Spark Control over 1.36G/Cyl

[carlrx7]

What are you guys doing?

This is my band-aid solution:

Step 1)Right now I hit the bottom line 1.36 g/cylat 8psi boost. So i set my main table to that 18 degrees.

Step 2)I set BOOSTPE to 1.2(12.2afr) up to 8psi then 1.25(11.7) up to 12psi then 1.30(11.3afr) up to 16psi, then 1.35(10.9) up to 21psi

Step 3) Using the Spark AFR Correction table zero it out, then starting at the 1.25 line add -2 degree, 1.3 add -4 degrees, and -6 degrees for 1.35

verify.

8psi commands 18*
12psi commands 16*
16psi commands 14*
20psi commands 12*
If only the Spark AFR correction table had more resolution or had an adjustable axis for PE labels. you could get away from dropping the afr so much.

This with the IAT table makes it douable. and if you're a big dog like 5_litr, you could always start with 16psi, the crank it up to 21+ oke:

lets hear what you have tried. and i know, just scale the tune 50%, but i always end up with idle return issues doing that. cutting ifr and doubling stioch works flawlessly except the 1.36g/cyl spark table.

-Carl

PS. Airflow>General>Spark Airflow
If i half the value will it double my resolution on all my spark tables?

[Chris@HPTuners]

i dunno what OS you have but the newer ones have configurable airmass axis on the spark table.

[DSteck]

I do exactly what you do, Carl.



FYI, don't scale idle parameters and you won't have a problem.

[eficalibrator]

Step 1)Right now I hit the bottom line 1.36 g/cylat 8psi boost...
...and i know, just scale the tune 50%, but i always end up with idle return issues doing that. cutting ifr and doubling stioch works flawlessly except the 1.36g/cyl spark table.

You have answered your own question. Scaling is the exact thing that fixes this correctly. You just need to be faithful about scaling EVERYTHING with g, g/s, g/cyl, torque, displacement, and throttle area. There is no halfway when it comes to scaling some things and not others if you want it to work correctly. Also, nobody says you need to scale 50%. Pick a different factor that gets you just inside of whatever limitation you're hitting first.

[carlrx7]

With my injectors. 50% is the minimum I have to scale in order to make them fit. Can anyone key in on the spark airflow multiplier table if .5 works?

06 Corvette E38 FTL

[LSxpwrdZ]

I know its been stated that you cannot simply use the multiplier vs volts or IAT to get IFR back up to actual flow rate because of the 63.xlb/hr limit. But I like tying stuff anyway to see what it'll actually do. My reasoning for trying this is from back in the Gen3 LS1's. They have a 512g/sec limit on airflow, in SD that limit is not there but datalogging a healthy car in SD with dynamic airflow still pegged the 512 g/sec limit even though it was actually getting more and targets fueling was kept in sync. So I wanted to see if the limit for injector flow actually existed or was just a scanner and table limitation. Turns out it is true... Using some 80lb Siemens injectors halved in the IFR table and a multiplier of 2.0 in the voltage multiplier table the MAF table was off. A 550-600rwhp Cam'd LS7 was running commanded fueling with only ~300-325g/sec of airflow. That was my sanity check on the flow and told me that injector scaling and tune scaling is a necessary evil on these cars.

Anyway just wanted to show my results from a little testing I had done.

[carlrx7]

I know its been stated that you cannot simply use the multiplier vs volts or IAT to get IFR back up to actual flow rate because of the 63.xlb/hr limit. But I like tying stuff anyway to see what it'll actually do. My reasoning for trying this is from back in the Gen3 LS1's. They have a 512g/sec limit on airflow, in SD that limit is not there but datalogging a healthy car in SD with dynamic airflow still pegged the 512 g/sec limit even though it was actually getting more and targets fueling was kept in sync. So I wanted to see if the limit for injector flow actually existed or was just a scanner and table limitation. Turns out it is true... Using some 80lb Siemens injectors halved in the IFR table and a multiplier of 2.0 in the voltage multiplier table the MAF table was off. A 550-600rwhp Cam'd LS7 was running commanded fueling with only ~300-325g/sec of airflow. That was my sanity check on the flow and told me that injector scaling and tune scaling is a necessary evil on these cars.

