Hacked MAF vs JWT

[AceInHole]

Orion on Freshalloy was able to run a test of the hacked MAF setup (which he used to run, and which I currently run) vs. a JWT ECU setup.

The thread can be found here (http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=67521633&page=0&view=collapsed&sb=5&o=&fpart=1)

Results from the thread:
Hacked MAF: 8psi, stock ECU, 2.75" ID MAF, base timing at 16 BTDC, 4th gear pull =
248rwhp and 255rwtq

JWT: 8psi, stock MAF, base timing at 20 BTDC, 4th gear pull =
239rwhp and 238rwtq

But the big difference is the torque = 20ft/bs more from 3500 until 5000 with the Hacked MAF setup...

And it was the clear winner across the board - At no time did JWT make more power.


The quick reason: timing. The JWT ECU runs too conservative of a timing map for "low" boost.

My thoughts?? For someone running under 10psi, stock ECU with retarded base timing is the way to go. Hopefully this week or next I'll be dyno'ing with an S-AFC I got recently from CIP Motorsports (http://www.cipmotorsports.com) to see how much more power there might be with a more accurate fuel map, but according to Orion's dyno, the hacked MAF is more bang on than the JWT ECU.
My original plan was to go with an E-manage since it can control timing as well, but if I can get to 300rwhp safely (enough power, hopefully, to run with the supercharged M3's in National Tour autox events) I might just stick with stock, maybe with an MSD ignition, and a boost controller. Actually, the e-manage would be nice to just tweak the stock setup, kind of like how i'm only using the SAFC currently to datalog throttle and revs during autox and tweak the deceleration air (prevent from stalling with an open atm BOV... SAFC REALLY helped there). Guess I got more to talk about with CIP Motorsports (http://www.cipmotorsports.com) in the near future :p


BUT.... more power to us DIY'ers! We make more power than the "proven" setup :D

[Bill Roberts]

Ace, did they add some resistance to the MAFS (electronically) or lower the inductance (by adding some windings) or a combination of L/R?

I was thinking of actually putting a 2.22pF cap in series with mine and do a full LCR network and this would mean lowering the inductance( 0.007mH), raising the resistance (1.2ohm resistor)and of course the capacitor. But it also would mean one more cap of unknow valve in the secondary position.

My idea is too fool the MAFS at approx. 3700 to a leaner condition and then to a richer condition at about 5300.

So, how was the mapping..and what was their hack?

Any details or is the secret? I disclosed my hack for the SOHC...so I am curious.

Shed some light if you can...BTW, I can be in Gainsville in 3 hrs...so I may want enlightenment..checkbook in hand.

[AceInHole]

the hacked MAF is simply taking the stock MAF sensor and placing it into a larger MAF body, increasing the amount of air flowing per flow velocity.

Some threads on it:
Theorizing large injectors on a stock ECU (http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=152961&page=&view=&sb=5&o=&fpart=1&vc=1)
Bigger injectors + modified MAF, part 2 (http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=67271369&Forum=UBB9&Words=hacked%20maf&Match=Entire%20Phrase&Searchpage=4&Limit=25&Old=allposts&Main=67271369&Search=true#Post67271369)
KAT: Blown up, rebuilt, and dyno'd... (http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=67301113&Forum=UBB9&Words=hacked%20maf&Match=Entire%20Phrase&Searchpage=4&Limit=25&Old=allposts&Main=67300771&Search=true#Post67301113)

We are the hackers of MAFs. We are the defeaters of high cost per gained horsepower.

[Bill Roberts]

Cool, I thought you guys were hacking the electronics like I do...wondering if some new parts were happening...cool!!


My JWD ECU is getting outdated. I mapped it out and now I have to improve the front end sensors to compensate. Thats all!

[SimpleS14]

Is the S-AFC easy to operate? I might do 12:1 for all the rpms (as mentioned by a friend). It's not the best route...but its doable.

