Just an update....

I swapped the DV off my brother's JCW, and noticed a little bit more (maybe 10-20%) smoothness, and the fluttering noise now starts a little bit later (3500RPM, instead of ~3100RPM), but both problems are still there

I think I'll do another ScanGauge run and send them off to Jan, see what he thinks...

 

@etalj: Well, crap. I feel like a cat chasing a laser pointer. I have the WMW DV on order (arriving later this week) and some ALTA plugs. My MINI has ~48kmiles on her, so it shouldn't need them, but...

 

FWIW,

Switching the scangauge sampling to Fast (or whatever they call it) will get you more instantaneous readings. Default is like once a second, you can change it to be much, much faster.

Cooler plugs will help as will top tier gas if your gas isn't the best it can be.

 

hehe, I know what you mean....I hate when this sort of thing happens.

@HRM, I had it on fast, but yeh the standard refresh rate is very slow

 

You will likely notice a difference with new plugs. I found that fresh stock plugs at about 30k miles made a noticable difference on our Just'a and I will be changing them on my S soon (27k miles).

 

They don't have the plugs for JCWs. And the flutter noise wouldn't be caused by plugs I think? Also, I only have 20k miles

 

No plugs for a JCW but 20k seems a little low for needing them unless you would think a lower temp plug would help. It might if it is a ping/knock issue that is sending the timing all over the place. Hard to tell these day...since they got rid of the vacuum advance

It is interesting that on the RMW thread (Official flash tool...) this problem is not discussed nor has it be a topic on the Alta Access Port thread. Just noting as it seems people are getting pretty high boost with those as I expect you are. Wonder what is different I'm interested to see how this comes out as a "tune" of some sort is on my Mod list

Maybe the Helix FMIC will help saw ya lookin'

 

Hehe yeah, it's a big discount. Of course, I lower temp plug would be ideal, since I'm running 23lbs of boost.

Could timing retardation somehow cause the turbo to flutter like mine?

 

Maybe anything more than that and I would be purely guessing. Ok a guess...high boost leads to knock leads to computer dumping boost but because it is high it dumps too fast, dump shuts, boost come back up fast and cycles. All the while the timing is retared to cut the knock. Thing have worn out because of the cycling. But this is just a guess.

dunphyj is running a highly modified Mini and doesn't seem to have this problem. He also posts a lot about stuff he has tried out and he seems to have tried a lot of stuff...
https://www.northamericanmotoring.co...ml#post3176958

Look at post #16...With that kind of Hp he must have a bit of boost. Maybe he has something that works for this?

 

Yeah to be honest I was envisioning the same scenario you're describing, but wasn't aware that the computer can dump boost while on full throttle.

This problem is so hard to track down.

 

WMW DV and Brisk spark plugs are in. Can't do the installations until Sunday, so I'll post results then.

 

waiting anxiously

 

Just an update.

Problem is still evident, and I've isolated another symptom. It's not new, but I can describe it more accurately.

When accelerating, especially 2nd or 3rd gear, and gently depressing the throttle pedal more and more, the car jerks and almost "dies" for a moment, and then continues up the rev range

 

I got the info from the Alta thread about their Access Port:
https://www.northamericanmotoring.co...thread-45.html

Look at Post 1109. Alta describes the boost as being controlled...As you know the turbo is capable of lot more than the stock boost (~10 psi?) and you are at 23 , so it must be dumping it some how.

Another thought...try the car with a lower peak boost, if you can, to see if the problem goes away or at least is less. 23 psi boost seem really high even by what I read here on NAM.

 

Remember, it's a JCW, they have 21 psi standard

That post was very interesting, and good reading (wish they told us even more).

My problems are not just at max boost, however. If anything, the more annoying problem occurs at quarter throttle, and is consequently hard to drive. The fluttering noise and retarded timing isn't quite as annoying, but I still don't want that to happen either.

Jan has been working with me quite extensively, and has sent me about 5 different maps, and none make any difference, which means the problem has to be with the car. I'm going to go to a different mechanic this week and see if we can find the problem together.

 

Good luck...Hope the mechanic finds something as this seems to be a strange one. Interested in hearing the results.

I did not know the JCW had that high of a boost. Do I assume correctly that is actual/total (above atmospheric) pressure? On my Scan Gage I see about 20 or a little less but that is "atmospheric". Subtract 15 for atmospheric pressure, leaves about 5 psi total boost for "normal" spirited driving. Have not look too closely when out on the track to see what pressures I reach.

 

No no, definitely not including atmospheric. It's actually noted down on motoring file.

 

Well, I got the DV installed, but the plug installation went south as I didn't have the right socket to pull the OEM plugs. That's going to have to wait a couple of days.

However, the DV did wonders for my MINI. It has almost completely eliminated the surge & stutter - hereby known as S&S. I did still feel/hear a clicking sound once under full throttle, but only once. I'm hopeful the plugs will take care of it. Partial throttle response has been smooth and consistent. Finally.

