Bigger turbo means lean mixture?

djtreble wrote:

0.5 bar is a pressure reading isn't it? So the MAP would see the 0.5 bar on both turbo's

The MAF measures the air before the turbo anyway so wouldn't the turbo be sucking in the same mass of air to build up 0.5 bar pressure in a system of the same size despite whatever turbo is on there?

Basically the air mass and air pressure would be the same at 0.5 bar no matter what turbo you use? Or am I totally wrong? 🙄

different turbo measure different at 0.5bar... coz the size different... both MAF and MAP are measure before entering the Turbine

Are you sure, as far as I am aware the MAP sensor is installed after the turbo as close to the manifold as possible, so it measures the manifold pressure (hence the name)? There is no pressure before the turbo, just air mass.

0.5 bar is a pressure reading isn't it? So the MAP would see the 0.5 bar on both turbo's

Yes BUT they will produce different power because of the temp of the air.

Gary57 wrote:

Yes BUT they will produce different power because of the temp of the air.

Makes sense colder air**=more dens air=**need more fuel

In this case, because you are running the MAP sensor and (I pressume) MAT sensor (temp sensor), any small changes will mean your map is off. The advantage of running a Z32 AFM (or any AFM/MAF capable of measuring your power) is that you can make small changes without the need for a re-map (such as running a bigger turbo at the same boost, changing exhaust system, changing intercooler and piping, etc).

Exactly, well almost, changing the intercooler will change the mass of air entering the motor and the MAF wont "know" about this.

In all of this I have just worked out your problem Draco.

Your car is mapped for higher heat air coming through at 0.5 bar. Now that you are running the bigger turbo, your air temprature is lower (more dense) and you car is fueling thinking there is colder outside air (overfueling for the 0.5 bar pressure).

I'd love to find out if I am right or not after you get your car re-mapped, would help in my learning to map cars.

And to your post Gary, that is fine as it takes longer to get up to full boost (laggy) so the air flows longer, and the ECU fuels for longer as result.

OK, Now saying it like that makes more sense then, the mass of the air changing due to lower or higher air temperature due to the more easily cooled larger surface area of the turbine ? OK, Now I'm getting that part of it.... But would that really be such an extensive change in temperature then?

It doesn't take much to mess up the fueling on a car mapped for running on a MAP sensor as it has a very sensitive map. Removing a decat, changing a pipe's length or diameter and most small changes requires a remap.

Running a MAF/AFM sorts out these small changes automatically.
So if you aren't planning on going for more than 500/550 BHP, it's worth using a Z32 AFM in my opinion and is the way I will be going.

This might be one of the reasons, I have a engine and air temp compensation map, on colder air and engine temps the maps added some fuel for colder temps....maybe... 😉

That I believe is the reason bud 8)

djtreble wrote:

That I believe is the reason bud 8)

Hope it's as simple as that....

Draco wrote:

djtreble wrote:

That I believe is the reason bud 8)

Hope it's as simple as that....

So do I for more than one reason

so with a little playing as far as the compensation maps are concerned, Draco could get his car going like one boing again. . . . Nice one...

POWDER wrote:

so with a little playing as far as the compensation maps are concerned, Draco could get his car going like one boing again. . . . Nice one...

I guess I will find out this weekend 😂

Draco wrote:

POWDER wrote:

so with a little playing as far as the compensation maps are concerned, Draco could get his car going like one boing again. . . . Nice one...

I guess I will find out this weekend 😂

ha ha, u go boi, tune dat biatch !!!!! 😈

POWDER wrote:

Draco wrote:

POWDER wrote:

so with a little playing as far as the compensation maps are concerned, Draco could get his car going like one boing again. . . . Nice one...

I guess I will find out this weekend 😂

ha ha, u go boi, tune dat biatch !!!!! 😈

Who you calling a boi 😂

Thanks for all the ideas and help guys...!!!

No thanks required cuz, Just keep us updated, I'm sure all of us would love to know what the problem actually is.......

Had some limited time this weekend, soldered all the wires that I made up just to get me home, fastened battery properly and with some help over the phone from Charl sorted the fuel pump relay.

Then I started the car, first start was always dodgy before, idled very low and blowed white smoke untill hot, now I udjusted the engin and air temp compensation as well as the battery voltage compensation....

Now when I start, idles good and the only "smoke" you can see is steam as the exhaust warms up, idles and starts very good in cold temps. So all the adjustment of the compensation maps seemed to do the trick, also adjusted the fuel acceleration trim maps.

Couldn't drive over the weekend, the normal issues 🙄 , so I decided to drive it to work today, on lower revs starting to boost has hesitation....according to data logging might be little lean there,,,,but when it really goes into boost...whalla....a bit lean now after I leaned all the compensations but is boosting like a mofo, did not have a clue where the boost would be...according to fong kong guage over 1.5 bar 😮 ...according to wolf 22.4 psi.... 😕

That is a bit to much....but let me tell you one thing, climed on the highway and gave enough pedal to get the boost going and I accelerated to 220 in no time...took my foot off and started to brake...got to 120 again and saw this super bike come in next to me, obveously he saw me when I climed on the freeway and started pulling....just pulled up next to me shaking his head in appreciation and giving me the thumbs up!!!

Now it's getting her to the dyno and getting the boost right and the tuning spot on....

Friggin "A" Bud, thats awsome, always fun having a Bike appreciate the power of our cars, lol

N E Way, u better take a Dyno Vid and Road vid when done, we wants to check it......