11sORbust

I plan on setting PE to come on at 95% and disable AE on one of my cars (730/8D). The idea is to get true VE all the way up to about 5000rpms. I'm not asking for advice, just wondering if anyone wants to know what the results are. I have ran 13.9:1 a/f ratio WOT at the track (in 90*+ ambient temps). Made several passes without a problem. I just pulled the heads off and everything looks great, aside from carbon that was cause by EGR and bad valve guide seals. At this point I'm more than willing to try a few near WOT passes at 14.7. Thinking about doing this on my bone stock 305/tpi when I convert it to SD (next week). Would not suggest this experiment for NOOBS.......

vernw

iTrader: (2)

Disabling the PE would be interesting to see the results of, but according to everything I've learned up to this point it should end up hurting you performance-wise shouldn't it?

11sORbust

It's not for performance. I would like to see how the engine responds and see if it'll reveal true VE over a wider range. Don't forget that I'm going to also disable AE. How many of you guys have disabled (just) AE to tune the VE tables?

RednGold86Z

iTrader: (1)

If you disable AE, it's gonna backfire when you try to get near WOT (by stabbing the throttle, or even rolling into it), and also remain lean for a few moments as the wall film builds up. AE, as you know only lasts for about .25 seconds and is meant to allow the VE table to be the VE accurately (to cover up wall film dynamics - not for actually accelerating a car from 0-100). Once the pedal stops moving or slows below a speed threshold it should decay out quickly - but dMAP accel *may* still trigger from MAP fluctuations (if not filtered enough) - depending on *if* there's a max throttle position for dMAP AE that is linked to PE TPS (have to mention all remote possibilities to prevent fire). I haven't read the 730 code hack, so don't know if there is a max TPS for AE, or a PE AE disabler.

I guess my point is: I don't *think* it would be necessary to disable AE, since it will be gone quick, and not mess up the VE readings once you reach 3rd. Maybe, since you're brave with your old 305, you can do a back to back comparison, and let us know if what I'm saying is true.

11sORbust

Aww, I'll try it wil my 406 too. I have learned one thing about tuning, it's hard to blow up an engine unless you don't know what you are doing. Anyways, I agree with you. AE shouldn't matter because of the short time it's "on"....

HaulnA$$

I did this on a TBI vehicle. I disabled PE as well but I was not able to disable TPS AE, made it get a bad lean pop, disabling MAP AE gave an ugly bog but it did not stall. This did nothing to help me in VE tuning, maybe you'll have better luck. I did better at high load VE tuning by loading up vehicle with fat chicks (no offense) and a full tank of gas and datalogging on the tallest steepest hill I could find in different gears. JMHO

11sORbust

That's wat I've been missing out on when tuning my VE tables!! Do you have the inside track on where I can find a few?



















J/K

Grumpy

If you want to know the true VE, then use a MAF, and data log that. Compare the theoretical AF to Actual, and you have your VE.
There's a good thread in the archives about that.

Disabling the AE should make for alot of tip-in preignition, and the Knock sensor probably will be blind to most of that. You stand a good chance of rattling the motor pretty hard.

On the later cars, they use min AE and enable the PE pretty early, a strategy I've always liked. Once you have the car running well, you can then look at the data logs and see where to change your main VE. ie set the PE to say, 13:1, and then trim the VE table so that you commanded, and actual AFR match up. This eliminates the run too lean way of doing things all together.

Grumpy

Seems like you can get about anything at Walmart, might try there first.

Grumpy

Only if your methodical, and take your time.
Do too many stupid big changes, or too many bad experiments, and you can pretty much instantly kill a motor. It's often just the straw that breaks the camel's back that's the ending shot.

11sORbust

Thanks for the advice, I found 3 plumpers in the produce section at super walmart. Now I can really tune my ve tables, yeah!!!

11sORbust

IMO, it would take someone that A.) didn't know what they was doing or B.) didn't care what they are doing to blow up an engine. I know of another way to kill an engine. Realtime tuning and your finger slips on the touchpad

11sORbust

I like the maf idea. Wonder if i could rig up a stand alone and log it to the laptop....

FYI, I run w/o a knock sensor on all my cars....

Grumpy

I've got a 8253 here on the table, with just enough wiring to support it, and plan eventually on using it to data log Airflow. At least as an approximatation (sp).

That can be flutern with death with as bad as an ocassional tank of gas can be nowadays. After the Shell fiasco this spring, I'd be real careful about that.

11sORbust

Me no worry bout that. Nothing a little touline(sp?) cant fix


Joking aside, I don't usually fill up the tank all the way. So if I do get bad gas it will be flushed out really fast. There is a few really good gas stations anound my house so quality is not an issue. The worst case scenerio would be to get a full tank and find out it's junk gas. Then I would just retard the timing a degree or two manually. If the KS is hooked up you might never know when you do get bad gas. Have yet to buy bad gas personally but i have seen it before. I don't think it would kill an engine unless you didn't care about the pinging sound and kept pushing the car hard. But not everybody tunes the same way(ks vs no ks) and I'm not one to decide which is better. Thanks for the heads up though.

Grim Reaper

I didn't disable AE, but I completely disable PE when I tune. I do it on a long grade up a hill, very gently accelerate (and if necessary apply a little brake). Due to the excessive speeds, I do most of that in 2nd gear (though occasionally in 3rd - just for a comparison).