Altering the MAF on a 1992 SC400....

[jibbby]

I have an extra Mass Air Flow unit and this is the most restrictive part of the intake system and is very sensitive to change...I tried removing the very front mesh screen to increase flow and the engine ran like crap..Quickly put it back on...Now looking down the inside there is a pertuding plug bolt end that looks like it may restrict some air flow...It is a plug bolt...I am thinking of grinding it down flush...Better yet if possible grind out the inside divider...Now do you guys think that will effect anything? Here are some pic's of what I am trying to explain....

This end bolt that I would like to ground flush is almost visible in picture #1 at the right side of the inside of the MAF near the wire screen.

Maybe I should have posted this in the engine section...ooooops. too late now..

 

[Lextech]

I believe that is an adjustment plug used for calibration from the factory. I don't think you should mess with it. I could be wrong, but I think I'm correct.

 

[Zuffen]

That little protrusion is part of the vortex reader.

Remove it and you've destroyed the AFM/MAF.

 

[UZZ30-Québec]

the honeycomb is very useful dude.

it divides your air flow equally trough the unit to ensure you,ve got a very clean and accurate reading.

did you test your MAF for airflow? i don,t think it's that much restrictive. maybe you should go with another sensor then, or use 2 AFM and multiply your reading by 2 or something like that. your throttle body plate is probably more restrictive than the AFM.

even if you'd build a bigger AFM, with the same electronics, it would probably run like crap because it is all calibrated for this size unit.

 

[Peewee]

Thats the air temp sensor Jibbby

 

[Lambo]

Jibby , the Honeycomb can,t be removed it is there to staighten out the incoming airflow so it travels at the right angle to hit the centre vane .there is some good info in this docment. http://www.suprasonic.org/lexusriemer/lexusnotes.html

I have also been thinking of a way to mod the AFM to allow more flow or a way of running two afm's for twin turbos, if you read the above article carfully it outlines how the altitude sensor in the ECU box adjusts the mixture for a given altitude, if you were to climb a mountain ie in Colorado its 7 miles up the air gets very thin, and a car i was once in had been turned for Texus altitude and the engine lost power the higher we went and failed to run, just not enough air for the amount of fuel, this got me thinking if we could modify the Altitude sensor output in some way to trick it into thinking it was 500 ft BELOW sea level then the standard computer would add more fuel provided we could either rebuild the AFM with a bigger flow so more air comes in, anyone have a throught on this idea.

Best regards
Lambo

 

[jibbby]

Man this MAF thing is more sensitive then my x-girlfriend... I would love to open it up some for flow and get ahold of a bigger throttle body......However, I Won't mess or try to allter my current MAF...thanks......

Hey, Does swictching to a MAP have any advantages over the MAF? If so what are they and what are the drawbacks?

 

[jibbby]

LAMBO, just read your post and I find your threory very interesting....Thanks everyone for the lowdown...

Any upgradeable swaps from the newer SC's that maybe interchangeable and flow better?

 

[Lambo]

Don't think i would be messing with the original AFM from my car, my thought was to buy another unit and disect it, and mod that, most of the Mitzi,s have a Karmen AFM so maybe a AFM off of a Twin turbo GTO is worth a look.

Lambo

 

[Toysrme]

jibby, oh lordy the map/afm(vane flap)/maf debate (Throw kv's away lol!).

*AFM is smoothest transition
*MAF has a better transition resolution
*MAP has superior transition resolution
*AFM not upset by turbulence
*MAF is susceptible to turbulence when used near bends
*MAP not upset by most turbulence
*AFM can be damaged by backfires during low deflection angles
*MAF can be damaged by backfires
*MAP not normally damaged during backfires
*AFM provides self means for mild tuning via the meter cog, Arm, and idle by-pass screw

