New NW103 low speed surge

[Bigred1]

Hey guys,

I have a heads Cam c6z with a ported msd intake. The cars tune is dialed and ran and idles great on the stock throttle body. I recently swapped in a NW103 and immediately the car starts good and idles where it should be. I didn?t change any settings and the idle seemed great. When I?m driving around, speeds greater then 20, and clutch in the rpm drops and finds idle immediately.

My issue is putting around a parking lot. I?ll be first at like 1500rpm then clutch in to slow down and the rpm drops to 400 rpm then surges up to 1200ish then back down 400 rpm and so on for about 4-5 attempts then it finds idle. Makes it extremely difficult to get moving again since the car is hunting for idle. (And not to mention embarrassing).

Can anyone shed some light on why it?s surging when I clutch in low speed but not high speed?

I do have a vararam snake charmer cold air intake that has a slot cut to take on air when the car is moving. My thinking Is at higher speeds the intake is taking in air and help feeding the engine so it doesn?t need to hunt. But when the speed is so low there isn?t enough air and therefore I need to increase minimum air flow or something.

Does that make sense or am I completely wrong lol

[kevin87turbot]

We can help you with this issue. Just post your tune and a datalog when you can.

[Bigred1]

We can help you with this issue. Just post your tune and a datalog when you can.

Thank you so much!

Can you guys send me a layout for the data log?

[01SLPSSM6]

You need to change your ETC Scalar. Post your tune file and a data log.

[Bigred1]

You need to change your ETC Scalar. Post your tune file and a data log.

That?s what I thought. I did some research on the forum and changed only the scalar from stock setting (like 4750) to 7300 like some ppl on the forum said. I cold started the car and it didn?t like it much. It was cold idling high and hunting for idle just off the jump. I change the scalar back to stock setting and it cold started perfect and idled great.

I?m assuming there other tables to change?

When I get home I will post up my tune file. Does anyone have a good data log layout I can use to make sure y?all get the correct information?

[Bigred1]

Attached is my tune and an attempt at a data log lol.

Silver 2008 C6 Z06 Updated 7-13-21.hpt
surging issue.hpl

[Knight123455]

i have the same intake manifold and TB. my etc scalar is set to 5635.000 and percent max is 1.78% percent max brake is 2.38
hope this helps. you may need to adjust the air flow final.

[Bigred1]

i have the same intake manifold and TB. my etc scalar is set to 5635.000 and percent max is 1.78% percent max brake is 2.38
hope this helps. you may need to adjust the air flow final.

I spoke with a local tuner and he said the NEW NW 103mm does not require a scaler change but min idle air and coast down spark.

This is my first time dealing with a larger throttle body. So I have no idea lol

[Knight123455]

I have the new NW 103 I put it on in December. I would adjust the scalar and increase the final air flow a little and see if that helps.

[Bigred1]

I have the new NW 103 I put it on in December. I would adjust the scalar and increase the final air flow a little and see if that helps.

How much would you increase the air flow to start? And Do you have a big Cam?

[cadillactech]

I spoke with a local tuner and he said the NEW NW 103mm does not require a scaler change but min idle air and coast down spark.

This is my first time dealing with a larger throttle body. So I have no idea lol

The right way to characterize your larger throttle body is to change the scalar. There is a reason GM's factory calibrations have these values and that they change with throttle size depending on the application. You can measure it pretty accurately with a caliper and basic math. Don't forget the shaft area needs to be subtracted from the over all bore area.

You will need to adjust your final running air flow a bit to trim it. If you have your MAF and VVE dialed in then there shouldn't be much to it.

[Knight123455]

I would start with small changes. maybe add 10 at a time across the whole board to the final air flow. mine starts at 144.5 and goes up to 200 + - i have no idea how much yours will need you will have to start with small adjustments.

[01SLPSSM6]

So I did some research and found that according to Nick Williams himself, the Nw 103mm throttle body does not need the etc scalar changed on an LT1 application because it flows about the same amount of air to about 15% throttle. Obviously this is an LS application, but it may be the same for an Ls too. I would try the stock etc scalar and add some airflow to your minimum airflow table. Is your idle spark at your commanded idle spark? Is it having to add idle spark? I won?t be near a computer until tomorrow so I can?t check. Once you get your min airflow where it needs to be, you can adjust throttle follower torque.

[Bigred1]

The right way to characterize your larger throttle body is to change the scalar. There is a reason GM's factory calibrations have these values and that they change with throttle size depending on the application. You can measure it pretty accurately with a caliper and basic math. Don't forget the shaft area needs to be subtracted from the over all bore area.

You will need to adjust your final running air flow a bit to trim it. If you have your MAF and VVE dialed in then there shouldn't be much to it.

I would start with small changes. maybe add 10 at a time across the whole board to the final air flow. mine starts at 144.5 and goes up to 200 + - i have no idea how much yours will need you will have to start with small adjustments.

I am trying to understand each step so please bare with me.

so only changing the scaler increased my idle and it caused it to hunt while just stationary.

so will increasing the final air flow bring the idle back down to the target?

can someone please share the formula for the scaler so I can do some math and get the proper scaler for the 103mm.

I appreciate all the support gentlemen!!

[Bigred1]

So I did some research and found that according to Nick Williams himself, the Nw 103mm throttle body does not need the etc scalar changed on an LT1 application because it flows about the same amount of air to about 15% throttle. Obviously this is an LS application, but it may be the same for an Ls too. I would try the stock etc scalar and add some airflow to your minimum airflow table. Is your idle spark at your commanded idle spark? Is it having to add idle spark? I won?t be near a computer until tomorrow so I can?t check. Once you get your min airflow where it needs to be, you can adjust throttle follower torque.

Yes that is what I read regarding not changing the scaler with the new 103.

so with keeping the stock scaler I would change the minimum airflow table ( which I am assuming is different then the final air flow table.)

[01SLPSSM6]

You would add to the Airflow Final Minimum table. Might be labeled final airflow minimum table.

[Bigred1]

You would add to the Airflow Final Minimum table. Might be labeled final airflow minimum table.

oh lol I just realized its the same table lmao. so because the idle when I start the car and am not moving is perfect I should the leave the scaler alone.... but slowly increase the Airflow final minimum table until the low speed surge when I clutch in disappears.

now would I adjust the whole table together or just 1st and neutral? or it doesn't matter to change the rest of the gears minimum airflow tables.

[Knight123455]

BTR3 cam and WCC stage 2 heads sorry i missed that question.

[Knight123455]

i just looked up my stock scalar and it is what i listed so yours must be different than mine from the factory. i have a 2009 z06 and it idles perfect.Screenshot 2021-07-16 225042.png this is what mine is set at.

[Knight123455]

those are the air flow final minimum settings.