Car running lean

[prj]

no question you will loose power if you do this, but raise the boost for 0.5 bar and richen up and tell me if you loose or gained power.

You won't be able to raise boost 0.5 bar, unless you were running too low boost in the first place.
You can try to tune to 11.2-11.3 in hot weather and get it just right with a bit of leeway.

After that, if you go richer AFR, EVEN if you raise the boost, you will lose power.
Seriously, this is like really basic knowledge. You can raise your boost if you want, but you won't make more power dipping into 10's. Torque falls off _very_ sharply after about 11.1 (give or take).

[Billman]

You won't be able to raise boost 0.5 bar, unless you were running too low boost in the first place.
You can try to tune to 11.2-11.3 in hot weather and get it just right with a bit of leeway.

I can raise boost another 1 bar and still have room for more.

however i am not running so rich but many people run in order to be on the safe side of things. In an ideal world with the ideal fuel and temp and engines we would all run 12.5

Don't know how long are you involved with cars and tuning but have your mind open....you are playing with toys there...people that need to run as low as 10.x AFR run with very high powered cars.

[pasbogdan]

raise boost and raise fuel,not flood.
More fuel should mean lower egt,less knock.What would show a dyno with the same car,at 13. to 1,12 to 1 and 11 to 1?(not thinking of knock or egt).Some just combat knock by raising fuel?
Just asking,not saying.

[prj]

I suggest reading a book instead of asking such questions...
For example this one:

http://www.amazon.com/Induction-Performance-Practical-Supercharging-Turbocharging/dp/1859606911

[prj]

I can raise boost another 1 bar and still have room for more.

however i am not running so rich but many people run in order to be on the safe side of things. In an ideal world with the ideal fuel and temp and engines we would all run 12.5

Don't know how long are you involved with cars and tuning but have your mind open....you are playing with toys there...people that need to run as low as 10.x AFR run with very high powered cars.

What is your point?
I said about AAN engine, that running below 11.1 AFR makes no sense, because it does not make more power. You answered "some people run richer", running richer = wasting power.
I would aim for about 12 on I5 with IAT correction upto 11.5 on hot days.
Running 10.xx AFR on I5 is not safe, it's stupid, because you are losing power. You can just as well run 11+ with lower boost and you will have the same power, and still be just as safe. There is not much difference between 12.5 and 11.5 in terms of power, but it starts declining very fast lower than that.

If you have 1 bar headroom at your AFR, then you are running WAY rich or you are running much less boost than you could, or bad ignition timing... and wasting power.

Stop questioning my competence and talk about facts. Physics are physics, flame front speed is flame front speed and combustion efficiency is combustion efficiency. You can twist and spin it any way you like, you will not change that.
There is "safe" and there is "stupid". 10 AFR on I5 is stupid.

[diesel des]

When my aan was stock with no problems, I measured afr. It was less than 12 :1 over 4k rpm and just over 11:1 at 7 k. I belief this is too rich for max power, but audi were also thinking about egt. I didn't measure egt stock, but I'm sure it was 900 deg at a guess.

[pasbogdan]

I suggest reading a book instead of asking such questions...
For example this one:
http://www.amazon.com/Induction-Perf.../dp/1859606911

Somethimes i have to be more explicit:I was thinking that the"real"and"big"tuners run 10 to 1 just to prevent knocking.To be realy explicit,i am thinking that "great" tuners that use 11 or 10 to 1 afr are not in the mood of trying to lower intake air temp and they fill this laziness with fuel,10 parts air,1 part fuel.

Thx for the link anyway

[Billman]

Sorry dude but once again you can't understand what I am saying. You are fixating your thinking at one specific point....

The raising boost was an example. You run 1 bar with 11.5:1 and I can run 2.5 bars with 10.5:1! Who has more power?
Everything is relative, stop fixating! I don't know if you are trying to prove yourself as a tuner or whatever. I am not.
This is my hobby and I am open to theoretical knowledge and experience.

Btw. Nice book but not for theoretical knowledge and physics...more for hobbyists.

@diesel des
Many factory turbo equipped cars run up the rev range in the region of 10.x:1 in order to be on the safe side with clogged up injectors and fuel filters and slowly failing fuel pumps in the future.

[prj]

The raising boost was an example. You run 1 bar with 11.5:1 and I can run 2.5 bars with 10.5:1! Who has more power?

On the same setup you will never have a difference of 1.5 bar going from 10.5 to 11.5 AFR, period.
If you can run 2.5 bar at 10.5, you can more than likely run 2 bar at 11.5.
You are still wrong, but hey... keep spinning.

In the end, the objective is to make best power reliably. Running 10.5 AFR is beyond best power. I can tune an engine to 9:1 as well, and it will run like crap, but hey, that's safe, right?
I say for the final time. Look what happens to torque after 11.1 AFR.

[Billman]

I know what will happen. But think with a prospective. If you tune a car you want to have it run for long time. Factory ecu is generic by all means so the must handle the tolerances also.

[prj]

Stop fixating you thinking. If I want I can raise boost and at the same time I can raise injection to lower afr. Is my English so bad??

Well, I do not understand what you are trying to say.
I said like four times now, that beyond a certain point you lose so much power from lowering AFR, that you will not make that power "back" by raising boost.

Boost is not power.

[Billman]

Change of subject: how did you listened for knock during this period where the car was running lean?

[prj]

Change of subject: how did you listened for knock during this period where the car was running lean?

Two ways (both at same time):
1) Looking into Motronic and see if it detects knock
2) Condenser microphone connected to the block with an amp and a high-pass filter feeding the signal to sealed headphones.

No knock from Motronic or headphones, even at 13.3 AFR in cold weather.

Btw, Motronic is better listening for knock than I am.. it detects knock before I hear it in the headphones, only if the knocking gets heavier can it be heard in the headphones... the knock sensors are very sensitive...

[Billman]

Can we somehow see if motronic adapts the sensor sensitivity to the engine noise produced at higher revs? My understanding is that it is looking into volt differece produced during knock compared to the noise (volts) produce during normal engine driving.

[prj]

Can we somehow see if motronic adapts the sensor sensitivity to the engine noise produced at higher revs? My understanding is that it is looking into volt differece produced during knock compared to the noise (volts) produce during normal engine driving.

I saw a schematic somewhere... about how Motronic processes the knock signals into counts... but I don't quite remember where.
It basically has a separate unit recording baseline samples, and if a too large deviation is detected, it registers it as knock.
Using an emulator with trace it is possible to see when Motronic hears knock by monitoring the ignition maps. When it switches to a different map, knock has occured.