Brake Boosting
04-26-2011, 10:28 AM
#1
Wash Rinse Repeat
Thread Starter
Join Date: Feb 2006
Location: Michigan
Posts: 6,312
Brake Boosting
So a couple of my friends with turbocharged cars and I got into it about brake boosting... ever since they found out about it they always talk about it like some super awesome technique that got them more power and a quicker car (so on and so fourth)
well I argued with them but there was like three of them eagainst just me saying that it's a HUUUUUGE deal this brake boosting.... well the argument came up again when I corrected them on an automotive term and would like some input from you guys... this is what I told them so far
this is probably the only rebuttal I have gotten worth much
they never race from a stop so they are all hung up on their coveted technique... just wondering what you guys think
well I argued with them but there was like three of them eagainst just me saying that it's a HUUUUUGE deal this brake boosting.... well the argument came up again when I corrected them on an automotive term and would like some input from you guys... this is what I told them so far
as I said before, "brake" boosting makes no difference in power at all... the only thing it does i...s get you peak power at the start of the race... whether you make peak power at the beginning of the race or 2 seconds into the race if the other car is faster it's going to pass you
you guys were arguing last time ...like brake boosting is some magical technique that allows you to beat higher horsepower cars, when in reality all it's doing is "maybe" giving you a slight head start so you can let off early and claim a win before the higher peak horsepower car passes you.... you guys race from a roll so it doesn't mean much to me but your idea of brake boosting is rather skewed... if you start a race in second gear and you are @ 4K RPM in a N/A car that makes 550WHP @ 4,000RPM against a brake boosting turbocharged car that makes 400RWHP @ 4,000RPM the N/A car is going to win regardless of brake boosting... even if the N/A car didn't make peak power until higher in the RPM range you only will have a couple second lead before the faster car passes you
in closing, if your idea of winning is buying a couple second lead before the clearly faster car comes up on you, then brake boosting is the technique for you.
if the turbocharged car is faster then brake boosting is not needed, people use brake boosting as a crutch against faster cars... it's been this way since before you started racing... that is my point
the only way you are brake boosting from a stop is with a drive line that can actually handle it... which nobody on your side of the state seems to care for when building their cars
100MPH is more than enough time for a 100WHP difference at the same given weight to catch up to the "magical brake boost"... even 50WHP would be enough... if not less
the only way you are brake boosting from a stop is with a drive line that can actually handle it... which nobody on your side of the state seems to care for when building their cars
100MPH is more than enough time for a 100WHP difference at the same given weight to catch up to the "magical brake boost"... even 50WHP would be enough... if not less
if you agree to go from 40-140, and i brake boost and car with more hp cant, and i win, then my winning is "skewed?"
they never race from a stop so they are all hung up on their coveted technique... just wondering what you guys think
Last edited by Morbid Intentions; 04-26-2011 at 10:33 AM.
04-26-2011, 11:05 AM
#2
Mish-ogynist
Join Date: Nov 2007
Location: Helena, MT
Posts: 3,780
i decided im never roll racing anyone again because it's stupid and designed for cars that aren't built right... so.... yarghh.. okay i probably will anyway..
and i dunno anything about brake boosting, except that you sound correct and whoever you are talking to is wrong.
and i dunno anything about brake boosting, except that you sound correct and whoever you are talking to is wrong.
04-26-2011, 03:11 PM
#4
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
Yeah, like you said, all brake boosting does is get the turbo spooling so you're making max power.
As far as roll vs dig racing, it really depends. Cars that are set up for drag racing 9/10 times are better from a dig, whereas cars that are set up for road racing 9/10 times are better from a roll. It's just a matter of where the power needs to be for it's intended purpose. In a drag car where you're leaving from a dead stop, how the car runs from a dig is critical since that's how the car leaves the lights(and has a HUGE impact on ET). A road racing car isn't leaving from a stop, it's powering out of a turn already rolling somewhere in the mid range, so how it performs from a roll(or from transition) is critical.
But most people get hung up on drag racing, then try to race from a roll, which is lame.
But arguably, if someone is roll racing a turbocharged engine and has to brake boost, then it's set up incorrectly(at least for roll racing). Turbo setups for drag racing are usually larger for more flow on the top end, but slower to respond, since you spool up when you stage(typically a result of a larger turbine side setup to prevent the exhaust restriction from strangling top end exhaust flow). Turbos on cars setup for road racing lose top end power by running "smaller" turbos(more turbine restriction, smaller compressor wheel), but they spool almost instantly so the response is just plain retarded. Look at WRC turbo 4 bangers, scrawny little turbos, the top end hp on the engine is only like 320hp(they also have flow limiters to limit power), but peak torque is over 400lbs ft and they have flat torque and instant response from like 1,500-5,000rpm. Even coming off a turn at like 2,500rpm and barely cracking the throttle, the turbo is already spooling.
