I think that a lot of people have a bad stigma when it comes to MAF sensors. I mean think, if you lay down a fuel and spark map, you won't have to reprogram it every time you change the VE of your engine! A lot of people think that they are restrictive, but it is really not true. There are some really big MAFs out there, and they will read up into the very high HP numbers. It is worth a look guys!

 

when was the last time you saw a F1 car using MAFS?????


If you understood the true fuel requirements of an engine under boost, when changing turbos etc you'd realise its not quite as simple as it seems

 

There are a lot of things that an F1 car has that many mortal cars do not have. Just because an F1 car has something, doesn't mean it is the best option for the rest of automotive world!
It seems that you understand the true requirements of an engine under boost, so perhaps you could share with us feeble folk...

 

I read somewhere (yamaguchi book I think) that mazda chose to use the MAP over the MAF for throttle response reasons. When switching to a haltech or other stand alone ECUs, you are left with an option to go either route. For most people out there, with upgraded ECU's, piggybacks, and possibly the PFC(not sure about this one), they are stuck with the MAP system whether they like it or not. I do believe that if MAF sensors were used then a lot less people would be blowing motors. But in the right hands the MAP is a superior setup and that's why madza went through the trouble of using it in the FDs.

 

exactly MAP/TPS pick up systems are superior to AFM systems, the thing is they require more programming oomph to run

 

The best reason I can think of to not run MAF on a turbo car is...the blowoff valve...with a tuned engine, you could putting out so much air from that thing (that the computer still thinks is present), you would stall the car...do you really want to flood it in the middle of a race? Didn't think so...

Edit: I actually prefer MAF systems, personally, especially for N/A cars, and sometimes blowers...that's what's going on the 355 I am currently building...

 

Blue Goose,

The solution to that problem is simple! Its called a recirulation valve, instead of venting to the atmosphere, you pipe the air back in after the MAF, but before the turbo. This is the standard method on OEM cars with have a turbo and that use a MAF system. You don't get quite the noise of a atmospheric BOV, which to some is a plus, others, a minus.

 

when you are blowing 20psi at 8500 and the throttle body slams closed and the BOV opens, it dumbs a HUGE amount of air, that would be enough to cause some kinda back flap flow.

Even on a N/A car a descent efi system with MAP/TPS can run a car perfectly

 

And every time you make a change, you need to reprogram. Some of us like to change things frequently. I like to drive my car, thank you, and not have it towed to a shop along with my next two paychecks so they can re-calibrate the computer for me every couple of weeks.

Meanwhile, check out the 10-second and less Mustangs still running stock computer... Gotta love MAFs, unless of course you happend to have a dyno in your garage for all that constant re-programming

 

Supra's top out on power because of thier MAF sensors Skylines also top out. They top at 450 at that point most supra owners have to get a HKS VPC wich reads speed density.

 

aftermarket efi systems were designed for usage on race motors and the like originally, how many race motors get something changed on them between meetings which is enough to warrant a re tune? You modify the motor to how you want it. you get it tuned, you race, in the off season if you wanna have a play with other things you do.

Peejay - by the looks of it you dont even have enough mods to need anything more than the factory computer anyway, aren't you running a carbie and distrubutor anyway?????????????. So unless you happen to frequently change significant things like, going from a std port to a bridge port, then bolting on a T03 turbo then swapping it to a T76 and so forth it wouldn't need to be touched. To be able to play around with things and have it still running on the factory computer, the changes cant be too major, remember playing in turbo land is very different to playing in n/a land

but......
If a motor is totally tweaked it'd need to be retuned if you change something of significance weather it uses MAP/TPS or AFM/TPS

 

It's funny you should mention fast Mustangs running with the MAF!
I guess you don't actually hang out with those guys, consistently messing with the FMU's etc. The best part is that every one of those cars I've converted to Map with stand alones couldn't believe the difference in power,driveability and consistency!. Plus the only people who are consistently making drastic changes with thier set-up are either lost or have no clue what they are doing!

crispeed
87TII
9.20@150mph

 

finally some other people with their head screwed on the right way

 

With a proper ECU and MAF sensor like maybe a late model Karmann, (one of the most accurate) you could achieve what your looking for.

Auto tuning is very desirable from an owners stand point, less time tuning means less money to pay someone else. The latest Mitsubishi MAF's are fast enough and more accurate than a UEGO sensor for auto tune. I know Doug At EFI systems has messed with this alot. His MAF setups run very well but some of them run a hotwire MAF.

There are a few problems with MAF systems, like if you blow a pipe, you cant finish the run, if you have a slight leak the car runs super rich. But these aren't really the problem with the MAF itself now are they?

Another solution is to put the MAF in front of the Throttle body. But a Karmann won't work well in turbulent air. So your stuck with a hotwire, there is a specific type you can run in line whose name eludes me right now, unfortunately it usually drops about 1psi across it. That kind of pressure drop is not acceptable to some.

I thought about using MAF a few years ago when UEGO was not yet available, but now that it is readily available, and new systems coming out everyday with this feature, racers, who traditional don't like the added complexity of MAF, can now settle for UEGO auto tune, which for all intents and purposes are fast enough. I personally would love to spend less time on the dyno and more time at the track, cause I try new setups all the time.

You'll notice almost all turbo cars come from the factory with a MAF, because if something goes wrong the ECU can compensate for the changes, or if something has been modified, the factory doesn't end up with huge warranty claims. In the case of the FD, this is probably where the car got its bad rap for grenading engines, combine the fact that you already have a fragile engine, a bunch of inexperienced tuners who just throw parts at cars, a heavy breathing motor now equipped with a monster turbo, stock fuel maps, presto, you now have a car that will blow motors constantly.

I believe mazda just went MAP for packaging, not enough space in the FD for a MAF sensor, whereas the Cosmo 13B and 20B all had MAF's

1 DSM 1st gen MAF car (hacked) I tuned made 540 hp. another 2nd gen car (with the better MAF) makes 435 @ 21 psi. These are street cars, most people who read this board would give a ******** to have that much power in their cars. I saw, I believe, the Apex-i skylne running twin MAF's that thing pumps out 1000hp. Jim Wolf gets creative, when the stock MAF becomes too small he puts a dummy MAF on, and effectively halves the signal coming from one MAF.

A GOOD MAF tuned properly can work well, stay away from Mazda flapper types.

 

Apexi Skyline - running a Power FC no doubt......... no thanks

 

HWO,

Map systems are far from perfect, every stock FD that comes in here, each one runs differently from either too rich or too lean on the wideband. Engine is a little weak, air filter is clogged, whatever. This is due to every particular car being different and a map that is the same for all the cars, that just can't compensate. From a manufacturers stand point MAF is superior.

Every Mass air car that comes thru here usually runs the desired A/F ratio. because it makes a calculation based on ACTUAL airflow, not guessed airflow.

Apex-i built that car with the power FC to showcase their products and show people like you that it can be done.

What the **** would I know anyway? I got my head screwed on backwards.

 

when it comes to modified cars, factory computer systems suck, end of story.

Nissan computers would be tthe best of all the factory ecu's out there, but they still dont have the input/output functions of a good aftermarket efi system