Yeah on the highway on the way home with normal boost pressures at around 23psi the car felt great, especially and i fill up the gas tank with 93 pump gas which probably deluted the 116 octane that was left in the tank...

Ok check this out...

My timeslip on 93 octane and 23psi spike:

R/T - 0.639
60' - 1.723
330 - 5.041
1/8 - 86.79 mph
1000 - 10.161
1/4 - 12.14
mph - 114.2

Now my last saturday's run

R/T - 0.638
60' - 1.711
330 - 5.018
1/8 - 88.2 mph
1000 - 10.191
1/4 - 12.19
mph - 112.2

With almost 5 psi more boost the car should have trapped over 116mph easily, but it clearly had issues up top...

in both runs my timing up top in fourth gear were 15-16 degrees. Now from what i understand i could easily run 20-21 degrees timing on the 116 octane and as you said before afrs in the low 12 range...

the car was running PIG RICH up top thats the low mph and bad times...

 

Well, the problem with that is if you do get heat soak on the dyno and tune the AFR's for it, when you are out in the real world, your AFRs will most likely be too lean.

The solution is really to box out open air filters and get fresh air to them.

The ultimate solution in addition to that is to get a temp sensor installed at the throttle body or just before and measure your actual charge temps in the environment where heat soak could be an issue. Then you can change your temp compensation map accordingly.

 

it takes time, but you can get your temp and barometric correction factors correct. I'm working on a excel spreadsheet to get them close.... I made one for the Honda's using their correction factors.....but the EVO's is nowhere near the same. I have to do some more tweaking.

AS for boxing up a open element filter..... the AEM intake uses a decent heatsheild which reuses the stock snorkel and it works great. i get a little more heatsoak at idle(over the stock airbox) but as soon as you start moving.....IAT's come down fast and stay just as cool as the stock box w/snorkel. It's really the best of both worlds. I tested the same intake w/out the heatshield and w/out the snorkel(to simulate other brand open element intake kits using a hard MAF pipe) and the difference was as expected.....super high IATS that got worse as you made a pull. With the heatsheild and snorkel, IAT's gown down significantly thru the pull.

CJ

 

well now the way i use the apexi induction box is without the cover and using the snorkel for cold air... Eventually when i find the best way to feed the air filter with cold air from outside i will reinstall the cover and isolate the air filter from the engine department almost completely!

In addition to control air temps especially now with the hot weather, i ordered a bunch of DEI products to protect vital parts like the UICP, turbo pipe, radiator hoses, wiring etc etc...

Now about the tune:

whats the average timing i could run after 5500rpm on C16 and 28-30psi boost? of course the 28-30psi is a spike which helps the car stay above 20psi after 7000rpm...
i would expect values even more than 20 degrees and now i run 15-16 degrees on the upper rpm...i now that my afrs have to be close to 12 +/- for maximum power but what about timing?

 

Due to differences between each engine and each set-up...it's hard to say where the average timing will be at any particular boost pressure, RPM or octane of fuel used. You will have to tune it the conventional way.

Keep advancing timing across the rev range until you hit knock in a particualr area. Retard ignition timing in that area 2 degs and keep advancing timing everywhere else 1 deg at a time until you hit knock somewhere else....repeat the process until you are at the optimized ignition timing for the whole rev range. Once you have ignition timing as far as it can go without knock, retard ignition timing across the whole rev range 1-2 degs for safety(1-2* below the knock threshold).

Be very careful when advancing timing though, as you advance timing, your AFRs will go lean. Don't let the AFR to lean out more than 12.0:1 while tuning c16. ONce you have ignition timing optimized, insure AFR's are nice and flat @ 12.0:1. NO spikes....a flat AFR.

PM me if you have any questions.

CJ

 

I had a similar problem with my stealth a while back. I was tuned for pump gas 93 octane and trapping 125mph. I put in 5 gallons of c16 at the house with the intention of tuning it at the track. When I got to the track I realized that my WB02 died so I wasn't able to tune it. I could monitor knock and timing so I raised the boost from 20 to 25psi and advanced the timing about 5-6* and went absolutely no faster, I kept adding timing until the traps slowed down.. no luck. When I got home I replaced the WB02 sensors and found that I was in the 10.0-10.5 AFR even after advancing the timing lol no wonder it wasn't going anywhere.

