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Discussion Starter · #1 ·
pop the car into neutral or let he slow down in gear?

what do you think are pro's and cons of each? Ive heard/read a few things such as

-going into neutral at high speeds will hurt the tranny
-leaving it in gear will just keep the strain on your postins/rings/motor
-taking your foot off the gas at 6500rpms stops the fuel, so now you have a 6500rpm air pump
 

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Discussion Starter · #3 ·
I leave it in gear to save the brakes some...but this topic will be interesting to watch...
when Ive read that...the next post was...."brakes are cheap, engines arent"...lol yes I want to see people opinions.
 

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Push clutch in and then start pulsing the brakes. When I'm slow enough I'll apply just brakes.
 

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I toss it in neutral and get on the brakes when im slow enough i will toss it in 3rd to make the turnout.
 

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If you have a KB/Whipple/Eaton, or any roots/screw type supercharger, it's best to keep the RPM down while slowing but don't let the throttle body close all the way. You just made the blower hot as hell making a pass. It needs some air going though it to cool it. So, for example, after crossing the traps, throw it in neutral, apply the brakes with the left foot, and give it a little gas with the right foot. 2-2.5Krpm is plenty. This keeps the throttle body open so some fresh air is going through the blower and reduces the rpm.

If you have the ability to watch your IAT's, and just get off the gas at the end of the race, you can see they continue to climb for a while. It's the same thing that happens during just normal driving. Cruising along and IAT's will be say 100* (for example) if you get off the gas to slow down or stop, the IAT's will start to rise. The throttle body closes and the blower just starts recirculating a ton of air, heating it again and again. This is multiplied when drag racing. You're running the car even harder and then just "close the door" on cool air.

Mike at KB told me that if a blower locks up while drag racing, almost every time it's on the return road after the pass, not while actually going WOT.

I watch it happen all the time with my little 2.1 at 14-15psi. I'd say it gets worse the more boost and the more you're spinning the blower.
 

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Why pulse the breaks?
So I don't take the chance at warping them. It's a habit and I drive my F-150 the same way. Of course not at the drag strip but slowing down getting off the interstate.
 

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1965 SPF 427 Cobra, & 2022 BMW M850
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Into neutral and use the brakes or chute if you have one.

Decelerating hard while in gear can cause an oil starvation problem and then a bearing damage problem with a stock pan. The oil rushes forward away from the pickup because of deceleration, the engine is still at a relatively high engine speed using lots of oil and the load on the motor is now reversed to decelerate the car but there is no oil by the pickup.

A lot of after the fact engine failures that look like oil starvation were initiated while decelerating in gear and the oil is all sloshed up to the front of the pan away from the pickup. The light weight oils we use look a lot like water once they get to operating temperature.

If you want to get a sense of what is happening in your oil pan under acceleration and deceleration get a cereal bowl, fill it half full of water, have your passenger hold it in front of him, and stand on the loud pedal. Thats what's happening in the oil pan. Same thing on deceleration. Canton sells a boat load of accusumps to guys who are trying to protect against loss of oil while the car accelerates, brakes, turns and also starts.

Ed
 

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i am slow enough that i don't need to touch the brakes at the turnoff....hell i am already slow going through the traps
 

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Just push in the clutch and hit the brakes on and off, then when you get slow enough just down shift.
 

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I usually toss it in neutral and hit the brakes slowly....
 

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^Man I was telling my buddies about your car but I had no idea you've got that many passes on it! Gotta love forged internals.
 

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Since you have an auto ( th400 if I remember right ) leaving it in gear and letting off or throwing it in neutral will do about the same thing. Unless your trans was built with " engine braking " it will not matter either way. If you wanna save your brake get a chute. :D hehe

When I ordered my converter from Lenny at Ultimate I asked him that same questions and he said it didnt matter wither way.
 
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