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Again ECU question.

Posted: Fri Oct 07, 2005 8:33 pm
by Baal
Well as you know i have the AFX, apparently it isnt working now, the problem is i dont have the time to wait 2 or 3 months for another ECU, the questions are:

1.- Would a DIS-II & a apexi fuel management work like an AFX?,

2.-I mean, ive heard you can get a high rev-limit with a DISII, is it 8000+rpms ?.

3.- Is it hard to install the fuel mangement

4.- Do i need a wideband fuel/air ratio gauge to tune the fuel management?

5.- Any pros/cons or suggestions?

Posted: Sat Oct 08, 2005 1:10 am
by Loud-e-nuf
with a DIS2 you're still stuck with the ECU's REV limit
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Posted: Sat Oct 08, 2005 4:57 am
by Baal
Loud-e-nuf wrote:with a DIS2 you're still stuck with the ECU's REV limit
are u 100% sure?

Posted: Sat Oct 08, 2005 6:52 am
by tamadrumr88
to the best of my knowledge, the DISII works like an SAFC. it just tunes the fuel coming through your existing ecu which means things like spped governors or rev limiters are still stock spec

Posted: Sat Oct 08, 2005 8:45 am
by Loud-e-nuf
100% I have the Crane HI6DI2 which is pretty much the same thing and my rev limit didn't change
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Posted: Sat Oct 08, 2005 12:47 pm
by Louie
dis2 can only retard your timing. unless you have the programmable one, then you can actually alter your timing curve a little. but you still can't advance, and the stock ecu's rev limit is your limit.

the apexi s-afc isn't that hard to install there's a few how-to's floating around. all it does is modify your fuel curve based off your current fuel map.

you need either a wideband sensor or a dyno to tune them.

if you bought the ecu from howell. call him. he'll take care of you.

Posted: Sat Oct 08, 2005 4:19 pm
by Baal
tamadrumr88 wrote:to the best of my knowledge, the DISII works like an SAFC. it just tunes the fuel coming through your existing ecu which means things like spped governors or rev limiters are still stock spec
i think the DisII is an ignition controler, and the SAFC is for fuel.

Posted: Sat Oct 08, 2005 4:28 pm
by Louie
Baal wrote:
tamadrumr88 wrote:to the best of my knowledge, the DISII works like an SAFC. it just tunes the fuel coming through your existing ecu which means things like spped governors or rev limiters are still stock spec
i think the DisII is an ignition controler, and the SAFC is for fuel.
yea

Posted: Sat Oct 08, 2005 5:06 pm
by Baal
Well i guess that option doesnt work for me since i build my car aiming for high revs (crane 14, 2.5" direct exhaust, big LTH), i have no low end torque, so the stock rev-limit slows me down a lot.

i havent taked to Gary because first i have to determina 100% if its the ECU, i sent my stock ECU, to test it, if the car starts then the AFX is fried.

Posted: Sat Oct 08, 2005 5:23 pm
by tamadrumr88
Baal wrote:
tamadrumr88 wrote:to the best of my knowledge, the DISII works like an SAFC. it just tunes the fuel coming through your existing ecu which means things like spped governors or rev limiters are still stock spec
i think the DisII is an ignition controler, and the SAFC is for fuel.
thats not quite how i meant it. i mean more in respect of altering something based of your ecu, and not a replacement for the ecu

but back on subject

Posted: Sat Oct 08, 2005 5:26 pm
by Louie
tamadrumr88 wrote:
Baal wrote:
tamadrumr88 wrote:to the best of my knowledge, the DISII works like an SAFC. it just tunes the fuel coming through your existing ecu which means things like spped governors or rev limiters are still stock spec
i think the DisII is an ignition controler, and the SAFC is for fuel.
thats not quite how i meant it. i mean more in respect of altering something based of your ecu, and not a replacement for the ecu

but back on subject
no one said anything abot replacement ecu's. ..these are piggyback units.

you mentioned that the disii works like an safc and tunes the fuel coming through your existing ecu. .. what you meant to say was that the disii works like a disii and tunes the ignition timing.

Posted: Sat Oct 08, 2005 6:03 pm
by Baal
and why cant a disII advance the timing?, then its almost useless.

Posted: Sat Oct 08, 2005 9:21 pm
by Louie
MSD’s DIS Ignition Controls are designed for engines with coil pack, waste spark ignition systems. The DIS-2 has two channels, to fire two coil packs, while the DIS-4 is capable of firing up to four coil packs (or even for individual coils). Each Control delivers full power Capacitive Discharge sparks from idle through racing rpm. Below 3,000 rpm there is a series of multiple sparks that last for up to 20° to improve idle, starting and throttle response.
The adjustable features of the DIS Ignitions have also been upgraded with rotary dials. These provide easier, and more precise adjustments of the overrev limiter and the holeshot rev limit. Also, there is now a step retard that can be wired directly to a nitrous system or switch for activation!

striaght from msd's site.

it's mostly used by turbo guys, or nitrous guys.

imo on a na car it has very little use. ..the most useful thing it has which i would consider getting one for is the two step limit. makes launching very consistent.

Posted: Sat Oct 08, 2005 11:04 pm
by Baal
wow its pretty limited, i tought you could absolutely control the ignition timing.

So about the fuel management, i dont quite get what you CANT modify, you can adjust the amount of fuel added in every 200rpm increment, how is it tied to a fuel map, well actually the question is, what is a fuel map :P

Posted: Sun Oct 09, 2005 3:45 am
by Louie
your ecu has a preset fuel and ignition map. it also has the ability to slighltly compensate itself for conditions/mods.

what an s-afc and the likes does it alter the voltage on the map sensor to fool the ecu into thinking it's seeing something its not. by doing that you can gain minor control of your fuel curve. lean it out whre you need to, richen it up where you need to.

piggy backs usually all work on the same principle, manipulating sensor voltages to fool the ecu into doing what YOU want it to do.

Posted: Sun Oct 09, 2005 5:45 pm
by Baal
Louie wrote:your ecu has a preset fuel and ignition map. it also has the ability to slighltly compensate itself for conditions/mods.

what an s-afc and the likes does it alter the voltage on the map sensor to fool the ecu into thinking it's seeing something its not. by doing that you can gain minor control of your fuel curve. lean it out whre you need to, richen it up where you need to.

piggy backs usually all work on the same principle, manipulating sensor voltages to fool the ecu into doing what YOU want it to do.
:( i always tought they went "deeper" into the ecu, now i see the HUGE difference between them and a stand alone.