# Nonlinear Engine Braking?



## spitpilot (Feb 14, 2000)

I've noticed that my Rabbit has a "nonlinear" spot around 2000-2500 RPM...when I take my foot off the gas it slows smoothly...then hits that RPM range and its like the throttle closes more or something and you can feel a lurch in the deceleration....is this "normal" or is it something to have looked at?


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## sagerabbit (Aug 14, 2007)

*Re: Nonlinear Engine Braking? (spitpilot)*

Mines does it too. Sometimes it's handy, other times it's jerky. depends if the wife is in the car and i'm trying to smooth it out for her. Another love/hate feature


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## sagerabbit (Aug 14, 2007)

the revs on the engine braking is the love/hate. Not the wife, just to clarify.


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## granth (Dec 5, 2001)

*Re: Nonlinear Engine Braking? (spitpilot)*

Yeah, I get the same thing. I find it best to keep the foot on the gas pedal...


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## absoluteczech (Sep 13, 2006)

engine braking is absolutely useless in this car, it doesnt do anything with the stupid revs hanging up there for so long before they start to drop, might as well just hit the damn brake pedal anyways....







damn car




_Modified by absoluteczech at 7:26 AM 12-18-2007_


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## Jimmy Russells (Feb 4, 2007)

DBW + Emissions controls FTL x infinity


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## absoluteczech (Sep 13, 2006)

seriously, its not even so much the dbw. my gf's old car was a 02 z3 which had dbw and when i down shifted there was never any weird issues with revs. i think its all the emissions junk 


_Modified by absoluteczech at 10:05 AM 12-18-2007_


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## thumper87 (Sep 11, 2007)

*Re: Nonlinear Engine Braking? (spitpilot)*

I have the same thing! And I drive an automatic, for reference. It is pretty weird though... It's not noticeable in 3-6th for me, but in 2nd it gets annoying and in 1st, it's a good reason to hit the brake pedal and forget about engine braking. It sorta lunges forward... I don't know how to describe it, really. Our cars are very non-linear, it seems, for an N/A engine. But I still love my Rabbit.


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## spitpilot (Feb 14, 2000)

*Re: Nonlinear Engine Braking? (thumper87)*

My Passat is DBW and it smoothly decellerates whenever I let my foot off the gas..no sudden extra jerks forward..its like the engine in the Rabbit wants to keep on reving after you let off the gas, then when the RPM's drop to about 2300-2500 it suddenly remembers.."Oh I'm supposed to be decellerating" and it drops suddenly lower.








I'm gonna bring it up when I take my car in for the 5k service and other warranty recall (lighting issue) stuff...I'm bettin that I'll get the ol "They all do that" DoDah... but gotta amuse myself by at least asking!


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## o6platg2pernt5 (Dec 29, 2006)

*Re: Nonlinear Engine Braking? (spitpilot)*


_Quote, originally posted by *spitpilot* »_My Passat is DBW and it smoothly decellerates whenever I let my foot off the gas..no sudden extra jerks forward..its like the engine in the Rabbit wants to keep on reving after you let off the gas, then when the RPM's drop to about 2300-2500 it suddenly remembers.."Oh I'm supposed to be decellerating" and it drops suddenly lower.








I'm gonna bring it up when I take my car in for the 5k service and other warranty recall (lighting issue) stuff...I'm bettin that I'll get the ol "They all do that" DoDah... but gotta amuse myself by at least asking!









When you talk to them that is what they should tell you. I read that in the manual, this is how this engine behaves. They call it somthing along the lines of engine braking controll or whatever. it does this so as not to skid in wet conditions. I guess people are not driving the cars they way vw thought you would







Just look in the manual information on this is in there


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## CA dub (Oct 27, 2007)

*Re: Nonlinear Engine Braking? (o6platg2pernt5)*

Mine did this as well. Adding the NST crank pulley has helped a bit with the revs climbing and dropping a bit faster than before. I wonder if a lighter flywheel would help as well. Stock setup FTL


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## Unilateral Phase Detractor (Aug 23, 2005)

*Re: Nonlinear Engine Braking? (spitpilot)*

Mine does that as well. I think it's fine once you get used to it and shift down in anticipation. The other thing is you need to be in a lower gear than you expect for it to have any measurable effect. If I'm cruising along at 30 mph in 4th gear, I need to shift down to 2nd to slow down significantly.


