Ahh can't take it. For me, every time it's warm out now (new England is finally starting to get warm again), My boost cuts.

I'm rmv tuned, and normally see about 19psi partial throttle, 17 psi wot. But once it's about 70+F out, boost spikes to 22 and then drops to 5psi, regardless of wot or partial. Usually more often in 6th gear, but will happen in any gear.

Are other people's boost cuts temperature sensitive?

 

It is temperature sensitive because tables in the ECU will try to run more boost as inlet temps rise...

Gladly though...I no longer have desire to run 22 psi

 

lol, i know you dont =p
hows that going btw? I saw that piece of the piston you sent me......

Did you experience the cuts over and over at some points? You're down where its hot all the time, how did you ever drive the car??

 

Flash the car to stock, then flash the tune back on...and reset adaptations.

That always made it better for me...

 

See I thought I was crazy, and thought after ref lashes the car always felt to drive better. Once it learns my driving again then it gets numb. I can't reflect right now because Jan is MIA and hasn't sent me the file he gave me a few weeks back in person.

 

What are people's thoughts on a mechanical boost controller? Would this cause all our sensors to go haywire? It's so common on "older" cars to control boost levels... If we could get away with it without map and mad sensors going crazy, we could set it to 21psi, before the mad sees the air, so when it's compensating and upping boost,the mechanical valve releases the extra pressure before reaching the MAP, which sees 22psi equiv (+atmospheric) and cuts boost to about psi

 

If it was that "simple" alta or someone would have offered it already.

 

He is at the Dragon right now, was driving cross country all week....in his MINI. Not bad when you can drive a 400whp MINI cross country!

Yea, not going to happen!

The ECU does not play well with a mechanical boost controller. There are too many calculations in the ECU which go into determining boost. This is why our boost is never consistent number, rather it falls into a range...it takes many things into account and then runs a boost level based off of those factors. Load, temp, etc...

My friends tuned STi was tuned to run 18psi...and it runs exactly 18psi everytime you go WOT. Not so in the R56....

 

Just get a stand alone ECU then you can do anything you want

 

Thanks for that bit of wisdom.

/s

 

^^
lol

standalone wouldn't be worth it in our cars, as we'd lose any and everything. I mean, maybe if I tore everything down and out, but its my daily, so that would never happen.

It sounds so easy in theory, a valve before the map sensor, see 22psi, purge till under 22, and let it continue on its merry way. Damn these little cars. At this point I'm not even as interested in getting every bit of power out of the car anymore, and would rather just have something decently quick that has the daily driving reliability (reliability meaning not cutting boost when i need to accelerate to pass someone or merge on the highway).

We didn't have this issue when we still had 1st gear boost/torque limiters right? Maybe that should be looked at a bit more closely.

 

Yea lol...in response to my quest for a fast R56 and constant issues....my mini dealer told me "why don't you just get an STi, make 400hp and be done with it???"

That'd be too easy.

People also weren't boosting 20+ then...

 

I have only hit boost cut one time in 6th gear.


I would say itd be tough for you since your over in the northern bits, to get tuned on a warm day(per jan's schedules). Above 56 degs i believe is one limit and then again above 72 degs (dont quote me on that) . Definitely sucks when you dump boost though


Just have to wait until somone can translate the jcw sensor voltages to the s ecu.

 

Also my mini tech friend and i have been discussing trying to see if i can come up with a fuel cut defender using a specific type of diode which allows the ecu to only see a max of that voltage. Just wonder how the ecu would respond if more boost was in the system... not for a long period of time but it should in theory eliminate the boost spike cut offs.

 

Yeah, this would work in theory, and would solve our issue for the boost cut, but like you said, I also wonder how the ecu would respond to more boost than it thinks there is. AFR's would probably be thrown off and slight timing possibly.

I rarely see 20psi when its under 55F out, if I am partial throttle, I'll see maybe a quick spike to 20 then tapers to 17, if I'm WOT it only hits 16.5 or so max. So I think my tune's parameters are set to allow 16psi, but due to all the crazy voltage and matrices within the ECU's mapping, its always trying to 'correct' itself or adjust for everything, and thus we see these spikes.

In the past before a recent file, I used to get a boost cut when going WOT, but I could then instantly let off the throttle and back on and there'd be no issue. Now if its hot and I get the cut, I'll let off the throttle, back on, and tries to boost but cuts again, even at partial throttle (which I assume seeing that I hit higher spikes with partial throttle, I would def hit 22 with partial if I hit 22 WOT).

