Downshifting and brake boosting q's....

[Sbeing1]

Alright first the downshifting,
What mph can i downshift manually from Drive to 2nd and 2nd to L??

Break boosting,
When i brake boost, after hitting about 13-15psi my car just starts moving forward. My boost is set at 25psi, i was hoping to get about 20psi launches. Are my brakes at fault? they dont stop that great.

 

[bnpimpn]

did you try pulling your e-brake up as well as mashing the brake pedal?

 

[Mirage1]

Safe downshifting should be more of a function of what RPMs you will be at if it downshifted. It could vary slightly depending on the gear ratios. Just run it up 6 or 7k, shift and see what RPM you are at in the next gear. Plus I'm almost positive the TCU will not allow you you downshift until it is at a safe RPM.

What RPM is the car moving at? It is either bad brakes, you have found where your torque converter stalls at, or both. This is the main reason to get a high-stall converter.

 

[Catbox_95]

What RPM is the car moving at? It is either bad brakes, you have found where your torque converter stalls at, or both. This is the main reason to get a high-stall converter.

Plus, the more you boost, the less effective your brakes will be. Your brakes work on a vacuum assist, where vacuum makes the pedal easier to push. When you boost, vacuum turns to boost and you have to press much, much harder on the pedal to achieve the same amount of braking force.

 

[Sbeing1]

did you try pulling your e-brake up as well as mashing the brake pedal?

i disconnected my ebrake drums so i cant do that.


and yes u can downshift to 1 from 80mph if you want. my friend did it in his eclipse... made a loud clunking sound and like total possible redline ever then it shifted itself into 2nd then 3rd automatically.

my abs light IS on, would that play a factor in my boosting?? maybe i just need to get some new brake fluid, they dont feel very powerful, the stopping is really crappy and i have brembo drilled rotors

 

[91Bomb]

and yes u can downshift to 1 from 80mph if you want. my friend did it in his eclipse... made a loud clunking sound and like total possible redline ever then it shifted itself into 2nd then 3rd automatically.

Your freind must be a friggin GENIUS

 

[Lee'sGSX]

Alright first the downshifting,
What mph can i downshift manually from Drive to 2nd and 2nd to L??

Break boosting,
When i brake boost, after hitting about 13-15psi my car just starts moving forward. My boost is set at 25psi, i was hoping to get about 20psi launches. Are my brakes at fault? they dont stop that great.

You are going to have to use the e-brake for good strong high boost launches. The front wheels won't be enough to hold the car.

 

[Sbeing1]

i could have swore that when u step on the brakes, half way down is front brakes and other half down is back. can someone tell me if this is tru? i know it is in 350zs but i dunno about our cars. if so, i wouldnt need the ebrake for launches

 

[asexton6969]

Front brakes have the most stopping power. The rear brakes are there just to say "o hey, want a hand?" Honestly its like a girl standing underneath a couch with one hand on it when two guys are on the ends. Shes just there, not doing much but atleast doing something. I cant remember what our brake ratio is but i believe its somewhere 60 or 70% in the front to only 30-40% in the rear. Meaning the front brakes account for 60-70% of your braking power. Etc. Etc. Shit it may be 75/25. The e-brake in your case would certainly help out considering it doesnt need vacuum like our normal brake system. Try re-engaging it and doing a brake boost. You should feel a difference.