didn't work. Surged bad at startup. It wanted way more air on startup, and returning to idle. First error I found: TB idle air bypass value was much larger than actual airflow around the TB. I opened the throttle stop way up to where it improved idle and guessed on the bypass value. It was way better on startup, better overall, but not perfect. The stop was opened so far it was great at cold start, but not closed enough for hot idle control. But thanks to the magic of interpolation that gave me the answer of where to set them both. Perfect, right? Nope. Still surged hard on startup. Looking at the data, it wanted 4lb/min at cold start high idle, and 0.6lb/min at hot idle. How could I account for that?

The answer is a table hardly anyone talks about. There's a table called ISC idle air multiplier. It's a 3D table that multiplies ISC neutral idle air based on ECT and run time. I set the stop as open as possible to control hot idle, and calculated what the multiplier would have to be to max out the ISC air at cold start. That required increasing the multiplier table by 1.8x in that region. It made a huge difference. A few cells I didn't multiply definitely needed to be increased, but still, big improvement.

The other big improvement came in timing. In reviewing my total timing table I realized it still had a 2V based table in it, not a 4V. What's the difference? It's massive. Stock 2V timing is around 14 deg. 4V timing is more like 25 deg. I put in a stock 4V table and pulled 7 deg for safety. Night and day difference, especially at light and part throttle. It picks up WAY harder.

But what good are words? A picture is worth a thousand words. So a video must be worth a million, right? Excuse the obnoxious rattling of the camera in the mount. For some reason it didn't do that in the wagon.


But I suppose we'll have to wait until spring for more of that sweet, sweet mod motor music.

The fox is getting new frame rails, but I'll be using winter as an opportunity to upgrade to Cobra brakes, a battery disconnect, and other miscellaneous improvements. Like air filters.
 

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Moderator
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13,573 Posts
one step closer.

Hey have you ever thought about taking it somewhere to have tuned? Then use that tune to roll around town, get WOT with it, race it ETC and enjoy the car.. then work on your tuning skills in between when you have time?
 

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King Trashmouth
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21,886 Posts
Discussion Starter #1,258
one step closer.

Hey have you ever thought about taking it somewhere to have tuned? Then use that tune to roll around town, get WOT with it, race it ETC and enjoy the car.. then work on your tuning skills in between when you have time?


It's actually been WOT tuned for the longest time. That was the easy part. It's the weird, oddball stuff like this ISC multiplier table and little driveability issues that I've been chasing my tail on. If I had a tuner do it, it would be a 3+ month wait, they'd strap it down, do a couple pulls to tune WOT, and then I'd be chasing after them to fix this minor stuff. This way I get to learn, I get to change it whenever and however I want, and I have total control over all the finer features. I'm a bit of a perfectionist; I want this OEM quality or better. And to tell the truth it actually drives better than some of the ones we tune at work.

And of course the other benefit is when I want to turn it up to 25psi I can put that tune together in no time.
 

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I hope this works out for you the way you wanted it to. I know you certainly have put in some hard work.
 

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6 Cylinduh, Really Bruh?
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5,215 Posts
I hope this works out for you the way you wanted it to. I know you certainly have put in some hard work.
Yeah no kidding. It'll work out for you in the end. You probably also learned a lot along the way. I know I have versus having someone do it for me.
 
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