[AceInHole]

Originally posted by 95KoukiS14
Is the S-AFC easy to operate? I might do 12:1 for all the rpms (as mentioned by a friend). It's not the best route...but its doable.
12:1 RRFPR? that's a lot of fuel pressure... probably unsafe past like 5psi....

S-AFC is pretty easy to use. Only really useable on a dyno though. I just use mine so far to tweak my fuel settings. The only big changes I have are for Lo-throttle settings, which only affect throttle below 50%, for daily driving, and the Deceleration Air function for my atmospherically vented BOV. It's used as a compliment to the hacked MAF, in my case.

[SimpleS14]

Originally posted by AceInHole
12:1 RRFPR? that's a lot of fuel pressure... probably unsafe past like 5psi....

S-AFC is pretty easy to use. Only really useable on a dyno though. I just use mine so far to tweak my fuel settings. The only big changes I have are for Lo-throttle settings, which only affect throttle below 50%, for daily driving, and the Deceleration Air function for my atmospherically vented BOV. It's used as a compliment to the hacked MAF, in my case.

AH...ok I gotcha...so what's good for 10 psi?

I was looking at a Z32 or Cobra ('93~) MAFS.


BTW....is the install very DIY?

[AceInHole]

Originally posted by 95KoukiS14
AH...ok I gotcha...so what's good for 10 psi?

i wouldn't recommend running 10psi with just a RRFPR, but that's just me. People have claimed to do it, but fuel pressure above 100psi on a system designed to run 30-40psi (stock is a 3 bar pressure fuel setup) doesn't sound like a good idea at all.


I was looking at a Z32 or Cobra ('93~) MAFS.
that's gonna require some dyno tuning, where with a hacked MAF it wouldn't be necessary.

BTW....is the install very DIY? the directions that came with the S-AFC were great. I've heard of people getting stuck with directions in Japanese, but the unit I got from CIP Motorsports provided decent english documentation. It even had the ECU pin-outs for the KA24DE and KA24E.

[orion::S14]

Originally posted by AceInHole
Orion on Freshalloy was able to run a test of the hacked MAF setup (which he used to run, and which I currently run) vs. a JWT ECU setup.

...more power to us DIY'ers! We make more power than the "proven" setup :D

I've been back on the Hacked MAF setup for a while now...I think I ran the JWT for less than a week - IMO, it felt pretty ball-less.

I thought the JWT was better the weekend I installed it, but after some hard runs, it proved to be no fun. I remember saying that "there's no replacement for proper fuel and timing control"...and that holds true, but not for less than 300rwhp on the KA, IMO.

But one thing to note: The theoretical new ID needed to run 370cc injectors is 2.8711" by the numbers...but proved to be WAY too lean on the dyno. I'm using an insert that gets it down to 2.75" ID and it's as the dyno chart shows from above - A decent fuel trim, but a little lean as boost comes on.

In any event, JWT is a good solution for the 50lb injectors and those running +300rwhp daily - I'll probably keep mine to use with an AFC and 555s...someday.

Anyway, I'm glad you saw that thread and posted it here, Ace...it was my next stop.

Later - Brian

[240Driver39]

Okay this is all very interesting for those shooting to setup a low boost ka-t setup..Ive read all of the posts involving the hacked maf idea a while ago and recently re-read them lookin for more information on an s13 hacked maf setup. Few questions that i didnt think were cleared up in those threads, often it seemed they were bout to, but didnt. Okay the s13 maf is obviously a lil more difficult to setup, due to the material used for the housing and that the chamber narrows down. Now would the s14 ka maf work on the s13? i was under the understanding previously that it would not, however after reading more recently people have been talkin that it would, they are both 3 wire correct?. Are the voltages different? or would they be interchangeable. I was told that there is only one set of settings for safc for all dohc ka's, is this correct? which could imply that it could be used? Just curious cause ive been entertainin the idea of a lowboost setup on my ka for quite sometime...and this information is great

thanks

Adam

[240Driver39]

nevermind my question was just definatively answered by wiisass on freshalloy later in that thread.

s14 mafs works for s13, or so it did for him

[DuffMan]

Speaking of hacked MAFS, i was looking at KA24E and KA24DE mafs (both S13) and thinking that since the E and SR mafs are interchangeable, and the KA24DE MAFS is a bit bigger, a KA24E wire in a KA24DE housing would be a nice upgrade for an SR. It seems to match up with 480cc injectors pretty well, being a little small so it would be on the rich side which is probably good.

