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Old 12-29-2011, 05:27 AM   #1
Sideout
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12.35 @ 109

Default Rotational Idle, Anti Lag and Spark Cut launch on a stock ECU?

You can have it on your stock ecu, but only if you own a 02-03 WRX
Thank you Carbibbles!

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Old 12-29-2011, 07:48 AM   #2
ride5000
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please watch that ign cut LC on early bugeyes, as any afterfires tend to float valves and cause over-bucket shims to get ejected.

a costly repair.
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Old 12-29-2011, 06:06 PM   #3
Sideout
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That is good to know! I have already switched back to "Aggressive Fuel Cut" launch control, where the ignition timing is held at 0* and fuel is cut to hold revs. This was just for testing just to show it can be done!
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Old 12-30-2011, 10:44 PM   #4
Bimmubishi
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Old 01-01-2012, 05:46 PM   #5
Carbibbles
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More rotational idle


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Old 01-14-2012, 06:28 PM   #6
daddyphatsax304
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Some great work getting this stuff out there carbibbles...

dont forget to donate ppl!!
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Old 01-14-2012, 08:51 PM   #7
langsbr
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ride - is that the only issue with ignition cut launch control? I always hear on this site how it is so bad, but nothing besides that. I have a 207, so I figured I'd be ok.

With mustangs and camaros we always ran ignition cut and never had issues.

I'd love to use it, but not if there are other risks.
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Old 01-15-2012, 02:04 AM   #8
slinkyWRX
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O.P. i shared that link to my FB account. so awesome! i cant wait for SD.

Quote:
Originally Posted by ride5000 View Post
please watch that ign cut LC on early bugeyes, as any afterfires tend to float valves and cause over-bucket shims to get ejected.

a costly repair.
yes please explain more.

like is it a design flaw. in like the early 02-03. but un affected late 03 on up?

does it happen at higher rpm LC only?
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Old 01-15-2012, 09:28 AM   #9
ride5000
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what happens is that the ign cut causes a LOT of fuel to be dumped into the exhaust tract. it tends to combust there (which makes it "better" at spooling up large turbines), which is generally not a problem.

the only issue is that you'd periodically get a BIG afterfire which creates a large pressure spike in the exhaust manifold. this pressure works against the topside of the exhaust valves and pushes them open, and that relaxes the tension holding the cam/shim/bucket/valvestem together.

the '02 and early '03 ej205s had shim over bucket, which was the "worst" when it comes to this failure (a good search term is "spitting shims"). there is/was some conjecture that at some point FHI went to shim under bucket sometime during '03 production, which would be better than over bucket, but i've never seen a definite answer. finally i believe that there was a complete switch to shimless buckets in '04. the ej257 has always had shimless buckets.

the ONLY advantage that i can see to the shim over design is that lash can be adjusted WITHOUT pulling the cams, and the shims are far, far cheaper than buying specific shimless buckets for each valve.

fuel cut rev limiting does not have the same failure modes. i've been using fuel cut two step for years and years with a utec and have never had an issue (or a single afterfire).

incidentally i've also heard of plastic cam gears grenading while using ign cut rev limiting, so even if you have shimess buckets there is no guarantee of reliability.
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Old 01-15-2012, 01:31 PM   #10
slinkyWRX
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ok thanks for the explanation.

i have a late model 03. and was wondering what the deal was.

so spark cut for show off purposes only for me.

i currently use fuel cut LC and havent had and issues except a little knock every once in a while.
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Old 01-18-2012, 05:04 AM   #11
lukeskywrx
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What MAF? -Speed Density!

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You can also do this with 04-05 engines if you swap in a 02-03 ECU. They drop right in.

Love speed density.
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Old 01-19-2012, 12:03 PM   #12
slinkyWRX
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i love the speed density as well.

i got to get a video up of the aggressive fuel cut LC. building 15psi
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Old 01-20-2012, 11:37 PM   #13
slinkyWRX
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set up the ffs tonight. spring cant come soon enough to get track time in.

aiming for high 12's on the td04!
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