Turbos, VCM and Tuning on J35Z2 - Honda Accord Forum : V6 Performance Accord Forums
Ribbon Banner

Go Back   Honda Accord Forum : V6 Performance Accord Forums > CAR SPECIFIC DISCUSSION > 8TH GENERATION HONDA ACCORD (2008-2012) > 8G HONDA ACCORD PERFORMANCE DISCUSSION
Register FAQ Members List Calendar Insurance
V6Performance.net is the premier Honda Accord Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old August 4th, 2019, 11:29 AM   #1
Registered User
 
Arrnav's Avatar
 
Join Date: Jul 2019
Posts: 13
Question Turbos, VCM and Tuning on J35Z2

I've read up alot in posts around here and followed the long thread from NVA-AV6 about a 7th gen turbocharged accord v6 build project a while ago.

Owning a 2010 Sedan 3.5L V6 with the J35Z2(Auto) VCM Engine, I'm having a hard time finding actual tested information about this motor as very few/none have actually shared details about actually modding and dyno-testing this engine, besides general pointers.

1. Why does nobody tune the J35Z2 for a turbo build? Let's say hypothetically I procure a custom turbo manifold for a single turbo setup, acquire all parts required. I know people keep saying VCM is a hindrance. But where Exactly does VCM stall me in terms of tuning?

As I understand, VCM engages only on very light throttle, which is not enough to spool the turbo. As I go WOT/heavy foot, VCM immediately disengages, so I don't see how it interferes with forced induction.

Reading up more on it, the cam lobes on J35Z2's camshaft for VCM-deactivating cylinders are just circles, so the valves for those remain shut in VCM mode.

I just don't see how VCM can mechanically affect tuning.

Of course I am just getting started with knowledge and hands-on experience with all this and might be completely wrong or missing a major point here.

People mention that maybe the OEM ECU triggering a secondary map under VCM mode interferes with the primary map. But all this information seems to be speculative most of the time and I haven't yet come across any tested results.

Has anyone ever actually turbocharged the J35Z2 successfully while preserving VCM (maximum fuel economy under part throttle, even if the difference in gas mileage with/without VCM is about 2 mpg)?

2. Seeing that KTuner has the ability to disable VCM and tune AF ratios/timing, etc. on the J35Z2, can KTuner be used to tune a turbocharged J35Z2 setup?

Also with the above questions, I also am ignoring the weaker automatic tranny's ability to handle any significant power (340 whp+).

I'm also ignoring the fact that the Accord handles like a boat stock and is a FWD not ideal for such power (Wheelspin/A family sedan).

I'm also not taking into account the general hate for VCM due to part failure/design issues, as I personally like having the extra 2 mpg and haven't yet come across any fouled spark plugs/worn engine mounts/noticeable vibrations on a properly maintained 10+ years old car (Maybe I got lucky).

I'm strictly speaking about just tuning this particular VCM engine.

What I can't wrap my head around is if people have poured down money for built FWD inline 4 turbo civics with 800hp+ (which indicates sometimes money isn't really the issue), why are built turbo J35Z2/Z3 so rare/non-existent?
Arrnav is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old September 4th, 2019, 02:33 AM   #2
Registered User
 
Arrnav's Avatar
 
Join Date: Jul 2019
Posts: 13
Bump. Anyone?
Arrnav is offline   Reply With Quote Quick reply to this message
Old October 7th, 2019, 09:57 AM   #3
Registered User
 
Join Date: Oct 2019
Posts: 10
Couldnt agree more
Mohdilohka is offline   Reply With Quote Quick reply to this message
 
Old November 3rd, 2019, 04:59 PM   #4
Registered User
 
Join Date: Nov 2019
Posts: 1
The cam lobes for VCM deactivated cylinders are NOT just circles. When VCM activates, it triggers a solenoid that stops the cam follower from pushing the rocker arm, so the rocker arm can't open the valves. Not that this answers your question, I just figured it was good to clear it up.

It is definitely possible to turbo an 8th gen. My biggest fear is that it will force the auto trans to give out sooner than its already short life expectancy.
There are plenty of things that you can be afraid of, but if you are willing to risk it, I don't see why you can't.

The one thing I don't understand is why you would bother to keep VCM enabled. Even on low boost you are going to be throwing way more fuel at the cylinders, way more than you will be saving with VCM. Could you keep VCM on? Maybe, but why risk something going wrong when you could totally eliminate the risk by turning it off?
BrokeBoi is offline   Reply With Quote Quick reply to this message
Old November 9th, 2019, 08:11 PM   #5
Registered User
 
jum861706's Avatar
 
Join Date: Feb 2017
Posts: 43
I have an 04 accord coupe j30a4 stock internals boosted which has been riding good since 2017. Havent had any main issues.....can only use the hondata flashpro with the jseries motors
__________________
7th generation
03 accord coupe
j30a4
HFP lip kit
Spec stage 4 clutch
Modified siemens injectors 560cc
Hondata Flashpro
6speed tranny
60mm borg warner
9 pounds
jum861706 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply


Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Honda Accord Forum : V6 Performance Accord Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Chapter
Choose your AV6 Chapter Location
Ride
What do you drive?
Insurance
Please select your insurance company (Optional)

Log-in


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On