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## Servo888 (Feb 25, 2007)

*Re: Nonlinear Engine Braking? (CA dub)*


_Quote, originally posted by *CA dub* »_Mine did this as well. Adding the NST crank pulley has helped a bit with the revs climbing and dropping a bit faster than before. I wonder if a lighter flywheel would help as well. Stock setup FTL









The issue is that we need to reprogram the computer and get rid of the emissions crap. No external modifications will help, afaik, as it's the computer and not the flywheel that's keeping the engine spinning. Also notice that there is a 'speed mode,' if you take your RPM past 4000, the engine speed should drop as normal.
This honestly is my *biggest* gripe about this car. I can handle the notchy transmission, but not this.


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## spitpilot (Feb 14, 2000)

*Re: Nonlinear Engine Braking? (Servo888)*

Funny that I didn't notice this "quirk" when I was test driving..guess I was too involved with car handling, position of controls, fit of the seats etc and miss this..guess I'll have to learn to live with it!


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## granth (Dec 5, 2001)

Preemptive down-shifting seems to be the only way around this.
It would be really nice to see this feature disabled in some aftermarket software (if possible).


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## MANU01 (Aug 7, 1999)

*Re: Nonlinear Engine Braking? (CA dub)*

I think the real problem here is a very heavy flywheel. Notice how even on up shifts, the flywheel has a hard time losing momentum, and sometimes doesn't match the revs?


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## rustlerdude (Aug 13, 2007)

The problem is NOT from the flywheel or "emissions" crap. It is from the programming to prevent wheel slippage when abrubtly removing your foot from the gas on icy pavement. DUMB design IMO. It takes 5 seconds for the throttle to close fully after removing your foot from the gas. This also yields bad fuel mileage because the throttle is open even though we are not stepping on the gas.


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## buckowheat (Mar 16, 2007)

Wow. 5 seconds huh? At least you have some consistency to work with. Mine lagged randomly between 2 to 7 seconds. That one design flaw made the car unacceptable for me. No other car I ever owned did it and no car I own ever will. It is an unacceptable way to drive a manual transmission car. I traded my '07Jetta in for an '07 A4 Quattro. Problem solved! 
I didn't read that crap in the owner's manual before signing on the line. I also didn't notice it during the test drive...I was too consumed the the impressiveness of handling, steering and braking to notice the Rev-Hanging and Nonlinear Fuel Injection mapping.


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## Jefnes3 (Aug 17, 2001)

*Re: (rustlerdude)*

The problem is EASILY solved with software.
(delayed/slow throttle closing upon quick release of pedal)
I sorted this on the manual trans cars.

-Jeffrey Atwood C2


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## Servo888 (Feb 25, 2007)

*Re: (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_The problem is EASILY solved with software.
(delayed/slow throttle closing upon quick release of pedal)
I sorted this on the manual trans cars.

-Jeffrey Atwood C2


What software would this be?


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## Jefnes3 (Aug 17, 2001)

*Re: (Servo888)*


_Quote, originally posted by *Servo888* »_
What software would this be? 

C2Motorsports
N/A software I made for the Rabbit based on things learned making Turbo
2.5L software.
The issue is particularly bad when running boost...
i.e. the car will accelerate after lifting off pedal.

-Jeffrey Atwood


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## mujjuman (Jul 29, 2004)

*Re: (Jefnes3)*

ah i miss the vortex. 
its because of the ECU programming, not the flywheel 
alot of newer cars have this, even the Civic Si


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## 5_Cent (May 22, 2007)

*Re: (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_
C2Motorsports
N/A software I made for the Rabbit based on things learned making Turbo
2.5L software.
The issue is particularly bad when running boost...
i.e. the car will accelerate after lifting off pedal.

