Best way to kill power at launch
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Best way to kill power at launch Car is making 1150 tq and 800hp on a twin turbo setup. Not my car but a friends. The car is turned down on boost to about 800ish tq.
my question is what way do you change the tune when your not hooking at the track? No time for suspension changes or chassis stuff. Set a lower 2 step for less boost then kill timing for a moment?
the Holley has a setting to set boost control for X seconds I think after releasing the brake. issue though is car makes bunch off spring pressure. So can I kill the timing during that window on a different map?
my question is what way do you change the tune when your not hooking at the track? No time for suspension changes or chassis stuff. Set a lower 2 step for less boost then kill timing for a moment?
the Holley has a setting to set boost control for X seconds I think after releasing the brake. issue though is car makes bunch off spring pressure. So can I kill the timing during that window on a different map?
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Yeah this is automatic. Was thinking moment it left it would grab the stall and no real way to touch tune cause would be at stall rpm unless a temp. Table for that few moments after brake is released.
What ECU? Pulling timing over time from the TB release works really well. Boost ramp is a bit more lazy, but also works. Depends if it spins on teh initial hit, or slightly after. I tend to stick/plant pretty hard the first 10-20ft or so then spin after. If you spin initially, drop the 2-step RPM.
Bra careful pulling power and ramping it back in, it can be a fine line. If the car gets out too far, the chassis can “settle” so to speak and we lose the ability to really plant the tire. Seems backwards, but sometimes we need to get the car moving faster quicker to keep it on the tire.
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It’s going to be 1/8 mile. Th400 MVB. Drive by cable. Holley dominator ecu. Trans brake w/bump.
right now it’s in 16psi spring pressure and he was spinning pretty good last time at launch and the. It carries the spin of course.
so we can lower 2 step to have less boost to hook but if he spins 10-20’ out is what I’m unsure of. Once he’s launched I’m sure the car will flash to stall and go.
right now it’s in 16psi spring pressure and he was spinning pretty good last time at launch and the. It carries the spin of course.
so we can lower 2 step to have less boost to hook but if he spins 10-20’ out is what I’m unsure of. Once he’s launched I’m sure the car will flash to stall and go.
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The time based retard from launch is the easiest way to deal with it spinning after the "hit". I'd Ramp out 10* over 2-3 seconds. If that doesn't spin anymore then dial it back until it spins again and give yourself a little cushion. Or pull more. What ever is necessary. If you have less than ideal suspension you may have to pull 20*+ Thats fine...
The time based retard from launch is the easiest way to deal with it spinning after the "hit". I'd Ramp out 10* over 2-3 seconds. If that doesn't spin anymore then dial it back until it spins again and give yourself a little cushion. Or pull more. What ever is necessary. If you have less than ideal suspension you may have to pull 20*+ Thats fine...
May as well hang beater bombs weight bar off the back too!I agree with other posts since its on Holley its super easy to setup boost control and timing retard tables to meet whatever need he may have.
Gotta do what ya gotta do! Esp. if you don't have drag specific suspension capable of putting down big power. I happened to be in that boat with a pretty poor setup in the Rx-7. I was at 28-30* on the 2step and dropped down to 10* on the TB release for 2.2 seconds, then ramped it back in.Believe jack roberts and capizzi both have single digit timing on the TB release for a few seconds so they could launch at big RPM and boost and ramp the power in. Both in the 1.1x 60' range as well I believe. Then if their traction control kicks in, Capizzi said he is in the negative timing on the launch for a few seconds.
Gotta do what ya gotta do! Esp. if you don't have drag specific suspension capable of putting down big power. I happened to be in that boat with a pretty poor setup in the Rx-7. I was at 28-30* on the 2step and dropped down to 10* on the TB release for 2.2 seconds, then ramped it back in.Believe jack roberts and capizzi both have single digit timing on the TB release for a few seconds so they could launch at big RPM and boost and ramp the power in. Both in the 1.1x 60' range as well I believe. Then if their traction control kicks in, Capizzi said he is in the negative timing on the launch for a few seconds.
The SBE guys are probably trying to keep the load off until higher RPM as well as fighting traction. Did anyone ever beat the 7.1 pass?
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Gotta do what ya gotta do! Esp. if you don't have drag specific suspension capable of putting down big power. I happened to be in that boat with a pretty poor setup in the Rx-7. I was at 28-30* on the 2step and dropped down to 10* on the TB release for 2.2 seconds, then ramped it back in.Believe jack roberts and capizzi both have single digit timing on the TB release for a few seconds so they could launch at big RPM and boost and ramp the power in. Both in the 1.1x 60' range as well I believe. Then if their traction control kicks in, Capizzi said he is in the negative timing on the launch for a few seconds.
Is the cars speed sensor driveshaft speed, GPS speedo, front wheel speed? You could do by time, or if you have two speed inputs use that as a form of traction control for more than just the launch.
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I have speed sensor off driveshaft only. Was going use that for boost in future. Car has a tune for 28psi so it puts out plenty if wanted. For now we working on hooking and running on 16 since that’s the min. Afterwards I can start adding boost when cars moving.
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cars a small tire car right now with full suspension. The car itself has everything needed to make it hook. I’m just helping out with the computer part of things. Surprising to me how many people don’t want to learn how PC side of things work. Not too bad when start seeing your changes take effect. Obviously I’m still learning myself but the changes I’ve made so far has help the car a lot.
is it possible they are slacking on the suspension side for it to grip and go? Yes very much so but I wouldn’t be able to help them do that. They have around 1100tq to work with and they spin good. Lowest boost has power down further than that but the timing maps are the same so the tq is always high.