Jeff
Nitro Member
- Joined
- Aug 18, 2006
- Messages
- 1,203
- Age
- 61
- Location
- Magnolia, Texas
While I don't agree with any of that is being advanced because it totally ruins the sport's interest for me the lowly crew chief I'll chime in a bit to give more life to what I do and what those I race against say they do.
The blower combinations leave the starting line with WAY more torque and HP than the tires/track can handle. So they have zoomies which kill low end torque (and greatly improve the top end breathing) and, as Alan points out, huge reductions in timing to keep the piston from being pushed down from its most power inducing point in rotation (generically you want maximum cylinder pressure 15-17 degrees after top dead center to make maximum power but it depends on the duration of your power pulse .... and nitrous motors definitely have the shortest power pulse of any combination so they are hyper sensitive to timing changes ... a 1/2 degree timing change has me so puckered I can barely walk up to the line to help stage the car). Even at the sportsman level 30% or more of the teams i compete against are making timing changes within 10 minutes of staging the car to make sure they go down as intended. If they couldn't manipulate timing they wouldn't be able to run the back half of the track like they do (because they would have less HP throughout the run).
The assertion that within TD/TS that the cars can run the number every time and its just a driver's race is beyond ridiculous. If you see a car running in the fastest 1/3 of the field and compensating for top end driving ET impacts you can tell the car is consistently running the number you should either follow that team into a casino or realize there are some people working their butt off to make that happen. It is challenging beyond belief.
90%+ of my runs start at 26.5 degree BTDC timing and end at 4 degrees BTDC. That said the vast majority of that timing change is because the more nitrous you turn on the faster the flame front of the combustion moves and the more you have to slow the timing to keep the power pulse where you want it. So that kind of timing change is to make more power, not manage for the track. Now, I am not in the norm on pulling timing to manage for the track. I don't try to kill (run super quick) the 60ft so it is rare for me to pull any more than 1 degree (roughly 200hp) to mange for track conditions. When I'm trying to make a fast run my three stages come on (relative to the car first trying to move forward) at 0.00, then 0.35, then 0.70 second out .... so by 3/4 a second out I'm fully uncorked in terms of power. Generally any power management happens between 0.20 and 1.5 out .... and I'm mainly looking at the G meter to decide what I need to do .... I want the G meter to look like a tabletop for as long as possible. I try to use timing as a bandaid, as I learn what the chassis wants most of my tuning is in the torque converter, tire pressure, and what we call a wheelie bar (its a tire set device to me, I use it to manage tire speed ... intentional over rotation). When trying to keep G's high and flat and having multiple large stages of nitrous come on, you are make lots of very little timing changes .... my power management timing map is 15 lines long .... meaning at an extreme i will make up to 15 power management changes between .2 and 1.5 or down track to deal with bumps (pulling more like 1000 hp to keep the car from becoming a Cessna 172). It's fun, and no you don't have to do that to be reasonably predicable and run relatively slow, but the tools that have existed for roughly the last 7 years are very valuable to someone who likes to walk a fairly fine line doing this.
Turn TD/TS into stock/superstock and I'll either move to super stock or another sport. Now do most of the teams approach the class like I do ... hell no, you don't have to and it will drive you crazy .... but its what makes it enjoyable to me.
The blower combinations leave the starting line with WAY more torque and HP than the tires/track can handle. So they have zoomies which kill low end torque (and greatly improve the top end breathing) and, as Alan points out, huge reductions in timing to keep the piston from being pushed down from its most power inducing point in rotation (generically you want maximum cylinder pressure 15-17 degrees after top dead center to make maximum power but it depends on the duration of your power pulse .... and nitrous motors definitely have the shortest power pulse of any combination so they are hyper sensitive to timing changes ... a 1/2 degree timing change has me so puckered I can barely walk up to the line to help stage the car). Even at the sportsman level 30% or more of the teams i compete against are making timing changes within 10 minutes of staging the car to make sure they go down as intended. If they couldn't manipulate timing they wouldn't be able to run the back half of the track like they do (because they would have less HP throughout the run).
The assertion that within TD/TS that the cars can run the number every time and its just a driver's race is beyond ridiculous. If you see a car running in the fastest 1/3 of the field and compensating for top end driving ET impacts you can tell the car is consistently running the number you should either follow that team into a casino or realize there are some people working their butt off to make that happen. It is challenging beyond belief.
90%+ of my runs start at 26.5 degree BTDC timing and end at 4 degrees BTDC. That said the vast majority of that timing change is because the more nitrous you turn on the faster the flame front of the combustion moves and the more you have to slow the timing to keep the power pulse where you want it. So that kind of timing change is to make more power, not manage for the track. Now, I am not in the norm on pulling timing to manage for the track. I don't try to kill (run super quick) the 60ft so it is rare for me to pull any more than 1 degree (roughly 200hp) to mange for track conditions. When I'm trying to make a fast run my three stages come on (relative to the car first trying to move forward) at 0.00, then 0.35, then 0.70 second out .... so by 3/4 a second out I'm fully uncorked in terms of power. Generally any power management happens between 0.20 and 1.5 out .... and I'm mainly looking at the G meter to decide what I need to do .... I want the G meter to look like a tabletop for as long as possible. I try to use timing as a bandaid, as I learn what the chassis wants most of my tuning is in the torque converter, tire pressure, and what we call a wheelie bar (its a tire set device to me, I use it to manage tire speed ... intentional over rotation). When trying to keep G's high and flat and having multiple large stages of nitrous come on, you are make lots of very little timing changes .... my power management timing map is 15 lines long .... meaning at an extreme i will make up to 15 power management changes between .2 and 1.5 or down track to deal with bumps (pulling more like 1000 hp to keep the car from becoming a Cessna 172). It's fun, and no you don't have to do that to be reasonably predicable and run relatively slow, but the tools that have existed for roughly the last 7 years are very valuable to someone who likes to walk a fairly fine line doing this.
Turn TD/TS into stock/superstock and I'll either move to super stock or another sport. Now do most of the teams approach the class like I do ... hell no, you don't have to and it will drive you crazy .... but its what makes it enjoyable to me.
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