370cc inj with s-afc

[cesar khabbaz]

can i get by,using 370 cc inj on my turbo ka24det with or w/o s-afc. and what the best set up on the s-afc ( like -27,or=27,etc..) thankx

[themadscientist]

how are you going to fine tune it without some sort of fuel control? You could use an adjustable pressure regulator but the fuel delivery would be too rich in some spots and too lean in others. If you are playing with boost that sounds needlessly risky.

[Structure240sx]

:withstup and no one is goin to be able to tell u the best setup on tuning your car because everyones engine and setup is different.

[encasemyheart]

ummm...nope not without the fuel management. With it you can if you go dyno tune, or else you will be running wayy rich.

If you have an EGT gauge you could probably get it driveable by leaning it out until it runs without sputtering. In fact on my DSM we used to tune it by ear just so it would run until we could go to the dyno.

DON'T EVEN THINK ABOUT TUNING WITHOUT A DYNO though, if you lean it too much out you're screwed.

[Structure240sx]

an air/fuel gauge would be easier to tell if it was leaning out. i know with an egt if the temp go up too high that means its lean right. but an air/fuel would be a lil easier

[encasemyheart]

I thought about that, but the EGT is 10000x better and not useless blinking lights. If your o2 sensor is screwed and you tune by it than you are screwed. The EGT gives much more accurate results IMHO. But yes, hotter temps = leaner

Although something like the jumptronix A/F meter would serve you well, it's digital with actual numbers for a readout.

[Structure240sx]

i didnt think about the o2 giving out. its good to be proved wrong sometimes. but how do you relate the temp to being rich or lean. how high of a temp on a KAT means ur running lean?

[encasemyheart]

The best thing is to correlate the EGT with a wideband o2 on a dyno, that way you have a pretty good idea of what's going on and can coorelate temps with leanness/richness

-or-

see what other people are getting

-or-

put it on stock and get readings while the car is stock/not too modded and use those assuming the car runs fine at those temps

IIRC most of the time when EGTs start getting above 850 or so you are leaning out pretty bad. Maybe 825 degrees is optimum? I don't remember exactly, but I will look around and see what I can find.

[AceInhole]

1. He said with or w/o S-AFC. So just say with instead of implying he has no S-AFC.2. Yes, you CAN run 370's without an S-AFC. I pioneered it, and have already autoxed it. Orion on FA has also done it, dyno'ed it, and dragged it. Orion runs about 5.8psi non-intercooled. I'm running 7psi with a DSM sidemount. The way we got away with it?? We hacked our MAFS using a larger MAF body to increase the amount of airflow per voltage reading linearly. Do a search on zilvia.net or freshalloy.com for more information.3. Using the S-AFC, he'd just have to program a linear decrease in fuel injected per MAF reading. Dyno'ing the setup would definitely be better, but at least going to the dyno with some point to start at would help save a lot of time.4. You're saying an EGT, which is MORE prone to fluctuation by factors OTHER than air/fuel ratio is any better than an A/F meter?? Exhaust gas temp is not solely determined by the air/ fuel mixture. For instance, timing affects exhaust temps, which changes throughout the rev range. If you want to tune your car yourself, buy (http://www.fjoinc.com/automotive/) or make (http://www.diy-wb.org) a wideband O2. Otherwise, hit a dyno that has one.5. Running rich is much much much much much safer than running lean, or attempting to "lean it out".

[encasemyheart]

1. He said with or w/o S-AFC. So just say with instead of implying he has no S-AFC.

He didn't say he had an AFC either, quit arguing semantics.

2. Yes, you CAN run 370's without an S-AFC. I pioneered it, and have already autoxed it. Orion on FA has also done it, dyno'ed it, and dragged it. Orion runs about 5.8psi non-intercooled. I'm running 7psi with a DSM sidemount. The way we got away with it?? We hacked our MAFS using a larger MAF body to increase the amount of airflow per voltage reading linearly. Do a search on zilvia.net or freshalloy.com for more information.

Pioneered it? People have been doing this unreliable method for years...But I'll be the first to admit it is a decent temporary fix until you can get some real fuel management. Get injectors with a cobra/z32 MAS to cancel each other out...same thing.

But please post some info on the subject, I would like to read more into it for the KA application.

3. Using the S-AFC, he'd just have to program a linear decrease in fuel injected per MAF reading. Dyno'ing the setup would definitely be better, but at least going to the dyno with some point to start at would help save a lot of time.

Agreed.

4. You're saying an EGT, which is MORE prone to fluctuation by factors OTHER than air/fuel ratio is any better than an A/F meter?? Exhaust gas temp is not solely determined by the air/ fuel mixture. For instance, timing affects exhaust temps, which changes throughout the rev range. If you want to tune your car yourself, buy (http://www.fjoinc.com/automotive/) or make (http://www.diy-wb.org) a wideband O2. Otherwise, hit a dyno that has one.