I think I'm going to try it when I have some more disposeable cash to buy injectors.

[AceInHole]

Originally posted by orion::S14
But one thing to note: The theoretical new ID needed to run 370cc injectors is 2.8711" by the numbers...but proved to be WAY too lean on the dyno. I'm using an insert that gets it down to 2.75" ID and it's as the dyno chart shows from above - A decent fuel trim, but a little lean as boost comes on.
Yeah. I was using a 2.6" inner ID (dremeling rubber was only fun for that first .1") before I got the S-AFC. I was always wondering how you were so rich with the full 3" pipe while I needed such a large spacer. With the S-AFC I'm pretty much running it at +2 for hi- throttle with no spacer now. Trying to get on a dyno next week so I can fine tune it.

In any event, JWT is a good solution for the 50lb injectors and those running +300rwhp daily - I'll probably keep mine to use with an AFC and 555s...someday.
Will JWT make a more aggressive timing map if you tell them that you're only going to be running low boost, though??

Anyway, I'm glad you saw that thread and posted it here, Ace...it was my next stop.
yeah... you know me: always trying to keep things going :D I'm glad you were able to do what I wanted to do before I could get to it. Without your help the hacked MAF would still be in testing, but now it seems as though it's a fairly well proven setup.

[SimpleS14]

Originally posted by AceInHole

i wouldn't recommend running 10psi with just a RRFPR, but that's just me. People have claimed to do it, but fuel pressure above 100psi on a system designed to run 30-40psi (stock is a 3 bar pressure fuel setup) doesn't sound like a good idea at all.[/B]

RRFPR??? :confused:

I plan to use a Z32 fuel pump (and maybe regulator).

[sykikchimp]

He was talking about A/F ratio, not Fuel pressure risers.

[orion::S14]

Originally posted by AceInHole

Yeah. I was using a 2.6" inner ID (dremeling rubber was only fun for that first .1") before I got the S-AFC. I was always wondering how you were so rich with the full 3" pipe while I needed such a large spacer. With the S-AFC I'm pretty much running it at +2 for hi- throttle with no spacer now. Trying to get on a dyno next week so I can fine tune it.

So now you're at 2.875" ID exhaust piping with an AFC at +2 and she looks good?

I ran mine with just the 3" OD / 2.875" ID on the street for +2 weeks and it seemed OK, and didn't blow...but on the dyno the A/F showed OVER 15:1 as boost built. Scary.

Let me know - Brian

[SimpleS14]

ok...I'm semi-confused (engine n00b!)....

can I just use a Z32 MAFS, fuel pump, fuel regulator and call it a day?

The kit has a AFR of 12:1 and I would being using it at 10psi...


but those are my thoughts FOR NOW.....it may (or will) change.



<-- clueless newbie :-/

[Frappe]

Will JWT make a more aggressive timing map if you tell them that you're only going to be running low boost, though??

I was also under the impression that for (or so I heard) about $100, one could send in their JWT ECU and a modification list, and they would reprogram it to make optimal use of your engine modifications.

Of course, I heard this awhile ago. Someone correct me if I'm spouting :bs:

[vodka]

That's for a reprogram after the 1st daughterboard replacement(which is 5-600 bucks, usually)

[DuffMan]

Originally posted by 95KoukiS14
ok...I'm semi-confused (engine n00b!)....

can I just use a Z32 MAFS, fuel pump, fuel regulator and call it a day?

