Major noob question

[2fst4u]

So I see a few cars that push out high power, or even just show cars, that run with no airflow sensor ahead of the turbo intake. How does this work? How does the ECU know what A/F ratio the engine is running and what do I need to run my engine like this? I like how clean it looks but can't understand how it is efficient in any way.

 

[Chriscooke]

You need a different engine management such as a power FC d-jetro

 

[2fst4u]

Well there's no way I'm getting a Power FC. What aspect of that ECU is it that allows you to run an engine like this?

 

[Chriscooke]

It uses a map sensor in place of the afm. Wont be able to do it with the standard ecu as far as i'm aware.

 

[2fst4u]

So where in the system is the MAP installed? It's when I see a gigantic turbo under the bonnet of a non descript car with absolutely no air filter or anything in front of the compressor that I start to rack my brains about this

 

[spoonman]

in the intake manifold a stable location after the T/B, they measure air pressure instead of air flow, which is why you can lose the recirc system and run a atmospheric BOV without over fueling at low revs

 

[spoonman]

the other part is you also run a intake air temp sensor, the ECU determines the O2 density by the temp, then the pressure as it goes in to determine a exact amount of O2 going into the engine

 

[2fst4u]

in the intake manifold a stable location after the T/B, they measure air pressure instead of air flow, which is why you can lose the recirc system and run a atmospheric BOV without over fueling at low revs

the other part is you also run a intake air temp sensor, the ECU determines the O2 density by the temp, then the pressure as it goes in to determine a exact amount of O2 going into the engine

Ahh I see. Do any aftermarket intake manis facilitate the installation of a MAP sensor? Or do you generally have to drill a hole yourself (read, get someone else to)?

And hopefully final question, what ECUs allow the use of MAPs? Do Link?

 

[Auss15]

MAP (Manifold absolute Pressure) sensors vacumm pressure in the intake manifold and makes the adjustment for air/fuel ratios. Its really for big horsepower cars as it does away with part of the intake restrictions of a MAF sensor.

It's is harder to tune then a MAF sensor as the vacumm pressure in a manifold can vary and changes as an engine wears. If you are going to be spending a bit of time above 5000RPM then it's a better option.

The MAF is a lot easier to tune and hold tune as it measure air flow and air temperature via a hot wire sensor . It's what's called a closed loop system.

Motec, Autotronic and Haltec all have ECU's to run MAP sensors.

 

[2fst4u]

Rooooooger that. Cheers for the help, guys

 

[spoonman]

Yep the Link G4 uses MAP, but dont bother with a link until you are looking for a hell of alot more power, as its alot of money to spend on a lightly modded engine


and just thought i would chuck this in..

and before someone tells you that you have to get rid of the stock MAF "as its tiny little hole is really restrictive", they are talking out there arse, only upgrade it if you plan on running well above 200rwkw as the stock MAF can only read smaller airflow (voltage thing not a diameter size thing) the RB is in the middle for voltage and the Z32 has the highest airflow reading but RB & Z32 are the same size, which is why heaps of people buy them, but they arent really needed until you go for man levels of rwkw

 

[spoonman]

and to answer your first question , Your ECU measures air/fuel ratio's with the O2 sensor in your dump pipe, once you start upping boost and fueling you run the risk of running lean, or rich, which is where a wide band O2 comes in, aftermarket ECU's will understand wideband O2, stock ones dont, the stock O2 sensor only measures a small range, as its assuming the car is not running 1bar boost, but we all do anyway, this isn't normally a big problem but you dont want to run lean and risk DET you need to be able to accurately measure the ratios

 

[lvaleiron]

just to add some comments here, you can get with that clean look without getting rid of the maf but is a method that some people like and some other doesn't. You can do a blow-through maf installation, which basically means installing the maf before the t/b together with the intercooler piping (you can find specifics by googling as you'll need some ideal piping requirements to be effective), there are a couple of people that i've seen running this kind of setup for more than year and never had a problem with it, and fixes the issues with the bov or boost leaks that you may have on a normal maf system.

 

[spoonman]

just to add some comments here, you can get with that clean look without getting rid of the maf but is a method that some people like and some other doesn't. You can do a blow-through maf installation, which basically means installing the maf before the t/b together with the intercooler piping (you can find specifics by googling as you'll need some ideal piping requirements to be effective), there are a couple of people that i've seen running this kind of setup for more than year and never had a problem with it, and fixes the issues with the bov or boost leaks that you may have on a normal maf system.

interesting.. any links to site that show or talk about this setup?

 

[lvaleiron]

there is a lot of info on internet forums, just a bit hard to come by, but i would recommend reading thru these two pages:
http://www.lasotaracing.com/techdrawthroug.html
and
http://www.sr20forum.com/turbo/81442-blow-through-maf-setup.html

 

[2fst4u]

So basically just a straight as piece of intercooler piping is required to set up a blow through MAF? If that's the case then sign me up

 

[spoonman]

So basically just a straight as piece of intercooler piping is required to set up a blow through MAF? If that's the case then sign me up

before you go down that track, learn what you need to know about your current setup "the tried and tested route"..... then later on down the track try something like that as you wont be able to do it with your stock MAF you will need something like a Z32 maf

 

[2fst4u]

Fair call. I have a massive aversion to taking apart anything to do with my car anyway. I'm far too afraid I'll F*** it up blow something.

 

[lvaleiron]

before you go down that track, learn what you need to know about your current setup "the tried and tested route"..... then later on down the track try something like that as you wont be able to do it with your stock MAF you will need something like a Z32 maf

i don't know about that, the people i've seen trying this have z32 maf true, but i see no reason why it won't work with the stock one... it will be good to investigate though. I know i've seen webpages that sell an adapter that you weld into your piping and just screw the heating element of the maf on it.

 

[spoonman]

Fair call. I have a massive aversion to taking apart anything to do with my car anyway. I'm far too afraid I'll F*** it up blow something.

trust me that will pass, and beside how else are you going to learn