HKS SAFR vs. Apexi S-AFC

[ziggy682]

I know the differences between these two fuel computers, and everyone usually argues that one is better than the other.

WDRacing, you always say that the HKS is superior, but I've never heard you say why. In your opinion, why is it a better fuel management system than the Apexi system.

Opinions are welcome.

[WDRacing]

It's the only piggyback type with its own ecu. The install is about the same. The tuning is easier with the HKS SAFR.

Oh and it's not "Got Rice" silver and blue.

I'm also an HKS supporter, everyone has there prefered brands. HKS is a tad more expensive on some things, but the quality is far superior. Look at there turbo kits and intercoolers...

WD

[SLIMMY240]

are you runnin a ka? last time i looked theyy didnt have a kit for it. im goin just about all hks too, the turbo, wastegate, bov, ic, but i dont think they got the turbo manifold or downpipe for the ka. do you know something i dont?

[matt0941]

HKS SAFR

After reading both, the HKS has an 11 point map that can be set in 50 rpm increments., and this one costs $340.

A'pexi S-AFC

The A'pexi has (not sure how many points) adjustable curve that can be set every 500 rpm and costs $310.

EDIT: Oh yea WD, can you add what mean by its the only piggyback kit with it's own ECU? Also the website listed above says

Quote »The HKS Super AFR is the very first airflow meter correctional device in the industry with a built in CPU[/quote]

[ziggy682]

The HKS unit also has separate controls for adjusting idle fuel ratio. This seems like it would be good for emissions. It also has a function to control response time in different rpms. Does anyone know how useful this is? I also like that the unit can smooth out fluctuating MAF signals. Again, does anyone know how useful it's other features are?

WDRacing, what advantages does the unit having it's own cpu have?

[WDRacing]

Matt, ECU=CPU sorry, my bad for the wording mixup.

Ziggy, The HKS unit has a CPU so it can think by itself. Rather then just having a set perameter. Trust me on this one, being able to adjust fuel flow at idle is a good thing. Thats where big injectors will foul plugs and make you lose low end power. It will also help out if you run big cams with a long duration. Since most long duration cams are geared toward topend performance, being able to lean out the bottom end of the powerband will seriously help out your launch ability. As long as you richen up the mixture before boost comes on that is.

Being able to adjust a fuel or timing map at more points is a huge factor in any system, whether its a standalone or a piggyback.

Hope that helps a little...

WD

[matt0941]

I know I have asked this before WD, if you (or anyone else) could give me a more precise answer that would be helpful. When do I know to switch to standalone rather than piggyback, at what HP/PSI? Here is a link to the motec M4 which I could not find how many points they had if anyone could tell me (http://www.motec.com/products/m4ecu.htm)

[WDRacing]

I don't think you need a Motec or Haltech for that matter. I'd say stick with the piggyback for now. If you run out of tuning room and need a standalone, try SDS. You can always sell the SAFR. SDS is a really good standalond alone for the money. You don't need a laptop to tune it either.

Its hard to give you an exact figure as to when you should swap. I ran my RB20 all the way to 498hp with all the stock sensors and ECU. Accept for the MAF that is, it was off a 300ZX.

To squeeze every last drop out of your motor you need a standalone with a tone of tuning points, like the Motec or Haltech. To build a 400 hp motor, at the most I would get a JWT ecu rewrite and use the SAFR. When you get the rewrite done, you can have the ECU mapped for a bigger MAF. That way you won't ever have to worry about running out of signal.

That will leave you with upgrading injectors and tuning the A/F mix with the SAFR.

Actually, thats probably exactly what I would do.

WD

[matt0941]

Interesting, since I value your opinion a whole lot that is probably what I will do. But if I do get the JWT rewrite (that allows for a bigger MAF), would I also have to BUY a larger MAF?

So then I would be looking at:

JWT ECU Upgrade ~ $560HKS SAFR ~ $340Cobra 70/73mm MAF ~ $190-----------------------------------------------------Total ~ $1090

But if I stuck with just the stock MAF and ECU and ran the HKS, I would only be paying the $340. What am I really paying for then to justify the cost of $750?

