[alohasurftoad]

Originally Posted by Bmw doubles

I'm getting the stutter too. I only have the GSR tune and the rest stock. Getting DP in a few days. My stutter is accompanied with vent to atmosphere purge. Let me know if you have any updates on yours and when I get my DV+ installed I'll report back too.

bummers, i was hoping stock w/GSR tune had no issues. i hope GSR is going to resolve this...

[FSociety]

teapain any videos of how the car sounds idle and at WOT ?

[Stubok]

Guys, I have been doing a lot of research on this. It appears the Engine is prone to developing a stutter as stock (http://f30.bimmerpost.com/forums/sho...d.php?t=873019). And that tunes amplify the effect. I know of stutters in exactly the same place (around 3000rpm under load and medium to hard acceleration) with various tunes including this one.

There are various items that probably should be looked at, cleaning MAF, Injectors, PCV, and most importantly chargepipe's and their seals. Some folks have changed coils and plugs, but that seems to be less of a fix.

I also have a suspicion that once the car gets a few miles under its belt some carbon or dirt build up has an effect on how the car transitions from normally aspirated to boost. The crank case ventilation system is very complex. I think something may be going on here. Speaking to the guys that provided the DV+ (they have a lot of experience with the newer VW/VAG group engines that suffer with this), apparently the PCV can also be a real PITA.

[Bmw doubles]

Wow. Great discovery. How the hell do we clean the injectors? It's pretty much replacement, isn't it? I mean we could run some techron, I guess. Damn, back to the drawing board. Thanks again for the update.

[jmaak]

Originally Posted by Stubok

Guys, I have been doing a lot of research on this. It appears the Engine is prone to developing a stutter as stock (http://f30.bimmerpost.com/forums/sho...d.php?t=873019). And that tunes amplify the effect. I know of stutters in exactly the same place (around 3000rpm under load and medium to hard acceleration) with various tunes including this one.

There are various items that probably should be looked at, cleaning MAF, Injectors, PCV, and most importantly chargepipe's and their seals. Some folks have changed coils and plugs, but that seems to be less of a fix.

I also have a suspicion that once the car gets a few miles under its belt some carbon or dirt build up has an effect on how the car transitions from normally aspirated to boost. The crank case ventilation system is very complex. I think something may be going on here. Speaking to the guys that provided the DV+ (they have a lot of experience with the newer VW/VAG group engines that suffer with this), apparently the PCV can also be a real PITA.

Thanks for posting this!

I am experiencing the stuttering issue intermittently as well.

[CalCarNut]

Nice to hear it's not the tune that's the cause and seemingly more an annoyance ..

[teapain]

Originally Posted by ROBNYC

teapain any videos of how the car sounds idle and at WOT ?

Not yet. But will try to do some runs tomorrow night!

Nice find, Stu!

[rustyminded]

hey man i think you have carbon build up problem had this stutter on my previous car with bms st.1 although after removing the bms , the car seemed smoother but sttuter was still there so i got system cleaner and did 2 tank cleans then with injector sprayer spayed in intake directly. problem was gone. Hope it helps

[Stubok]

Originally Posted by rustyminded

hey man i think you have carbon build up problem had this stutter on my previous car with bms st.1 although after removing the bms , the car seemed smoother but sttuter was still there so i got system cleaner and did 2 tank cleans then with injector sprayer spayed in intake directly. problem was gone. Hope it helps

Can you give us more information in the system cleaner? Is it a BMW one or techron type cleaner? Is it the injector cleaner or something else?

You put it in with a full tank?

With this being a direct injection engine I'm not so sure how the intake/valves are effected. I don't think that much?

Also what was the spray cleaner you used? And where did you spray it in? Before the MAF? In which case it went through the turbo, intercooler and Chargepipes too?

