91mm TB and lid install. Small issues. Necessary changes for running condition?

[ZLRob]

I installed both a lid and 91mm Soler TB on my ZL1 and every once in a while when I remote start it I hear the idle surging a little bit. The surging goes away after about 3-5 seconds, however. Everything else seems to be running right and AFR is within proper scaling from what I can see based on the logs. No vacuum leaks for the record. What changes do I need to make in HPT to make the issue go away? I can throw up my tune file and latest log (which does not reflect the momentous surging idle FYI) here to the post shortly if anyone wants to give me a hand. I've never messed with the VTT's and/ or with the VE tables either so I'm a little bit of a newbie in those categories.

[kenand1988]

I installed both a lid and 91mm Soler TB on my ZL1 and every once in a while when I remote start it I hear the idle surging a little bit. The surging goes away after about 3-5 seconds, however. Everything else seems to be running right and AFR is within proper scaling from what I can see based on the logs. No vacuum leaks for the record. What changes do I need to make in HPT to make the issue go away? I can throw up my tune file and latest log (which does not reflect the momentous surging idle FYI) here to the post shortly if anyone wants to give me a hand. I've never messed with the VTT's and/ or with the VE tables either so I'm a little bit of a newbie in those categories.

Is the car already warm or is it dead cold when this happens?

[ZLRob]

It's usually cold or has to have been sitting for a while since I drove it that same day but I'm not 1000% sure and it doesn't always do it.

[TriPinTaZ]

I have found that the cranking airflow and torque tables need adjusting for the 91mm TB.

[ZLRob]

I have found that the cranking airflow and torque tables need adjusting for the 91mm TB.

Are you referring to the cranking airflow and torque > base airflow and virtual torque tables?

[ZLRob]

I have found that the cranking airflow and torque tables need adjusting for the 91mm TB.

Here's a copy of my tune file BTW:Attachment 129222

[TriPinTaZ]

I wasn't referring to Virtual Torque. You shouldn't need to mess with that for a ported 87.

Screenshot 2023-03-11 215800.png

[ZLRob]

I wasn't referring to Virtual Torque. You shouldn't need to mess with that for a ported 87.

Screenshot 2023-03-11 215800.png

Awesome! I'll take a look at those tables, thank you! I added about +5% to the base airflow table and the Split/CLO across the board. That should be fine I would think right?

[TriPinTaZ]

Awesome! I'll take a look at those tables, thank you! I added about +5% to the base airflow table and the Split/CLO across the board. That should be fine I would think right?

Logic would dictate that a larger throttle body would want less airflow at startup. These tables are torque tables but you can treat them as if they were airflow tables. Lower values tell the ECU to close the throttle blade more and higher values tell the ECU to open the blade more. Assuming your Airmass and Torque model is good, you would want to lower the values at and near cold startup. And strangely enough, increase the values for hot start.

If your airmass and torque is off, this will also cause hunting. Looks like you have Alcohol torque modifiers still active. Give this file a try, I made a couple of changes.

test1.hpt

[ZLRob]

Logic would dictate that a larger throttle body would want less airflow at startup. These tables are torque tables but you can treat them as if they were airflow tables. Lower values tell the ECU to close the throttle blade more and higher values tell the ECU to open the blade more. Assuming your Airmass and Torque model is good, you would want to lower the values at and near cold startup. And strangely enough, increase the values for hot start.

If your airmass and torque is off, this will also cause hunting. Looks like you have Alcohol torque modifiers still active. Give this file a try, I made a couple of changes.

test1.hpt

Very interesting! The base tables need to be conversely modified in their hot and cold sections respectively. I'll upload this in a few minutes and get back to you. Thank you for giving my file a look Jason!

[ZLRob]

Logic would dictate that a larger throttle body would want less airflow at startup. These tables are torque tables but you can treat them as if they were airflow tables. Lower values tell the ECU to close the throttle blade more and higher values tell the ECU to open the blade more. Assuming your Airmass and Torque model is good, you would want to lower the values at and near cold startup. And strangely enough, increase the values for hot start.

