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1G Running rich @ WOT

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SoonerTalon

Proven Member
73
0
Aug 11, 2013
Moore, Oklahoma
I have a 1992 Eagle Talon TSI that I installed a wideband O2 on. During non-boost and low boost [up to 5 PSI] I stay around 12.5 to 14.5 AFR which is right in the middle of where I need to be. When I go to WOT the AFR pegs out at 10 which is the lowest reading available..

I have tested for leaks and @ 16 PSI which is what i currently have my MBC set to and everything appears to be fine. I have a 2G MAF with stock injectors all running on a DSMlink v3. This is the same setup that I had when I sent the EPROM to them to set the chip installed. The wideband was added after the dsmlink.

Should I capture a test run and send it in to the dsmlink guys? Any other thoughts/suggestions on what could be going on?
 
Turbos gonna run rich when doing WOT anyway - it's their nature.

Operations are at proper A/F when no boost or low boost, but when tonnage of air is being shoved, there has to be some compensation with the compressed air making a more denser mixture, thus more fuel is needed to compensate..

The turbocharger increases the density of the air resulting in a more needed fuel mixture.

The denser mixture raises the peak cylinder pressure, therefore increasing the probability of knock. As the A/F is leaned out, the temperature of the burning gases increases, which also increases the probability of knock. This is why it is imperative to run richer A/F on a boosted engine at full load. Doing so will reduce the likelihood of knock, and will also keep temperatures under control.

There are actually three ways to reduce the probability of knock at full load on a turbocharged engine:
1) reduce boost,
2)adjust the A/F to richer mixture,
3)retard ignition timing.

These three parameters need to be optimized together to yield the highest reliable power.
 
Yeah I guess that I should have specified how rich the car is currently running. I have an AEM UEGO which has a low reading of 10:1, it is pegging during WOT so I am sure that I am getting lower than a 10:1 ratio, from what I have read a 11:1 ratio is ideal for turbos.
 
I missed they keyword in your original post, being that you're running STOCK injectors, which were the 450's-which is fine since your A/F numbers looked good when in no boost to mild boost as you mentioned. But when you do WOT your ratios really take a leap to the rich side big time.

You got quite the boost pressure, which is just the air, but is the air dense enough to compensate the heavier mixture?

Unless you simply aren't getting the cool denser air in to lean that heavy mixture up to the required power levels during WOT.

You could be pulling in hot air to rich that mixture down to those low levels you posted.

How's the air flow through the FMIC?
 
Last edited:
Great add Jharsman!

The FMIC is large and great access to airflow.

Snowborder714, I will try to get the log to you guys by Wednesday. I found an additional thread on how to prep for dsmlink assistance and will try to ensure that I have accounted for those check points. That is great info that the default table is set to run rich. Look forward to your help.
 
Not to hijack the ops thread, but I'm having a similar issue. This question may be beneficial to him also. What all values would need to be captured in the log?

Here's a thread showing captured values for each part of tuning:
http://www.dsmtuners.com/threads/list-of-values-to-log.444831/


Snowborder714, I will try to get the log to you guys by Wednesday. I found an additional thread on how to prep for dsmlink assistance and will try to ensure that I have accounted for those check points. That is great info that the default table is set to run rich. Look forward to your help.

Glad you did some searching and found those other threads!! :thumb:

Once you've going through the prep thread that Calan posted, make sure to post any logs you want checked out in the proper ECMlink forum on here.

This thread has pretty much run its course since you got your answer. You will have other questions in the future about tuning that belong in a different forum.
 
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