[rustyminded]

I use what we have in my country gunk, cyclo ect. any American stuff that's for trucks so it can be concentrated. i pour it on more than half or half then empty tank and do it again. then

i got injector sprayer i use known brands not cheap chinese stuff. open intake spray quarter can then turn car on and press pedal to remove all that gunk its all black stuff coming from exhaust. as for maf we don't have maf cleaner so i use carb or alcohol but that's on your own risk, get MAF cleaner I'm sure you'll find it in usa.

lastly open chargepipe from throttle side and spray throttle cleaner on throttle body you'll find it dirty as well. if you can take it off but that's pita so it's up to you. Hope it helps,

I'm starting to get stutter between 2.5 to 3 k rpm but that's a first in this car il do a system cleaner shot

[CalCarNut]

MAF cleaner is pretty easy to find. I have a can that I use on my SS. I don't know how the BMW unit is, but you can use a qtip and clean the wire sensors GENTLY as well if the design is similar. I have to dissect my GC to learn this stuff at some point but right now I just hit the button and go

[Stubok]

Originally Posted by SoCalDave

MAF cleaner is pretty easy to find. I have a can that I use on my SS. I don't know how the BMW unit is, but you can use a qtip and clean the wire sensors GENTLY as well if the design is similar. I have to dissect my GC to learn this stuff at some point but right now I just hit the button and go

I used the spray MAF cleaner. The MAF sensor has 2 screws securing it in the air filter housing. Pretty easy to get at and clean.

I did it and it certainly helps.

I also just used techron fuel system cleaner in my tank. Early on yet to be sure, but so far it has done the trick. I got the car upto temp and also did some high rev runs.

Car is pulling strong and smooth.

I plan to put some cleaner (seafoam) through the induction and vacuum lines per the can instruction. Even though the car is running great I got a can with the techron so going to give it a go.

Definitely give the fuel system cleaner a go though.

[CalCarNut]

Originally Posted by Stubok

I used the spray MAF cleaner. The MAF sensor has 2 screws securing it in the air filter housing. Pretty easy to get at and clean.

I did it and it certainly helps.

I also just used techron fuel system cleaner in my tank. Early on yet to be sure, but so far it has done the trick. I got the car upto temp and also did some high rev runs.

Car is pulling strong and smooth.

I plan to put some cleaner (seafoam) through the induction and vacuum lines per the can instruction. Even though the car is running great I got a can with the techron so going to give it a go.

Definitely give the fuel system cleaner a go though.

Based on this, would you say the GSR tune is problem free? Whats the mileage on your car? I only have about 2200mi on me GC so far..so I'm guessing I'm good for awhile....(stutter wise).

[Stubok]

My car has just gone through 10k miles. Was serviced at 8k if I remember rightly and there were no issues then.

I'll give it some time and a dyno before I say everything is 100%

[SeanWRT]

Originally Posted by Stubok

Using a OBD wifi module and torque pro app. Logs so many things it's unreal.

It's a hesitation of sorts. Hard to explain but under firm to hard acceleration in higher gears (3rd and up) you just don't get as much punch and it also starts to stutter. you have to listen out for the hissing, similar to the blow off from the diverter during a gear change, but during this period the DV should be sealed and not diverting.

As I said for me it is as I step on the gas in 3rd or higher from 2500rpm and start building big boost things obviously start to not add up for the ECU as air is leaking. The engine starts to pull timing and throttle.

I'm working on replacing the DV with a DV+ from GFB (at a standstill right now but that's another story) since apparently it is very common for the stock DV to leak or fail at higher boost.

So how much boost were you running in conjunction with your mods?

[Bmw doubles]

EDITED

[wolves]

^ Thanks for the tip. I'm just starting at 65k miles.

[Rival]

have you ran it at the strip yet??

any plans to do so??

my camaro put down also exactly the same numbers but a tad higher hp and ran a low 13 @ 104 ish at the track. But that was at 3250 raceweight too.

[Rival]

have you ran it at the strip yet??

any plans to do so??

my camaro put down also exactly the same numbers but a tad higher hp and ran a low 13 @ 104 ish at the track. But that was at 3250 raceweight too.

[Bmw doubles]

Originally Posted by wolves

^ Thanks for the tip. I'm just starting at 65k miles.

If you do have this issue. Just fill it to the point where it literally overflows and then cap it. I used the 50/50 mix, but you can just add distilled water.