1st Gear and Dynamic Traction Control

[racer_x]

Gents,

I've only had my 135i (6SP Manual) for a couple of days. It's completely stock and I was wondering....

How does the ECU "nerf" the engine when the car's in 1st gear?

It feels to me like the car is running little or no boost in 1st compared to all the other gears. Am I on the right track?

Sorry if my questions sound silly. This is my first BMWs and I am traveling for work so I don't have the car on hand to experiment.

Thanks in advance.

[dan_brooks]

In first gear, turbo cars always take longer to reach max boost as there's less load on the engine, thus less exhaust gas.

Is your traction control system cutting in at all?

[racer_x]

I've driven the car twice so far, and not for very long so I'm still getting used to it. It's my weekender.

To me it feels like the engine is down on power in 1st gear all the time.

In all gears other than 1st you feel the turbo spooling up and a surge of power once you get to 1500-2000 RPM. This does not happen in 1st, and there are no indications on the dash that the traction control is kicking in.

I normally shift from 1st to 2nd at around 3500-4000 RPM because of that lack of power delivery (perceived or otherwise). In 2nd gear, the car's a whole other story.

The pre-purchase inspection made no mention of any drivetrain issues or ECU error/warning codes.

I just assumed this is the car's attempt at self preservation.

[Simonnn]

I think understand what you're referring to.. my second gear seems to pull a lot stronger than first almost as if the boost is higher.

Passengers in my car have commented on this too!

[racer_x]

Originally Posted by Simonnn

I think understand what you're referring to.. my second gear seems to pull a lot stronger than first almost as if the boost is higher.

Passengers in my car have commented on this too!

Yep, same here.

When I get home tonight I will try turning the traction control off and see what difference that makes.

If I don't report back tomorrow, send the search and rescue party

I also found this old thread discussing the different traction control modes which is quite interesting: http://www.1addicts.com/forums/showthread.php?t=250656

TIM YOYO

[Smiley1175]

it's been a while since I've driven a standard 135i, but from memory the little traction control light should be blinking like mad when you nail it in first. Perhaps not at 1500-2000 rpm, but by 3500 and above it would.
I agree that in first gear it won't make as much boost but still enough to have traction control kick in.

[Simonnn]

Forgot to mention that my car is currently stock as well, I was actually wondering if a tune would change this behaviour. To me the power delivery of the stock car almost feels too smooth sometimes :P

[froop]

Originally Posted by Simonnn

Forgot to mention that my car is currently stock as well, I was actually wondering if a tune would change this behaviour. To me the power delivery of the stock car almost feels too smooth sometimes :P

It may but probably not to the extent that you guys are expecting. Most of the extra power will come from increasing the boost pressure which therefore will be felt more in the higher RPMs and/or in 2nd/3rd.

If anything, it might even increase the disparity that you're experiencing/feeling.

[Smiley1175]

Originally Posted by Simonnn

Forgot to mention that my car is currently stock as well, I was actually wondering if a tune would change this behaviour. To me the power delivery of the stock car almost feels too smooth sometimes :P

Easily fixed .. tune and meth and hang on!

Best bang for buck without a doubt.

Oh and did I mention I have a Procede forsale

[froop]

Originally Posted by Smiley1175

Easily fixed .. tune and meth and hang on!

Best bang for buck without a doubt.

Oh and did I mention I have a Procede forsale

And on that note I have an unused BNIB Vishnu Meth kit for sale!

[racer_x]

Originally Posted by froop

And on that note I have an unused BNIB Vishnu Meth kit for sale!

Who do you guys use for insurance?

[froop]

Originally Posted by racer_x

Who do you guys use for insurance?

NRMA for me. Cheapest quote I could find and they cover all drivers and all modifications (exterior, interior, performance etc). I had a look at the PDS and it didn't even specifically state that the modifications had to be legal. You don't even have to list your mods as long as the value of them is taken into account in the agreed value of the policy.

Even Just Car states that the mods have to be listed and legal.

[flinchy]

Originally Posted by froop

NRMA for me. Cheapest quote I could find and they cover all drivers and all modifications (exterior, interior, performance etc). I had a look at the PDS and it didn't even specifically state that the modifications had to be legal. You don't even have to list your mods as long as the value of them is taken into account in the agreed value of the policy.

