turbo lag

[Pig Farmer]

That's great news. I'll have to keep these "symptoms" in mind when it's time for a cleaning.

[Eddie135]

Originally Posted by BrokenVert

well since you all asked for it heres the explaination. Ive now slept for 13 hours and feel fantastic!

In thermodynamics we give most things in terms of efficiencies. Flow efficiencies, thermo efficiencies (heat transfers), pressure efficiencies, etc... Thats what im going to talk about.

This is a typical DCI configuration



note the open ended intake piping from the kidneys.In the factory system this is connected directly to the filter box.

That exposed end leads to so many inefficiencies in the system, I cant list them all. but here are the main ones.

Without a direct line from the front of the car to the turbos (the turbos in this case sucking air into the intake stream) less clean air from the front of the car will make it to the engine. But, the engione still needs air. So where does it get the rest of it from?

It gets it from underneath the hood. Some people will say fine. air is air, but it really isnt.

For stagnant air underneath the hood is hot. Hot air in an intake stream is bad, as anybody selling an intercooler will attest to.


And thats the main issue with DCIs. You have a drop in total pressure of the system because you shift the source of air from the air ahead of the car, to air under the hood.


Now some people say that at speed that effect is negated because air is sucked in under the hood, and yes the hot air isuuse is lessened.

But that leads to a new problem that again acts to drop the total pressure in the system - roughness.

Roughness is a very bad thing, it adds to drag. And drag may not seem like a big deal in something as small as an intake stream, but thats arguably where a decent flow is most important.

now I really dont feel like doing an N-S analysis of the intake stream. So ill put it in words like the rest of this has been.

By sucking in air from under hood that air has to pass over the engine, the radiator, the shock towers, everything in the engine bay. This will induce vortices and perturbations in the flow field. This, again, acts to reduce the total pressure of the system, inducing drag.

A less efficient system is less capable of delivering air to the engine. This is why DCIs are shown to lose power, with a fan running on the dyno or not. Because the factory intake stream reduces flow instability compared to sucking in air from under the hood.


Could the stock system deal with using a bit more area? Absolutely. Thats why the Dinan and Mr. 5 systems are the way they are <- those two designs are my personal choice.

You can look up the dyno comparisons. I dont feel like searching, but what I said has been mentioned and documents many times in the past.

I just gave you the theory behind why that is (scientific theory - not a shot in the dark theory).

anyway have fun, im going to be enjoying my time off.

thanks for the explanation.

[Wibbles]

Originally Posted by Dackelone

Link? I not sure I have seen it.

Here you go:

[marconi118]

Originally Posted by Dackelone

Yes. There are sooo many threads on this. Here is a mega one over on the e90 forum. It effects both N54 and N55's.

Has anyone contacted BMW regarding 29.2 and lag?
http://www.e90post.com/forums/showthread.php?t=147781

Is it still the case with the last BMW program with the WG retrofit activated?

Is it linked to MSD80 or MSD81? It seems that MSD81 suffer less the lag?!

Does the procede eliminates the lag by controlling directly the WG and bypassing the ECU?

And finally Is the 1M with the MSD85 suffering this lag?

[Dackelone]

Originally Posted by marconi118

Is it still the case with the last BMW program with the WG retrofit activated?

Is it linked to MSD80 or MSD81? It seems that MSD81 suffer less the lag?!

Does the procede eliminates the lag by controlling directly the WG and bypassing the ECU?

And finally Is the 1M with the MSD85 suffering this lag?

I can only speak for what I experience with my 2010 135i, N54. I have MDS81 (I believe). And the lag was very subtle, but noticeable to anyone who drives with some speed/lead under their right foot!

Since that thread on the e90 forum is some 220+ pages long... I have seen N54 AND N55's have this problem. Until recently most have reported when they pruchase BMW's PPK1 SW this seems to fix the "lag" issue. But recently there have been a few (two 1addicts) that report the lag is still there even with the PPK installed.

