Brake Boosting??

[Integra21]

hey, this might be a stupid question but Im curious what exactly brake boosting is.

You always read about a guy racing a supra or evo,..etc.. and saying "well he brake boosted on me and got me by a car...."

is this simply applying the brakes while pushing the gas until the turbo spools up and letting off the brake, essentially "launching" the car from a roll.

does this have any negative effects on the car?

<----- TuRbO n00b :sadwave:

[Billy]

Yeah, that's basically it. And aside from not being the best for the brakes it isn't really bad for the car.

It lets you add more load so that you can leave under some degree of boost. Different cars and different setups will make different boost when brake boosting. You might see 25% of your max boost when brake boosting, you might see 50% or anything really...it all depends, you'll just have to try it and see.

Realistically if you have your car in the right gear you should spool fast enough that brake boosting really won't help all that much unless you are in a very close race.

[PLATANO]

I've Tried It In My Car Really Does'nt Make That Big Of A Diff. Like Billy Said Depends On Ur Setup

[InsaneCivicCoupe]

My brakes suck so I cant brake boost :(

[TNathe]

i imagine it would work better as turbo size increased since there is that much more lag with huge ass turbos

[fathead]

My brakes suck so I cant brake boost :(


your car s also broken so brake boosting isnt much of an option now..... plus you 2 step cha cha cha!!! :lol: :hehe:

[InsaneCivicCoupe]

no more 2 step unless its from a dig... ;)

[flubyux2]

brake boosting can kill stock turbos... stock twins on MKIV's die all the time due to abuse and brake boosting... both my friends have twins that suffer from leaky oil seals now. im not saying it will kill YOUR turbo, but its not exactly everday wear and tear ;)

[TIM TIM TIM]

how would it be bad for a turbo? I dont see how holding the brakes affects a turbo in any way, I know it hits boost but what is the differance in hitting the brakes or pulling a jet ski? I doubt increased load is going to hurt a turbo, It will just spool up

[flubyux2]

probably because everyone w/ a BPU car runs at least 16psi. so spooling stock turbos harder, more often up to higher pressure levels does increase the wear and stresses that they are forced to endure. especially if you are running sequential still, brake boosting under 3800 is gonna work that 1st turbo pretty hard. then when the crossover happens, that 2nd turbo is gonna go from 0rpm to 180,000rpm in under a second. its a good way to annihilate some stuffs. both myfriends brake boost, and they now have turbos that are starting to blow oil... one has 30k on the stock twins.

[Jordan Y.]

That just sounds like a problem with the twin turbo systems themselves. I have friends with mkiv tt's and 3rd gen rx-7's and I have to say that the twin turbo setups are pretty lame. In the mkiv, all the twin turbo setup does is cause funky inconsistant boost as you accelerate from low rpm with boost dropping off and then picking back up as the second turbo kicks in. The setup doesn't spool any faster than an appropriately sized single would and adds a lot more complexity and trouble. Even then it's worlds better than the FD tt setup- god, the issues my buddy has had with vacuum leaks and solenoids going bad. There's a huge spaghetti mess of vacuum hoses and solenoids and one of them will go wrong and cause big problems with spiking boost, boost dropping off, hesitation and running too rich, it's terrible.

On any proper turbo setup, it shouldn't be any different than normal spooling and boosting. The turbo really doesn't care how it gets its exhaust energy, it just spools when it does.

[flubyux2]

sorry J-dawg... if youve been in a BPU MKIV, they feel real damn fast. the twice-turbo setup isnt linear at all except at stock boost levels or unless they have a pre-spooler. spooling up to 12, drop to 8 and snapping the 2nd turbo to 18psi is VIOLET. its enough to break the tires loose in 2nd and 3rd gear during the shift. w/ a pre-spooler, you can make it more linear by getting the first turbo up to 18psi before the change-over, that way its not such a violent experience when the 2nd turbo comes online. the only problem w/ brake-boosting is just when you subject STOCK turbos to excessive load and heat as well as higher shaft speeds. it doesnt care How it gets the exhaust energy, but subjecting it to TOO much energy can kill it. raising the boost creates more heat and more wear. stock turbos arent bulletproof and brake boosting and/or higher than stock boost levels cause accelerated wear. instead of crapping out at 120k, they could wear 3x as fast, and crap out at 40k.

