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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Brake Boosting a manual launch? Possible?



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      11-10-2007, 04:18 PM   #1
PresaMat
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Brake Boosting a manual launch? Possible?

This is my first turbo car so I might be talking out my ass. I was wondering if it were possible to break boost a manual on launch kinda like an auto (to get the turbos going)?

My idea... get the car in first gear, roll to the line... hold the brake and the gas like and auto... off the break and go. I would think it would spool the turbos and be softer on the clutch but I dunno. What are yalls thoughts?

Mat

EDIT: Just to clarify... i was playing a little... if you put it in first left out the clutch (completely) while giving a bit of gas like normal... then press the brake and the gas (hold up the rpms so it doesnt stall). It seemed to work the only time i did it... but i dont know.
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Last edited by PresaMat; 11-10-2007 at 05:27 PM..
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      11-10-2007, 04:21 PM   #2
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How would you hold the clutch?
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      11-10-2007, 04:27 PM   #3
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i think he is talking about using the right foot to hold both brake and gas like in heel toe, but i don't think its a good idea because it would require you to hold the clutch half way in and result in a burned clutch.
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      11-10-2007, 04:29 PM   #4
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Unless he has three feet
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      11-10-2007, 04:30 PM   #5
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Unless he has three feet
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      11-10-2007, 04:43 PM   #6
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Load it up against the e-brake until the back squats a shade. Be sure to release the clutch quick to avoid burning it & feed the power (no stomp).
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      11-10-2007, 05:28 PM   #7
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What about if you are doing a slow roll in first... press the brake and the gas... it stops but doesnt stall... Toughts?
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      11-10-2007, 05:31 PM   #8
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e-brake is a method for this. But you do have to feather the throttle or you will burn through the clutch quick, fast and in a hurry. With practice you can get the e-brake down and the car moving forward very fast and without much slippage
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      11-10-2007, 06:05 PM   #9
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^^^^

I completely agree with what he said(jam0321).


Owner of 15 turbocars speaking(yours truly). You can do the Ebrake or the step launch control. E brake is in my opinion the best way, I do not like the step launch control.

I just used the Ebrakes less tha n a hour ago to propel my 95 Eclipse GSX to a 11.639@119.33 mph cutting a 1.684 60'(twice) on stock 205/55/16" tires (Kumo all season)with stock 16x6" stock rims at the AWD -SRT-4 shoout we had in Tucson, SIR today.

Definately you can't go wrong with the Ebrake technique. I had Step launch control on my Evos and I hated it, I never used it. That silly vroom vroom vrom vrom sound followed by a bog down it really never fly to me. You get excited watching the boost gauge building some partial boost with the launch control to just later on get yourself bogging down the car as soon as you release the clutch.

If you do the technique of the Ebrake just like jam0321 explained you will master the 60' times, it just needs some practice and he is right, if you do it properly you will not stress the clutch much at all.

You can practice in a ramp, like a garage ramp. Think about holding your car steady in a ramp with just the clutch and the gas. The car wants to move forward but the clutch pedal is holding the car from moving any. Apply that principle and hold the car stricly with the Ebrake.

The main two advantages is that you can let off the clutch pedal half way(saves you time), secondly the car is already in the optimum torque range, the engine /car is physically pushing forward but is being retained by the e-brake. Think of when you hold someone by the hand when they are pulling in the opposite direction, you let it go and they will instantly move with rapid movement.

You should feel that the car wants to move forward but the e-brake is holding it. When you see the amber changing to green then give some gas and rapidly release the clutch. You will then propel yourself forward very fast, the bogdown will not occur ever if you give enough gas, mostlikely the tires will spin.

As far is launching my auto 335i, I am the most roockie, this is my first auto.

Last edited by Evo8MRto335I; 11-10-2007 at 06:22 PM..
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      11-10-2007, 06:12 PM   #10
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Quote:
Originally Posted by Evo8MRto335I View Post
^^^^

I completely agree with what he said(jam0321).


Owner of 15 turbocars speaking(yours truly). You can do the Ebrake or the step launch control. E brake is in my opinion the best way, I do not like the step launch control.

I just used the Ebrakes less tha n a hour ago to propel my 95 Eclipse GSX to a 11.639@119.33 mph cutting a 1.684 60'(twice) on stock 205/55/16" tires (Kumo all season)with stock 16x6" stock rims at the AWD -SRT-4 shoout we had in Tucson, SIR today.

Definately you can't go wrong with the Ebrake technique. I had Step launch control on my Evos and I hated it, I never used it. If you do the technique of the Ebrake just like jam0321 explained you will master the 60' times, it just needs some practice and he is right, if you do it properly you will not stress the clutch much at all.

As far is launching my auto 335i, I am the most roockie, this is my first auto.
Interesting. Thanks for all the replies. Another question to yall turbo people what do you think about "anti-lag" launch control?
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      11-10-2007, 06:41 PM   #11
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Quote:
Originally Posted by PresaMat View Post
Interesting. Thanks for all the replies. Another question to yall turbo people what do you think about "anti-lag" launch control?
From my experience on turbo cars, the N54 is a gifted engine. There is virtually no turbolag and the max torque is almost at idle.

Anyone with decent knowledge of turbos on this forum will tell you that the stock N54 engine is already a winner, the excellent torque and fast spool up makes this car friendly when it comes to launching it(except the traction).

Basicly you don't need to rev it much(unlike other turbo cars), the problem is that it puts too much torque to the ground too soon. Start with a decent set of gripier tires. Some people are cutting 1.7 and 1.6 with wider tires.
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