MAF/AFM = Load sensors
*Load sensors read actual mass of charge
*MAP reads density of charge, ECU round about computes mass
*Load sensors are more accurate than MAP sensors
*Load sensors require more tuning under boost, have problems measuring flow when used out of parameter
*MAP sensors easily tuned under boost, creates problems tuning N/A
*Load sensors cope easily with large flow changes, require less re-tuning VS MAP during modifications
*MAP sensors require more re-tuning during changes
*MAP sensors easily confused by most powerful N/A modifications
*Load sensors in common size(70-80mm) pose 5-15 in/water of restriction, will flow a vacuum maximum of 500-600cfm. Most Load sensors are designed to read 175-250CFM under typical vacuum - regardless of what the "package testing data" tells you & how big it really is!.
*MAP sensors pose microscopic flow restrictions, are limited to pressure range, not outright flow.



The best thing many times is a large MAF/AFM, with a MAP sensor to refference under boost.
N/A, you're much better off with a load sensor, than a map sensor, any pressure drop be damned.

 

[Toysrme]

Lambo.
Personally, I would leave the KV sensor. Then grab one of the more advanced piggybacks around now (that you can afford) that can tune multiple things, using multiple data entries.
A load sensor works well when you're tuning that, but scaling all of your tune based off a MAP sensor under boost. It eliminates alot of tuning to get something dialed in.

 

[jibbby]

Toys - You always take the time to break it down in length and I for one really appreciate that....It even sounds like this is repititious and boring for you to post.. Which makes me even more appreciative....Thanks toys...I will do some research on your info and suggestion......

 

[jibbby]

Uzz30- I also dought the throttle body is more restrictive then the MAF unit...Ther Throttle body is larger in diameter...The MAF I would think would defenitely have to be the most restrictive part of the intake system..no?

From my readings and tinkering it appears the NA intake volumes is more a matter of streamlining airflow over increasing passage since the air intake demand really isn't very large with an NA motor....That is why you don't see any real benefits from changing from stock intake to an after market intake like the BFI, Injen, K@N, etc..on an NA motor...

An AFI engine setup is a different story for sure......

Best flowing intake for an NA would be these little babies, but not practical.....

 

[jibbby]

Toys you broke it down..thanks again... However, Just wondering why I am hearing and reading that the MAP's are the way to go?? You are saying the MAF's..and others are saying different which is confusing me...I believe and trust what you say...Just need a little more reasurring....

Also Lex talked about dual MAF's on his 1uz-fe AFI application? How is one to enlarge the single stock MAF for increased airflow or change to duals? How does one have install dual MAF's and run them both off the single stock ECU and MAF sensors? I am thinking you need a Stand Alone or high end piggy to pull off that Dual MAF.. I can't imagine you just splice each MAF sensor and feed each into the two MAF's?...It seems if you touch anything on the stock MAF the car goes crazy. I can only imagine what two headaches would be like as apposed to just one....Like the stubborn person I am, I contiunue to tinker with my extra unit, grinding, tweaking, etc..nothing works... Yet I have read one or two people have altered the MAF for the better but can't explain how they did....I get, "my mechanic did it, I don't know"?????

I really am trying to leave my MAF alone but I can't when I see how small the air passage is......I start wondering what if? Kinda like a little kid in the candy store...Even though I realise there is very little benifit to a modified MAF on an N/A 1uz-fe...I figure anything I get now can only help and I can also swap later on down the road on a turbo setup or something crazy... I don't see it as wasting money...Just looking for a way to upgrade this intake and throttle body..??

Peewee - Am I driving you crazy yet?

Lambo - That link you provided is very informative but still really doesn't show how you can alter the MAF for the better...

 

[Damien]

Jibby, about a year ago I removed my MAF and replaced it with 90mm PVC pipe and fitted a MAP-ECU which uses a MAP sensor to calculate load. It only does fuel (not spark as well like most piggybacks would) but I noticed much improved torque at part throttle and more peak power without the MAF slowing things down. With a heat shielded pod filter, Rush headers, dual 2.25" exhaust with cats and the MAP-ECU I got 160rwkw or about 214rwhp. With a standard plenum and throttlebody I didn't have any tuning issues.

