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Drag racing tonight - two questions

Old 05-12-2016, 02:27 PM
  #41  
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Originally Posted by pdexta View Post
All you need is more power. At your power no-lift shift, launch control, a better tire seem unnecessary to me.

I would think with those times you're probably a touch under 200whp. Add another 50whp to it and you'll drop way more time than any other little thing you could change.
You... I like you. You think the same way I do.

And the only reason I'm not at 250whp is because I don't know how much HP I have, and I'd rather have less than break something. And I'm too lazy to bring it to a dyno. They're all so far away!
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Old 05-12-2016, 02:34 PM
  #42  
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Well, no lift shift would probably get him .5 seconds, thats a pretty big difference.

Obviously get more power though.
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Old 05-12-2016, 02:52 PM
  #43  
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Originally Posted by thumpetto007 View Post
Well, no lift shift would probably get him .5 seconds, thats a pretty big difference.

Obviously get more power though.
Where'd the half a second number come from? That seems awfully optimistic to me. If it's accurate I wish I'd bothered to set it up when I was running mid 11's!
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Old 05-12-2016, 02:56 PM
  #44  
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Originally Posted by pdexta View Post
Where'd the half a second number come from? That seems awfully optimistic to me. If it's accurate I wish I'd bothered to set it up when I was running mid 11's!
It makes a huge difference if set up correctly.

FFS on a turbo vehicle is a really big deal.
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Old 05-12-2016, 03:01 PM
  #45  
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What is the actual difference between proper FFS and just keeping your foot on the gas between shifts? The latter would just bounce off the rev limiter; what does the former do?
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Old 05-12-2016, 03:02 PM
  #46  
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I have timeslips for before ffs and after ffs, on a naturally aspirated car, not only do I chirp 2nd AND 3rd gear, but at the same mph trap speed, my ETs were .4 seconds faster, a little over .1 seconds per shift.

Since skidude would be shifting 4 times, even without a turbo, I'd estimate .5 seconds faster over all. With the turbo, not losing boost because you are never off the power would most likely benefit even more per shift.

I would say .8 seconds at the same power level, (once he gets more consistent 60 foots) is easily attainable with the ffs on his car.

Launch control will help you get your launches more consistent, leading to a more consistent 60foot.
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Old 05-12-2016, 03:03 PM
  #47  
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Retards timing. Helps keep boost up. Puts you at the correct RPM for the new gear.
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Old 05-12-2016, 03:04 PM
  #48  
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Originally Posted by skidude View Post
What is the actual difference between proper FFS and just keeping your foot on the gas between shifts? The latter would just bounce off the rev limiter; what does the former do?
I am probably wrong, but I think it allows you to shift faster, because it reduces the load on the transmission with ignition timing, making the synchros job easier? Just a guess
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Old 05-12-2016, 03:07 PM
  #49  
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Originally Posted by skidude View Post
What is the actual difference between proper FFS and just keeping your foot on the gas between shifts? The latter would just bounce off the rev limiter; what does the former do?
When you put the clutch in, it activates a new set of parameters for the rev limiter and ignition timing. I have mine set up so when the clutch goes in, limiter is temporarily reduced to 5700. Almost feels like a V8 going through the gears since the lag is noticeably reduced. Almost. If you flatshift without a flatshift program/setup, your revs could go dangerously high. Even with my actual limiter at 7300, and my FFS at 5700, I've seen logs where the RPM will hit 7600 which I'm not a fan of. Without FFS activated it would probably go even higher. Plus it will be harder on the clutch/drivetrain. When I actually go used to using it, the shifts feel smoother than without using it because power actually comes on at the perfect time as the clutch is engaging, rather than the ricer flyby Hondaboy "power shifting" where they slam the throttle 100% and dump the clutch in each gear.

Originally Posted by thumpetto007 View Post
I would say .8 seconds at the same power level, (once he gets more consistent 60 foots) is easily attainable with the ffs on his car.
Edit: 0.8 seconds? That sounds extremely optimistic. Unless it's a monster turbo that takes forever to spool between gears, which the 2560 is not.
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Old 05-12-2016, 03:07 PM
  #50  
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Originally Posted by aidandj View Post
Retards timing. Helps keep boost up. Puts you at the correct RPM for the new gear.
Sounds handy. For next time I go racing, I'll try setting it up. It doesn't ruin the cat does it?
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Old 05-12-2016, 03:17 PM
  #51  
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I mean, think what you want, but if a naturally aspirated car can drop over a tenth PER shift, I think it is likely that a turbo car, maintaining full boost after each gear shift, over 5 shifts, gains .3 seconds?

Even with a responsive turbo, going from vacuum to 10psi is not instantaneous.

I agree, the larger the turbo, and/or the higher the target boost pressure, the more no lift or flat foot shifting will benefit the elapsed times.
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Old 05-12-2016, 03:23 PM
  #52  
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Originally Posted by thumpetto007 View Post
I mean, think what you want, but if a naturally aspirated car can drop over a tenth PER shift, I think it is likely that a turbo car, maintaining full boost after each gear shift, over 5 shifts, gains .3 seconds?

Even with a responsive turbo, going from vacuum to 10psi is not instantaneous.

I agree, the larger the turbo, and/or the higher the target boost pressure, the more no lift or flat foot shifting will benefit the elapsed times.
I guess it also depends on where the car sits also. Going from 13.8 to 13.0 sounds a lot more plausible than going from 12.8 to 12.0. I'm sure it is faster though, feels faster for sure.
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Old 05-12-2016, 03:41 PM
  #53  
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my MSM went from 13.9-14.1 without, to 13.6-13.7 with
my Subaru went from 12.0-12.2 without, to 11.7-11.8 with

pretty significant in my opinion
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