True the wideband is the best, but have you ever used a regular LED o2 sensor gauge to tune? The thing flashes incoherently except at WOT, at which case it is usually just a very rough estimate. The digital o2 meter isn't too good either because it follows the stock UNRELIABLE o2 sensor. The EGT gauge shows exactly what is going on in the engine, and the response time isn't too slow either. If the engine is running too hot it is running lean.

There is a fair amount of repetitive information with an EGT gauge and A/F mixture gauge. Both will warn of a leaning condition for example. The difference is that an A/F Gauge shows the instantaneous mixture, not what is actually going on inside the engine. Honestly if I had to chose between the two, I'd go with the EGT since it shows the actual engine's condition, the A/F only shows mixture (which is only related to the engine's condition).

5. Running rich is much much much much much safer than running lean, or attempting to "lean it out".

Lean = unsafe, rich = safe...I are smrat! Hab you theen my batheball?

There is a difference between leaning it for power and leaning it by small percents at a time so the car doesn't stall from too much fuel being injected. read my post again, obviously I am not implicating that he try and lean it for power off the dyno.

[AceInhole]

He didn't say he had an AFC either, quit arguing semantics.

perhaps i should have phrased that better. I meant to say, just tell him he "can get by with (theS-AFC)".

Quote »Pioneered it? People have been doing this unreliable method for years...But I'll be the first to admit it is a decent temporary fix until you can get some real fuel management. Get injectors with a cobra/z32 MAS to cancel each other out...same thing.[/quote]well, yes, in a way I pioneered it with 240's. People have done it with other cars, such as DSMs to get more airflow out of their MAF, then using an S-AFC to tune it out. No one did it on a 240sx before I did AFAIK, and as of now, Orion on FA is the only other person with the same setup (he's flogged his car repeatedly already and it's holding up well he says). Using the z32 MAFs changes the airflow/ voltage curve. By hacking the MAF you get a linear increase instead and follow the stock fuel curve. It's already been dyno tested with a WB O2, and run for a little while on 2 cars so far.Quote »But please post some info on the subject, I would like to read more into it for the KA application.[/quote]Hacked MAF part I

Hacked MAF part II

Quote »True the wideband is the best, but have you ever used a regular LED o2 sensor gauge to tune? The thing flashes incoherently except at WOT, at which case it is usually just a very rough estimate. The digital o2 meter isn't too good either because it follows the stock UNRELIABLE o2 sensor. The EGT gauge shows exactly what is going on in the engine, and the response time isn't too slow either. If the engine is running too hot it is running lean.

There is a fair amount of repetitive information with an EGT gauge and A/F mixture gauge. Both will warn of a leaning condition for example. The difference is that an A/F Gauge shows the instantaneous mixture, not what is actually going on inside the engine. Honestly if I had to chose between the two, I'd go with the EGT since it shows the actual engine's condition, the A/F only shows mixture (which is only related to the engine's condition).[/quote]The only problem with the EGT, as I stated before, is that it is not entirely air/ fuel based. Also, you're still going to be in some general "area", same as the O2 sensor. How do you know where 12:1 will be with an EGT? IMO, you can tune the car to near your ideal A/F knowing which LED corresponds to what A/F at it's fully heated temperature. I'm not saying that the EGT isn't a good gauge to have, and I'm not saying to go out and tune solely on a generic O2 sensor.

Quote »There is a difference between leaning it for power and leaning it by small percents at a time so the car doesn't stall from too much fuel being injected. read my post again, obviously I am not implicating that he try and lean it for power off the dyno.[/quote] I'm just wondering why you were so insulted by my statement. I was just stating that running it a bit richer would be better than attempting to lean the car out to some temp, when he can't even be sure what temp he has to get to. Obviously you know that. Maybe I should've stated that he could've driven the car with the stock MAF and larger injectors without too much of a problem. I know a few people who have done that, one case where a JWT ECU needed to be taken out on a stock MAF/ 370cc injector setup, and the stock MAF performed better than the JWT unit.

[C-Kwik]

[quote=" AceInhole I know a few people who have done that, one case where a JWT ECU needed to be taken out on a stock MAF/ 370cc injector setup, and the stock MAF performed better than the JWT unit. [/quote]

If you're referring to Abijeet then I think you meant to say his stock ECU performed better than the JWT unit. He reverted to using a stock ECU to run the 370 injectors and he's having less detonation. Which does make sense since it would run richer. I keep telling him to get on a dyno with a wideband. Not sure if he did it yet. Though, he drove me down the street for a run and I heard no detonation.

[encasemyheart]

Thanks for the hacked MAS info, after reading over it it seems to be a sound idea. It's alot better idea than I originally thought. So in theory (I haven't read it all yet) you don't need any kind of fuel computer? Regardless, you're a smart guy. Good job with that. Also I do rememebr seeing online you could buy a MAS specifically to use with certain injectors, so you up the injectors and MAS and that's it and everything works fine. Not for the 240 of course, unfortunately.

