Tryin to find how you guys like/dislike driveability with using a safc or vafc....I have my low throttle map at -40 across the board...This seems to work ok, however sometimes the car tends to buck a little....Also, on and off the gas pedal, you almost get a slight throttle delay, followed by a little studder....Can anyone relate to this??????I have been running this setup for a while now, and kind of got used to it, but does anyone have any other suggestions for better drivability????Thanks.....

 

I'm hacked on 310cc's. I experience all the same symptoms.

Light throttling on and off makes the engine jerk around quite a bit, but sometimes it doesn't do it at all.

Medium to large amounts of throttle input make it bog for a couple of seconds before it picks itself off its face and gets going.

I believe this is also one of the faults of using the hack, aside from the ignition timing issues. It's probably due to the lack of an acceleration enrichment and deceleration enleanment function to optimize those correction factors for the bigger injectors.

Maybe somebody else will confirm it, or I will later on when I get the Hondata installed and tuned.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99lspwr &raquo;</TD></TR><TR><TD CLASS="quote">Tryin to find how you guys like/dislike driveability with using a safc or vafc....I have my low throttle map at -40 across the board...This seems to work ok, however sometimes the car tends to buck a little....Also, on and off the gas pedal, you almost get a slight throttle delay, followed by a little studder....Can anyone relate to this??????I have been running this setup for a while now, and kind of got used to it, but does anyone have any other suggestions for better drivability????Thanks.....</TD></TR></TABLE>

Got the same thing---- bitch bucks a lot sometimes. We've tuned the car a bunch, but can't seem to get rid of the part throttle, around 4%ish.

 

I have a little roughness below 2500 at less then 10% throttle. Otherwise it runs awesome, especially for agressive driving. I don't have any of the delay or bogging issues since i leaned it out a couple% in the midrange.

 

Yes, under full throttle the car runs and pulls perfect...

Bailhatch:::::How are your settings on the low map????

 

on DSM 450s

low

-18 1000
-38 2000
-36 4000
-36 5000
-35 6000
-34 7000
-34 8000

high is pretty much the same but 3-4% richer from 2000 up.

 

only prob i get is just the 5% throttle fuel inj shut off. it's normal, just more noticeable w/ 450cc inj compared to stock. i've gotten used to it, but only noticeable if i'm constantly crossing 4%-6% throttle.

 

I guess thats what I am feeling......I guess it is normal from what you all are saying...No big deal, I guess u cant complain to much since it does a good job for how much it costs............BTW, where are everyones ne points set at????Anyone ever mess with those at all???Mine are all different, but I hear some people just leave them at 1000, 2000 ,3000, 4000, etc.,etc....

 

Is it true that at partial throttle the ECU will advance the timing b/c it doesn't "see" the boost? I don't understand that. If the boost gauge isn't seeing boost at partial throttle, then how is the rest of the area inside the intake manifold seeing boost, or what I mean is, how is there compressed air getting in there? Also, with my SMC I don't have too bad of a hesitation problem, just slightly...

 

what size injectors are u using???

 

With 450's and a SAFC, I haven't seen this happen. Could be a small injector thing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by m R g S r &raquo;</TD></TR><TR><TD CLASS="quote">Is it true that at partial throttle the ECU will advance the timing b/c it doesn't "see" the boost? I don't understand that. If the boost gauge isn't seeing boost at partial throttle, then how is the rest of the area inside the intake manifold seeing boost, or what I mean is, how is there compressed air getting in there? </TD></TR></TABLE>

It's not just the ECU not seeing boost, it's in general the ECU is not seeing the pressure in the manifold.

The SAFC just reduces the pressure signal sent to the ECU. If the ECU thinks there is less pressure, you get more advance.

For example, you set the SAFC up so that at 9-10 psi of boost, the ECU thinks it's at atmospheric or so. The ECU thinks you have 0 psi, but you really have 9-10. So it gives you the stock advance for 0 psi.