Anyway just wanted to show my results from a little testing I had done.

I'm not refering to using any of those IFR multipliers

[LSxpwrdZ]

I know.

I use the AFR spark for different boost levels based on the EQ. Just like you stated. However most of the setups that I have tuned have scaled tunes to get the injector data correct around that 63.x limit and thus turns that 1.36g/cyl into 2.72g/cyl which is enough for ALOT of HP and keeps me on the table for timing adjustments.

[383_Stroker]

i dunno what OS you have but the newer ones have configurable airmass axis on the spark table.

^ I used this method on our Silverado... As fas as i can tell, it works like a charm..

[DSteck]

Too bad older PCMs can't get the editable axis labels for spark...

[carlrx7]

Too bad older PCMs can't get the editable axis labels for spark...

Yea, I put in a request and was given the same response.

http://www.hptuners.com/forum/showthread.php?t=42435

Should have sold my car way back and picked up a 09, even 08's have adjustable spark tables. Not sure why it would be hard to add it to the custom OS for those two years (06-07).. or at least mine!!! 1250202

[Pekka_Perkeles]

...and i know, just scale the tune 50%, but i always end up with idle return issues doing that.

FYI, don't scale idle parameters and you won't have a problem.

I've noticed this as well, but how come...:

Scaling is the exact thing that fixes this correctly. You just need to be faithful about scaling EVERYTHING with g, g/s, g/cyl, torque, displacement, and throttle area. There is no halfway when it comes to scaling some things and not others if you want it to work correctly.

For a guy who's tuning just a handful of engines per year, this is really challenging to follow.

[DSteck]

I've noticed this as well, but how come...

The idle airflow parameters have no bearing on actual fuel delivery. These airflow values are only a link to a throttle position. Scaling idle airflow parameters usually causes more problems than neccessary. I've scaled a lot of vehicles, and have never scaled the idle airflow, and it's always been perfect.

[Pekka_Perkeles]

The idle airflow parameters have no bearing on actual fuel delivery. These airflow values are only a link to a throttle position. Scaling idle airflow parameters usually causes more problems than neccessary. I've scaled a lot of vehicles, and have never scaled the idle airflow, and it's always been perfect.

Thank you.

[5_Liter_Eater]

This with the IAT table makes it douable. and if you're a big dog like 5_litr, you could always start with 16psi, the crank it up to 21+ oke:

LOL, well that didn't work out so good...http://www.youtube.com/watch?v=WjqqkgMttpw

I guess I'm lucky RE: the spark table. With the 50% scale I have for my 1k injectors my spark table maxes out where the 2.5 bar MAP does. On gates (~10#) it logs in the .92 row. 21# is in the 1.36 row. Maybe E40 FTW on this for once.

[AlphaTuning]

Magic smoke lol

[carlrx7]

LOL, well that didn't work out so good...http://www.youtube.com/watch?v=WjqqkgMttpw

I guess I'm lucky RE: the spark table. With the 50% scale I have for my 1k injectors my spark table maxes out where the 2.5 bar MAP does. On gates (~10#) it logs in the .92 row. 21# is in the 1.36 row. Maybe E40 FTW on this for once.

Turbos or engine?

[5_Liter_Eater]

Engine. Grabbed 4th and clicked it up to 21# and it started missing and then the car was engulfed in smoke. Oil pressure was fine and I was able to limp it a few miles but once I shut it down it didn't want to start again. Cranks very slowly. Tons of oil in the intake, pooled up behind each intake valve. Ahead of the throttle body is dry. I expect to find a hole burned through one or more pistons.

[carlrx7]

Ouch! sorry to hear! but when life hands you lemons you upgrade to a C7!!

[5_Liter_Eater]

LOL. If I did anything it would probably be a GTR. But I'm sure I'll end up going .005" over and throwing new pistons in, lower CR this time.