RobH

Hi all, Got a bit of a problem with the revs dropping below idle speed when slowing down - especially from 50mph+ speeds. It sometimes picks up again but often stalls (most embarrassing!). I can often avoid the problem by changing down through the box as I'm slowing down. This problem is definately worse since fitting Blitz BOVs on hardpipes. I'm pretty sure I've ruled ouut any chance of a leak. I've capped the points on the intake where the original recircs connected, capped the outlets from the recircs and connected my vacuum lines to the recirc vac lines. I've left the recirc vacuum connectors open - do these also need capping?? The BOVs seem to work ok but I'm not sure if they need adjusting (they're not hissing at idle) - second hand units so who knows what pressure they're set to!?! I've used the shortest lengths of vacuum hose I could get away with without any kinks but I'm wondering if the additional hosing is a bit excessive along with a good couple of yards for the boost controller as well. Must be something vacuum related as use of brakes and clutch seems to make it worse/more likely to stall. Car idles perfectly when stationary Any suggestions would be greatly appreciated. Best regards, RobH

Yep - I blew the top of my reservoir with Ben's ezi bleed - fluid all over the show :-( Those peeps with a really low clutch bite point, have a good look at your slave cylinder, mine had a slight leak and got gradually nearer to the floor. New slave and it was AOK. RobH

Have you checked the engine temperature sensor/connector? (the bigger of the two with two wires) Sorry if this is stating the obvious... Cheers RobH

Having just failed the MOT on a blown sidelight bulb, I've dismantled the offending unit (J spec) and replaced. While I was at it I pulled the lenses off (three pieces) as I had some unsightly moss growing inside at the bottom, gave it a scrub with my birds' toothbrush and now I can't get the blasted thing back together - one side has gone on and the main piece was lifted just enough to allow cleaning (held on by some sealant). Problem is I can't seem to get the final piece to clip back in. What a ridiculous design. Can anybody offer any pearls of wisdom as to the correct technique?? Was going to clean the other side while I was at it but think I'll give it a miss now :-( Cheers RobH

I've been thinking about this recently. Please correct me if I'm wrong but the advantage of bigger turbos is that they don't have to spin so hard to generate the same boost - the charge will be therefore be cooler and more efficient. Ultimately bigger turbos can generate more boost at a lower temperature, I s'pose effectively your putting more oxygen into the engine as the air's cooler and not expanded so much. The same boost will have a more pronounced effect on the power output. Hmm...I think I've just corrected myself....I'll get my coat.

Have to say mine was really dragging it's heels in the heat on a long haul yesterday, quite depressing. I guess a bigger intercooler would help (?) RobH

Hi All, Anyone have any info or know the whereabouts of a 'how to' specifically for the Blitz BOV install please? Best regards, RobH

Hi Van, I did something similar a couple of years ago, lower wishbone was bent and the corresponding HICAS/track rod arm end. Replaced parts courtesy of AndyZ. Haven't had anything similar happen since the change from Auto to Manual though (touchwood). RobH

OK thanks guys, it's the nut on the back of the clevis I can't get off at the mo' PITA!! Never mind, I've put it to bed for now, hopefully will be looking again with Ben on Monday...he has a nice big bar to use. Out of interest I've had some comedy quotes for the job of fitting these. - 4 hours at £35 per hour - sheesh! Ciao! H

Hi all, Just having a bash at replacing shocks and springs - problem is I can't get the old shocks off. The bottom bolt through the clevis is unmoveable. Is the nut on the other side a captive nut or does it need removing before the bolt can be withdrawn? It seems impossible to get a socket on it anyway... Advice mucho appreciatedo RobH(o)

Hi John, as far as I know it's a '6' (Denso 20) only BUT it is 'shrouded' like PFR6B-11B which should give the effect of running slightly cooler.

Oops! It appears that PFR6B-11B should still be available from NGK in the US. It just seems that my suppliers are no longer stocking it. Cheers!

LOL - I think we all have to agree to disagree on what works best. I s'pose if a particular plug works for you then don't change it. My US suppliers report PFR6B-11B as no longer in production - I would imagine it wasn't a particularly popular plug as it isn't recommended for any other engine (as the PFR6B-11C isn't). There may still be some shelf stock here and there. Projection of the spark is good for any engine but exposure of the firing end is not good in a turbo engine. PFR6B-11B allegedly gets the spark position right and keeps the insulator and centre electrode shrouded (i.e. protected). Bah - I only posted to try get some dimensions :-( LOL! Ciao!

Agreed to both. My only gripe with the ZFR7F-11's is that they aren't 'shrouded' as the PFR6B-11B's are. The insulator (and electrode) are fully exposed to the combustion process - pieces have been known to break off the ceramic insulator under harsh conditions. I'm expecting this 'new' plug I've found to have the same projection as ZFR7F-11 but also to be shrouded like the PFR6B-11B ;-) ++++ the Iridium version should last 120000 miles :-O John - I think you mentioed it was a surface discharge type previously (the NGK race plug), excellent for extreme conditions and preventing fouling but non projected. Cheers all! H

Hi Ian, Concensus of opinion is that a shiny new copper plug is difficult to beat. Problem is that copper plugs wear so quickly, ignition performance soon fades. I don't cover much distance in my Z at the moment but even so I wouldn't like to change the plugs every 2000 miles. Iridium plugs *should* theoretically perform better assuming they are a suitable design for the engine/combustion chamber - there is currently no 'perfect' design of Iridium plug (or copper for that matter) for the VG30DETT - that's what I'm currently investigating. Either BKR6EIX or Denso IK20 will be a good equivalent replacement for the PFR6B-11 in an NA and offer a compromise for the PFR6B-11C for the TT (cheaper, long service life and should perform approximately as well as the platinum plug). Iridium plugs are most useful for tuned engines where a colder heat range is required, it may be preferable to use a less projected plug than PFR6B-11C in this case to afford the firing tip some projection - BKR7EIX (BKR7EIX-11 if you're confident in your ignition system) or IK22. It's impossible to prove anything on a dyno - conditions of climate and engine temperature etc vary so much from run to run. Sorry....didn't mean to waffle. BR RobH