I'm just surprised the ECU would adjust/compensate that much boost from 16.5 to 22 is a pretty large delta.

 

I had this issue when i would shift fast in higher gears, once i "tuned" my dv valve the problem was cured. I think in regards to this description it could have been the dv not responding fast enough to the inputs/effects going on through quick shifts.


I could be wrong but i had literally the same issue where i would go from 3rd to 4th... it would dump boost via DV id let off then get back on it would close and build 20 again.



The psi targets set via ecu will be achieved, that being said the map sensor voltages are what give the readings along with the pipe pressure sensor. I wonder how the diode will help. Time to find out!

 

hmm, now that you mention it, my previous situation where it'd come back after throttle release, was with my stock DV.

I have the WMW dv on now, but its surging on hard shifts, so its not opening quickly enough. I bought it used so I'm not sure if anything internally has been tampered with or swapped. The diaphram looks good and theres no tears or rips. I was going to swap back to my OEM for now.

I've read about your multi-spring gadget you got going on. I wonder if people are still getting 22psi cuts with the Alta 1millionDollarSpring

...should i go back to stock DV or maybe even take internals from the wmw dv and put it in my stock dv? Maybe the electrical connection has some fault to it opening a split second later

 

Not at all, it surging at high boost is whaty i was looking for.



For a quick **** it keeps the boost in the system, but at smooth low psi shifts it diverts boost


i ran a closed system for a few days and it was awesome especially regarding response but low rev high load/high boost throttle lifts would cause a check sum cel. It would clear after 5 min and when my mini tech budyy (step) on here connected it to the icid(bmw factory scan tool) the cel was not in the icid logs.

 

But when it surges, the compressor wheel stalls, causing boost to need to build up again..

 

Have any of you data logged your cars going into boost cut? I have a few logs from a couple cars. It would be interesting to see how they compare.

So far my logs show boost cuts at and under 22 psi, some as low as 19. In all cases though the load limiter was hit. The standard load limit at 7200 rpm was 210 on the alta map I used. I could get boost cut on flat roads just from hard shifts the same way as BIG. We moved the load limit up to 215 and could only get it to trip boost cut on heavy load situations like WOT going up hill. At that point the fix seems simple enough, but I'm sure the ECU will freak if we play with that load map too much.

 

I've logged it a ton....mine are distinctly at 22psi. Sometimes if it hit it from hard spike it would register slightly higher (i've seen 23psi...) but its cuz it couldn't cut it fast enough.

I can post em up...even made them into graphs

I'm waiting to get bigger compressor & turbine wheels and run lower boost now. 22+ is excessive. 18-20, plus water/meth....I think would be perfect.

 

Yeah post them up. It would be interesting to see what was going on with yours compared to mine.

 

You are right, but when you have a stall say on a slow shift you will have to slowly build boost again(slowly speaking figuratively) but when your shifting fast you have a slight stall but your opening the throttle body almost immediately so the boost is still pressurized when it opens again. If your not opening it fast (shifting fast) then the stall will be significant.

 

I can agree to that. It does "feel" faster to build boost again, but I cringe just a bit everytime i feel it stalling upon surge, not a good thing for the life of the turbo.

BTW. I've been getting cuts after work everyday, when its been 60+ out.
Went to see fast five last night (lol) and after leaving was still getting cuts even at 10pm. I was driving with my friend in his supercharged mustang gt so we had a spirited drive, but wasn't really working with boost cuts.

I tried blasting the heat on high (man was it hot in there, cracked the window a bit helped), but, absolutely NO cuts, even after repeated hard runs. Water temp was still at a solid 215F, but don't have temp readings on much else, IAT was about the same I think, around 70-75 (was about 60F out). But I was very surprised I had no boost cuts. Maybe we need to figure out how to keep the thermostat to run the car cooler.......

 

not sure what the boost control setup is yet on the mini but have you tried a mbc in parallel with it?

I'm running a hybrid turbo setup on the Audi TT that I have and to control the boost spikes others with this setup have used a MBC valve in parallel with the EBC valve to control the boost spikes... (I currently dont have this installed on mine as mine is capped at 18psi at the moment, others are running 22psi IIRC and see spikes at 24psi... aka rod benders)...

maybe worth a try... ecstuning.com sells mbc's for $30 bux...