If your airmass and torque is off, this will also cause hunting. Looks like you have Alcohol torque modifiers still active. Give this file a try, I made a couple of changes.

test1.hpt

I went to start it today and found it was doing it for a good 4 seconds or so. Is there anything else that needs modifying or do I just need to increase the values another 5%?

[TriPinTaZ]

I assumed you were stock, but it could be a bunch of stuff. You really need to capture it on a log and see why its moving the throttle around. It's trying to find the right idle so if your startup airflow isn't helping it is either wrong or your airmass model is out of line which will throw your torque model out of line. AKA your MAF config could be causing this too.

[ZLRob]

I assumed you were stock, but it could be a bunch of stuff. You really need to capture it on a log and see why its moving the throttle around. It's trying to find the right idle so if your startup airflow isn't helping it is either wrong or your airmass model is out of line which will throw your torque model out of line. AKA your MAF config could be causing this too.

Oh yeah, definitely not stock. Exhaust is fully modified post primaries entirely rearward. I got a lid, 91mm TB (ported) ethanol tuned and different spark plug wires and heat range 7 plugs just that I can think of off the top of my head. I don't know how to scale a MAF so that doesn't help either. Lol.

[Joshinator99]

My humble 2 cents is that the ported TBs are a waste of time and are usually terrible to tune around. A ported 87mm TB (91 or whatever they pass it off as) will NOT out flow a stock 95mm TB, and the 95 is about $170 on Rock Auto… I went from a Katech 103 to a “Soler 107 effective” and the car became possessed. I even enlisted Ben Charles to help tune it and he was like WTF…. After a few days of struggling with it, I put the Katech 103 back on and no more problems. I later upgraded to a Katech 112 and again, no problems. I only see tuning problems with these “ported” units so you’re better off just going up a size if you need more airflow.

[ZLRob]

My humble 2 cents is that the ported TBs are a waste of time and are usually terrible to tune around. A ported 87mm TB (91 or whatever they pass it off as) will NOT out flow a stock 95mm TB, and the 95 is about $170 on Rock Auto… I went from a Katech 103 to a “Soler 107 effective” and the car became possessed. I even enlisted Ben Charles to help tune it and he was like WTF…. After a few days of struggling with it, I put the Katech 103 back on and no more problems. I later upgraded to a Katech 112 and again, no problems. I only see tuning problems with these “ported” units so you’re better off just going up a size if you need more airflow.

This isn't the first time I've heard of tuning issues or just general issues with the ported TB's. These LT's are super computerized and have way too many parameters available to tune so it can literally be anything. I'll see if I can get a log of when it does it as it is not an easy issue to pick up, but it definitely does it so maybe I'll just hook up the laptop before I remote start it and attempt to capture the idle.

Going up any further than "91mm" requires an adapter doesn't it?

[Joshinator99]

This isn't the first time I've heard of tuning issues or just general issues with the ported TB's. These LT's are super computerized and have way too many parameters available to tune so it can literally be anything. I'll see if I can get a log of when it does it as it is not an easy issue to pick up, but it definitely does it so maybe I'll just hook up the laptop before I remote start it and attempt to capture the idle.

Going up any further than "91mm" requires an adapter doesn't it?

Not necessarily. On a stock ZL1 blower, I believe you can just open up the snout a bit (no brainer to do anyway if you’re porting the blower) and slot the LT5 TB bolt holes a bit. If you do the adapter you just want to make sure it’s not necking down your gain in size.

[GHuggins]

It says you have an auto in the trans cal section - do you or did it just get changed by accident?

[ZLRob]

It says you have an auto in the trans cal section - do you or did it just get changed by accident?

Are you talking about what's in my tune? I have not touched the transmission stuff as my T87A has not been unlocked and I have not touched anything regarding transmission stuff while tuning and getting the car tuned.

It is an A10 BTW.

[GHuggins]

I figured it might be with you talking about remote starting it. Have you by chance done a trans fast learn recently - possibly before this started?

[ZLRob]

I figured it might be with you talking about remote starting it. Have you by chance done a trans fast learn recently - possibly before this started?

No I have not. I don't even know how to do that quite truthfully. This issue started seemingly out of nowhere one day from what I remember but have barely gotten around to addressing it as of now.