[parish8]

Originally Posted by Speedy1975

I'd be curious what Ted thinks about a near 13 AFR. Way different than what I'm accustomed to.

over on hptuners site both responses to this question said they go lean. my tuner buddy says go lean. lt4 is lean. ted says go rich.

[parish8]

Originally Posted by ADM PERFORMANCE

We also use the plex dual knock canbus system on our dyno and it really tells the truth about LT1 engines timing and Airfuel.

We run 12.9-13.0 on C-16 and 12.6-12.8 on 93 Texas fuel. All readings are before the catalytic.

You can always tell a 91-93 octane tune by how jagged the graph is due to a lower than happy timing map.

Race gas and nice timing make for smooth graph

since you mentioned timing. what would be a good place to end up at lets say 8psi of boost and e85 fuel?

[Speedy1975]

Originally Posted by parish8

over on hptuners site both responses to this question said they go lean. my tuner buddy says go lean. lt4 is lean. ted says go rich.

Can you post data to support this? I'd like to see what the LT4 is setup to run.

[parish8]

Here ya go

[parish8]

you do the reciprocal of those pe numbers to get lambda

if you want to convert to a/f for gasoline you take 14.7/pe or 14.7*lambda

[JANNETTYRACING]

Originally Posted by Speedy1975

I'd be curious what Ted thinks about a near 13 AFR. Way different than what I'm accustomed to.

With all the different fuels on the market AFR causes Mass confusion.

The reason I switch over to Strictly Lambda readings explained above.

A fuel like C16 is a True 14.7 Stoich value so you can run leaner than most are accustom to.

Where MS109 is 13.4 Stoich.

Either one will Read 1.0 on a Lambda meter.

We need to know if Andy is talking N/A for Forced induction.

Ted.

[JANNETTYRACING]

Originally Posted by parish8

over on hptuners site both responses to this question said they go lean. my tuner buddy says go lean. lt4 is lean. ted says go rich.

That is the internet Trend but I never follow trends I do my own testing.

I am not Here to tell you what to run, I will only Share what I personally found to be Valid, what you do with that information is solely up to you.

Rich is a When you go beyond the point of complete combustion.

Lean is when you go beyond the point of complete combustion and engine protection.

There are way more considerations to take in to account when deciding on a Lambda target for WOT.

How long will you be At WOT is a Major Player.

What works on a dyno jet will not work on a Quarter mile and will fail the engine on the Texas Mile.

Something to ponder on.

[JANNETTYRACING]

Originally Posted by parish8

Here ya go

Originally Posted by parish8

you do the reciprocal of those pe numbers to get lambda

if you want to convert to a/f for gasoline you take 14.7/pe or 14.7*lambda

These are not Lambda numbers these are an EQ ratio of Stoich which is 14.1 on this car.

(Stoich AFR for 10% ethanol fuels)=14.1 / 1.165 = 12.10

1.165 represent .86 lambda.

Stoich is always 1 in Lambda regardless of the fuel type

As I stated Earlier I shoot for .85 Lambda for N/A applications.

Ted.

[parish8]

Originally Posted by JANNETTYRACING

These are not Lambda numbers these are an EQ ratio of Stoich which is 14.1 on this car.

(Stoich AFR for 10% ethanol fuels)=14.1 / 1.165 = 12.10

1.165 represent .86 lambda.

Stoich is always 1 in Lambda regardless of the fuel type

As I stated Earlier I shoot for .85 Lambda for N/A applications.

Ted.

This is why we(me especially) need to all convert to lambda. It takes the confusion out of it.

Let's look at the higher rpms on that chart since they are the richer direction. At 6400rpm it is at 1.19pe or .84 lambda. They are assuming you are running e10 which is likely. This is the factory tune on an lt4 running 9.5psi of boost.

Many people say that lambda is what they run while some others run a richer lambda more typical of port injected motors. I am just looking for reasons why people choose one direction vs the other and you have given several good examples.

I have to admit I am looking to feel ok running the .84 lambda since I am currently fuel system limited and that would allow me to run a little more boost.

[JANNETTYRACING]

Originally Posted by parish8

This is why we(me especially) need to all convert to lambda. It takes the confusion out of it.

Let's look at the higher rpms on that chart since they are the richer direction. At 6400rpm it is at 1.19pe or .84 lambda. They are assuming you are running e10 which is likely. This is the factory tune on an lt4 running 9.5psi of boost.

Many people say that lambda is what they run while some others run a richer lambda more typical of port injected motors. I am just looking for reasons why people choose one direction vs the other and you have given several good examples.

I have to admit I am looking to feel ok running the .84 lambda since I am currently fuel system limited and that would allow me to run a little more boost.

I would suggest .78 for 9.5 psi boost on Pump Gasoline.

Ted.

[Speedy1975]

Originally Posted by JANNETTYRACING

That is the internet Trend but I never follow trends I do my own testing.

I am not Here to tell you what to run, I will only Share what I personally found to be Valid, what you do with that information is solely up to you.

Rich is a When you go beyond the point of complete combustion.

Lean is when you go beyond the point of complete combustion and engine protection.

There are way more considerations to take in to account when deciding on a Lambda target for WOT.

How long will you be At WOT is a Major Player.

What works on a dyno jet will not work on a Quarter mile and will fail the engine on the Texas Mile.

Something to ponder on.

Excellent information in this thread. More people should read and re-read the bold text above.

[MR 45TH]

I love threads like this! Whereas I have no intentions of tuning my car, the old saying is true knowledge is power. That and I try to learn something new everyday.

[JANNETTYRACING]

Originally Posted by Speedy1975

Excellent information in this thread. More people should read and re-read the bold text above.

I should have added We find best torque and Horsepower somewhere in the middle of the two.

[Speedy1975]

Originally Posted by JANNETTYRACING

I should have added We find best torque and Horsepower somewhere in the middle of the two.

My buddy holds the record for a Challenger in the TX Mile at 212MPH I believe. Seen lots of cars loose engines at that event. Whole different animal.