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View Full Version : PowerFC: MAF Vs. MAP



_Nzo_
05-23-2005, 12:43 PM
I have a normal PFC right now which I bought over the D-jetro version because people felt that D-j wasnt needed unless you are going for power over ~500. But recently I've been hearing people saying 'maf sucks', 'maf pcf is a waste of money', etc. I have a fpbig28 and dont plan on upgrading anytime in the future so I'm aiming at ~300+ whp. Should I sell the PFC and buy a D-j version or just keep the MAF?

Also, can the MAF version be converted to D-j with the addition of the sensor kit or are the ECUs programmed differently? I only ask because they seem to be the same price which is odd.

johnyQ
05-23-2005, 01:41 PM
***MAF

advantages:
-Measures actual amount of air entering engine, which gives accurate A/F ratios in variety of conditions and good transient response characterstics. Also makes it friendly to changes in VE (mods).

disadvantages:
-Sensitive to airflow reversions, resonant frequencies in intake tract, EMI noise, and presents a small restriction in airflow (in my mind a possible annoying point of failure and an eyesore if you are into engine bay looks).


***SPEED DENSITY (MAP)

advantages:

-Immediate response to throttle. With maf, the air cannot be metered until the low pressure front from the throttle opening travels back to the sensor (so the further back from the throttle plate the more lag in throttle response).

-No airflow restriction.

-Very robust (durable), and less sensitive to EMI.

-Simple/clean install, and allows atmospheric BOV, for the ricer in all of us.

Disadvantages:

-Does not actually meter air, but rather is based on load points/ VE maps. So when something small is changed that alters the VE, it must be tuned for. Also, older EFI programs could not handle transient throttle as smoothly as with a MAF, but at WOT there is no difference in capability between the two.



That is what I learned or experienced, and why I went with speed density. Hope it helps. I have a brand new in box d-j power fc for sale if you are interested (check fs forum). [list]




It is not possible to use your MAF power fc with a MAP.

sorce
05-23-2005, 04:27 PM
I'd probably stick with the PFC L-Jetro for now since you've already purchased this. If you're looking for around 300 HP then it should be fine. The only thing I don't like about mine is the fact that when the weather gets cold, the idle bounces due to the sensitivity of the MAF in these conditions. Other than that, load up the Enthalpy base PFC map, and tune it from there.

SilviaKs
05-23-2005, 06:51 PM
is the Enthalpy base map good has to be used with a Z32 MAF right? Does injector size matter?

cheez80
05-23-2005, 06:56 PM
just throwing it out there, but if you run a blow through setup, you can run an atmos bov too! =D

Hugh
05-23-2005, 07:51 PM
Just keep it the way you have it.

With 300hp and no plans to step it up, no need to change it.

If it runs well for you, why change? http://forums.freshalloy.com/images/graemlins/wink.gif

_Nzo_
05-23-2005, 09:01 PM
If it runs well for you, why change? http://forums.freshalloy.com/images/graemlins/wink.gif



For the same reason the fat kid with the StarWars lunch box asks his mom for a 50cent one http://forums.freshalloy.com/images/graemlins/wink.gif

Being able to run an open bov would be nice but honestly I'm at the point where I'd rather recirculate it anyway. So if theres no point in a MAP I guess I'll keep it and put the money into a datalogit instead.

Hugh
05-23-2005, 10:48 PM
I like the MAP better because I find it much faster/easier to tune.

If your computer is tuned well, then there's nothing to worry about. Thats all I'm saying.

If you're not looking to make massive power, I wouldn't even bother.

benevolent
05-24-2005, 06:39 AM
i haven't had any problems with idle or atmospheric BOV with a regular MAF based PFC. i haven't driven when it was below 50degrees or so either though. i didn't think that the PFC would look much at the MAF input at idle.

SRFiveTen
05-24-2005, 02:39 PM
i didn't think that the PFC would look much at the MAF input at idle.


[setting] - [air flow] - adjust the % values of 0.64v and 1.28v by say +/-20%, observe the changes in your idle quality.

SRFiveTen
05-24-2005, 03:08 PM
The only thing I don't like about mine is the fact that when the weather gets cold, the idle bounces due to the sensitivity of the MAF in these conditions.



do mafs data fluctuate in relation to air temperature?
monitor the voltage value of key-on at night and day.

champa
05-24-2005, 03:43 PM
i'm going with power fc d-jetro very soon for my engine rebuild. would it be possible to use a GM map sensor or should i buy apexi's sensor kit? and what exactly does this sensor kit come with anyway?

johnyQ
05-24-2005, 03:47 PM
It comes with a map sensor, intake temp sensor and 2 wiring harnesses. You would want to get the kit because of the harnesses.

_Nzo_
06-01-2005, 10:31 PM
Bumping this because someone suggested this possibility to me. Would it be possible to simply wire a MAP in place of the MAF (I'm told both use 0-5v operating voltage) and somehow use the TPS as a load source? I dont know anything about how the PFC works internally but what would prevent this from working? Not really planning on doing this, just an thought.