(Some of information obtained from http://www.angelfire.com/ab/turbo240sx/s2.html )

[WDRacing]

The good thing about the setup listed above is that you can upgrade to the JWT and larger MAF when ever that time comes. So until you reach the point of requiring the larger MAF you'll be fine with just the HKS. It also gives you more money to play with for your turbine and intercooler. Save up for the rest and get it as the funds become available. You have to walk before you can run my friend.

WD

[matt0941]

Ok so as far as my setup goes after my car comes I have now (after 5 days) decided that I will be going with an HKS SAFR... thanks for the help in this milestone WD, lol. But as far as the progress of my car goes if you guys have any interest (Ok I am just saying this cause I am kinda tipsy... <----- yea the guy in the avatar), it is getting inspected this wednesday at a dealership and is a red '97 with auto (that I am converting) and 15k miles on it.

[cnichols]

I'm in the process of installing my standalone and want to sell my JWT and Cobra MAF....$400 and it's yours shipped. Programmed for 50 lb. injectors which aren't that expensive...not cheaper than 370cc of course, but still not too bad, and might as well get them new. Or, you could get on corral.net or some domestic website and buy some used ones off a Rustang or Gaymaro.

[matt0941]

Wow thats pretty cheap, but I am going to do as WD said and if needed upgrade later I guess, thanks though.

[huguetpj]

I'm in the process of installing my standalone and want to sell my JWT and Cobra MAF....$400 and it's yours shipped. Programmed for 50 lb. injectors which aren't that expensive...not cheaper than 370cc of course, but still not too bad, and might as well get them new. Or, you could get on corral.net or some domestic website and buy some used ones off a Rustang or Gaymaro.

damn! where were you when I was buying stuff for my project?

I guess I'll have to stick to my original plan now... :rolleyes

[Maxin]

Does the s-afr or s-afc store settings in memory (incase of battery disconnection)?

[cnichols]

damn! where were you when I was buying stuff for my project?

I guess I'll have to stick to my original plan now... :rolleyes

I just got the standalone about 3 weeks ago.

[huguetpj]

jeje...

now... if only I had the $$$ for a standalone

maybe further down the road

Quote »Does the s-afr or s-afc store settings in memory (incase of battery disconnection)?[/quote]

Don't quote me on this but I think most of them do. The probably use FLASH or EEPROMs to do it.

[ziggy682]

Two things.

1. The Apexi SAFC can do different settings for hi and low throttle positions. Do you think this is much of an advantage?

2. The HKS SAFR has a function that smoothes out erratic MAF signals. This is supposed to allow your car to idle smoothly even if you have an open atmosphere BOV that is not adjusted correctly. Would this function compensate for running rich between shifts with an open atmosphere BOV? I don't see how it could, but some of the things I have read make it sound like it can.

[WDRacing]

The SAFR does have idle stabilization as well as being able to stop your car from stumbling do to the BOV venting to the atmosphere.

WD

[matt0941]

[quote=" ziggy682

1. The Apexi SAFC can do different settings for hi and low throttle positions. Do you think this is much of an advantage?

[/quote]

I don't understand... (I wish I had all knowledge of everything automotive)

[ziggy682]

I don't understand... (I wish I had all knowledge of everything automotive)

With the Apexi S-AFC, you can adjust fuel +/- 50% at 8 different rpm points. You can do this on two completely different maps. One for high throttle, and one for low throttle. You can also define what is hight throttle, and what is low throttle. Say you want to make low throttle 10%, and high throttle 50%.

Anytime you are under less than 10% throttle, the Apexi unit uses your low throttle map. Anytime you are over 50% throttle, it uses your high throttle map. If you are between 10% and 50% throttle, it will interpolate between the two, and do something in the middle of your maps depending on how much throttle you have applied.

Basically, you can tune the low throttle setting for no boost, because I don't think your car would ever see boost with less than 10% throttle application. Then you can tune the high throttle setting for boost. Anything between the 2 settings, the unit will just figure out on its own.

