b_real45 said:
Ok Perfworks. Which Audi runs 14:1 at WOT... show me the A/F on the dyno.
And no s***... it's called closed loop operation.. all internal combustion engines run 14.7:1 at closed loop. But how many of these cars are running 18psi at closed loop? Go ahead.. tune your car to stoich and see what happens when you do WOT runs at 14.7:1 A/F.
When you are pushing a little 4cyl to its edge by forced induction, you are seriously diminishing the margin of error for a correctly/safely running engine. I want you to continue running 13:1 or even higher.. and I'd like you to take it out on a cold night and push it to its limit. Monitor your EGTs and give us the readings. Do this for half a year and let us know how the engine is holding up.
I never told you it won't hold. I just wished you luck. You're right, 13:1 can be safe... as I just said my friend's GSR is at that A/F with a T04E-57 trim. No need to get all offended and saying my post was based on "myths and excuses for improper tuning."
let me start by quoting what I SAID ( not how you took it)
""
Only and only at WOT would you like to see a richer ratio when your basically guessing on fuel and ignition enrichment. It is then that tuning becomes a challenge because too many variables take place and your chances of detonation and max power are in the balance."""
this was what i said word for word. I agreed with you on WOT operation when the majority of the vehicles are thrown into open loop.
Secondly i wont do the research for you. To many people have been led to believe that you need to run rich to get results with forced induction IT IS FALSE. a myth. your car driving daily is just WASTING fuel when not at WOT. at partial throttle and cruise operation there isnt that need for a overly rich mixture. Again though taking a N/A vehicle and turbo charging it with out proper tuning to the fuel and ignition maps will FORCE you to run rich so that you are safe.
You may be forgeting the fact that peak cylinder pressures is what you need to keep in check anywhere between 5-15 degrees AFTER top dead center on the power stroke to maintain a safe range.
As far as your EGT claim that is not an absolute measurement to reliabilty. You can have a cast manifold versus a tubular manifold and see a difference of 300 degrees in temp. At the same A/F ratio. There is alot more to it than that. I have tuned and turbo charged many vehicles that way with no issues
Also you are not efficiently burning the mixture at those levels. If your exhaust sensor is reading a rich mixture you think its making things better? Your reading is telling you that your not BURNING the extra fuel. Think about it for a second. When do you get your reading before or after the combustion. If it is after then how can you tell me your getting all you can out of the motor safely when you wasting the majority of the energy your giving it to burn.
As far as the Audi, Saabs, Volswagons and volvos out there with turbos they have been running for years with close to Stioch readings even at WOT. they are the most reliable vehicles around.
They were just an example.
And again the only time you are unsafe is when you turbo charge a vehicle and dont tune it right. Period.
Peak cylinder pressures and lean spots cause detonation. So does carbon build up from an overly rich mixture.
Ignition has always been the key. Fuel needs to be a monetary enricher in direct relation CFM density. Keep a nice A/F mixture at the right temp and the right flow charateristics thru the head and youll be fine. (assuming that the timing maps are in accordance and slope with the boost pressures thru the manifold.)
So again i say the rich theory is a bandaid to poor tuning or the lack there of.
This was not meant to insult you at all. I thought we could have a discussion maturely about it. Thats why i said no offense from the begining of my post. That was in no way directed toward you.
take it as you may.
I have given you facts ...
not tradition passed down from the turbo demi gods.
