Cascade Crew

fiveoformula · Posted: Sun Aug 26, 2012 7:58 pm Post subject: Tuning.... progress?

Normally after I spend a day tuning with my EBL on the 'bird, I'm in a bad mood, complain a lot, or make a "please help me" thread. BUT today was different! Things went right and my tired 305 with a voodoo cam finally is getting enough fuel in the high RPMs! 12.4 AFR at WOT all the way to 5600RPM. And pulls nicely all the way through. Pretty exciting progess! Actually felt like I was getting the hang of it today. next is some driveability tuning, it mostly runs rich driving around town, the exhaust is realllllly stinky. Then maybe mess with timing more, I have it set at 4* base (EST wire unplugged), 24* at idle, 34* total (all in at 2400RPM).

fiveoformula · Posted: Tue Aug 28, 2012 4:06 pm Post subject:

Well all that fun whinning it up the other day going thru the gears ended up taking out my slave cylinder. Its leaking now and the clutch bearly disengauges. YAY.
But I have a tuning question, what is a good way to make the engine keep the revs up longer when let up on the throttle? It seems to nose-dive a little to much for my taste. Any thoughts?

Twilightoptics · Posted: Tue Aug 28, 2012 4:21 pm Post subject:

That's not as much a tuning thing. You can work the off throttle IAC steps to be more open or a slower ramp and that will kinda keep it up there.

Rotating mass is what brings the revs down fast.

fiveoformula · Posted: Tue Aug 28, 2012 5:01 pm Post subject:

Are you thinking that something is dragging or binding then? It just seems like when it was stock and I let up on the throttle it would coast a little easier in gear. Now it wants to come down to idle faster it seems like.

Twilightoptics · Posted: Tue Aug 28, 2012 5:47 pm Post subject:

Nothing mechanical necessarily.

Another thing to look at is your decel or fuel cut off. No combustion means less force keeping the motor reved even just a little.

We are talking about neutral or in gear coasting?

fiveoformula · Posted: Tue Aug 28, 2012 6:21 pm Post subject:

Well both I guess, I notice it most in a parking lot with speed bumps, ill be constantly driving clutch-in, clutch-out to avoid making the car buck so much when I let off the throttle. If that makes sense. It got much better after I gave it more timing at idle.

aaron_sK · Posted: Tue Aug 28, 2012 8:52 pm Post subject:

Timing.

Specifically not enough timing on the low-load area of the table in the RPM range you are having trouble.

Also fix any tip-in issues you have as they will be magnified with the clutch out.

Alphius · Posted: Wed Aug 29, 2012 7:54 am Post subject:

Parking lot smoothness has a lot to do with making sure you have smooth timing and a lot of timing at low-load low-revs. For instance, my table has around 28-30 degrees at very low load and revs. Also make sure you aren't getting any fuel variations as you let off/get back on the throttle, if so that could cause bucking. Make sure your fuel tables are nice and smooth down there with no big peaks or valleys. Also make sure your AE settings aren't giving you a burst of fuel as you get back on it while driving slowly. Also try disabling your decel fuel cutoff at low RPM, mine won't activate unless I am over 1400 RPM and has a delay of 1 second before activating in normal driving even. I don't know what settings the EBL gives you as far as that goes but it's worth looking and making sure it's not activating at low speeds.

fiveoformula · Posted: Wed Aug 29, 2012 3:04 pm Post subject:

Awesome that gives me a few things to try that I didnt even think of. Ill give an update as soon as I fix the slave and get the laptop in the car.