[Kelvin1000]

Would there be a benefit to possible lower EGTs when running richer?

[OpenFlash]

Originally Posted by Kelvin1000

Would there be a benefit to possible lower EGTs when running richer?

The main reason running richer usually results in lower EGT is due to its ability to suppress knock through in-cylinder evaporative cooling. This means that the DME is running more ignition advance. More ignition advance means that more thermal efficiency because MORE of the combustion energy is being used to push the piston downwards and LESS of it escapes in the form of heat that bleeds into the cooling system and out the exhaust in the form of heat (higher EGTs). Generally speaking, in a standard recip engine combustion energy splits somewhat evenly between the these three components.

If running richer doesn't mean that you can run more ignition advance, then you aren't getting the assumed EGT cooling benefits. We've run EGT probes in these cars before and they are remarkably insensitive to max load lambda. Which is not a surprise considering how insensitive knock thresholds are to max load lambda.

my 2c,
shiv

[Kelvin1000]

For some reason, the GIAC guys are pretty set on keep EGTs down and may actually make the removal of secondary cats a requirement for stage 2.

The tune seems to be pushing a lot of timing pretty nicely so maybe their testing has revealed some benefits to richer AFRs.

[a32guy]

Btw I was unable to dyno today as my car is at the dealer for a VANOS code. Will update when I get it up there.

[OpenFlash]

Originally Posted by Kelvin1000

For some reason, the GIAC guys are pretty set on keep EGTs down and may actually make the removal of secondary cats a requirement for stage 2.

The tune seems to be pushing a lot of timing pretty nicely so maybe their testing has revealed some benefits to richer AFRs.

If stg 2 pushes the 16+psi of boost that I've heard about, then yes, it does make sense to make exhaust mods a requirement. Trying to support that much boost on a stockish car on pump gas is going to be tough.

shiv

[btrav1226]

Originally Posted by Kelvin1000

For some reason, the GIAC guys are pretty set on keep EGTs down and may actually make the removal of secondary cats a requirement for stage 2.

The tune seems to be pushing a lot of timing pretty nicely so maybe their testing has revealed some benefits to richer AFRs.

with a Bt cable, would you be able to log timing/igniton, retard?

[Former_Boosted_IS]

Originally Posted by Kelvin1000

For some reason, the GIAC guys are pretty set on keep EGTs down and may actually make the removal of secondary cats a requirement for stage 2.

The tune seems to be pushing a lot of timing pretty nicely so maybe their testing has revealed some benefits to richer AFRs.

Kelvin, I can show you my big hp pull with almost identical timing as the GIAC when I had the 5.5k resistors in. Shiv also verifies what was stated earlier about leaner A/F ratios acceptable on DI motors.

Now, I am running richer, but only for headroom on my nitrous setup.

[a32guy]

Dealer replaced VANOS solenoid and no more limp mode. Should be good to go for this weekend on the dyno. Will do a stock pull without JB3 installed, then install the JB3 v2.0 and do a map 0 pull, and a map 3 pull.

[a32guy]

mad dataz coming yo

[jpsimon]

nice, glad to hear the car is back in order! can't wait to see the stock results