Even Just Car states that the mods have to be listed and legal.

except they'll insure you with a carbon fiber hood (just not the value of it)

ED: and it always confuses me, you guys with 135i's... you turn traction control fully off and you still have the e-diff.. when *I* turn it fully off.. i get nothing but one tire fires.. DTC on = my e-diff on, brakes the spinning wheel.. not to mention.. damp grass + DTC = one wheel spinning it's tits off.

why did they do both cars totally differently?.. unless my rear brakes are simply THAT useless that they EFFECTIVELY do nothing. but burn up?

[racer_x]

I've been playing with the traction control over the weekend and i am still in one piece.

Car launches harder with everything off but i ran out of time and underpants to do more testing. I put DCT back on and left it at that.

Also the wet weather in Sydney yesterday did not help.

[DR-JEKL]

my 335i always had the dtc light flashing on the dash in 1st when stock, maybe even if you have a member who lives nearby who you can compare with or even better attend the advan dyno day whack it up on the dyno see what transpires and there will be quite a few guys there that day who could give you a demo of their cars (albeit i doubt many of us would still be stock!)

[sparoz]

Originally Posted by racer_x

I've been playing with the traction control over the weekend and i am still in one piece.

Car launches harder with everything off but i ran out of time and underpants to do more testing. I put DCT back on and left it at that.

Also the wet weather in Sydney yesterday did not help.

I assumed you meant DTC? Just be careful with the DTC mode. It just let you slide out, but it corrects itself very quickly. You need to hold your line in DTC mode. If you start to anticipate the counter steer you will just ended up on the wrong side of the road.

[Jeef Beef]

Originally Posted by racer_x

Gents,

I've only had my 135i (6SP Manual) for a couple of days. It's completely stock and I was wondering....

How does the ECU "nerf" the engine when the car's in 1st gear?

It feels to me like the car is running little or no boost in 1st compared to all the other gears. Am I on the right track?

Sorry if my questions sound silly. This is my first BMWs and I am traveling for work so I don't have the car on hand to experiment.

Thanks in advance.

No idea about stock but most tunes limit the boost in 1st gear, otherwise you won't be going anywhere.

[Dackelone]

The DTC will first apply the rear brake caliper of the spinning wheel. IF that does not stop the spinning wheel... DTC will then start to reduce engine power by way of ignition timing and e-gas(pedal).

[racer_x]

Originally Posted by sparoz

I assumed you meant DTC? Just be careful with the DTC mode. It just let you slide out, but it corrects itself very quickly. You need to hold your line in DTC mode. If you start to anticipate the counter steer you will just ended up on the wrong side of the road.

Sorry. I meant DTC... I have a mild case of dyslxeia!

And yes, I crapped myself a couple of times when it came on. So I decided that discretion was the better part of valour, turned DSC back on and left it at that.

[racer_x]

Originally Posted by DR-JEKL

my 335i always had the dtc light flashing on the dash in 1st when stock, maybe even if you have a member who lives nearby who you can compare with or even better attend the advan dyno day whack it up on the dyno see what transpires and there will be quite a few guys there that day who could give you a demo of their cars (albeit i doubt many of us would still be stock!)

Great idea. I'll be on the lookout for the next dyno day.

The car is telling me it needs a service in another 4300 kms so I might look into this again then.

[racer_x]

Originally Posted by Jeef Beef

No idea about stock but most tunes limit the boost in 1st gear, otherwise you won't be going anywhere.

That's what I thought. Given the amount of power at hand, and the fact it kicks in so low, you'd be going through rear tyres pretty quickly.

[DR-JEKL]

Originally Posted by racer_x

Great idea. I'll be on the lookout for the next dyno day.

The car is telling me it needs a service in another 4300 kms so I might look into this again then.

Its on Sat the 16th March.

Most guys recommend oil changes every 5k kays (instead of every 10-15k kays) with a high quality full synthetic. Most guys I have spoken to with FBO's run a mixture of 5W30, 0W40 or 0W30.