Supercharged Intake air temps and max timing.

[caver]

What kind of airtemps are the guys with Superchargers seeing? Fitted a Starr Performance kit.
Runs .5bar boost at my altitude and one 4th gear run from about 3k to 6k gets the intake temps up to 100deg C. Ambient temp was about 23deg C.

Normally aspirated lS1's need about 25deg adv to make power but I am battling to run 12 deg without knock retard under boost.
What kind of timing are the other guys seeing?

[mistermike]

Things to check:

1. Make sure coolant pump is flowing freely. The magnetic drive on the pump will disengage if there's too much restriction like a kink in a hose or trapped air.

2. Was this on a dyno or actual driving? On a dyno, you need a pretty stout fan to keep temps down.

3. Additional considerations for IAT's: I applied some foil backed foam to the cold air box to insulate it, and used some Tyvek to redirect hot air exiting the radiator from being drawn into the area under the air box. I sealed the edges of the cold air box with some weatherstrip and also removed the skid plate to improve underhood ventilation.

The timing figures you cited aren't all that bad. Remember that at the compression and temperatures you're dealing with, the fuel burns much more quickly than an N/A motor at 30 deg C IAT, so not much spark advance is needed to get your peak cylinder pressure in the proper place.

Water or alky injection remains a worthwhile option. I use it on my setup as an "insurance policy" rather than something I tune for.

I'm sure Delco has better advice than I, as his experience with the Starr kit goes back centuries.

[caver]

Thats on the road. On the dyno I dont have a problem with the airtemps just back off when they start to climb.
Criusing at a steady 140km/h or so I get around 55 degC.

The power difference between 8 and 12 degrees is significant and with -11deg adv at 100 degC I have seen max 3deg adv thats a serious power loss its so bad the car surges.

I can get the timing higher but even at 12 deg I am getting about 2deg of knock retard. seems to want about 17 deg to make serious power.

Even with a Vortech at the same boost it's difficult to make decent power without some knock.

[34Koop]

I have a Starr kit also and have been wondering why table B5911 Spark IAT Table seems to have no correlation to the IAT that shows on the sensor.

It appears that the table says Degrees C but uses Degrees F. My IAT never went over 79C but the correction was jammed at 90 on the table from a few minutes after start up.

Does this table use a multiplier or add in ECT or something else to arrive at these weird points ?

cheers
Mal

[Delco]

I have a Starr kit also and have been wondering why table B5911 Spark IAT Table seems to have no correlation to the IAT that shows on the sensor.

It appears that the table says Degrees C but uses Degrees F. My IAT never went over 79C but the correction was jammed at 90 on the table from a few minutes after start up.

Does this table use a multiplier or add in ECT or something else to arrive at these weird points ?

cheers
Mal

There area few adders and multipliers in play there Malcomn , B5944 is multipier vs coolant temp and B5943 is the multipier vs rpm.

On startup there are other adders coming into play , log all the spark pids and you will see what is taking the timing out. I doubt it would be the iat contriburting to it.

[34Koop]

There area few adders and multipliers in play there Malcomn , B5944 is multipier vs coolant temp and B5943 is the multipier vs rpm.

On startup there are other adders coming into play , log all the spark pids and you will see what is taking the timing out. I doubt it would be the iat contriburting to it.

I understand the built up nature of the final timing figure, its the fact that the "blue square" in the tuning file B5911 does not line up with the indicated IAT in the log file that confuses me. I checked a few of the sample files and the same thing shows in there.

I checked the 2000 camaro tune which I hope lines up with the Camaro 0 to 60mph log. The IAT only varies between 23 and 24 degrees C but the IAT v DYNCYLAIR is showing values of either 75c or 80c which to me sound like a rounding of 23c and 24c to 75F and 80F ???

I have been using the magic blue square a lot to see what happens where but this has thrown me off track.

cheers
Mal

[caver]

The IAT is blended with the ECT to get a more accurate idea of the charge temps.
The theory is that the air picks up heat from the manifold and ports after it has been measured.

[34Koop]

Caver,

Is there anywhere where this is shown as a multiplier or a table?

With the Starr kit the IAT is already in a manifold runner and as such is not really going to be further effected by manifold or coolant temp unlike the standard IAT.

The current setup also limits you to a one line parameter at 90C most of the time rather than a real table.

Do your logs show this also ?

cheers
Mal

[caver]

Yep but only with Efi Live 7.3
Cant give u the address as my laptop is downstairs but its with the VE table.

[caver]

I dont read through csv files much anymore.I have made a whole lot of maps so I can see at a glance what is happening where.

[kbracing96]

I understand the built up nature of the final timing figure, its the fact that the "blue square" in the tuning file B5911 does not line up with the indicated IAT in the log file that confuses me. I checked a few of the sample files and the same thing shows in there.

I checked the 2000 camaro tune which I hope lines up with the Camaro 0 to 60mph log. The IAT only varies between 23 and 24 degrees C but the IAT v DYNCYLAIR is showing values of either 75c or 80c which to me sound like a rounding of 23c and 24c to 75F and 80F ???

I have been using the magic blue square a lot to see what happens where but this has thrown me off track.

cheers
Mal

I had a problem with the "blue" square not matching the log like you say and it turned out to be that the DATA page (F-9) in the log was set to the imperial and needed to be set to metric. I switched it and they matched up perfect! Hope that helps.

[34Koop]

OK I have looked at all the tables mentioned and just want to clarify I have this straight in my mind.

The blending when operational takes Kelvin + IAT + ((ECT-IAT)*Factor)

The factor references to Grams/S and the factor typically reduces as airflow increases.

In relation to a supercharged engine:

The MAF has more than likely been removed and Airflow is defaulting to 3 Grams/S so the airflow factor is going to be the maximum ~0.8 at all times.

It is not impossible for the IAT to exceed the ECT which would actually reduce the the reference temperature the the motor is using :shock:

Is this right ?

cheers
Mal

[caver]

Would still like to know what timing figures the S/C engines are running.

[GMPX]

Ask Starr?, I'm sure the tuner there will tell you.
torque@starperformance.com.au

Cheers,
Ross

[caver]

Have sent them a email am waiting for a response.

[Delco]

Have sent them a email am waiting for a response.

The ex-tuner will tell you that 12-14 deg is all they will support safely 8)

[caver]

Thanks for the input

That email is from there website and is incorrect
mailto:torque@starperformance.com.au

Should be
torque@starrperformance.com.au

[dc_justin]

Would still like to know what timing figures the S/C engines are running.

With much lower intake air temps, ~35*C, around 0.5bar boost on an LQ9 6.0L, I command 18.5* from 2800rpms on up at WOT. This has been perfectly fine for me in the past, with less than 1* KR until today when I randomly got 5.6* of KR at 2800 / 1.00g/cyl, well under peak boost. Has me a bit scared wonderin why I saw that and if there is any damage...