BTW, etalj, I noted that even under full throttle, my scangage topped out at 35psi absolute. In AZ, that's about 21psi boost. Mine's only an "S", so that could be why this worked better on my MINI than yours. Maybe consider knocking the peak boost back down a couple of psi?

 

You are only running 5psi? But the gauge states 20psi? They read above atmosphere. You do not subtract 15psi from boost. If there is no boost, you are running vacuum, & if the engine is off you are running 0 boost, not 15. 15psi is just a benchmark for 1bar= 1 atmosphere.

If some one is running 2bar of boost it's around 30psi, not 30psi=15psi, so 15psi.

 

1bar = 14.5xxx psi,

@stealth


OPC stated absolute readings, absolute does not include atmospheric pressure in readings. Which is where you are correct of readings in vacuum/boost.

 

I'm very glad it worked for your car buddy Always good to hear

I would consider doing that if it wasn't for the mere fact that all other JCWs have nary a problem with the very same maps! I honestly don't think it's a boost issue, my money is still on vacuum control. I'm going off tonight to a mechanic friend and we're gonna tear the sucker apart to find this damn problem

 

My Scangage is set on MAP which the book says is "Manifold Absolute pressure" and it states that "at sea level the pressure at wide open throttle can be as high as 15 psi. If the engine is turbo...pressure can be higher...". So according to Scangage I do need to subtract the atmospheric pressure to get the "boost" pressure, same as OPC did in his post above. I know that 5 psi boost doesn't sound high, but I must admit that I don't drive that hard generally and I am new to the track, so I am concentrating on the road and the tach and have not looked at the Scangage other than to see the boost temp. So I don't know what the boost tops out at. However, I believe that my car is making every last Hp Mini intended a pure stock S to make as I have been able to reach similar top track speeds as other Minis, even some not so stock ones. Maybe, after a little more track time I will relax enough to actually take a look

 

Man am I happy I found this thread. I've had the canned RMW tune installed on my S since it first became available, and while Jan was able to smooth out most of the rough edges that were issues during my first few tune files, it's never been a smooth and happy relationship. All of the problems people are calling out in this thread I've dealt with for as long as I've had the tune- the hesitation, the boost cut, the unpredictable throttle response...but most recently I started noticing a flutter when getting onto the highway or accelerating up large steep inclines. It's really irritating, honestly, as it's not consistent whatsoever. As soon as I hear it, I can't replicate it no matter what gear I hit or how I manage the throttle, but I want it fixed.

Most recently, I was getting on the highway and experienced the surge/flutter and happened to have my eyes in the rear view, and for the first time I noticed the puff of smoke that coughed out alongside the flutter.

Now, my car's getting up there in miles at this point compared to a lot of the 2008s people are running on this forum (~60K), and I'm game to giving the WMW diverter valve a shot, and I'll even admit it's probably time to swap out my plugs. In the meantime, however, while I hem and haw about what exactly I want to do, I want to at least encourage you guys to keep posting as you chase down these issues. You're doing me a great service just by exploring the issues that I simply can't tackle on my own (limited time, mechanical ability, blah). So thanks.

 

OK, that explains it, I just don't understand why you subtract 1-bar. Now I feel dumb. I still have never known to subtract from a MAP sensor. It should be calibrated for our cars, & should read 0 with the car on, but not running? Have you checked what it reads with the engine off? That to me would be what you should subtract.

My guess is you are running well over 5psi. 5psi is what aftermarket turbo system run on a high compression engine. Their is NO WAY you are making max HP on 5psi.

Mine (vacuum boost gauge) runs well over 5psi on application of 50% or more throttle. 1st gear does limit my boost.

Smart ***!
FWIW, it's 14.7psi

But changes with altitude, temperature, & humidity.
I still don't fully understand subtracting 1-bar, unless our MAP si calibrated to 1-bar with the engine off.

"MAP stands for Manifold Absolute Pressure. This means that the sensor measures pressure referenced to absolute vacuum, not atmospheric pressure like many vacuum and boost gauges. Engine parameters like fueling, ignition timing, compressor efficiency and so on are dependent on the MASS of air (in pounds per cubic foot or kg per cubic meter) entering the engine. As air is a gas, it’s mass is dependent on it’s ABSOLUTE pressure, referenced to absolute vaccuum and it’s temperature."

Here is another read on MAPs
http://www.autoshop101.com/forms/h35.pdf


I'm not saying your wrong, or that I am right. I'm just trying to under stand this. I have tuned a few MAP based cars, & few of them were forced induction, & we have never subtracted from the MAP.

 

What management systems? I have also tuned many cars and motorcycles and dependant on management will get different scales of read outs.



ps: [SIZE=5]1 bar = 14.5037738 pounds per square inch[/SIZE]

lol