[GyroCap]

I've noticed on full throttle runs that backing off to about 3/4 throttle actually improves acceleration. Generally I'm in third gear when I let up and the car pulls a little harder.

Is this a stock ECU issue? I've heard that the WOT map is overly rich. Will an SAFC help and is it worth it?

For power mods I have a Cobb CAI, custom Magnaflow cat-back and Bosch platinum plugs.

If this has all been discussed before...sorry.

-G

 

[yamarocket630]

Some people claim that at WOT, the stock ECU does richen the mixture way too much (like 8:1). I'm personally not convinced, especially if you're flowing more air with your CAI and cat-back. Bear in mind that you need a richer than normal mixture at extended periods of WOT to keep combustion temps in check and for smooth power delivery, but that is not always the best mixture for power. Check to see if your throttle stop is letting the throttle plate travel past WOT (where it is 180 degrees to the air flow), and is actually starting to reclose the throttle. I had an old Mercury that used to do that. If that's not the case, and your car is actually making more power at 3/4, then it probably has something to do with open loop vs. closed loop operation, and could indicate another problem that the ECU is working around in closed loop operation, like an out of range coolant sensor for example. Often a sensor can be out of range far enough to affect performance but not set a code because it is still working, and therfore th ECU has no way of knowing it is out of range.

 

[Elite421]

I have felt the same way but only at lower RPM
Alex

 

[m750]

propper throttle modulation will yeild better results than just mashing the pedal... you've got to feed it in. Just pressing it to the floor (in my car) tends to bog it a bit (prolly too much fuel).
AO

 

[10th Warrior]

i've never had any such problem. i guess check to make sure that your air filter is clean. also, how have you determined that you accelerate faster at >WOT? i suspect at the strip, WOT would yield the lowest ETs.

 

[Imprezawd]

Good Post !!

I have noticed this as well!! Instead of giving it the old GOOSE fell that power out!! SO good post and I think u are right about your thoughts!!

Richie

 

[ivbdn]

That's pretty interesting. I've never experienced anything like that. I hope there are more posts to this so I could learn more.

 

[Storm]

Does the ECU pull back timing during WOT situations along with the preset fuel tables? If so...you'll see a drop in performance when you go to WOT. I don't know for sure if the Subaru does this or not, but some other makers do this to ward off detonation with cheap gas, heavy loads, less than optimal maintenance levels, etc...

 

[SalPhotek]

Ive also experienced this not only in my impreza but in my old 84 sentra but thats a whole other story

 

[GyroCap]

Does the ECU pull back timing during WOT situations along with the preset fuel tables? If so...you'll see a drop in performance when you go to WOT. I don't know for sure if the Subaru does this or not, but some other makers do this to ward off detonation with cheap gas, heavy loads, less than optimal maintenance levels, etc...

Can the ECU detect any of those conditions or is it global? I run 94 octane fuel in a car that's usually empty (except for me ) and with just over 9k miles on the clock. Theoretically the state of tune should be pretty good, so timing shouldn't be pulling back too much. Of course, I may be assuming too much...

I seem to remember reading somewhere that automakers purposely set maximum power at less than full throttle. I'm not sure if this is really the case. The article was in either C&D or R&T and if I remember right was about a Volvo they were testing. It seems strange to me, but if it's true, I'd be really curious to know why.

 

[10th Warrior]

i dunno...i'm still skeptical of the claim. i'd like to see some numbers, not that you can accurately control how much % throttle you give when its >100%, but still, i don't think it would much matter.

 

[Keith99RS]

Same thing here

I have felt the same thing. It seems if you go to 3/4 and slowly depress the accelerator to WOT, you seem to have a stronger pull by seat of the pants feel. May be going straight to WOT dumps fuel into the cylinders faster than it can use it at first then balances out in a few seconds. This does seem like a good thing to check out at the track. Not sure how though, because there are too many factors that could incease or decrease times whether you mash the throttle or not, like reaction time. It doesn't feel like some thing that would drop 0-60 or 1/4 miles times a huge amount.

 

[10th Warrior]

keith-the ecu can change the pulse width of an injector faster and more accurately than you can control your foot.

It seems if you go to 3/4 and slowly depress the accelerator to WOT, you seem to have a
stronger pull by seat of the pants feel.

are you taking revs into account here? if you start at a baseline Xand then go straight to WOT or straight to 3/4 WOT, pause, and then go to WOT, the engine will be at a higher speed since it keeps accerlating at 3/4 WOT. thus when you do go to WOT it is at a higher rpm and thus on a fatter part of the torque & power curves, which would cause it to seem like this is better when in fact it is not. i still think this is all a placebo.

 

[Retsyn]

I dunno... I too have experienced this. I have a lot of opportunity to start from a dead stop (tolls) and I've noticed that I seem to be able to get up to speed faster this way too. I only give it as much throttle as it's willing to take. It's kind of a "feel" thing. If I just go straight to WOT it seems to bog a little...

 

[10th Warrior]

what rpm are you launching from?