Bigger turbo means lean mixture?

Draco · Post by **Draco** » Thu Feb 24, 2011 8:03 am

I collected my car yesterday, fuelling is way out though, had the map for the T28....don't really understand, bigger turbo ? supposedly means more air and that translates to lean mixture....not the case....the car is overfuelling like a mofo...dark smoke clouwding the sky while I was driving home.

So if my logic and limited knowladge is anything to go by....the T28 flowed more????....but while they were working they pulled on the harnass from the CAS and I picked up a very bad connection....whether it was there before or just caused by the new install i don't know....but I made a plan just to get the car home....better connection might mean the voltages to the injectors is now what it should be and thats the reason for fuel...

Any ideas?

aep886 · Post by **aep886** » Thu Feb 24, 2011 9:02 am

the standard mangement will automatically add more fuel once it detect more air... to prevent detonation

Draco · Post by **Draco** » Thu Feb 24, 2011 9:03 am

I run wolf 3D, map sensor.

POWDER · Post by **POWDER** » Thu Feb 24, 2011 9:43 am

Hey Draco,

Either way, 0.5 bar is 0.5 bar, regardless of turbo size, especially with a MAP sensor. The throtle possition sensor also has no effect on fueling as this is controlled by the FeulMap vs MAP Sensor information. You wouldn't even need to calibrate your Throttle position sensor and it would still work fine. In the case where we are in, the tps is purely for US to see the persent press on the throttle. The throttle controlls the body flap, the body flap controlls amount of air in, the map sensor reads that, and compensates as per the fuel map.

Hope this info helps you out boet, If there is a bad wire, it should not affect ur fueling. The compensation of diffirent type of airflow vs. Timing I could possibly see causing some issue though, but don't know enough about timing to say for sure.

U can test the TPS info by disconnecting the TPS sensor and u can still rev ur engine just fine.

I would though check your vacume line to the MAP sensor, if that is not pressurising right, then u could have fueling issues, ensure no leak or has not popped off......

Draco · Post by **Draco** » Thu Feb 24, 2011 9:47 am

If a vacuum line popped off to the map....it would not overfuel, as boost increases the map adds fuel...so the lack of boost will make it run leaner rather than richer....mine is running lank rich....

Grobblere · Post by **Grobblere** » Thu Feb 24, 2011 9:48 am

Hi powder

Sorry but i will have to disagree with you about the .5 bar theory. Remember that's just the pressure and does not amount to the total flow.

A T2.5 vs T3/4 @ .5 boost cant even be compared to each other.

Look at it this way you have a 5mm pipe that flows at .5 bar boost, and a 10mm pipe flowing at .5 boost, the 10mm pipe "should" will deliver allot more cfm

Draco · Post by **Draco** » Thu Feb 24, 2011 9:51 am

Grobblere wrote:Hi powder

Sorry but i will have to disagree with you about the .5 bar theory. Remember that's just the pressure and does not amount to the total flow.

A T2.5 vs T3/4 @ .5 boost cant even be compared to each other.

Look at it this way you have a 5mm pipe that flows at .5 bar boost, and a 10mm pipe flowing at .5 boost, the 10mm pipe "should" will deliver allot more cfm

True....which then means with the bigger turbo I have now....the map should be too lean....why is it so rich?

Charlvdw · Post by **Charlvdw** » Thu Feb 24, 2011 10:08 am

Does your bigger turbo has wheels in it?
How does she feels?

Draco · Post by **Draco** » Thu Feb 24, 2011 10:12 am

She feels quite torqey....but as soon as you give some foot it starts spitting dark smoke...some power and shows on boost guage but heavy overfueling....if I rub my finger in exhaust....laods of carbon!!!

Charlvdw · Post by **Charlvdw** » Thu Feb 24, 2011 10:49 am

The spitting and smoke point towards under fueling.

Draco · Post by **Draco** » Thu Feb 24, 2011 10:53 am

Charlvdw wrote:The spitting and smoke point towards under fueling.

Ok...when I said spitting I meant it blowed alot of black...dark smoke...no spitting....

can you explain how dark smoke refers to underfueling please?

Charlvdw · Post by **Charlvdw** » Thu Feb 24, 2011 11:01 am

Draco wrote:
Charlvdw wrote:The spitting and smoke point towards under fueling.
Ok...when I said spitting I meant it blowed alot of black...dark smoke...no spitting....

can you explain how dark smoke refers to underfueling please?

I said, spitting and smoke = under fueling.

Draco · Post by **Draco** » Thu Feb 24, 2011 11:05 am

Charlvdw wrote:
Draco wrote:
Charlvdw wrote:The spitting and smoke point towards under fueling.
Ok...when I said spitting I meant it blowed alot of black...dark smoke...no spitting....

can you explain how dark smoke refers to underfueling please?
I said, spitting and smoke = under fueling.

Ok...lets get rid of the spitting...no spitting...

Smoke= underfeuling.... as you said....colour?

Grobblere · Post by **Grobblere** » Thu Feb 24, 2011 11:05 am

Draco wrote:
Grobblere wrote:Hi powder

Sorry but i will have to disagree with you about the .5 bar theory. Remember that's just the pressure and does not amount to the total flow.

A T2.5 vs T3/4 @ .5 boost cant even be compared to each other.

Look at it this way you have a 5mm pipe that flows at .5 bar boost, and a 10mm pipe flowing at .5 boost, the 10mm pipe "should" will deliver allot more cfm
True....which then means with the bigger turbo I have now....the map should be too lean....why is it so rich?

To be honest i don't know, there is 2 many things which could lead to this. I recon u would have to dyno it again.

Draco · Post by **Draco** » Thu Feb 24, 2011 11:08 am

Grobblere wrote: To be honest i don't know, there is 2 many things which could lead to this. I recon u would have to dyno it again.

That goes without saying....but I just find it strange that it seems to overfuel....when it should actually under fuel...