Steve

Paul, not likely to happen in a hurry:) flow testing wont prove much in the way of interference will it? Usually just test 1 runner at a time? Warpspeed, thanks for the novel:) I dont really have much in the way of fabrication facilities at home, so I cant see myself doing more than a very innacurate version of the above - would there be much point? Cheers

I knew as soon as I drove the car that something was seriously amiss. I first thought that perpaps my cams had been incorrectly installed, but I just have so much trouble believing that the HKS step one cams are causing so many problems - surely this would have come to light before. Richards first thought was that something had been installed incorrectly, but he checked everything and its ok - I really wish it wasnt:) Another anomoly, the idle is almost perfect (apart from intermittent hunting) there is absolutely no lumpy idle sound? Its pretty frustrating, but if you can give me a heads up on how to use the degree wheel and dial indicator, I will give it a go. Cheers Steve

Could you explain how to use a degree wheel and dial indicator? I agree that the problem is insufficient exhaust gas velocity, but wouldnt the reversion be caused by a poorly designed manifold?

Sydneykid, also, you wouldnt have a URL for online exhaust design software would you? Cheers

paul, I know that something is wrong, I am not saying the longer runners are the entire fault, and I agree that boost should be alot earlier than where it is, even with a manifold with longer runners (although they will make a difference to how boost is made). I am thinking that there must be some sort of crazy interferance happening where the runners join - what else could it be? If you know something I dont, please do tell. freebaggin, oops, my bad, it was late and I was tired when I posted that one, sorry for the misleading info. Sydneykid, 1 bar of boost now happens at around 5000rpm, so lag has increased by 2000rpm. Positive boost doesnt start building until just before 4000rpm. Richard who tuned the car, and has done a couple in this trim, said he couldnt understand why it was taking so much ign timing, didnt say exactly how much, but did say 20odd degrees more than he would expect. He did a great job of improving off boost driveability and getting the lag down - before he started it was around 800-1000rpm more lag. I dont know what rwkw, it hasnt been on a dyno, only street tuned. Before I go replacing the cams, I will change the turbine housing, Richard said he wants to have a good look at the manifold - which is understandable, next will be the inlet cam, then the exhaust cam. Only thing delaying me is that I paid over $1700 more than I was quoted to get the cams etc changed, and with christmas around the corner, well it may be a back seat for a while. If it isnt the manifold, what the hell could it be? Cams are a good thing, turbo is a good thing, head gasket has the CR above a GTR CR, so it wont be hurting things too much. The 0.87 is the recommended AR for that turbo for the street (by HKS) and shouldnt useable boost in after 4000rpm, which is where I need to get it back to.

Man, life isnt fair:( I have HKS step 1 cams and (apart from hunting when its in the mood) it sounds like normal when it idles. All that money spent and no lumpy idle, you just change a gasket and you get lumpy idle - there is no justice:p

If you cant get any info off him (Rory Thompson), drop me a pm, as I may know another way to find out

Dean, maybe just raise your car a little bit so it isnt too low, also, ask regency what height the car can be (if you are lucky they will tell you it can be no less than 100mm) and ask for a cert to say your car can be xxx height. If you are unlucky, you will be required to get an engineers report done, then have the car inspected. The rule is 100mm, and have 2/3rds of the original suspension travel. AFAIK, there is already an engineer who has certified Tiens for a skyline, and knows what the eyebrow height has to be. I think his name is Rory Thompson from memory, anyway he is in the phone book, if you give him a ring he may tell you what height is allowed - then if you go through Regency and they ask you about height, just tell them that he (rory) told you this was legal. It might work, then you can ask politely for a cert to say the ride height is legal (Tim Ireland, the boss, told me that they will do this). Give it a go, dont let the pricks get you down. Either that, or go for a drive to queensland, get the rego transferred, cos they can do what the hell they want. Then if you ever get pulled over, you just bought it last week;)

From the Road Traffic Act 1961: Not bad eh? rights? what rights, you have none.

And remeber, the interior of your car has to comply with ADRs too, make sure no turbo timers are cleverly disguised as child anchors:D

what about smashed ringlands, does that only happen after xxxxxx kms. Read back a bit, car tuned, 2 days good then lots of smoke, hmm, either bad tune, bad fuel, too hot, could be alot of things - but in my experience (be it limited) a good tune is not going to smash ringlands unless there is something else happening, and a good tune should be able to protect the car somewhat from the driver.