-Jeffrey Atwood


so you guys are developing programming for NA 2.5L's?


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## Jefnes3 (Aug 17, 2001)

*Re: (5_Cent)*


_Quote, originally posted by *5_Cent* »_

so you guys are developing programming for NA 2.5L's?

Yep.
-Jeffrey Atwood


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## 5_Cent (May 22, 2007)

*Re: (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_
Yep.


and that is all the convincing I need to buy it.








::waits patiently::


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## Jimmy Russells (Feb 4, 2007)

*Re: (rustlerdude)*


_Quote, originally posted by *rustlerdude* »_The problem is NOT from the flywheel or "emissions" crap. It is from the programming to prevent wheel slippage when abrubtly removing your foot from the gas on icy pavement. DUMB design IMO. It takes 5 seconds for the throttle to close fully after removing your foot from the gas. This also yields bad fuel mileage because the throttle is open even though we are not stepping on the gas. 

You do know this car (and most modern cars with a manual trans) use zero fuel when coasting in gear...


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## Brianjk (Apr 15, 2002)

*Re: (RedRabidRabbit)*

OK before this thread becomes filled with bickering and hearsay can anyone referencing the owners manual please give a page #number where we can all read about "wet skid protection"?
I'll get around to it, but if someone knows off the top their head...


_Quote, originally posted by *o6platg2pernt5* »_
I read that in the manual, this is how this engine behaves. They call it somthing along the lines of engine braking controll or whatever. it does this so as not to skid in wet conditions.


_Quote, originally posted by *Servo888* »_
No external modifications will help, afaik, as it's the computer and not the flywheel that's keeping the engine spinning. Also notice that there is a 'speed mode,' if you take your RPM past 4000, the engine speed should drop as normal.

I've also noticed this difference when keeping the revs up...almost a if VW tried to eliminate the effect for performance driving. Anyone know of any documentation on this? owners manual, ect...
btw i could swear there is a slight improvement in the 08 vs the 07, but then i swear the drivetrain is lighter as the throttle response seems improved as well...slightly reduced rotating mass will allow the engine speed to respond quicker to throttle/computer inputs http://****************.com/smile/emthup.gif


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## Jefnes3 (Aug 17, 2001)

*Re: (RedRabidRabbit)*


_Quote, originally posted by *RedRabidRabbit* »_
You do know this car (and most modern cars with a manual trans) use zero fuel when coasting in gear...

Correct, but:
STOCK software
1. TB does not close ~abruptly (like a cable TB or like most drivers might expect) when you lift off throttle.
2. fuel does not shut off immediately upon pedal lift. (All cars do this)
combine the 2: the car 'drives' even though the driver has released the pedal.
you can log both these conditions yourself with vag-com.
-Jeff


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## 5_Cent (May 22, 2007)

*Re: (Jefnes3)*

to be honest I never noticed this, I read the thread last night and drive the car a 100 miles today. I can't say that I noticed any lurching or anything out of the ordinary. Maybe it is non existent or less noticeable on the 08's?


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## oceanjetta (Jun 12, 2002)

*Re: (5_Cent)*


_Quote, originally posted by *5_Cent* »_to be honest I never noticed this, I read the thread last night and drive the car a 100 miles today. I can't say that I noticed any lurching or anything out of the ordinary. Maybe it is non existent or less noticeable on the 08's? 

I agree, but it could be because I got the automatic.


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## Turb0Chipped (Mar 28, 2003)

*Re: (oceanjetta)*

it is an annoying feature....It is for emissions only (Engine management) it leaves the throttle cracked/injectors on when you snap off the accelerator to "clean up" hydrocarbon emissions. The 5 cylinder is considered an ultra low emission vehicle (check window sticker on new cars) and the feature is a part of that. I work on these all day and many new customers ask or complain about why the car does it. OBD1 2.0L and VR6 had a similar purpose with the little diaphragm on the throttle body (didn't let it snap closed as fast, for emissions reasons)...anyway I have a new rabbit and still dont like the feature










_Modified by Turb0Chipped at 11:24 PM 1-8-2008_


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## AdamVC (Jul 26, 2006)

*Re: Nonlinear Engine Braking? (spitpilot)*

C2 software is out!!
http://forums.vwvortex.com/zerothread?id=3623535


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## TXBDan (Dec 29, 2002)

*Re: (Turb0Chipped)*

Ah, this confirms my suspicion. To me seemed like a delay in the injectors turning off. 
http://****************.com/smile/emthup.gif


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## rabbit07 (Feb 22, 2007)

I have noticed the same thing with my car and I like it. It doesn't bother me.