In reading that mega thread... some said they had their dealer reload the SW update... but this time with the tech checking off wastegate activation boxes in the GT1 menu before the SW downloads. I suspect its like doing an easy or expert program download for ones pc. You can do it the easy way... in which case BMW just gives you the "lag" SW. Or... the tech can click advanced (and do it the harder more time consuming way) mode. It looks like that is what people have reported.

I have no idea about the 1M SW issues. I have not seen anyone report about lag with a 1M. Not yet. Maybe once BMW comes out with the new F80 M3 with twin turbo six... maybe then we will see BMW doing the same thing they are doing to our 135i's to the 1M. Cutting its performance by way of a SW patch/update - in order to limit warranty claims/buy backs.

Piggys are just that - piggy back system. I only see them tricking the DME to run more boost and enhance performance that way. I think IF you have an issue with the base SW, you will still have that problem. Then again... all the guys with JB3/4's seem to like this latest BMW SW. ?

[Dackelone]

Originally Posted by wibbles

Here you go:

Wibbles... when I go to watch your video... it says it is a private video!

Youtube.com... "This video is private, sorry!"

[Wibbles]

[foghat]

Originally Posted by Dackelone

Piggys are just that - piggy back system. I only see them tricking the DME to run more boost and enhance performance that way. I think IF you have an issue with the base SW, you will still have that problem. Then again... all the guys with JB3/4's seem to like this latest BMW SW. ?

I don't know all the ins and outs of what the jb4 does, but it is more than just boost. In fact on equivalent maps, jb4 gets similar numbers to cobb using less boost than cobb. At least so I've read.

[Exite]

Originally Posted by foghat

I don't know all the ins and outs of what the jb4 does, but it is more than just boost. In fact on equivalent maps, jb4 gets similar numbers to cobb using less boost than cobb. At least so I've read.

He wasn't knocking the jb4 he was just saying it can only work within the bounds of the software in the ecu because it's a piggyback. So if the "lag" is part of the software in the ecu a pggyback may not be able to do anything about it. A full flash like giac or cobb may make the "lag" go away since it re-flashes the ecu.

It's really all guess work, because without having access to a bunch of different cars with different mods and the software versions on each car you can't know for sure.

[foghat]

Originally Posted by Exite

He wasn't knocking the jb4 he was just saying it can only work within the bounds of the software in the ecu because it's a piggyback. So if the "lag" is part of the software in the ecu a pggyback may not be able to do anything about it. A full flash like giac or cobb may make the "lag" go away since it re-flashes the ecu.

It's really all guess work, because without having access to a bunch of different cars with different mods and the software versions on each car you can't know for sure.

Not saying he was knocking it and I get the point being made I was just commenting on the statement: "I only see them tricking the DME to run more boost and enhance performance that way."

Boost is not the only way jb4 enhances performance. And know I am getting a little OT here.

[Dackelone]

Originally Posted by Exite

It's really all guess work, because without having access to a bunch of different cars with different mods and the software versions on each car you can't know for sure.

^^ +1. Yup, we really do not know bc this stuff/info is kept secret from us.

Dack

[Dackelone]

Originally Posted by wibbles

Hi Wibbles, Ok now I can watch your video. Seems like your car is really sluggish. I don't ever remember mine being that bad. Why is your engine check light on though? The yellow light in the top left of the center of the instrument panel. Also I see your can is an Auto while mine is a manual. Perhaps that might have something to do with it. ???

I will try and make a video of my car this weekend. But I will be driving the Stelvio Pass with some otehr 1addicts, so the video making is on the "back burner".

[Wibbles]

Dack - the check light isnt a check light it's the parking brake indicator.

Mine is a 6 speed manual, not an automatic

I've fired off an email to Marcel who tuned your car, does he speak good English?

He is my last resort as I'm just thinking of getting shot of the car in the next couple of weeks.

[Dackelone]

Originally Posted by wibbles

Dack - the check light isnt a check light it's the parking brake indicator.

Mine is a 6 speed manual, not an automatic

I've fired off an email to Marcel who tuned your car, does he speak good English?