The kit has a AFR of 12:1 and I would being using it at 10psi...


but those are my thoughts FOR NOW.....it may (or will) change.



<-- clueless newbie :-/

Nope you cant just swap MAFS without something to re-tune for it.

Hacked MAFS are where the area of the MAFS is increased the same amount the fuel injector size (or fuel pressure if you wanted to do it that way) is increased, but its still the stock hot wire.

[SimpleS14]

Originally posted by DuffMan
Nope you cant just swap MAFS without something to re-tune for it.

Hacked MAFS are where the area of the MAFS is increased the same amount the fuel injector size (or fuel pressure if you wanted to do it that way) is increased, but its still the stock hot wire.

so even if the fuel pump and regulator are from the Z32, I still have to re-tune it?

re-tune = using dyno + S-AFC ??

[DuffMan]

Fuel pump and regulator dont matter. Fuel pump just pressurizes the system to what ever the regulator is. And all regulators are 3 bar as far as I know, so that wouldnt matter either.

You could use a SAFC to tune for the different MAFS or a tuned ecu or standalone.

[AceInHole]

Originally posted by orion::S14
So now you're at 2.875" ID exhaust piping with an AFC at +2 and she looks good?

I ran mine with just the 3" OD / 2.875" ID on the street for +2 weeks and it seemed OK, and didn't blow...but on the dyno the A/F showed OVER 15:1 as boost built. Scary.

Let me know - Brian

yeah. i was running that for 6psi and it seemed ok. Cheap A/F meter read +2 green into rich, but recently I upped to 9psi and it's now at +10 from 3krpm up. I really wanna play with fuel pressures now, though. Need to start calculating what the pressure needs to be... keep forgetting to do that instead of fall asleep in class :bash:

[AceInHole]

Originally posted by DuffMan
Fuel pump and regulator dont matter. Fuel pump just pressurizes the system to what ever the regulator is. And all regulators are 3 bar as far as I know, so that wouldnt matter either.
Well, you could use an adjustable fuel pressure regulator to raise baseline fuel pressure, which would give you a linear increase in fuel delivery just like larger injectors would.

Kind of makes me wonder if you could run something like a 5 bar fuel pressure or whatever it would take to get 270's to act more like 370's.....

[sykikchimp]

To find flow rate of new pressure:
B x (squareroot(X/Y)) = A

A = New Flow rate
B = Orig Flow rate
X = New Pressure
Y = Orig Pressure


You get ~348.5 cc/m with 5bar fuel pressure

OR to find Fuel pressure to reach specific flow rate (probably more usefull, since you can get an adjustable fpr, and a fuel pressure gauge.)

Y(A^2) / b^2 = X

for 360cc/m = ~77.3 psi or ~5.3 bar

But remember that with the Stock 1:1 FPR you will be adding 1psi of fuel pressure for every psi of boost.

If you tried to run an RRFPR, things would get out of hand fairly quick at 5 bar, because you'd already be taxing the injectors pretty hard.

Also, I have no idea how well the injectors would flow at 77.3 psi. The spray pattern could be disrupted, or not be properly atomized. Let alone add another 8-10 psi for boost.. I wouldn't think almost 90psi of fuel pressure is good for injectors built for 43.5.

Of course I haven't tried it, so I don't know.

[AceInHole]

thanks for breaking it down. i've been pretty lazy about things lately... most of the calculations I end up doing are done during boring classes (Linear Systems Theory for one).

As for pressures: consider that a 10:1 RRFPR is adding 10psi of fuel per lb. of boost. Running only 7psi of boost, you've got an extra 70psi of fuel pressure: or 113.5psi of total pressure. Some people even run 12:1 RRFPRs at that much boost.

Staying under 100psi doesn't seem so bad in comparison.

Still need to crush a FPR to see if it'll even work, though.

[sykikchimp]

So can you just buy a 5 bar fuel pressure riser??

I wonder what kind of range the Nismo/tomei Adjustable risers have?