Bigger turbo means lean mixture?

djtreble · Post by **djtreble** » Fri Feb 25, 2011 10:36 am

I can only think that the standard management over-compensating is to blame then, but a tuner will be able to tell you on the dyno. Only so much can be diagnosed on the net.

Good luck dude!

Draco · Post by **Draco** » Fri Feb 25, 2011 10:38 am

djtreble wrote:I can only think that the standard management over-compensating is to blame then, but a tuner will be able to tell you on the dyno. Only so much can be diagnosed on the net.

Good luck dude!

I am running full management, no maf, wolf 3D with map sensor.

djtreble · Post by **djtreble** » Fri Feb 25, 2011 10:40 am

And running at the same boost as before? That makes me think there is a leak somewhere post turbo (or even at the turbo). Was it a new/proven turbo?

Draco · Post by **Draco** » Fri Feb 25, 2011 10:51 am

I was running 1 bar boost according to wolf, according to guage a bit more.

With the new turbo I am not taking it so far...the boost pics up and will boost to and over 1 bar if I keep giving throttle....but the black smoke starts just before boost if you give throttle and gets worse the more you give throttle.

I have not tried to drive it hard because I know the feulling is off...

djtreble · Post by **djtreble** » Fri Feb 25, 2011 11:00 am

I'm not a mapping expert but in theory I'd say that the black smoke is because your turbo is more laggy and the car is recieving too much fuel too early. The boost curve will be different to the T25.

When I start mapping I will be able to give you a more in depth diagnoses.

Draco · Post by **Draco** » Fri Feb 25, 2011 11:03 am

Maybe it is as simple as that...to much to soon...thanks for the help in anyways...

djtreble · Post by **djtreble** » Fri Feb 25, 2011 11:04 am

No prob, let us know what the problem was when you find out.

Draco · Post by **Draco** » Fri Feb 25, 2011 11:05 am

Will do thanks.

Gary57 · Post by **Gary57** » Fri Feb 25, 2011 1:00 pm

What you are proposing would be the diffirence between a cold and hot day, does ur car smoke on a hot day or cold day?

Yes this will cause your car to smoke on a hot day if it was tunes on a cold one, this is why you should have a IAT sensor if you are running MAP.

Simple formular of PV=mRT, use this and see what the difference in mass of air per 5 degrees of air temp...

I'm not going to get into any arguments but 0.5 bar is still 0.5 bar, this is the reason you can run a T28 at the same boost as a T25 on a standard map without problems. But what's the point of that?

This is because the standard map uses MAF which measures the mass of air, not the pressure.

djtreble · Post by **djtreble** » Fri Feb 25, 2011 1:08 pm

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?

aep886 · Post by **aep886** » Fri Feb 25, 2011 1:41 pm

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

djtreble · Post by **djtreble** » Fri Feb 25, 2011 2:03 pm

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.

Gary57 · Post by **Gary57** » Fri Feb 25, 2011 2:11 pm

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.

djtreble · Post by **djtreble** » Fri Feb 25, 2011 2:18 pm

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).

Gary57 · Post by **Gary57** » Fri Feb 25, 2011 2:24 pm

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