And about the EGT, generally when you tune with an EGT you know that the hotter the gas, the leaner the motor, and once you know the right temp to tune for, you tune by that. You don't actually need the A/F ratio, just tune for the correct temp. After doing this if you go to a dyno, the wideband A/F should show a pretty linear A/F ratio across the board. Since it wouldn't make you lean out since you are going for a conservitive temp., if the wideband A/F ratio was a little rich, you would just tune for about 50 or so degrees hotter.

It sounds like alot of work, but once you are able to match up the EGT readings with your desired A/F ratio, it will be very reliable since you know exactly what temp to tune for. And BTW, you generally install an EGT on the #1 cylinder, which tends to be a little leaner than the others. If you go by #4 or somehting besides #1, it could show you are fine when you are about to lean out on #1. You don't install it by the o2 sensor.

And I was a little insulted because I thought you were saying for more power just blindly lean it out. I guess I didn't read your post clearly enough. Sorry about that.

[AceInhole]

Thanks for the hacked MAS info, after reading over it it seems to be a sound idea. It's alot better idea than I originally thought. So in theory (I haven't read it all yet) you don't need any kind of fuel computer? Regardless, you're a smart guy. Good job with that.

No problem with the hacked MAF info. If you look in FA under "hacked MAF" you should find Orion's dyno results and the amount of stuff he's actually pushed his setup through: 2 autoxes, a few drag runs, numerous street races, and a few dyno runs. I won't be dyno'ing untill May 4th with 240sxONE's dyno day. For me, I can "tune" the airflow, or if I can change it to affect certain points in the flow range, then I should be all set. My friend compared it somewhat to tuning a carb, just trial and error, since I have spacers that I dremeled out of 2.5" ID radiator hose to slip into the 3" mild steel MAF body I have. So far, the car is running well, A/F meter well into rich as some backup proof, and I also pull the plugs occasionally to make sure.Here's what my setup currently looks like:Thanks for the compliments.... I actually used to be on here at the same time I was on FA. Back in the day I had some 2000 posts, then I left and started hanging out on zilvia more after some frustration with some members here.

Quote »Also I do rememebr seeing online you could buy a MAS specifically to use with certain injectors, so you up the injectors and MAS and that's it and everything works fine. Not for the 240 of course, unfortunately.[/quote] Yeah, Mustangs have specific MAFS avaialable for specific injectors. This actually means that you might be able to have JWT program your car for the stock Cobra MAF and stock Cobra injectors (which I believe are 24lbs/hr??), then upgrade injectors and MAF from there, speculating that the linear increase works on 4 injectors as it does on 8.

Quote »And about the EGT, generally when you tune with an EGT you know that the hotter the gas, the leaner the motor, and once you know the right temp to tune for, you tune by that. You don't actually need the A/F ratio, just tune for the correct temp.[/quote]The problem is, the "correct temp" is different under different conditions, and IIRC, the temp rises through the rev range, so you also need to know what value you need at what RPM.

Quote »after doing this if you go to a dyno, the wideband A/F should show a pretty linear A/F ratio across the board. Since it wouldn't make you lean out since you are going for a conservitive temp., if the wideband A/F ratio was a little rich, you would just tune for about 50 or so degrees hotter.[/quote] A little rich is never really a problem on a turbocharged car. On an NA car you'd want to lean it out just a bit, but with a turbo, generally speaking, the richer the better. Ideal A/F is something like 12:1. Orion is happy to be pulling around 10.5:1 A/F ratios. I'm happy my Autometer A/F gauge is pulling above the 12:1 LED, so even considering inaccuracy of the gauge, I'm still in the general "safe zone".

Quote »It sounds like alot of work, but once you are able to match up the EGT readings with your desired A/F ratio, it will be very reliable since you know exactly what temp to tune for. And BTW, you generally install an EGT on the #1 cylinder, which tends to be a little leaner than the others. If you go by #4 or somehting besides #1, it could show you are fine when you are about to lean out on #1. You don't install it by the o2 sensor.[/quote] I've actually always heard of placing the EGT on the #4 cylinder, which is furthest away from the water pump, and likely to be the hottest cylinder (as the coolant will take in heat from the first 3 cylinders before getting to the 4th). This is part of the reason (oil pump being near the #1 cylinder also plays a role I think) the #4 cylinder is the one that usually fails. Any time it's 1,2, or 3, it's valve damage or FOD of some sort. When I blew out a turbine and starved the engine with shrapnel (shrapnel in the oil pan is never good) it was the #4 connecting rod (probably the 2nd strongest part of the bottom end) that melted.

Quote »And I was a little insulted because I thought you were saying for more power just blindly lean it out. I guess I didn't read your post clearly enough. Sorry about that. [/quote] No problem. Sorry I didn't phrase my responses better.