# Is my small turbo working?



## nuclearbeef (Dec 19, 2012)

Just bought a 2010 335d two weeks ago. Space Grey/black leather, sport, premium, cold weather, no nav. 70,000 miles. I don't know if I just got a great deal, or if this is bad news for everyone's resale value once out of warranty, but I got it for $23,800.00.

Main question. There is more turbo lag than I expected. Dealer in Memphis has no 335d's on the lot and I haven't driven another 335d, so I can only compare it to my other diesels; 2001 F250 with 7.3l diesel and my 1976 FJ55 Toyota Land Cruiser with a 3.4l 3b diesel with a Garrett turbo out of a Volvo stuck onto it.

My 335d, while obviously faster, doesn't seem to have as much "punch" down low as either of my other diesels. If I want to squirt ahead in traffic, I need to push the pedal far enough down that the car downshifts so the engine is above @ 2500 rpm. 

Is this just the way the TPS is calibrated? If so, I don't mind. I can drive like Granny, hypermiling around town with ample pedal travel. Then when I need to go; just push the skinny pedal hard. (I've hated american cars since the 80's for having touchy accelerator pedals. Make the engine produce 70% of it's power in the first mm of pedal travel and you FEEL like it's twice as powerful as it is)

This question may just be too subjective for the internet, but how much lag should I be experiencing? Is there a way to test the small turbo? Say, put it in manual and in a high gear where the RPM's are @1700; then floor it?

PS: I put a JBD tuner on it a couple days ago set at 60%. I definitely can tell a difference high in the rpm range, but can tell no difference in normal driving.

Oh yeah, no codes. Pre-buy at BMW Nashville and service last week in Memphis brought no mention of it from the techs. I didn't mention it to them.

Thanks in advance,

JW


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## Pierre Louis (Oct 23, 2011)

There was a thread that discussed this and it was the small turbo, although some found no fault. I think since you are used to other diesels, especially the ones you mentioned, its likely that its the small turbo.

Mine has very little lag, and I may be just used to the "German throttle response algorithm" which to me means a more linear response instead of what I would describe as exaggerated on other cars to make them seem more powerful. I also am used to "priming" the automatic a bit when I drive so that it doesn't have as much of a delay, if that makes any sense.

As I recall, there were no codes reported.

I found this post on the other forum: http://www.e90post.com/forums/showthread.php?t=843292&highlight=335d+small+turbo+-working

Welcome to the 335d fold!

PL


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## nuclearbeef (Dec 19, 2012)

Thanks for the link.

From that, I take it that if the actuator has failed it would produce a code, but if the vacuum line has failed you might not get a code.

It might just be the linear pedal response that I'm not used to, but I have no frame of reference to compare it with. 

Any other ideas on how to check & see if the small turbo is working would be greatly appreciated.

JW


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## floydarogers (Oct 11, 2010)

nuclearbeef said:


> ...
> Any other ideas on how to check & see if the small turbo is working would be greatly appreciated.


There are two ways I can think of:
1) Buy the Bavarian Technics OBD II cable/software and monitor the boost (check TDIWyse's threads for specifics)
2) I can hear my turbo spooling up from a dead stop if I have the windows down and stereo off (flat ground, slow acceleration). Probably if you take the cover off the air filter (it's actually called out as a "silencer" on realoem) it would be louder.


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## F32Fleet (Jul 14, 2010)

IMO any delay is due to the AT and not the engine. You'll see rpms climb before the AT engages. It's a BMW thing. Also mashing the pedal will cause a delay because the AT has to take a second to find the right gear.


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## TDIwyse (Sep 17, 2010)

This might be helpful:

http://www.bimmerfest.com/forums/showpost.php?p=6875655&postcount=56

In my experience there's an extremely small lag. I might have some finer time step data on my home computer than the link above, but you should be able to hit ~max boost in 1/4-1/2 sec across the whole rpm range.

Try forcing it into 3rd gear at ~1800 rpm and step on the skinny pedal (but not hitting the kick down button). If you don't feel near immediate thrust I'd suggest getting a BT or the Android Torque App with a cheap OBD dongle. You can log boost vs rpm (or time) and quantify the boost delay. If you don't make max boost at low rpm's I'd guess there's something wrong with your small turbo.


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## jdclay (Oct 6, 2010)

I'm experiencing something very similar with my 335d. Acceleration from a stop seems to not be producing the torque feel that I had back when I first bought the car in 2010.

I used to be able to slowly accelerate yet feel the "thrown back in the seat" torque during acceleration. Nowadays 0-40 seems to not produce nearly as much torque feel as it used to.


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## nuclearbeef (Dec 19, 2012)

I'll try holding it in 3rd @1800rpm and gauge the response. (Wife took it to work today, so maybe tonight)

It could be that it feels like I'm lacking in low rpm torque because the transmission is so eager to downshift. 
My 7.3 in the Ford takes a MIGHTY stab at the pedal to get it to downshift. Stomp it 3/4 of the way down and it just surges forward in whatever gear it was already in. (I do have the diablo predator tow safe tune installed which changed the shift characteristics) The Toyota is standard transmission.

1/4 to 1/2 sec lag sounds about like what I'm experiencing. Probably just that I'm still getting used to the way the car drives.


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## 335dFan (Nov 8, 2012)

The only time I have ever noticed what could be termed a delayed response is when the traction control nanny intervened. Or I suppose, like someone already mentioned, when it was having a hard time deciding what gear it wanted to be in.

I have actually thought about getting a couple of those pads from Lowe's with adhesive on one side and a non-slip surface on the other, cutting two pieces the right size, sticking one on top of the other, and then placing it under the go pedal to inhibit the down-shift mechanism. With all that torque one rarely needs the downshift to get moving very fast in almost any gear.


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## nuclearbeef (Dec 19, 2012)

That reminds me of another reason I thought my small turbo might not be working at full capacity. I've read on this site, owners comment that the torque of this engine is not fully usable in this chassis because it would just smoke the tires without the traction control.

From a dead stop, at idle, in drive; if I floor it; I don't get the traction control stepping in if I'm going in a straight line. Going around a corner, definitely, but not going straight. 

The car came with fairly sticky non-run-flats, if that makes a difference.


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