[722ish]

probably because everyone w/ a BPU car runs at least 16psi. so spooling stock turbos harder, more often up to higher pressure levels does increase the wear and stresses that they are forced to endure. especially if you are running sequential still, brake boosting under 3800 is gonna work that 1st turbo pretty hard. then when the crossover happens, that 2nd turbo is gonna go from 0rpm to 180,000rpm in under a second. its a good way to annihilate some stuffs. both myfriends brake boost, and they now have turbos that are starting to blow oil... one has 30k on the stock twins.

30k mile stock twins checking in ;) blown to shit.. there is actually a big writeup on Supraforums, in MKIV tech chris, remind me to show ya, on how the mkiv's kill stock twins. Besides, that sequential shit sucks. i dont like it whatsoever, so i went true twin - however, as youve said, the car will break the tires loose on the switchover/shift... either way, stock twins on an mkiv arent so much the deal always.. i would assume that the load generated by brake boosting can create a pressure ratio that is likely to surge.. i can hit 18 psi without taking my foot of the brakes!

[Jordan Y.]

Yeah, I've driven a BPU car. It was an auto, plant your foot at 30 mph or so on a suitable road and it takes off with that awesome Supra growl, then a few seconds later you look at the speedo and slam on the brakes because you are doing more than 100 on Dale Mabry... they're sweet cars, I'm not debating that. But the sequential system still sucks :p. If it were my car I'd go true twin just to get rid of that weird feeling of up and down acceleration/boost at lower rpm.

As far as surge goes, it depends on what RPM you're holding at. If you're brake boosting in the meat of your powerband just for that small advantage, I don't see it, but stock turbos spool really quickly with mods, on the DSM I make boost by 1500 rpm in 4th. That's probably surge territory.

[722ish]

Yeah, I've driven a BPU car. It was an auto, plant your foot at 30 mph or so on a suitable road and it takes off with that awesome Supra growl, then a few seconds later you look at the speedo and slam on the brakes because you are doing more than 100 on Dale Mabry... they're sweet cars, I'm not debating that. But the sequential system still sucks :p. If it were my car I'd go true twin just to get rid of that weird feeling of up and down acceleration/boost at lower rpm.

As far as surge goes, it depends on what RPM you're holding at. If you're brake boosting in the meat of your powerband just for that small advantage, I don't see it, but stock turbos spool really quickly with mods, on the DSM I make boost by 1500 rpm in 4th. That's probably surge territory.

See, i would think something bigger along the lines of an SP63 or so on an MKIV would surge. Its a very common turbo, and spools super fast, but i could see it spooling pre 4k rpm brake boosting, and the pressure ratios may go all wacko, on a stock turbo/turbos, i dont see it happening because they really typically dont move much air.... but im not sure...

[Cronic]

Yes brake boosting is as described - however I BB on stock turbos and hit full boost in seconds. Even on the 57 trim I hit 18psi in a matter of a couple seconds. Brake boosting is something that I use, and will use forever, because of the instant power you recieve from a roll. Once you get good at it you can time things as you need.

[Cronic]

Chris, you shouldn't even be in this thread, :lol: - I cannot believe you wont fix your brake system. You're using that two-step way too much and getting almost no gain from it. the 3-6psi you get from that is garbage compared to the 18psi start you can get from brake boosting.

[flubyux2]

yo jeff, which chris are you talkin aboot?

btw, if you want to keep brake boosting, you should check out your brake system. each and everytime we went from a roll, your car would creep out while i was holding 40mph, so on the 3rd honk, you were always half of a car infront of me while i was doing my rolling "two-step". :dunno: of course youd get the jump and id be spinning at 40mph and get ready to ride right on past you and then hit the 118mph speed cut. too bad your car went down cuz i fixed the speed cut the next weekend, ready for the rematch :naughty: guess youll have to run kelly when you car is done

[LT1turboTA]

I have a 3200 stall ,so when I brake boost I can build full boost.
Stalls rock!!!

[Sneakin Deacon]

you have a 3200 stall, so you can boost off the line.

a stall has nothing to do with you building boost from a roll. its dependant on how much brake and load.