The same happens at part throttle, the ECU always thinks you're at a lower boost level than you really are.

 

its not bad once you get used to it. I dont think there is a way to fix it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nevin &raquo;</TD></TR><TR><TD CLASS="quote">its not bad once you get used to it. I dont think there is a way to fix it.</TD></TR></TABLE>

ya cuz....its just a hack

 

Yeah, I am allready used to it, but I was trying to see if there was a way to make the driveability better....

 

The problem isn't bad at all. I sometimes notice it, but it's not a big deal. For me, overall drivability with the hack is NEAR stock. You may notice a bad idle every once in a while, but overall, it works great for the price.


I have the VAFC hack @ 6psi with 450cc injectors and have it set at 38% all the way down. It works great and my compression is still 180psi.

I've got timing retarded about 2-3 degrees. The car runs great. Im using a T3 .63/.60 turbo.

 

Do u have the low map set the same as your high one???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by scttydb411 &raquo;</TD></TR><TR><TD CLASS="quote">only prob i get is just the 5% throttle fuel inj shut off. it's normal, just more noticeable w/ 450cc inj compared to stock. i've gotten used to it, but only noticeable if i'm constantly crossing 4%-6% throttle.</TD></TR></TABLE>

So that is what we are feeling? It makes sense i just never put 2 and 2 together. Wonder if anyone can come up with a creative solution to smooth this out. or maybe the 'hack' is doomed to have minor drivability problems.

What does every one have their lowest (idle) setting at?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bailhatch &raquo;</TD></TR><TR><TD CLASS="quote">

So that is what we are feeling? It makes sense i just never put 2 and 2 together. Wonder if anyone can come up with a creative solution to smooth this out. or maybe the 'hack' is doomed to have minor drivability problems.

What does every one have their lowest (idle) setting at?</TD></TR></TABLE>

just watch your afr gauge and you'll see it drop off below 5% throttle...if you have a wideband it's really noticeable...it'll jump lean to like 20 afr...not a big deal since no load on the engine and once you step on the clutch or you stop rolling the ecu will bring it back up to 14-15 afr idle.

i've got my lowest (idle) setting of 1k at -47 and the rest on the low th% at -46 to make it like stock 240's. high th% is totally different and everyone gasps when i say they are actually at -48 to -50 along the rpm band. before everyone starts freaking...remember that every setup is different and i also run a wideband full time. also...it's good to think about what the afc is really doing during lo/hi throttle in terms of map and fueling and 450cc injectors dumping large amounts of fuel and how rich it really gets.

my throttle % is 49%lo and 50%hi instead of doing the 98/99 that everyone seems to do. i've experimented with a lot of different ways to set it and that's just what seems to work the best for me.

 

my car runs perfect on the hack, i'm open downpipe though. not sure if that makes a difference or not.

 

Delslowest:::::So you are telling me that u expierence none of these symptoms with the afc that we were discussing.....I would not really call them problems, just something associated with this fuel set-up....

 

My car has afc hack and is set -40 at 1000,and 2000 rpm then it goes to -38 at 3000 and 4000 -37@5000 And i never have any hiccups or misses or anything of the sort. I actually could not believe how good the driveability is with the hack. i have to agree with delslowesst in saying i experience none of the problems either

 

I noticed that when I replaced my distributer with another used one the 5% throttle thing went away for a couple days then slowely got like it was before. It was nice being able to stab the gas in 1st and not have it buck at all. anyone know why this happened?

 

I'm on 500cc with -40 to -48%. I also get pretty bad buckling around 3-4% thr. Its still pissing me off having run it for over 9months now.. Apart from that tip in buckling, in boost is very smooth.

 

I dont see how some people dont have the tip in throttle bucking.....I thought that was all part of the "hack".....Everyone knows that I am referring to light throttle only correct???As in when the car is in vac????My car runs and pulls perfect in boost, as well as everyone elses....Its just light throttle I am reffering too....