It's really all in the setup. But if you have a setup that requires brake boosting to run effectively from a roll, then you shouldn't be running from a roll. Also if your ET is mostly dependent on your 60', then you shouldn't be running from a roll either. Conversely in a car like mine where the power and suspension are set up for road racing and not drag racing, running from a dig usually isn't in my favor.
As far as roll vs dig racing, it really depends. Cars that are set up for drag racing 9/10 times are better from a dig, whereas cars that are set up for road racing 9/10 times are better from a roll. It's just a matter of where the power needs to be for it's intended purpose. In a drag car where you're leaving from a dead stop, how the car runs from a dig is critical since that's how the car leaves the lights(and has a HUGE impact on ET). A road racing car isn't leaving from a stop, it's powering out of a turn already rolling somewhere in the mid range, so how it performs from a roll(or from transition) is critical.
But most people get hung up on drag racing, then try to race from a roll, which is lame.
But arguably, if someone is roll racing a turbocharged engine and has to brake boost, then it's set up incorrectly(at least for roll racing). Turbo setups for drag racing are usually larger for more flow on the top end, but slower to respond, since you spool up when you stage(typically a result of a larger turbine side setup to prevent the exhaust restriction from strangling top end exhaust flow). Turbos on cars setup for road racing lose top end power by running "smaller" turbos(more turbine restriction, smaller compressor wheel), but they spool almost instantly so the response is just plain retarded. Look at WRC turbo 4 bangers, scrawny little turbos, the top end hp on the engine is only like 320hp(they also have flow limiters to limit power), but peak torque is over 400lbs ft and they have flat torque and instant response from like 1,500-5,000rpm. Even coming off a turn at like 2,500rpm and barely cracking the throttle, the turbo is already spooling.
It's really all in the setup. But if you have a setup that requires brake boosting to run effectively from a roll, then you shouldn't be running from a roll. Also if your ET is mostly dependent on your 60', then you shouldn't be running from a roll either. Conversely in a car like mine where the power and suspension are set up for road racing and not drag racing, running from a dig usually isn't in my favor.
04-26-2011, 03:25 PM
#5
Brake boosting kills lag time in the turbo. Not faster cars with more HP. Your turbo budies are dumb. Brake boosting works with any size turbo but I'd have to agree that it'll work better with the bigger turbos that suffer more lag than the smaller turbos.
Last edited by bluebeastsrt; 04-27-2011 at 11:17 PM.
04-26-2011, 03:42 PM
#6
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Join Date: Apr 2007
Location: California
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Some of the newer turbos we're seeing in factory setups are essentially 0 lag turbos. Things like the new BMW 335 and the 997 Porsche tt's, the tiny variable geometry turbo stuff. But they're usually giving up a chunk of top end power to get the immediate response. They work exceptionally well for what they were intended, which was not maximum top end power for drag racing.
04-26-2011, 06:48 PM
#7
5th Gear Member
Join Date: Sep 2006
Location: VA
Posts: 2,374
Weight in question has a lot to do with it as it seems like it's a 4cyl vs V8 thing here instead of a straight set XXX peak power vs XXX peak power. ~2 seconds of lag is a lot to make up for if the cars are a pretty evenly matched.
All it takes is a WOT box to leave off the line with a lot of boost.
All it takes is a WOT box to leave off the line with a lot of boost.
04-26-2011, 08:16 PM
#9
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04-26-2011, 09:22 PM
#10
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Join Date: Aug 2009
Location: Michigan
Posts: 142
Lets race from a roll and I can show you the difference.
First race I wont brake boost, three honks, beep, beep, beep. GTO is in good power and pulls right away. I fall way back in das fuhrer and wait about 2-3 seconds for tiny 4 cylinder to spool my fairly large turbocharger, gradually I catch up and blow by. :P
Second race Ill brake boost, three honks, beep, beep, beep. No waiting for power this time, the heavier GTO falls behind in a hurry
Same thing goes for a dig, you are pretty much saying staging in a turbocharged vehicle does nothing. Bluebeastsrt, you would be a high 13 second car if you took off like you were at a traffic light wouldnt you.
First race I wont brake boost, three honks, beep, beep, beep. GTO is in good power and pulls right away. I fall way back in das fuhrer and wait about 2-3 seconds for tiny 4 cylinder to spool my fairly large turbocharger, gradually I catch up and blow by. :P
Second race Ill brake boost, three honks, beep, beep, beep. No waiting for power this time, the heavier GTO falls behind in a hurry
Same thing goes for a dig, you are pretty much saying staging in a turbocharged vehicle does nothing. Bluebeastsrt, you would be a high 13 second car if you took off like you were at a traffic light wouldnt you.
