Because you don't need 11.5 throughout the entire RPM range. As intake temps rise, you want the richer mixture to help cool, but you won't need it at lower RPMs and it would actually be detremintal to the overall power production and longevity of the motor. 13:1 is fine below a certain threshold where intake temps are still reasonable, but spin an M45 with a 15 or 17% pulley above that threshold and you're going to see the intake temps skyrocket, hence the richer mixture at higher rpms. You seem eager to criticize Jan without knowing any of his credentials. I have no idea of your background, nor you mine, but Jans record speaks for itself on this site. The very links you posted seem to back up Jans tuning technique and all the tuning I've seen done on F/I applications looking for a reliable streetable setup have had similar curves to the A/F ratio.

 

I agree perfect for a dyno queen. In that you only make one high powered run.

In the real world If I hammer down from a redlight and jam through all the gears and then slow down and hammer back down. The intake temps will be high and not based soley on RPMs. So you could need a richer mixture at lower RPMs.


Nothing to do with any person. Just engine talk. The links posted show that A/F ratios need to be a certain range for power or MPG. They do not say that the A/F ratio can be very lean at low RPMs.

 

True, the intercooler and intake tract can heat soak, but at the same time as the supercharger moves less air and compresses it less it's efficiency increases and the intake temps will still drop, relative to where they were at higher RPMS.

 

I still don't get this dyno A/F reading. If the results are 1 point to lena and the actual results are 1 point richer. 15.5:1 reading verse 14.5:1 actual Big Difference.

I'd change my thoughts on the tune job if the leanest point was 14.5:1 verse the really lean 15.5:1.

 

Sure I get that. The intercooler will heatsoak and that takes some time. But the combustion chamber and piston surface will hold the heat. That's the danger. You can run through gears in seconds and your engine will see a huge range of RPMS on the street.

The point of running rich is to cool down the chambers. And at the lean ratio under WOT the combustion chamber could just as hot. EGT would need to be measured to confirm.

 

 

 

you really don't get it .... do you?

nice photo shop though

I do have CP pistons in stock along with other high quality parts

 

Guess not.

I'm used to seeing a much flatter A/F ratio coming from n/a engines.

I get that you use a rich A/F ratio to cool things down and for saftey. I do the same on my high compression Harley -just change plgs often. Just don't understand or agree with the lean ratio's under 4k. Or why from 6200+ rpms you lean out the ratio. If 12:1 (lean) is good at 7k why not at 6k?

Nothing personal. Just like to learn about engines. Do you moniter EGT, IAT and water temps during your testing/tunings?

 

this IS NOT a N/A motor....

 

Wake up and smell the coffee, even your DINAN tune varies from 15 to 11!
http://www.dragtimes.com/2005-Mini-C...phs-11754.html

 

That is a much smoother A/F curve than the one in question. From 6k to redline it stays even. The tune in question begins to lean out past 6k. Which is bad or at least that whats been said in this thread.

also the link you provided has the green program making the best power which it very quickly changes from lean mixtures to a nice smooth A/F ratio.

Compare the two A/F ratios. Then think about how much testing and years of tuning Dinan has.

 

Dinan is out for your money

 

for some reason you don't understand what I told you.... the a/f at redline is really 11.5 NOT 12.5 .......... if you are trying to say something in all this repeated hogwash... JUST SAY IT....

we are patiently waiting

 

Dinan I agree has been around for awhile, but that don't mean anything. When I have called there the guy I talked didn't know anything and he said he would let someone else know and they never called me back, great customer service . Not to cheap either for what you get.

 

That A/F charts shows that your only under 11.5:1 for a short RPM range. At the end of the run your at 12.2:1

Don't understand the reason for the V shaped A/F ratios. When every other S/C dyno I've looked at start lean and ends richer. No W or V curves to them. Be it the Mini, cobalt SS, or Ford SVT truck.

http://home.earthlink.net/~aquez57/s...yno_sheet1.jpg
http://www.nwgmtuners.com/_images/Dyno1.jpg
http://cobaltss.net/gallery/files/3/1/9/0/scan0072.jpg

All good A/F ratios on S/C engines.

 

You seem to be the only person in this thread who doesn't understand what I told you.

 

The AF UNDER 4000 is ok to be leaner, the compression ratio at those points is significantly low.

As for your smooth AF lines. Different Dyno software view differently. Make sure when you buy your Dyno you get a Dyno jet since you want it to look smoother.

here, I ahve AF graph for you


11.5 _________________________________________ 11.5

/\ nice and smooth huh? It's from a one million HP NA honda with Pistons, Rods, Calamari, and Dinan tune.

 

unpossible!

 

So how does the Mini alter compression ratios based on RPM's?

The reason for richer mixtures on a S/C engine it to cool things down and prevent detonation. Engine saftey. I just question the V shaped A/F ratio beyond 6200rpms. Why go leaner beyond 6200rpms.

 

If you dont know, I guess you should do more reading and less blah blah blah, we have enough internet experts.

 

:-)

 

 

All I can say is that I had almost the same type of experience with my RMW tune. My car initially dynoed 215 with MTH software. This with most of the usual performance modifications one can put on their car. My car ran great for almost a year without any problems. After the dealer flashed my ECU without my consent with stock software to supposedly solve a SES light issue, I had a custom tune put on the car which was not done on the dyno. For six months my car ran inconsistently hot and cold, continued to throw codes, had supercharger, coolant and exhaust leaks, and was becoming a big pain in the ****. After getting fed up with all this nonsense, I gave Jan a call to have a look at my tune. He immediately could see why the tune was causing me a lot of problems. The next week we met at the dyno and right off the bat I had another supercharger leak. He sent me to Danny at Minicorsa and he fixed the problem in about 30 minutes. He's another class act and one of the best at working on the mini. Needless to say after racing back to the dyno, and several test runs later, the car finally put down 227HP and 188TQ. With the other custom tune, these numbers were significantly fless. Without getting caught up in all the numbers, graphs, and hyperbole that surrounds tuning, I can say that my car drives stronger across the entire spectrum, doesn't have constant idle problems like before, doesn't have a lag between shifting, and definitely puts out more power especially across the top end. I now cannot comfortably get into 6th gear now unless I'm going at least 100MPH. I never had this problem before.

Throughout all of this, I was fortunate enough to hang out with Jan at his fabricator and see the quality of the RMW parts. It really made me envious that I didn't know him a year earlier because quite honestly after seeing how beautifully made they look in person I would not hesitate to put all of his stuff on my car. For me, the mini has become an obsession. It is the funnest car I have owned and have driven. I would not hesitate to recommend Jan and Danny. They are very good at what they do and I'm lucky to be in the area to utilize their services.

Next stop-RMW turbo mini!