Hey all (who are running MS) Got the car fired up and running well, thanks a lot to Nate (ner947) and his help with the VE table. Works well and runs great in vacuum. Need to fix a pretty major manifold to turbo exhaust leak to start playing with boost, but hey, it runs!

I'm in need of some help with my accel table though. Been playing with numbers, and sometimes getting somewhere, and sometimes not. Wondering what you guys are running for the settings. (TPS based, not MAP) I understand they're not in stone numbers, but it'll give me a good place to start. Nate, if you're out there, since I'm using a close version of your VE, maybe you could help me set these other numbers as well.


As always, any help is most appreciated.

Brian

PS. I'm retarded. I didn't sign out of my buddies account. This is actually ForceFed420a (haven't been on in a while) with a 97 GS custom turbo with MS. Sorry for the wrong signature.

Your accel enrich numbers may be very different depending on throttle body, fuel injector size, etc... I have 780's with about 35 psi of static fuel pressure. It's not 43.5, I found that lowering the pressure a tad helps keep the duty cycles up which makes the idle smoother.

I used TPSdot for a while, but these days I'm using MAPdot. Mine look kind of like this:

ms kpa/s
3.2 240
2.4 170
1.4 100
0.8 30
threshold is 30 kpa/sec, duration is 0.3 seconds, decay accel enrichment, 0.0 value at end of accel time

Tuning AE is tricky. These settings seem to be always changing on my setup. You have to be able to hit the same kPa/sec consistently and watch your WB at the same time. It's not easy! To make life more difficult Megatune has a poor interface for tuning this, there is no way to read your exact kPa/second, you have to watch this bar that has a fixed scale from 0 to 300 kPa/second.

If for example you are cruising around 40 kPa and bring it up quickly (within 1 second) to around 100 kPa, you have to watch the wideband and see if it goes rich or lean. Ideally it should go rich a bit from your cruse AFR, maybe to around 13:1 then it should go back into closed loop.

Thanks Nate. Glad to know that it's not something super easy that I'm struggling with. Thanks for the advice and help with some numbers and how to tune. I'm going to put my buddies WBO2 on it next time I work on it. Narrow bands are not very good to tune with or to see the (right)AFR.

Again, thanks for the help.

Brian

Accel enrichment is kicking my ass too. I can't seem to get it quite dialed in, and i keep having to adjust my threshold. Seems like i can bump 30kPa/s in cruise, but if i se it to 40, light throttle adjustments lean the car out and it bucks.

Originally posted by DarkOne
Accel enrichment is kicking my ass too. I can't seem to get it quite dialed in, and i keep having to adjust my threshold. Seems like i can bump 30kPa/s in cruise, but if i se it to 40, light throttle adjustments lean the car out and it bucks.

30kpa/s is way too low for MAPdot. Bump it up to 50 for starters, but you'll likely ending up around 70 after it's all said and done.

If slight throttle adjustments are pushing you lean, then you're probably running too lean in your VE buckets. What AFR are you cruising at?

Actually, i turned on the accel decay, and fixed most of the problems. Why the hell isn't that on by default?

You'll still likely to have issues with oscillating AFR if your using MAPdot only and the threshold is set as low as 30kpa/s.

Try this:
When you're cruising, open the MegaTune realtime display (on the tools menu) and watch for the "Accel" light at the bottom right side of the screen. If it's trigger Accel during cruise or light throttle conditions, then the threshold is set too low. Try this in different gears and different RPMs while cruising. Mine would trigger Accel while cruising at ~3200 in 4th gear.

I'd be suprised if 30kpa/s worked very well, considering that I had problems with that and typical threshold is usually 60-80 kpa/s. But hey- if it works, it works... right? ;-)

It works. I'm still tweaking. it won't stay this way i am sure, but throttle response is fantastic and the accelleration transistion is seamless like this.. so i'm just enjoying it.

It does reset the EGO counter, though. It'll change eventually.

Originally posted by DarkOne
It does reset the EGO counter, though. It'll change eventually.

I found that to be pretty annoying as well, but I also found that if the AE and VE numbers are dead on it won't affect the AFR nearly as much.