He is my last resort as I'm just thinking of getting shot of the car in the next couple of weeks, this saga has been going on since February & has broken me . I fucking hate what BMW has done to my car.

Marcel's English in writing is limited. But he will reply back. Just do not write a book! keep things simple. You can always call him on his mobile too. He speaks English very well.

[SixBanger]

I just wanna say after having my car for 4 days now, what an improvement that was. My head was cleaned by BMW with walnut shells. For the peoplle claiming that they have lag, I would definitely look into this. I've had this issue for a long time thinking that the most recent update to my DME was doing this, but that wasn't the case. With the performance software and head cleaning it actually feels like the car I took delivery in June 2008.

[Dackelone]

Originally Posted by wibbles

Ok Wibbles... here is my video of my car with Marcel's stage two tune.


Btw... I suck at making videos... so keep that in mind. Its really hard to show you the throttle response action. Even though it looks like it lags... it does NOT!

[Wibbles]

Dacklone, you are an utter legend! the bad, or maybe the good news is, I decided I had had enough opf being dicked around with my 135 & part exchanged it in for a 530d F10 at the weekend.

Thankfully the new car has no lag & bags of torque.

Hopefully I will be back in a 1M at some point in the future, thanks for all the help and advice form everyone on this thread.

If the N55 ever gets cracked I might buy another, otherwise, the N54 is the way forward

Dacklone - if I'm over in Germany I will buy you a beer!

[Dackelone]

Originally Posted by wibbles

Dacklone, you are an utter legend! the bad, or maybe the good news is, I decided I had had enough opf being dicked around with my 135 & part exchanged it in for a 530d F10 at the weekend.

Thankfully the new car has no lag & bags of torque...

Congrats Wibbles!


Thats funny bc lately I have been thinking of a diesel F10....


AuoBild recently compared the new M5 to the new M550d. They called the M550d the better M5! Well... almost.

http://www.autobild.de/artikel/bmw-m...h-3486732.html

[sacha101]

Originally Posted by Dackelone

That is what I noticed too. Basically you have to press MORE THAN half way down on the gas pedal to get the SAME performance as before the SW update. Before the SW you only needed to press down on the throttle 1/4 to get that kind of oomph! That is the "lag" I am talking about.

I also noticed the engine was a whole lot quieter running or staring cold. Less injector noises/rattles. Better fuel economy too. And the exhaust was slightly louder on cruising 40~60 mph. At higher speeds I did not notice the exhaust too much. But at say 40 mph it was way louder than before the SW. Also... on start up the exhaust was a lot quieter. Before when the car would warm up at idle... it was loud for the first few minutes, then you would hear a CLANK and then it would be quiet. After the SW, the exhaust was MUCH quieter on cold start. And also all those lovely crackles and pops on deceleration when you let off the throttle... were gone after the SW update.

Dack

Exactly ! I'm in the same boat ! Aren't aftermarket flashs bad for my warranty ?? are they expensive ??

[sacha101]

Originally Posted by wibbles

My car seems to be exactly in the same situation....
a real pisser...

did you find a way to fix it ??

[Wibbles]

Originally Posted by sacha101

My car seems to be exactly in the same situation....
a real pisser...

did you find a way to fix it ??

No, there is no fix for an N55. Get rid of the car & buy an N54 + Cobb, sorry I can't help more.

[Dackelone]

Originally Posted by sacha101

My car seems to be exactly in the same situation....
a real pisser...

did you find a way to fix it ??

You can have BMW install the PPK-I (Performance Power Kit) which is only the SW that increases the Hp by 20 Hp or so. But its mainly the added torque in the mid range and the great throttle response why people get the PPK. That and the fact they still keep their warranty. Some have even been able to have BMW pay for the PPKI tune(~$700 to $1K depending on the dealer).

Or... you can get a tune. That is what I did, bc I knew only 20 Hp wasn't going to be enough for me. I have now 380 PS and 520Nm.

Got my car tuned in Germany…

http://www.1addicts.com/forums/showthread.php?t=528152


Or you can do like Wibbles did and sell the car. He got himself a F10 BMW.


Dackel