stock LS7 cam light surge EOIT expert step in

[Sébast19X]

Hi, all, like title said , I'm experiencing some light surge with my stock cam Bolt-On Z06 at light throttle low load. I have lowered the timing in main spark table low load. I'm now at around 34- 35 degre between 1200 - 1800 . Great improvement. MAF are perfectly dialed ( pure maf only) I'm wondering if this have somethings to do with the EOIT normal RPM.

Why the stock LS7 have the EOIT drop like that at 848 RPM till 1920 RPM ???.
What would be happening if I'm put 32.5 till 2048 RPM ?
Should I will see some of this light surge improvement
Let me know,



I'm living with this light surge since I've improved the airflow of my car a couple years ago now. Headers, FAST 102/102, Vararam. ( I'm trying to figured out to tune this if possible )

[HRD]

Datalog and see if the timing advance is ramping up and down with the surge.

[Sébast19X]

Yes I have plenty of data log, and when those surge haapens, you see a dip of 4- 6 degre in timing. I'm thinking that timing deep is not the cause of surge. It's reacting at something related to the airflow and fueling IMHO.

Like airflow characteristic of my engine vs stock have been altered, some table need adjustment.

This is why I'm suspecting EOIT in this RPM area. Fuel is probably the root cause of this surge. Timing deep is a reaction to this ...

[HRD]

Yes I have plenty of data log, and when those surge haapens, you see a dip of 4- 6 degre in timing. I'm thinking that timing deep is not the cause of surge. It's reacting at something related to the airflow and fueling IMHO.

Like airflow characteristic of my engine vs stock have been altered, some table need adjustment.

This is why I'm suspecting EOIT in this RPM area. Fuel is probably the root cause of this surge. Timing deep is a reaction to this ...

I'm interested to see what you find. Good luck.

[IDRIVEAG8GT]

Is the TPS changing as it surges?

[Sébast19X]

Is the TPS changing as it surges?

No, TPS at 15% or 16%.

[IDRIVEAG8GT]

Ok so long as the throttle body isn't opening/closing randomly, it's mainly timing related.

Throw up your tune and I'll browse through it to see what I can find. Remember, timing is directly affected by airflow change, and since the TB isn't changing positions, Cyl Airmass shouldn't be either. So somewhere you either have a glitch in the timing tables or something else.

[Mez]

Is your "spark smoothing" turned "off"? There are threads that traced weird spark dips to spark smoothing set to "on". Try turning it "off".

[Sébast19X]

No spark smoothing is on. Maybe is something to do with proportianal idle. Since the light surge is comon since the fast 102 / 102 tb and ARH 1 7/8 headers.

[Michael_D]

I wonder if cranking / engine start is why the EOIT are set up the way they are?

[HRD]

No spark smoothing is on. Maybe is something to do with proportianal idle. Since the light surge is comon since the fast 102 / 102 tb and ARH 1 7/8 headers.

Turn it off and see what that does.

[Sébast19X]

Turn it off and see what that does.

I have installed the new beta version and this allow me to tune the spark smoothing by gear. I will give it a try as soon as I will received my new NW102. ( I have cut the value in a half for startup point.) Because spark smoothing completly turned off suck driving condition in town traffic ( bucking).

I think also, if I remember right this light surge have started when I have installed the ARH 1 7/8 headers ... and then the fast 102/102 setup.
Maybe the closed loop proportional have something to do with this ... The car is dialed on the edge MAF only and soon as I reactivated the closed loop, I see a swing in the fuel trim between 1000 to 2000 rpm in the range of +-12%



Seb

[Sébast19X]

Hey gentleman, I have played around with a C6 2007 who I have installed an ASA cam ( 226-236 110 LSA 108 ICL) today. I have played with the new spark smoothing table that come with the new beta version. To greatly reduce the low speed city cruising bucking, from 3rd to 5th gear light throttle, I have upped the value by 0.2 from 0 to 2000 RPM. And let the timing table alone. The bucking effect of the cam are mostly completly gone.

Also reduced by 0.1 to 0.2 from 0 to 2000 RPM gear 1 and gear 2.

That have mostly removed the light surging in those area .

Something that I have to play with my car as soon as I will received my NW 102.

