VTC on decel

FlashPro questions & answers specific to the 2006-2011 Americas Civic Si
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

VTC on decel

Post by MM082001 »

I am wondering which way most of you set this. My tuner left this at 0 on decel. What are the differences of this being set to zero, set to a set number, or set to VTC table?
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

Leaving it set to 0 puts a lot of strain on the timing chain and tensioner. Say you have 30* of advance, then you let off the gas and the advance goes to 0* immediately, it puts a lot of strain on the timing chain and tensioner. When you set it to follow VTC tables, it will gently rotate down to 0* as you come down to idle, granted your tuner didn't set that portion of the table to 0* anyways. Following VTC is also good practice so the actual cam angle follows the cam commanded angle from the tables. The VTC can only rotate so fast, so if it is constantly going from a high value back to 0* and back, it makes it very difficult for the cam to follow commands. If the actual cam angle has trouble following the cam commanded angle, the tune will always be chasing itself. You want to guide the VTC system so the actual cam angle can always follow the cam commanded. Gradual increase or decrease in cam commandments should always be addressed in the cam angle map.

Are you able to post or email me the calibration? I can look it over to see what the cam angle map loops like. If you have a datalog that would help too.

There used to be a video showing the tensioner stress from being set to 0*. I'll keep looking for it.
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

Thanks, I will try to post it as soon as I get home.
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

Here's the tune. I will get a short datalog on my way to work tonight. Thanks.
Attachments
hywo1.fpcal
(20.17 KiB) Downloaded 2 times
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

Quick glance at it, the cam angle map would allow it to rotate somewhat smoothly down to idle and through the shifts if the VTC wasn't set to 0 on decel.

I don't know how much help you want with this, but there are some concerns I have a number of sections in the tune. On your drive to work, throw in one wide open throttle pull in third gear from 3000-8000 rpms if you can. Only do one pull like that, and make that your only hard acceleration pull, I can already tell you it will be incredibly lean or very rich in some parts of the pull. It will be impossible for the WOT fueling to be consistent throughout the pull. The fueling on the high cam is not properly done at all, which is why I ask how much help you want this.

It also looks like it is an older style race calibration, which Hondata recommends not to use anymore. Either way though, we'll see how the datalog looks and I will give you my feedback. I'll let you know what I see, what that means, and my recommendations.
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

Yes, would love the help, but everything is going to change shortly. I am changing up to the Hybrid Racing cai, silicone intake gaskets for both sides, and the ZDX throttle body with Hybrid Racing adapter plate. Monday the parts come in. I will get a datalog just to see if it's safe.
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

Sounds good. I'll get you cleaned up then once I see the datalog. Then if you want some help when you get the new parts, I can help you with that too.

The HR intake is a nice piece, I have tuned quite a few of them. HR and the Skunk 2 are the highest performers I have tuned. What are your list of mods then, just the HR intake and TB next week? For now, it's just the Injen intake? No exhaust or anything?
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

Yes it has a 2020 GMC Denali exhaust. Full 2.5+" with 2 resinators and a DC straight thru 2.5 to 3. Welded it together myself.
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

Interesting exhaust setup for sure. Thought I was in the wrong forum for a minute. Haha.

Stock exhaust manifold or do you have a header on it?
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

No header, not willing to remove the cat.
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

Gotcha. Sounds good. We’ll make the best of the setup for sure.
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

Is the 0000 datalog the newest or the highest number (0004)
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

0000 is the oldest, unless you’ve deleted 0000, then it starts over. 0004 should be the newest. It also has the date in the file. Send both if you want.
MM082001
Posts: 27
Joined: Wed Aug 26, 2020 7:53 pm

Re: VTC on decel

Post by MM082001 »

Ok, this is from city to freeway with warmup. I usually cruise the freeway at or just under where VTEC kicks in (3850 I think). The second pull on the other file was an inclined onramp, on flat ground.
Attachments
city to freeway with warmup.fpdl
(4.19 MiB) Downloaded 2 times
2nd full.fpdl
(1.31 MiB) Downloaded 2 times
08 civic si proline springs koni orange Hondata Injen short ram and peeling and faded Blue paint
EFICU
Posts: 631
Joined: Mon Feb 25, 2019 10:14 pm

Re: VTC on decel

Post by EFICU »

Yeah it is pretty rich all over. The WOT fueling wasn't as bad as I thought it would be, but still very rich.

It certainly has too much timing in it. There were 43 knock just on that first third gear pull. I also watched the VTC throughout the drive, and it is all over the place as expected since it was set to 0* for decel and off throttle. With it the way he had it, it goes to 0* between shifts too, which is tough on the whole system. I honestly haven't watched a cam angle fluctuation like that in a long time because I always set it to follow the cam angle map. It's crazy watching the actual VTC chase the commanded VTC all over the place. Obviously the system can handle the strain for a long time since Honda tunes it that way, but thankfully Hondata provides the option to follow the cam angle map which reduces the straing and helps the drivability. Now the cam angle will stay static between shifts instead of going from say 25* to 0* and back to 25* on every shift.

So I put together a starting file for you. I generally like to tune each cam angle one at a time, but since you're changing some stuff next week I am going to start you on a completed base map and we will clean it up as needed for now. Then if you're happy with everything, and you want to continue working with me, we will redo it properly for your new intake mods once you get them on the car.

Take this one for a drive just like you did in those other datalogs. twenty minutes or so in length, longer is fine. And throw in one WOT pull in third gear from 2500-8600rpms. It should only take a revision or two to dial this one. Also, I adjusted for the ignition in this file based on your old calibration and that datalog with 43 knock. So the knock should be gone, if not drastically reduced. I am guessing you're running 91 octane based on what I see for ignition and knock.

Here is the first file. Vtec is at 4350 which is where it is happiest in the file I am starting you on. See what you think. 3850 is generally too low for NA cars, boosted applications like them lower like it was. The vtec engagement should be a lot smoother too. The cam angle jump was almost 20* of rotation at vtec in your calibration, which is a lot. They crossover cam angle should be the same or very close.
MM082001.SD.Rev01 (Vtec4350).fpcal
(22.19 KiB) Downloaded 2 times
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