Power Brakes / Vacuum Pump For Staging
07-12-2018, 08:43 AM
#1
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Power Brakes / Vacuum Pump For Staging Has anyone tried running an electric vacuum pump to get additional braking power while staging? My can has very little vacuum (~8") at 3000+ RPM, at which point the rear tires creep (stock LS brakes, ABS delete with max bias to rear wheels, stainless braided hoses, HAWK pads, no air in system, really good pedal feel).
I'm sure the electric pumps are sized for street driving - I'm wondering if the moderately-priced units (like the popular Summit pump) have enough capacity for sustained vacuum loads while staging. Any experience would be appreciated.
I'm sure the electric pumps are sized for street driving - I'm wondering if the moderately-priced units (like the popular Summit pump) have enough capacity for sustained vacuum loads while staging. Any experience would be appreciated.
07-12-2018, 01:51 PM
#2
Having max bias to the smaller rear brakes can't be helping braking power.
One thing when you are staging - be sure to go in at idle. A lot of guys rev up the motor a little as their going in, which eliminates all vacuum. For the ultimate in holding power, get fully staged, then throw a quick rev in neutral while pressing the brake down hard. That will give you maximum braking vacuum, but does nothing for reaction times!
An old buddy used to have a Hydraboost system on his Syclone. It worked pretty well.
Al
One thing when you are staging - be sure to go in at idle. A lot of guys rev up the motor a little as their going in, which eliminates all vacuum. For the ultimate in holding power, get fully staged, then throw a quick rev in neutral while pressing the brake down hard. That will give you maximum braking vacuum, but does nothing for reaction times!
An old buddy used to have a Hydraboost system on his Syclone. It worked pretty well.
Al
07-12-2018, 02:00 PM
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The whole point in bringing the engine RPM closer to the stall speed is to help reaction time. Our car will run quicker leaving at an idle, but you can not bottom bulb it for reaction time.
And FYI, we did a lot of testing and talked with Steve at SMJ (who makes the ABS delete kit). He recommended turning the proportioning valve in, to put more on the rear brakes and it did work.
And FYI, we did a lot of testing and talked with Steve at SMJ (who makes the ABS delete kit). He recommended turning the proportioning valve in, to put more on the rear brakes and it did work.
07-13-2018, 06:54 AM
#4
I've not tried this as I just started to deep stage instead, but you could try to get a vacuum canister and plumb that in before the booster. I'm pretty sure that would be much cheaper as well .
07-14-2018, 04:33 PM
#7
Vacuum assist most certainly does change the effective braking power, since these are power brakes. It would take superhuman strength and both feet pressing on the pedal to match the braking power you get with vacuum assist and one toe on the pedal.
Al
Al
Last edited by T6Rocket; 07-15-2018 at 07:38 AM.
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07-15-2018, 03:15 PM
#8
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Brake Boost
Vacuum = power assist
Manual Vs. power the rod goes in a different hole on the pedal to assist with leverage (power) to the master cylinder.
I get my best launch off idle or just over it (foot brakeing)
If you're launching at higher RPM's than your brakes can/will hold....maybe its time for a trans-brake ?
Vacuum = power assist
Manual Vs. power the rod goes in a different hole on the pedal to assist with leverage (power) to the master cylinder.
I get my best launch off idle or just over it (foot brakeing)
If you're launching at higher RPM's than your brakes can/will hold....maybe its time for a trans-brake ?
Last edited by Doug G; 07-15-2018 at 03:24 PM.
07-30-2018, 03:00 PM
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Vacuum Pump OK - did my own testing. Hooked up my pickup truck engine as a vacuum source to my F-Body brake booster; could hold the car to 3300RPM with no issue at all, with no other brake changes. So, vacuum definitely helped a bunch.
I bought a rotary style electric vacuum pump from Leed Brakes, because it seemed that their pump pulled the vacuum down faster. It is also quieter, but that didn't matter to me. Took it to the track and holding the car to stage was drastically easier. 3,000 RPM every run, which is what I was looking for. Total solution. A vacuum canister just buys you a little time. It would be hard to put a canister on with enough volume for the staging process, especially if you're giving a long handicap.
FYI - we run a footbrake, non-electronics class, so a trans brake is not an option.
The Leed Brakes pump is a quality piece, although more expensive than the typical Comp Cams or Summit piece. It draws about 6A and you can see a small voltage drop (less than 1/2V) on the Log file. If you'r running an alternator, it won't cause a problem. I did have an issue with the relay and the pump initially, but Leed made it right, so I have no complaints.
I bought a rotary style electric vacuum pump from Leed Brakes, because it seemed that their pump pulled the vacuum down faster. It is also quieter, but that didn't matter to me. Took it to the track and holding the car to stage was drastically easier. 3,000 RPM every run, which is what I was looking for. Total solution. A vacuum canister just buys you a little time. It would be hard to put a canister on with enough volume for the staging process, especially if you're giving a long handicap.
FYI - we run a footbrake, non-electronics class, so a trans brake is not an option.
The Leed Brakes pump is a quality piece, although more expensive than the typical Comp Cams or Summit piece. It draws about 6A and you can see a small voltage drop (less than 1/2V) on the Log file. If you'r running an alternator, it won't cause a problem. I did have an issue with the relay and the pump initially, but Leed made it right, so I have no complaints.
Last edited by MikeSp; 07-30-2018 at 03:17 PM. Reason: Added more info on vacuum pump
09-03-2018, 02:00 PM
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Had a private request for plumbing details - here is a picture. I hooked up one line to the original manifold vacuum hose (left side of picture) and another to the vacuum pump (right side); has two opposing brake booster check valves and a tee. So, if the vacuum pump fails, the manifold vacuum takes over.
This might be overkill, but I didn't want an expected hard pedal at 118 mph. If you do this, make sure you test your plumbing carefully to be 100% certain you have the check valves in the right direction. Disconnect the vacuum pump and make sure you have power brakes with the engine running, then in key-on, engine off, make sure the pump gives you a proper pedal.
We raced with this pump for a few weekends now and I really like it. It makes staging against the converter (2500+) so much easier.
This might be overkill, but I didn't want an expected hard pedal at 118 mph. If you do this, make sure you test your plumbing carefully to be 100% certain you have the check valves in the right direction. Disconnect the vacuum pump and make sure you have power brakes with the engine running, then in key-on, engine off, make sure the pump gives you a proper pedal.
We raced with this pump for a few weekends now and I really like it. It makes staging against the converter (2500+) so much easier.
09-03-2018, 10:12 PM
#14
I used a 2010 Camaro lfx v6 electric vacuum pump to help the booster with a micro controller but, for drag, you could hook up a switch easy:
Initial test:
Full test (waited until pump shuts off after 4 minutes):
if you need brake booster vacuum...
-Don
Initial test:
Full test (waited until pump shuts off after 4 minutes):
if you need brake booster vacuum...
-Don