The photos you posted above are from my website and after I fitted the ITB's peak power went up to 178rwkw (238rwhp) and it feels more torquey too. They really aren't that impractical to run (bumper to bumper traffic is fine) but a PITA to initially set up.

However, there are other examples out there where a piggyback that does both fuel and spark (like the Unichip) have netted 230rwhp or more with the standard MAF in place. So you have options to remove it or leave it but trying to alter something as sensitive as the MAF wouldn't be advised.

 

[jibbby]

Damien - 90mm PCV pipe? Wow, very creative.....I would love to see a picture of that... So on your N/A motor you felt gains off just that intake MAF mod?.... It was my undersanding on an NA 1UZ-FE motor there is little benefit or gains to be made with any MAF or throttle body mod.. Were you running stock cams with that engine? This is encourging news... WOW, So with your MAP ECU reading only the capacity load you had no tuning issues or problems at idle?

I really am not suprised you noticed torquey mid range gains just off that intake mod...I always thought the stock MAF is so very restrictive even for the small 4.0 liter V8 motor.. If I were to throw that on one of my older small block Chevy's I would have choked the engine out...that is why I keep messing around with this MAF.. I can definetely see how that can help with increased effortless intake flow.... Thanks for the input Damine....

Oh, Sorry for stealing and posting your 8 TB pic..very nice.... I have no doubt that there are gains to be made with that setup....You also said this can be street friendly? I would think keeping them dirt free would be a challenge, and I would think after continued use you would get one or TB butterfly's sticking or something...8 TB'd as apposed to 1 for regular everyday driving...Are you sure about that, that sounds like trouble with so many moving parts?

 

[Damien]

When I installed the MAP-ECU I was also able to tune the fuelling better so that also contributed to the better performance... it might have been the main factor as it's hard to tell when changing 2 things at once but I was pleased with the end result. The engine is internally stock as a rock.

I have a large foam airfilter covering all 8 trumpets at the moment but I'll be changing to twin airfilters behind the headlights to get cold air in. It's not like I drive on dirt but with more moving parts there is more scope for things to go wrong.

 

[cjsupra90]

hey you'll, check this out. http://www.maftpro.com/ I cant tell you a hole lot about it as I have never really looked into it as I am running a full standalone unit and have been for several years. This is a big item in the MKIII supra comunity and works quite well for the turbo MKIII supra's. Being that both the lexus/toyota V8's and the turbo MKIII supras both use Karman Vortex type AFM's I dont see why this wouldn't work on a V8 car Especially being that one of the common cheap upgrades for supras is to run a lexus V8 AFM which allows for the use of 550 injectors in the supra. So being that the lexus AFM works on the supra, the MAFTPRO should work on the lexus.

 

[jibbby]

hey you'll, check this out. http://www.maftpro.com/ I cant tell you a hole lot about it as I have never really looked into it as I am running a full standalone unit and have been for several years. This is a big item in the MKIII supra comunity and works quite well for the turbo MKIII supra's. Being that both the lexus/toyota V8's and the turbo MKIII supras both use Karman Vortex type AFM's I dont see why this wouldn't work on a V8 car Especially being that one of the common cheap upgrades for supras is to run a lexus V8 AFM which allows for the use of 550 injectors in the supra. So being that the lexus AFM works on the supra, the MAFTPRO should work on the lexus.

That can help with tunning but still does not open the airflow passage on the MAF...I am interested in increased effortless intake flow....However, that maftpro does look like a good tool for fine tuning...Good find...

 

[jibbby]

I wonder if any one has tried an old fashion 850CFM Carb or even two on the IUZ-FE and just dumped all the computer and fuel injection crap....I am a bit old school and those carbs were so simple to work out even a 1st grader could figure them out on an older Chevy....You almost have to be a rocket scientest to figure out all this sensored MAF,MAP, ECU crap.......Give me a couple of massive carbs and a custom intake manifold dump the injectors and see what we can get......(ha ha)