On boost judder??

[madaboutboost]

Hi all

Just took my VR-4 out for its first proper run (around 100 miles round trip) And noticed a lack of power up top and lots of judder/hunting. It feels like an air leak after the AFM, which may be buggering up the AFR and leaking out boost, hence, no power. It seems to do it more on heavy load situations, 4/5th gear and going up hill. Especially noticed going up a mountain road today in 5th, I actually had to change down to 4th because it was slowing down.
Is there anything obvious I should be checking that may be common to the VR-4? Is there a problem pipe that I don't know about yet?
It does have a rubbish cone filter fitted (which will be going soon, already bought a stock airbox and snorkel) but I can't imagine it would be this extreme, just from a cone filter?
Your help will be much appreciated :D

[Subaru ETA]

I would be looking at spark plugs

[madaboutboost]

I would be looking at spark plugs

I'm planning to do a full service on it next weekend, oil, filter, (New airbox and K&N panel filter should be here then as well) ordered some new plugs as well but haven't checked existing ones. Do you think this would cause the symptoms I mentioned, it runs fine the rest of the time?

[Subaru ETA]

Yup it could be getting blow out at high revs. Def need to do them if you are planning to up the boost

[madaboutboost]

If plugs solves it, I'll be one happy boy :)

[Subaru ETA]

What plugs did you order?

[madaboutboost]

Bosch plats, swore by them in my GT4 days running silly boost :)

[Subaru ETA]

What are the numbers on them. You need to go 1 colder then factory if upping the boost

[madaboutboost]

These guys are just an interim fitment until I start to play more, so just gone direct replacement for now :)

What do people tend to use on here, or is there no popular type? I've used the Denso racing iridium in the past as well with good results but don't know if you can get them for the 6A13TT? I'm sure there is one out there that will fit though.

[madaboutboost]

What are the numbers on them. You need to go 1 colder then factory if upping the boost

Sorry I didn't see the first bit, ordered FR5DPP222 plugs.

[Gly]

NGK bkr7eix would be the most commonly used for raised boost app's on the 8th gen vr4, the NGK bkr6eix is the standard replacement plug

the plugs need to be gaped to between 0.6mm & 0.8mm regardless of brand.

[Gly]

oh and to add, buy the right plugs the first time, the rear bank... lots of parts have to some off, its time consuming.

[Nick Mann]

I can't find any specs on the Bosch plug - the gap should be 0.8mm not 1.1mm. Other cars with the VR4 title and non-turbo 6A13 engines use a 1.1mm gap, so sometimes the 1.1mm gapped plug gets incorrectly recommended for our cars. (Sometimes that can cause spark blow out under load too!)

[madaboutboost]

never been a fan of NGK, but thats another story :)

[ILLEGAL]

are you running high octane? just asking.

[madaboutboost]

I only ever use Shell V power in it :) its not very high octane though, its only 95 :( std unleaded in the UK is 95 and V power over there is 98....

[Gly]

bp 98 or gull force10 would be better.

[madaboutboost]

ahhh, didn't realise others did higher octane... will check out the local BP instead :)
Don't think we have a Gull round here?

[madaboutboost]

Mobil S8000 looks OK as well, min 97.5 octane and one right next to the Shell garage I go to :) Just hope they sell it...
BP, the nearest place to have ultimate on the forecourt is quite far from me. The 2 local to me, don't sell it
Gull, none round here according to their website...
What do other Wellington dwellers use?

[low_vr4]

They have BP ultimate 98 at johnsonville BP, melling in lower hutt and the BP by Te Papa which is on taranaki st i think

[madaboutboost]

yeah the Te Papa one is the closest to me but that means having to drive into the city for fuel. I'll see if the Mobil services near me sells S8000, if so, I'll give that a try :)

[CANDEE]

Pierre run his on 95 with no issues... And I know he runs about 17/18psi on his. :) Come along to the meet on Sunday and you can have a chat with most of us. :)

[madaboutboost]

Where is the meet? I looked in the events place but didn't see a Wellington meeting, maybe me having a blonde moment :(
Don't know what happened with my membership either? Paid through paypal yesterday and it came up that a member of the staff would contact me? Wanted instant access so I could get access to the manuals. I can start to suss out where everything is then. Who is best to contact about this?

[CANDEE]

Meet thread is here:http://www.clubvr4.com/forum/showthread.php?60407-Club-photo-s Am talking to Ryan about it to get it all set up. :)

Send Richard(OnBoost! (http://www.clubvr4.com/forum/member.php?56416-OnBoost!)) a pm, he is the NZ Membership person. Unfortunately the process is manual, so requires someone to get it sorted for you. :)

[madaboutboost]

Sorted now :)
Trying to figure out fitment of my EBC, never done it on a twin turbo before. The manuals I've downloaded must be USA ones because the VR-4 isn't covered :(
Are there any Jap spec manuals about that cover all the pipes/wiring for the 4?

[Nick Mann]

The tubs run in parralel, treat it as a single turbo system. ;)

[madaboutboost]

Ding dang do :)

Need a wiring diagram and vac pipe layout now though...

[BEG4ME]

waste gates are actuated off the red tipped vacuum hose that is connected to the plastic hard pipe to throttle body. That vacuum line goes down to factory boost solenoid.

[madaboutboost]

Ahh, think I've seen a pic of that on here somewhere... Should be easy enough then, especially with it being up top and easy access :)
Need to lay my hands on some silicone vac pipe now, replace the lot :)