Don't know if I cleared that up any, or just made it really confusing. Read this, and scroll down until it talks about the Hi and Lo setttings.http://www.apexi-usa.com/elect...w.asp

[matt0941]

Quote »From the link... "]Both the Hi and Lo Throttle setting maps are used for adding or subtracting fuel throughout the fuel curve. This unit takes the input airflow signal and converts the signal into an air volume value. This value is modified through the Air Flow % Correction Setting. The modified output air volume value is then converted back into an airflow signal and sent to the ECU.

The Hi and Lo Throttle setting maps can be adjusted at eight different RPM points that are user adjustable. The range of fuel adjustment is +/- 50%, which can be done in 1% increments. During tuning, the Hi Throttle map should be set first, and Lo Throttle map second. All values between the predetermined RPM points will be interpolated. Only a professional, using engine monitoring equipment should be tuning the S-AFC. [/quote]

Thanks for the link, but after reading it (not your response) I am more confused

[WDRacing]

Just get the SAFR, it's better. No questions about it. The SAFC has been out for years now, its way behind the power curve.

WD

[matt0941]

I don't think you need a Motec or Haltech for that matter. I'd say stick with the piggyback for now. If you run out of tuning room and need a standalone, try SDS. You can always sell the SAFR. SDS is a really good standalond alone for the money. You don't need a laptop to tune it either.

And god matt, stop looking so sexy in your avatar!WD

I can't help it WD.

As far as the SDS goes if anyone was interested I wrote them an email as WD told me to and got the following response (the first is my question)

Quote »Matt Wrote:

Hi I have a 1997 240SX and am turboing the engine witha turbo kit from a company like Nsport, TurboXS, orGarret. I know that the stock Mass Airflow Sensor cannot really handle horsepower higher than 260. I wasinterested in your system and how compatible it iswith my car. I read your webpage as well and was notcompletely sure which product (Em-4) package I wouldbe going with, and is it a full standalone system... does it replace my stock ECU? Any help that you could spare would make me grateful.

Thank you, Matt Rac.

Response:

Hi Matt

The system we would recommend for your application is the EM4F4. This setup would replace the engine management part of your stock ECU. You may have to leave the stock computer in place as it probably controls other features in your car. The 4F system costs $1165.00 USD for the base system. You would also need a MAP sensor either 2 Bar (up to 15 LBS boost $70.00) or a 3 BAR (up to 30 LBS boost $90.00). All the other options are optional and you can look at our website and look at whichyou may like to have. If you are unsure give us a call and we can help you decide.

[/quote]P.S. Go 100 posts! :rockon

[encasemyheart]

didn't the new S-AFC come out or is coming out soon? I remember seeing pictures of it and it updated alot of features, more rpm points and such. If it hasn't come out already, it is about to. It looks similar to the current one except a few cosmetic differences and instead of four arrow keys at the right, it is a rotary knob...only complaints I've heard are the fact that it's harder to adjust while driving because if you hit a bump, you hit the rotary knob while trying to adjust.

I prefer the HKS for features, but I'm sure the new AFC will have many of these features and I like the screen and maps instead of adjusting based on numbers alone. Plus I've used the S-AFC on my turbo eclipse and my Celica, and it works pretty well.

ANyone have any more info on the new afc? There is an advertisement which lists most of the new features and stuff if anyone can find it.

[matt0941]

I searched around and couldn't even find it on their website

[encasemyheart]

http://www.takakaira.com/asp/t...cat=2

here it is. you get 12 rpm points at 200rpm intervals. It also has a knock sensor and a warning mode to tell you if you're knocking.

DISPLAYThe new Super AFC-II utilizes a state of the art visual display lighting called Vacuum Flourescent Display (VFD) to provide a bright & clear visual information. A new dot matrix monitor enabled a variety of information to be displayed simultaneously where the driver can check quickly. Information relayed can be either displayed numerically (analog gauge style) or graphically.