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## mujjuman (Jul 29, 2004)

*Re: (rabbit07)*


_Quote, originally posted by *rabbit07* »_I have noticed the same thing with my car and I like it. It doesn't bother me.

ive noticed it and it doesnt bother me, but i dont like it. i dont care though ill just leave it. im not complaining


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## buckowheat (Mar 16, 2007)

bull****! No software has fixed this revhanging yet. No one has been able to find the coding for the revhanging yet. The top aftermarket software suppliers for this 2.5 engine have not yet addressed the issue. Read the posts. It improves in some cases, but is not eliminated. Either live with it or without it. A damn shame if you ask me.


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## artistict (Jun 10, 2004)

*Re: Nonlinear Engine Braking? (spitpilot)*

I have seen this post a thousand time already come on guys that is just the way this car is you just have to deal with it or get another car.


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## 5_Cent (May 22, 2007)

*Re: Nonlinear Engine Braking? (artistict)*


_Quote, originally posted by *artistict* »_I have seen this post a thousand time already come on guys that is just the way this car is you just have to deal with it or get another car.









your wrong, we dont have to deal with. 
why do you think GIAC, C2 and other tuners are working hard to eliminate it? because we DON'T have to deal with it.


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## mujjuman (Jul 29, 2004)

*Re: (mujjuman)*

the Civic's have the same problem. i think its a new car problem


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## RINGSROC (Apr 2, 2007)

*Re: (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_The problem is EASILY solved with software.
(delayed/slow throttle closing upon quick release of pedal)
I sorted this on the manual trans cars.

-Jeffrey Atwood C2


Would someone with this software confirm for us. This could be good!


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## RINGSROC (Apr 2, 2007)

*Re: (07JettaMK5)*

Anyone have this yet?


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## spitpilot (Feb 14, 2000)

*Re: (07JettaMK5)*

Wanna bet the first time vW gets sued because someone has an accident who's not familar with how these @!#@!% cars behave..we'll have a TSB and a fix...Every other car I've ever had (stick shift all of 'em) gave dramatic engine braking when I let off the gas...now suppose someone anticipates this and doesn't brake as fast or as hard and hits some one...They get up on the stand and testify "I took my foot off the gas, expecting the car to slow..when it didn't I hit the brakes and it was too late"...Attny: Have you ever experienced this with any car you've driven B4?...NO! How many different cars have you driven with stick transmissions that all "engine braked" immediately upon lifting your foot off the throttle?..."30-50"...Remember Ford's lame attempt to move the horn to the turn signal stalk?....You wanna bet they dropped that after losing a few lawsuits?...VW should study history B4 the design their cars with stupid features like "engine braking control"! I've never heard of a car skidding because of engine braking...too hard pressure on the brakes yes..engine..no!










_Modified by spitpilot at 12:25 PM 2-10-2008_


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## spdfrek (Feb 28, 2002)

*Re: (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_i.e. the car will accelerate after lifting off pedal.

such a stupid design


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## mujjuman (Jul 29, 2004)

*Re: (spdfrek)*

i wish they would make cars like the good old days.


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## rangerbrown (Jul 12, 2007)

read my review, the c2 has taken all of the rev hang away


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## RINGSROC (Apr 2, 2007)

*Re: (rangerbrown)*

Link to your review??? http://****************.com/smile/emthup.gif


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## rangerbrown (Jul 12, 2007)

http://forums.vwvortex.com/zerothread?id=3679254


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