After reading that twice, it makes sense. Occasionally I actually learn something on this forum (Other than which cat-back makes less/more noise).

 

Yeah, its theoretically possible to get more timing then you want, but its nearly impossible to achieve....Maybe if you had the safc at -40 making 550+ whp or some such rediculous combo. Even so its very unlikely.

 

I think you understood just fine
How does the AFC have positive effects on the timing lead?
Allowing the knock sensor and stock ecu to pull timing when it "sees" detonation is the solution to this?

How are you going to make over 250 WHP more than stock with just the AFC for fuel enrichment safely.? Are they getting these numbers on race fuel or pump gas?
Im sorry ISO but to say that all you need is an airflow modifier to make that much power on pump gas safely is rediculous.
If you plan on making that much modification to your system you need igntion upgrades and a seperate control module.
There are even people on this board with Bone stock evo's that have misfire and detonation problems after rolling off the lot.
Dont get me wrong. I'm know you can make power with the AFC, but at the level we are talking about it is not the option i would give to my customer.

 

It could create a lean condition only if the stock injectors were still in place. If you have upgraded them the chances are slim.
Now knock, yes that can and will happen. No matter the A/F ratio.
The stock ignition map will be at a completely different load site. How drastic the timing lead will depend on how much you negatively affect your airflow output to the ecu. I would never expect the stock knock system to "save" the engine every time i step on the gas

 

ISO,
You are right the stock ecu will stop adding timing every time the load value increases depending on many things.. But as engine speed increases so does the lead proportionately.
The stock ecu will divert to secondary mapping once knock is detected for several drive cycles.
Are you saying that:
The stock ecu will pull timing at every load site? Then add until it hears knock?
Maybe I misunderstood you..


The knock sensor is there for safety and should never be used for performance enhancing.
You need to have complete control over the entire ignition spectrum. Whenever going to these extremes or really any induction modification that yields that much power, a new remapped ignition is in order.
My 2 1/2 cents

 

But you are relying on the stock mapping that is inherently generic to begin with and full of flaws

 

I assumed as much (As I wouldn't think of trying to make 400+ WHP on the stock injectors).

Thanks for the rest of your information as well.

 

First of all, making one post with multiple quotes might be a bit of a cleaner solution. Second of all head never taken off block 4G63 with 160k made over 100 passes... the slowest I ever ran being 12.6, that fastest being 11's at ~119 MPH. It saw 24 psi daily; I beat the living **** out of it. It never lost a single PSI of compression in any cylinder. It had merely an AFC for tuning, and was as fast as Al's car (albeit 300 lb's lighter) off the bottle.

My current GSX has 230 thousand miles, original engine, a bigger turbo and 720's, and still nothing but an AFC.... drag racing, carving through mountains or going 160+ mph.

Ryan Fellows EVO has 493 whp. The car is the only car he drives, completely daily driven, and it uses an....AFC.

Without an SAFC, you generally try to keep knock under 7-9 counts on 91 octane. This yield very mild timing pull while still allowing you to be lean enough to make power.... On a stock car this yields roughly 17 degrees of ignition timing. Running richer might yield as much as 22-24 degrees of timing with as little as 0-4 counts of knock but on 91 octane, it will not feel good.

That only applies to a stock car though. On a heavily modified car you want to keep knock fewer than 7-9 counts on 91 octane. This yield very mild timing pull while still allowing you to be lean enough to make power.... Running richer might yield as much as 22-24 degrees of timing with as little as 0-4 counts of knock but on 91 octane, it will not feel good.

****, that’s the same thing at both 180 and 420 whp.

The knock system DOES save the car every time you step on the gas. Take a stock EVO at 20 psi and move the knock sensor to the glove box. Listen carefully (Ping ping ping ping). The knock sensor is NOT a back up safety device. It’s a completely integral part of your cars ability to allow the amazing level of performance it offers reliably.

I am NOT suggesting using the afc without fuel upgrades, but all the afc does is allows the car too operate at a lower load value (inherently more aggressive) area on its timing map. It's still not as aggressive as the timing maps likely created by Dynoflash or Shiv....

Generally there are not flaws in the timing maps, especially at full throttle, which tends to be conservative. Most off the lot pinging occurs at partial throttle within a certain rev range.

I am going to say in fact that the SAFC, used in conjunction with larger injectors, is both easy to learn and very safe to use up until the 400 whp area. Controlling your own ignition timing is something you should not do until you are confident about how your car reacts to fuel tuning. The AFC allows you to get the timing you deserve, but it does not cause you to get too much, and it does not cause you to get too little (at full throttle). At partial throttle you have both an O2 sensor and fuel trims to allow the car to adjust. Just get it in the ballpark. Easy as pie.

I have tuned EMS's. In fact I owned the first one ever sold for the first generation eclipse. Timing control still makes me wary, it’s not for the faint of heart. I am not talking about adding a few degrees here and there, but the remapping of your timing table. It is a powerful thing you’re playing with.

Nothing beats the ease, safety and on the fly tuneability of the SAFC for low-mid powered cars.

I'd put 11 seconds on it (again and again and again)

 

As a side note that I am purposely putting in a seperate post:

I like reflashes alot. They are cheap, affordable, and do very good things for you. I also believe, assuming you have a good tuner, they enable you to learn alot about how your car works.

An SAFC works with them very well. Imagine having a reflash, and after you change mods, the SAFC can adjust for them, never having to exceed a 10% change. A flash can be a very very good baseline from which to work.

Use them in conjunction. Get great base tuning, and the ability to compensate for changes in your setup.

 

Same Idea as the xflash+xede but it (the xede) has far finer resolution and parameters of control

 

ISO I couln't have said this better myself.. I personally was planning on doing a good reflash with a tune specific to my modifications, and use my S-afc to adjust accordingly... That is until I feel there's an option out there that I feel comfortable with using.

 

Interesting post. I was considering this... Especially if I go with a larger turbo. It'd be nice to have a low boost/pump gas reflash and have the SAFC to modify fuel as well as turn up the boost on race gas.

I'm assuming this has been done alot in the DSM community, correct?

 

No, it has not, we don't have reflashes in our community. The 95-99 DSM'ers have a thing called DSMlink which using a laptop alters the ecu's fuel and timing maps directly. Its a software setup that allows you to do your own reflashing for only about 400 bucks, very cool. Those with that ability don't need safcs.

90-94 DSM can't do that, not because its impossible but because it was simply never developed. We merely use safc's or have to skip to ems. Alot of people have been working on developing the reflash your own ecu thing for 1g's though. It looks like the code is getting near cracked, and once it is, it should be possible to alter it with almost no cost. Very exciting actually. They are even talking some very insane idea's, for instance using MAP sensor tables from Mirages adapted to work for our cars and converting them to speed density for dirt cheap on the stock ECU.

All exciting stuff....but reflashes are EVO only territory for now. I belive that within a year or a few your ecu will probably be undergoing to the same, but I know NOTHING about software/hardware engineering so it may be unfeasible for some reason.

 

This is exactly how Mitsubishi set it up. This is why a bone stock EVO makes more power on 93 octane than it does on 91 octane. The ECU advances timing until it hears knock and then retards it a little. I know that 93 gives you more power for this reason, and I would suspect that 100 unleaded would give awesome power with no tuning used....but I am not sure how far mitsubishi's stock ignition maps will push the issue. If Buschur can make 380 HP at the front wheels on an AFC it seems like it would work pretty damn good for anyone who plans to stick with the stock turbocharger.

Keith

 

I don't doubt it. Every car I've owned has had some similar product released.

LT1_Edit was popular with the Z28 crew. I can't remember the product's name for my Cobra right now...