Hi all, I think I may have found an equivalent to PFR6B-11B which ceased production some years ago. Unfortunately I'm having difficulty getting the original specifications of PFR6B-11B so would appreciate some help if anyone has an old/new PFR6B-11B lying around. Even better would be if someone could send me a used plug. Why NGK stopped making this plug is a mystery. I need a measurement of the total thread length from the base of the metal shell (not the gasket) to the end of the shell (not the end of the thread). Also a measurement from the end of the shell to the outside of the ground electrode. The plug I'm thinking of is available in standard copper and also extreme longlife Iridium/platinum mix. Any help appreciated as ever. Best regards, RobH

Hmm... Anyone got any views on whether new suspension would cure my problem?? I'd rather rather fix the cause than the symptom (+ it's pretty sloppy on handling anyway). I don't want to lower as I'm forever scraping bits off the splash guard/front spolier anyway. Can anyone recommend a good (pref cheap!) replacement set of springs and dampers. TIA! RobH

OK thanks guys, will get it looked at. Can I assume that new dampers and springs would help considerably?? I suppose all the geometry would need resetting anyway if I replace the suspension... Cheers!

Hi All, My front passenger tyre has extreme wear on the inner side (i.e. bald) the rest of the tyre still looks like new. Drivers side still has plenty of tread although is slightly more worn on the inner side. I'm guessing this means it's not a tracking/alignment problem. Rears are also fine. Using Toyo proxys (about 3000 miles) and energy suspesion poly bushes in tension bars (checked and very tight). Any suggestion as to what coud cause this would be welcome. Possibly a suspension component bush somewhere?? I think the suspension's getting a bit tired, 105000 miles and still original. Thanks in advance. RobH

I guess that would be the ZFR7F-11 that John Dixon uses. The point of my photos earlier was to illustrate that the UK Z32 recommended plugs (PFR6B-11C) are actually the same length as the aftermarket 'upgrade' plugs so the spark is actually in the same position, therefore there is no major disadvantage in replacing UK standard plugs for Iridium plugs. PFR6B-11B are a different prospect with quite a different spark position. Can't think why NGK UK are pushing the 11C instead....

Hmm..maybe so, but I'm pretty sure NGK aren't making the 11B anymore. Maybe the 500BHP blokes would see an improvement with a colder plug. 1 heat range per approx 100BHP upgrade is the general rule of thumb most tuners work to I believe. John, the shell is usually extended to offer some protection to the firing tip, wear being more rapid in a turbo engine. Not sure if the NA/TT use different heads - anyone?? R

Hi All, Hopefully I've attached an image of the four most commonly used Z plugs. It's not perfectly square, think the camera was on an angle. You can see though that the 'spark position' is the same for PFR6B-11C and Iridium BKR6EIX-11 and IK20. The big difference is the shell extension which the PFR6B-11C has and the others do not. From left to right: PFR6B-11 (NA), PFR6B-11C (TT recommended), BKR6EIX-11 and IK20. I think the US link and photos refer to PFB6B-11B judging by the even further extended shell. You may have no choice but an aftermarket plug if mods mean you need a colder heat range. Sideshowbob - Not sure who makes Greddy plugs, bound to be NGK or Denso though. Not car specific at all, make sure they're the same length as the ones you take out as retailers have a nasty habit of supplying JIS plugs where they should be ISO and vice versa, this is important with direct fire ignition. Cheers! RobH

Hi Mike, self learning is considered not to work on the AVC-R on a twin turbo, mine kept creeping ever higher. I've completely disabled it and just set it manually, been pretty close to the mark ever since given the odd change due to climate. Might be worth checking for boost leaks too as I'm sure these will play havoc with your settings. Cheers RobH

Don't get me wrong John Dixon (a bit confusing John Dixon and DixonJohn posting on one thread) if ZFR7F-11 work for you then that's great - just a bit of an unusual replacement for the standard recommendation that's all. A word about durability - NGK's Iridiums should last up to 60000 miles (same as double platinum PFR plugs), Denso (aka HKS) recommend a 30000 mile replacement schedule. Plugs (Iridium and platinum) are well past their best a long time before this. Some of Denso's blurb actually recommends 20000 to 30000 kms (!). The only way to get Denso Iridium performance and extended service life (60000 miles) is the hideously expensive VK20PR-Z11, Iridium centre and platinum ground - over £20 per plug. Cheers! RobH

Hi John, PFR6B-11C is a special for the VG30DETT engine - PFR6B-11B is a revision reputed to have been made for the North American market and lightly tuned or hard driven cars, running slightly cooler. Not available from NGK in the UK and no longer available in the US (at least last time I tried to get some). Both of these plugs have an extended shell which allows the spark to be placed more toward the centre of the combustion chamber while still affording the ceramic insulator and centre electrode some protection. From what I can make out the '11B has an even more extended shell but I don't have one to compare unfortunately. ZFR7F-11 will put the spark in a similar position but without the shell protection of the PFR6B-11C/11B. The extra extended centre electrode and insulator also means an extra extended ground electrode - not a good thing in a high performance or tuned engine. Only putting my 1/4p's worth in because plugs is something I actually feel qualified to comment on. Ciao!