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Old 04-10-2012, 03:18 PM   #1
faeflora
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Default Hard fuel cut rev limit

I have an '04 forester, manual, self tuned with opensource. 16g, 3" turboback.

At redline I have a very hard fuel cut. It sucks because it's very very jarring.

How can I tune this out? I am not trying to raise the redline, just have a soft fuel cut.
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Old 04-10-2012, 06:50 PM   #2
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Not much you can do other than setting your open loop fuel targets rich and pull timing out just before your redline rpm.
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Old 04-10-2012, 07:46 PM   #3
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Shift earlier... You aren't doing yourself any favors by running the car to redline.
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Old 04-11-2012, 08:03 AM   #4
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Quote:
Originally Posted by Black94Snake View Post
Shift earlier... You aren't doing yourself any favors by running the car to redline.
This is the obvious answer. Either don't hit the limiter or raise it 200rpm.
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Old 04-11-2012, 11:13 PM   #5
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Throttle by wire, or throttle by cable? I'm not familiar with the Foresters.

If it's by-wire, you can force the throttle plate to close a little when you get within a couple/few hundred RPM of redline.
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Old 04-12-2012, 03:40 PM   #6
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Quote:
Originally Posted by NSFW View Post
Throttle by wire, or throttle by cable? I'm not familiar with the Foresters.

If it's by-wire, you can force the throttle plate to close a little when you get within a couple/few hundred RPM of redline.
By Wire.

Frankly, the above replies of "don't shift at redline" suck. There's nothing wrong with a soft rev limiter. By design, the Subaru rev limiter is inexcusable. You may as well suggest shift at 4000RPM.
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Old 04-12-2012, 03:47 PM   #7
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You can use the Requested Torque (Accelerator Pedal) table to take care of this. Just ramp the requested torque values down quickly before redline. This will cause the throttle plate to start to close as you approach redline which will be a lot softer like you are wanting.
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Old 04-12-2012, 04:35 PM   #8
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what is your Rev limit on/off values. if you change it to for instance 7000 off above and on below 6999 it should help some. I notice when there is a bigger delta to have what your describing. Also you can change your rev limit resume boost setting higher too.
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Old 04-12-2012, 04:41 PM   #9
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Quote:
Originally Posted by faeflora

By Wire.

Frankly, the above replies of "don't shift at redline" suck. There's nothing wrong with a soft rev limiter. By design, the Subaru rev limiter is inexcusable. You may as well suggest shift at 4000RPM.
You clearly have very little track experience. The BEST time to shift is actually based off when your car stops producing more HP vs what rpm you will drop to, and how it correlates with your peak torque.

Example: I make peak torque at 3822 rpm, and peak HP at 5360rpm. On my 2-3 shift, if I shift at 5400rpm, when I hit 3rd gear my car should drop to ~3800rpm. This puts me right at my peak torque. I will get the most pull at that rpm. On my 3-4 shift, shifting at 5400rpm, I would drop to 3850rpm. Again, right at my peak torque.

Now, if I wound my car out to say, 6500rpm, on my 2-3 shift I would drop to 4600. And on my 3-4, I would drop to 4550. Not only would I have slowed my acceleration after 5500 rpm, but I would be making less torque on the shift, resulting in an even slower elapsed time at the track.

So, truth be told... You are wasting time at the rev limited!
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Old 04-12-2012, 11:48 PM   #10
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Those numbers don't take into account the amount of wheel torque that you lose as a result of shifting into a higher gear.
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Old 04-13-2012, 12:25 AM   #11
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Bingo. Horsepower is the name of the game when you have a gearbox
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Old 04-15-2012, 11:02 AM   #12
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Quote:
Originally Posted by WRXt4cy View Post
You can use the Requested Torque (Accelerator Pedal) table to take care of this. Just ramp the requested torque values down quickly before redline. This will cause the throttle plate to start to close as you approach redline which will be a lot softer like you are wanting.
^^ this. You can vary the rpm range and the reduction to how you want it to feel


Last edited by Phatron; 04-15-2012 at 11:07 AM.
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Old 04-15-2012, 08:14 PM   #13
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Thank you, I did indeed remap my throttle to be linear and it was 100pct at redline when floored. I will soften it out a few hundred before redline.

As for mr "you dont know jack about racing, yeah. Gears. Also, I have raced horses my whole life. Lame
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Old 04-15-2012, 08:36 PM   #14
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Quote:
Originally Posted by faeflora
Thank you, I did indeed remap my throttle to be linear and it was 100pct at redline when floored. I will soften it out a few hundred before redline.

As for mr "you dont know jack about racing, yeah. Gears. Also, I have raced horses my whole life. Lame
Horses... You can't be helped. Enjoy being slow!
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Old 04-15-2012, 08:56 PM   #15
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There are also plenty of times when racing that it is faster to stay at the revlimeter. Arguing with idiots.
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