BODYThe body of this new product is slimmer & smaller (H52 mm x W126 mm x D18 mm) than the previous offerring. This ergonomically designed body houses only a "center button" which toggles & rotates where it enables the driver to navigate (4-axis toggle: up& down, and left & right) and to select functions of the Super AFC-II. This button also has a feature that enables the driver to fine tune any parameters. All these features in the new model's user interface made it much easier & efficient compared to the older model. KNOCKING MONITORThe new Super AFC-II has a new knock sensor function which alerts the driver. This ensures that the engine is tuned to perfection at every stage. This function only works on vehicles that has an engine knock sensor.

MEMORIZE 2 TYPE OF SETTING DATAThe new Super AFC-II can save two data setting from data collected with respected to air flow adjust rate, throttle duration, engine RPM, etc. The driver could use these two settings in a variety of driving conditions, be it track, street, or just plain cruising.

PASSWORDTo avoid the new Super AFC-II from tampering by unauthorized users, a password can be set for protection.

WARNINGThe driver can set up various warning functions inorder to monitor the engine operation. These functions includes incoming air flow rate, suction pipe pressure, engine knock RPM, etc.

OthersSettings & data stored in the new Super AFC-II will not be lost even if the it is disconnected from the vehicle battery power.RMP signal for air flow & pressor sensors can be adjusted in 12 points in 1% increments depending on fuel settings in +50% to -50%. Or the RSP can be set in increments of 200 RPM. Throttle opening duration: Adjustable by size.

INSTALLATION For installation, connecting to 6 sensors such as the air flow signal, the throttle sensor, the rotary signal, ignition and the knock sensor. Comparation of Super AFC to Super AFC-II Previous Suer AFC New SUPER AFC-II Air Flow Setting choose 8point choose 12point Air Flow Engine RPM every 500rpm every 200rpm Drive Voltage Circuit Safety None more stable Display Monitor Adjustment None setting up display (air flow/pressure) Display Color Blue Standard model:BlueLimited Edtion:White Other Functions None -Knocking Monitor-Digital Display-Setting Memory function-Warning function-Password-Lock function Limited Edition- Production made 1000pcs only solely for Japan domestic market . Rare and hard to find outside Japan. Stock release date from Apex will be End of Jan. Reserved Order is accept now.

And it's only $311. Japan only for now but it should work fine on US cars I would assume since it's universal.

[WDRacing]

Hmmm....sounds nice, give HKS a few months to come out with a better one.

But as for now, i like SAFC datalogging type stuff. A built in knock sensor is a very good idea. Since most people have no idea that there stock ecu is pulling out 12 degree's of timing everytime it gets knock indicated.

WD

[oi138]

I'm in the process of installing my standalone and want to sell my JWT and Cobra MAF....$400 and it's yours shipped. Programmed for 50 lb. injectors which aren't that expensive...not cheaper than 370cc of course, but still not too bad, and might as well get them new. Or, you could get on corral.net or some domestic website and buy some used ones off a Rustang or Gaymaro.

Oooh ooh I'll buy that!!!!email me.

[email protected]

James Poe

[encasemyheart]

I've always liked Apexi products over HKS. HK$ is too overpriced usually. The only thing I really think is superior is the HKS EVC IV, the electronic boost controller. That thing absolutely kicks ***. The Apex boost controller is wayyyy too complicated when all you need is boost control. Too bad the HKS is $550+...

In this case SAFC > SAFR simply because I'm more familiar with HKS' offering. I love the display and was never a fan of those units where you turn a knob and see one variable at a time. But the new one looks even better, I might actually buy one soon. The Apexi has similar functions and it has always been a solid unit. I didn't like the 500rpm increments, but now with 200 that's all you need. I don't see a need to be able to set it every 50rpm with only 11 points to set like the HKS has, 500 was almost enough, 200 should be perfect. I do like the HK$ idle control however, but I will likely never need it for my purposes. But the SAFC's Hi/LO throttle settings are awesome. On boost and off boost, it's perfect.

WD: The new SAFC should work on all cars, US or Jspec regardless, correct?