what is a stand alone?

[Proud Galant Driver]

i read that when you get high hp you need one to prevent knock or something???

the kit i was looking at promises 400 plus hp and comes with an ecu upgrade so would i still need a stand alone?

[sabzi5858]

a standalone is a replacement for the stock ecu, giving you more control over the engine. you will probably not need one for 400hp even, you should be fine with an eprom ecu and a chip programmed for the size injectors you have.

actually, the ecu is important to have not because of the hp that you are pushing, but because of how large your injectors are. because when you run huge injectors, you will run rich, but when you lean them out too much with a piggy-back computer like the s-afc, you will get too much advance which will cause other problems. this is the problem i am having right now.

if you do not know about this, you should do some serious research before buying a 400hp kit. timing advance can kill your engine just like running lean can.

[Proud Galant Driver]

well i shouldn't have to worry right? because it comes with the ecu upgrade?

[b-boy_sky]

<div class='quotetop'>QUOTE(sabzi5858)</div><div class='quotemain'>because when you run huge injectors, you will run rich, but when you lean them out too much with a piggy-back computer like the s-afc, you will get too much advance which will cause other problems. Â*this is the problem i am having right now.</div>

Just out of curiosity....what kind of problems are you getting with this....

[peanotation]

<div class='quotetop'>QUOTE(Proud Galant Driver)</div><div class='quotemain'>well i shouldn't have to worry right? because it comes with the ecu upgrade?</div>

you still need to worry, because you now need to tune the car, and if you don't know what's going on, well, thats bad https://www.thegalantcenter.org/style_emoticons/default/laugh.gif

[sabzi5858]

well, you want to get a logger, and i don't know much about altimas so i don't know what options you have. for us, we have pocketlogger, and even a freeware logger that we can use with an eclipse ecu. you're going to have to research that further because it is car specific.

b_boy, the problem i am having is that i am running extreeemely rich. if i try leaning out with the s-afc, i get too much timing advance which is dangerous. (the ecu advanced timing more when it thinks there is less air. the s-afc leans the fuel curve out by fooling the ecu into thinking there is less air than there really is)

lowering the fuel pressure is an option, but to get close to a good fuel curve, i would have to lower my fuel pressure to levels that are too low for comfort.

[Proud Galant Driver]

so a logger monitors my system right? or can i tune with it too?

and are you telling me that i will need the ecu upgrade and a standalone to tune? those things are like $1500 :shock:

[sethmo]

You do tune with it but not directly. You use the 02 readings and timing data and what not that the logger gives you and you tune off that whether it be with a piggy back system or stand alone...

You do not need a stand alone. Just good tuning with a piggy back system

[sabzi5858]

you will never need an ecu upgrade and a standalone at the same time (well, i have never heard of a case anyways lol). a standalone replaces the ecu, so there is no point in upgrading it if you're just gunna trash it anyways.

like seth said, you use the logger to see how you need to tune with whatever device you have, ie. s-afc or standalone, etc.

not everyone uses loggers to tune, sometimes people use a combination of gauges, such as air/fuel gauges (only accurate with wideband o2) and egt gauges etc. it is by far easier to tune using a logger, but there has to be a logger available that is compatible with your ecu.

the benefit of a standalone such as an aem ems is that it has its own logging system which is usually superior to what you can get with a stock ecu.

dsmlink is like a chip upgrade, except it changes the code in your ecu to basically act like a standalone, but with the ecu as a starting point. with a standalone, you have to start from scratch.

as seth said, you should be fine with an s-afc or similar piggyback controller. if you don't know what a standalone is, you definitely won't be able to tune one. the general concensus is that they are a pain in the ass to tune.

the reason i am having problems is because i am using 750cc injectors with an ecu programmed for 450cc injectors. that is a 66.7% increase, which is pretty large, atleast by dsm ecu standards. dsm ecus will advance timing to 16degrees (2g) in normal circumstances, and will stop there, but with as much fuel as i have to pull to get anywhere close to proper fuel trims, i was seeing as much as 39 degrees at WOT (lower rpms, it would slowly go down as rpms went up, but not enough), which not only reduces performance, but too much advance can kill an engine. this is something car specific as well, to a point (too much advance will kill any car, but how your ecu handles advance depends on your ecu)

but yeah, since you are getting a kit, the injectors will not likely be too much bigger than stock, so you should be fine with a piggyback system. but you should do research on that and find out anyways. the s-afc is good for up to 50% correction either way, but 50% may be too much for your ecu in terms of timing.

[b-boy_sky]

<div class='quotetop'>QUOTE(sabzi5858)</div><div class='quotemain'>b_boy, the problem i am having is that i am running extreeemely rich. Â*if i try leaning out with the s-afc, i get too much timing advance which is dangerous. (the ecu advanced timing more when it thinks there is less air. Â*the s-afc leans the fuel curve out by fooling the ecu into thinking there is less air than there really is)</div>

That's what I thought was happening. I think I'm having the same problem but won't know until I hit the dyno again.

[sabzi5858]

what kind of setup do you have? injectors? ecu? turbo??

[b-boy_sky]

<div class='quotetop'>QUOTE(sabzi5858)</div><div class='quotemain'>what kind of setup do you have? injectors? ecu? turbo??</div>

intake, headers, 2.5" exhuast, HFC, FPR, NX 75 shot and s-afc.....

My suspicion is my car is tuned too rich and the timing gets advanced and causes me to misfire somewhere in mid 2nd gear....

[sabzi5858]

i'm not sure with the stock 7g ecu, but with the dsm ecu's (and i would assume it would be the same case here), the ecu will advance timing up to a certain point (about 16degrees on a 2g) based on airflow and some other things. if you lean out the airflow (not richen) then it thinks there is less airflow and things it is safe to advance timing more. this problem is caused when you lean too much using the s-afc (ie more than -20%).

if you are getting misfire, it could very likely be caused by being too rich. but don't go leaning things out on hearsay, talk to some of the guys here who have installed nitrous and know what they are doing. i believe shane had a pretty good setup if he still frequents the board? but to me, it does sound like you are running rich.

how many hz are you seeing on the s-afc when you start misfiring?

(the dsm ecus slow down timing advance/retard timing with more airflow because detonation is more likely with more boost, and it is also more likely with more advance, so it lowers the advance so you can run more boost)

[b-boy_sky]

I have an 8G ecu. Yeah I'm not going to lean it out myself....I'll wait until it hits the dyno again then I'll see what it says. Next time I run with the nitrous I'll check the HZ and see what they do when/if I misfire. Remember this isnt a problem that happens all the time. Usually at the track up through the first part of 3rd gear I don't misfire.....but every now and then it will (the last time was mid 2nd gear but bottle pressures were high).....