My Stealth runs best at 12.0:1 on C16 I treed 12.5:1 a few times but it didn't allow as much timing/boost. I've made some changes since then so I might have to try it again.

p.s. the vid of the stealth at the track is in my sig

 

I didn't read through every last post, so forgive me if this has already been mentioned ...

I've logged a full 4th gear pull from 2k to 7k in the low 11's, and then about an hour later in the exact same conditions did a 1/4 mile run and the AFR's were in the mid to high 10's. The same RPM range in 4th was about .4 richer. The temp was nearly identical and it was the same tank of fuel.

I kind of assumed it has something to do with lean spool or some sort of intuitive action on the ECU's part based on TPS readings. Has anyone considered that this is the purpose of lean spool? I don't know much about how it actually works, just tossing out some ideas here.

 

Another thing thta I have noticed, which I think is worth mentioning.

I recently, not at the track, noticed on a few logs that my fuel trims were getting really out of wack, and really couldn't finger out what was causing the change, because nothing had changed with the car.

A few days later of monitoring, my Greddy Type-S blew itself appart. When i took the Greddy appart, I noticed that it was a slow failure, causing boost leaks, and was slowly causing my boost to drop because it was leaking back into the intake pipe. Since I don't/can't log boost, it wasn't readily apparent that I had a boost leak somewhere.

Basically, if you find out all else is OK with your ignition maps/fuel trim maps, check for boost leaks. I found out that boost leaks actually made my fuel trims go up, which is quite the opposite of what I actually expected.

 

oh yeah, meant to mention something about my earlier post with regards to tuning for c16..

Make sure you are tuning in 3rd gear only.... This will insure you are not running too lean in 1-2nd gear and too rich in 4th-5th(6th).... If you tune AFR's in, say second gear, your AFR's will be too rich in 3rd and way too rich in 4th and even richer in 5th...so on and so forth.

basically, the lower gear you are in, the leaner the AFR. So, tune in the middle(3rd gear) to in sure the correct AFR in all other gears.

CJ

 

A boost leak will deffintly cause a rich condition on a non speed/density ECU, using a MAF sensor @ the intake.

This is likely not his problem though, we have found his problem without a doubt.

CJ

 

for a track setup I start with 3rd or 4th gear road pulls to get the tune dialed in and then when I go to the track I tune around the 3rd gear data which is all high rpm.

my point is, a good road tune doesn't alway equate to a great track tune.

 

If you are tuning correctly and have all your comepnsation factors spot on.....it should. Unless you are changing your set-up for the track after your road tune. (i.e. slicks.....). This will cause more load on the engine and could cause issues with your tune. Other than that.....it should be good to go.

Again, if your compensation factors are perfect, the tune from the road should be just as good on the track.

CJ

 

What compensation factors are you referring to iTune? I'm still a pretty bug noob when it comes to this ... any thoughts on what I posted above?

EDIT: I found the compensation tables ... reading FTW. Still hoping for thoughts on what I posted earlier.

 

I love all these arm chair tuning experts who never even made a fast pass down a track speaking with authority on a specific situation of which they have no concrete data

It is hard to design one tuning rom which will drive your car safety on pump gas / handle 30 minute road racing situations and also get your car down a drag strip at an ideal a/f for the maximum power

I have certainly created some good compromises in the past

In this case the OP will prob benefit from some tweaking at the track and some more seat time to improve the launch and shifts

OT - We have tested pump gas vs race gas on dozens of occasions on the dyno and at the track and the claims made that adding race gas will significantly effect power delivery on a pump gas tune are false. Every time we have seen nearly identical power with pump and race gas.

Al

 

Assuming you drive the car on the road the same way you drive it at the track


Data loging race activities shows that coolant and charge temps rise significantly when running the car through 4 gears

Prudent tuners set up ecus to run richer when the car is under more thermal load

Al