Those image posted are not the real tune, but this is the same value. ( I didn't have my laptop with me now )

If my understanding was correct, that new setting will give more area for the computer to remove timing and correct bucking. As for the scan, I seem to have some real probleme with the new beta, my scanner always lost communication after 10 -15 sec of log .... So I could'n tell if I have spark deep ....

[Sébast19X]

I wonder if cranking / engine start is why the EOIT are set up the way they are?

Sir, I don't have any idea. I have put those low value all the way to 2048 RPM at 32.5, and honestly i didn't find anything .... I will probably put them back to stock soon.

[HRD]

Hey gentleman, I have played around with a C6 2007 who I have installed an ASA cam ( 226-236 110 LSA 108 ICL) today. I have played with the new spark smoothing table that come with the new beta version. To greatly reduce the low speed city cruising bucking, from 3rd to 5th gear light throttle, I have upped the value by 0.2 from 0 to 2000 RPM. And let the timing table alone. The bucking effect of the cam are mostly completly gone.

Also reduced by 0.1 to 0.2 from 0 to 2000 RPM gear 1 and gear 2.

That have mostly removed the light surging in those area .

Something that I have to play with my car as soon as I will received my NW 102.

Those image posted are not the real tune, but this is the same value. ( I didn't have my laptop with me now )

If my understanding was correct, that new setting will give more area for the computer to remove timing and correct bucking. As for the scan, I seem to have some real probleme with the new beta, my scanner always lost communication after 10 -15 sec of log .... So I could'n tell if I have spark deep ....

What is the latest version and did you get it by emailing HP Tuners?

[Sébast19X]

What is the latest version and did you get it by emailing HP Tuners?

Yes email hptuner and told them you want the latest beta.

[Michael_D]

Hey gentleman, I have played around with a C6 2007 who I have installed an ASA cam ( 226-236 110 LSA 108 ICL) today. I have played with the new spark smoothing table that come with the new beta version. To greatly reduce the low speed city cruising bucking, from 3rd to 5th gear light throttle, I have upped the value by 0.2 from 0 to 2000 RPM. And let the timing table alone. The bucking effect of the cam are mostly completly gone.

Also reduced by 0.1 to 0.2 from 0 to 2000 RPM gear 1 and gear 2.

That have mostly removed the light surging in those area .

Something that I have to play with my car as soon as I will received my NW 102.

Those image posted are not the real tune, but this is the same value. ( I didn't have my laptop with me now )

If my understanding was correct, that new setting will give more area for the computer to remove timing and correct bucking. As for the scan, I seem to have some real probleme with the new beta, my scanner always lost communication after 10 -15 sec of log .... So I could'n tell if I have spark deep ....

Sebast -

I am interested in giving this a whirl based on your findings. I'm a bit confused to what you did though. Can you clarify?

If I understand you correctly...

3/4/5 gears you added 20% from 0 to 2000 rpm in the low torque table, correct?

You reduced the values for the 1 and 2 gear by 10% from 0 to 2000 rpm? Or did you reduce this 20%?

The screen shots do not reflect this, unless my math is off anyway...

I currently have smoothing disabled, but I do get some bucking. I usually just shift around it, but if your method helps with this, I'm willing to give it a try.

[Sébast19X]

Sebast -

I am interested in giving this a whirl based on your findings. I'm a bit confused to what you did though. Can you clarify?

If I understand you correctly...

3/4/5 gears you added 20% from 0 to 2000 rpm in the low torque table, correct?

You reduced the values for the 1 and 2 gear by 10% from 0 to 2000 rpm? Or did you reduce this 20%?

The screen shots do not reflect this, unless my math is off anyway...

I currently have smoothing disabled, but I do get some bucking. I usually just shift around it, but if your method helps with this, I'm willing to give it a try.

Hi Michael,
Yes you're understand are right !! Those precedent graph is dumb example.
I will post the graph for you that I will run now and that thing run really great !! By dong this you will give more latitude for the spark the dampening the bucking and surging. Play around that and report. Diseabling spark smoothing is not the solution.

[HRD]

Sebast,

Thanks for posting. From your tables, it appears that you have also modified the values above 2000 rpm. What lead you to make those changes and what effect did it have?

[Sébast19X]

Sebast,

Thanks for posting. From your tables, it appears that you have also modified the values above 2000 rpm. What lead you to make those changes and what effect did it have?

This is just to be smooth and match the first part of the curve. Experienced almost nothing in this upper rpm range.