1-2 Shift Flutter

***Jackpine*** · #1 Wed, September 1st, 2010, 09:37 PM

Are you towing while you do this? If not, the shifting has been set up for towing and possibly that's the problem. I've hardly ever felt the need though to floor it in a 1-2 upshift situation. I HAVE had it floored in a 2-3 passing situation though and yes, there's a bit of a "kick".

I really think though, you're possibly feeling a transmission behavior that seems too aggressive because the load is too low (if you're not towing).

- Jack

RedFX4 · #2 Thu, September 2nd, 2010, 12:13 PM

No I'm not towing. That could be though, max load I think I saw was 75% when I had it pinned.

If I put 91 octane in can I run the 93 octane performance tune safely?

***Jackpine*** · #3 Thu, September 2nd, 2010, 12:34 PM

Quote:

Originally Posted by RedFX4

No I'm not towing. That could be though, max load I think I saw was 75% when I had it pinned.

If I put 91 octane in can I run the 93 octane performance tune safely?

According to Bill, you can. I've never tried it. He says the tune is fine for either 91 or 93 octane gas. If it seems to lose power, it's probably pulling timing for the lower octane and if this is the case, I'd back the timing off in 0.25 degree stages (in the Custom Options Menu) until it "feels right".

- Jack

RedFX4 · #4 Thu, September 2nd, 2010, 03:42 PM

Ok well I'll maybe give it a go next tank of gas and see. As long as it doesn't start knocking or anything. Thanks for your help.

RedFX4 · #5 Thu, September 2nd, 2010, 03:48 PM

Strangely enough I found a video where my that 1-2 flutter happens.

YouTube - 2008 5.4 F150 Magnaflow 12268 5x8x18 CAI and Edge

It occurs at 2:52 in the video so just advance it to 2:45 or so. Kinda nice when someone video tapes your problem. Makes it easier to explain.

***Jackpine*** · #6 Thu, September 2nd, 2010, 11:49 PM

Sorry, Red - I'm not seeing (hearing?) what you are. To me, it sounds pretty normal, once you get past all the exhaust noise. I personally like "quiet" and that noise would drive me right up a wall.

What you were describing made me think it was a "slip" and and an abrupt "lockup". I was not seeing that on the video. What you have COULD be a small needed adjustment in the WOT upshift RPM and the WOT max RPM.

I would not have the upshifts much higher than 5000, maybe 5100 max and then set the max RPM 400 higher. But, keep the 3-4 upshift quite a bit lower, at around 4500. You are getting a HP and a torque dropoff above 5K, so it doesn't make a lot of sense to go much higher than that. Bill has said to keep the 3-4 upshift lower to minimize stress on the transmission.

Above 5400, your Torque Converter starts to balloon, so that's why you really don't want to set the max RPM too high. I would never put it above 5600 for that reason and I sure would not consistently have it revving in that range.

The max RPM needs to be at least 400 above the shift point to allow the shift to take place. There is a moment when everything is "uncoupled" and the engine is freewheeling and accelerating rapidly. If the max is not set high enough, you'll hit the rev limiter before the shift completes.

- Jack

RedFX4 · #7 Fri, September 3rd, 2010, 11:06 AM

Ok maybe that is the issue then. I believe these canned tunes have the max upshift rpm set at 5200. I don't know what the max rpm is. Maybe what I'm hearing is the engine bouncing off the rev limiter when it shifts.

As for the video you won't see anything, only hear the motor "double peaking" (for lack of a better description) in rpms when its shifting. Not necessarily a quality I want with my truck.