SRFiveTen
06-01-2005, 11:11 PM
but what would prevent this from working?


simple laws of economics http://forums.freshalloy.com/images/graemlins/rolleyes1.gif

<edit>
apex-i would not be selling the d-jetro units if the conversion from l-jetro units were that simple.

if you were to send in your l-jetro unit to apex-i, they might be able to convert it for you for some unknown cost.

i did ask them if they would upgrade my d-jetro unit with two step and ignition cut rev limiter, apparently, they cannot, even at any cost.

inside the d-jetro unit, there is a third map not found in l-jetro unit, obviously mafs correction feature is deleted in the d-jetro unit,,,,
that someone needs to study more, as we all, including myself, do.
</edit>

_Nzo_
06-01-2005, 11:46 PM
Haha ok ok, so anything is possible with money http://forums.freshalloy.com/images/graemlins/tongue.gif

dryft_s15
06-02-2005, 05:31 AM
Actually, in the Fc-Datalogit group, there was a guy that used a MAP sensor on his Celica (2ZZ motor) in place of the MAF and it worked fairly well according to him. It's entirely possible to program the fuel values to work with a MAP reading instead of MAF (it's the same 0-5V scale).

The only issue I'd see is lack of air temperature correction, so it would run great under the conditions it was programmed in, and like poo with drastic changes in temp or altitude.

Sil_40sx
06-02-2005, 09:43 AM
I have one question on this matter, how much in cost for someone thats want to run a MAP PFC d-jetro? vs the MAF PFC l-jetro?

Btw, I'm think running a EFI Technology RACE 1.0 ECU check my signature for the web link. This will cost me $2000-3000 with harness. And you can transfer this ECU to another car just by sending it back for the modification to run on another car.

BlazedGlory
04-16-2006, 10:54 AM
I found this and thought I'd reply to it rather than start a new thread.

I'm almost done with my rebuild. I will be using a SC50-31E, so I don't plan on getting much more than mid-400s at this point. I guess there is always the possibility of upgrading my turbo, but at this point I don't see why I would...

I already have a Z32 MAF in my parts collection, and I was originally planning on running a blow-through setup. But I was also originally planning on a rom tune from enthalpy, but I haven't gotten an email response in months. Then I was thinking about a biki board, but it seems that guy has nearly discontinued his business as well.

It would be worth the extra money to me if the D-Jetro PFC would be a good idea for me. It seems most people that are getting a PFC these days are going ahead for the MAP setup. Would I be stupid to go with a L-Jetro PFC?

Thanks

champa
04-16-2006, 11:55 AM
either one will get you the power you want. it's just a matter of preference. i went d-jetro cus i got it for cost and the fact that i can ditch the air filter altogether was worth it for me. however i always recommend people to get a l-jetro and use the extra money you save to get a fc-datalogit.

JRODS_240
04-16-2006, 12:03 PM
I have the L-jetro pfc and a few others from the local group. I would use the d-jetro pfc if i had a inline six motor like the rb or 2j, 1j,ect; a motor that would push more than 600+hp
in which using the afm would hinder from getting full potential, due to the limited air flow of the afm.

IMO if you want 400 to 450hp the L-jetro would be cheaper and more than enough for the power you want. Also maf equip cars tend to run alot cleaner than map base car so they say.!! http://forums.freshalloy.com/images/graemlins/cool.gif

BlazedGlory
04-16-2006, 12:34 PM
either one will get you the power you want. it's just a matter of preference. i went d-jetro cus i got it for cost and the fact that i can ditch the air filter altogether was worth it for me. however i always recommend people to get a l-jetro and use the extra money you save to get a fc-datalogit.



Could I get an L-Jetro PFC without the commander and just get the datalogic to save even more money (although I'd have to also get a cheap laptop but it would be worth it because I could also use it for my wideband logs =P)

HIGHMILEHATCH
04-16-2006, 06:45 PM
Having the commander is worth it for the monitoring features alone IMO. You can pick up used L-jet Power FC's all day long for $500-$800 depending on application.

champa
04-17-2006, 09:35 AM
you don't need the commander if you have the fc-datalogit but i would still recommend getting the commander as well.

haven't seen any forsale for awhile but used l-jetro go for about 600$ around here.

oh, and if you want 600+ whp you can always use two MAFs and set the maf correction to 50%

AceDrifter
07-25-2006, 02:20 AM
I thought I would bring this back up because it is a helpful topic. My dilema is finding the D-Jetro sensor kit. I can get the D-Jetro version and the L-Jetro version for the same price new, so obviously i'd go with the D-Jetro, but I can't find the sensor kit. Do any of you know where I can purchase one? Thanks

faljukin
07-25-2006, 03:26 PM
http://www.nengun.com/
They have them listed.

http://www.greenline.jp/catalogue.php
I got my d-jetro with all parts from them.

Good chance shops in your own country have them too though..

vosko
07-25-2006, 11:39 PM
www.jdmfresh.com (http://www.jdmfresh.com)

they are a powerexcel dealer and might even have it in stock

XSDAILO
07-26-2006, 03:55 AM
Before switching to D-jetro consider where you'll be driving the car as the PFC d-jet lacks altitude compensation. If you live in Denver and are going up and down the mountains, it's going to suck. MAF helps in this respect because its actually metering air and density.

We have harnesses and sensors in stock and are a power excel dealer as well.

XSDAILO
07-26-2006, 03:58 AM
my bad, double post.