Road traffic act gives coppers and regency inspectors cart blanc to do what they want. It states that they only have to believe that your car is defective (not know) and they can send you to regency, and there is no way you can stop them, cos if you obstruct them you are guilty of an offence. Best part is, they have no liability if they get it wrong;) As mentioned, basically you only have rights if you are a criminal, not if you are just driving along minding your own business. Sorry to be one to give you the bad news, but thats the way the govt has seen fit to make the law.

Ben, by comparison the HKS GT3037 has a 84mm exhaust wheel. I suppose you could say ARs are not ARs:) Correct me if I am wrong, transposition of formula: A/R = .69 therefore, A= R x .69 By increasing the Radius, the Area will therefore increase too, to use arbitary figures: if R = 30mm, x .69 = an Area of 20.7 if R = 45mm, x .69 = an Area of 31.05 Add to these figures that you have a bigger exhaust wheel, and quite possibly a bigger exhaust opening, and you can see that a small turbo with an AR of 0.8 could be alot smaller than a bigger turbo with an AR of 0.6 So it is probably a bit inaccurate saying a certain size AR is suitable for a specific hp IMHO.

Ben, just noticed another interesting thing, the sub zero manifold has grouped sequentially firing cylinders to each side of the split - I am thinking along the lines of what happens in my manifold, ie the pulses will collide with eachother and possibly cause back pressure? Or am I mixing up the firing order/grouping of the runners? The nissans fire 1,4,2,5,3,6 dont they? Looks like the Jap manifold seperates the grouping.

It depends on the turbo, not all trust and HKS turbos are built like that (called split pulse), but of course some are. Usually seems to be the big hp turbo setups, which would alos explain the longer pipe design as they are built to perform at the top end.

Well if you have disconnected it, and cleaned the cooler andpipework, you wont get any more oil on the intake side, unless its via the turbo, which as I believe is very unlikely. Leads us right back to your rings.

I wonder where they get the 360mm bullshit from?

Another one, have you cleaned the AFM? Have you tried doing a reset on the ECU lately? If you have detonation it will retard the hell out of the timing and start to run like a dog. Perhaps it detected trouble when the SAFC was being tuned, compensated and needs to be reset (disconnect battery) then take it out for a flog so it can retune. I used to do this regularly when I was running stock ECU or it would loose power up top (but not nearly as bad as your dyno is indicating) Sorry if it sounds like I am guessing, but I am:) gotta try all the common problems.

could be anything, the knock sensor is only a microphone, it could be even be something like your clutch.

What sort of management are you running? What were your AF ratios? have you tried disconnecting the VCT, or NVCS as nissan call it? Plugs? Also, what boost are you running? if its over 12psi, you will hit fuel cut. What mods have you done?

If you got VIS, does that mean you have to go to Regency, or can you take it to any other place?

When under boost, the gasses from the crankcase get circulated into the turbo intake pipe, via the rocker cover, called crank case ventilation. It is necessary to stop your crankcase pressurising, and the gasses must be burnt through the cylinders to comply with emissions requirements. the gasses get into the crankcase as part of the combustion process. Its called blow by, and is gasses escaping past the rings and into the crankcase. If your rings are shot, you will be getting alot more blow by, which suspends oil in it, then passes that to the turbo inlet. From there it gets circulated through the entire intake system when under boost (when off boost the gasses are circulated directly to the plenum, via the vacuum in the plenum, but a one way valve, the Positive Crankcase Ventilation (PCV) Valve shuts when the plenum is pressurised to prevent boost leak, thus the gasses have to go out another way. Another test for bad rings is to take the oil filler cap off, or pull he PCV valve - if you feel air being forced out, even at idle, you have got problems. Unfortuneately this isnt 100% likely to show up problems, as if its just the oil rings and not the compression rings it may not 'breathe' very much. have you checked the pipe from the AFM to the turbo? This is where the blow by is fed under boost, and most likely it will be full of oil too.

As Joel suggested, get a compression test done. Heaps of smoke is a symptom often associated with smashed ringlands. Even if your compression rings are ok, it is possible that your oil rings are rooted. It just doesnt sound right that you have so much blow by. A catch can may hide the cause, and cover up the symptoms, but seriously, you are risking doing more damage. If you only had it on the dyno and it happened the next day - I would be asking questions of whoever tuned your car, it just shouldnt be doing what you describe unless its seriously rooted - sorry to say.

RiGo, reply sent, quite happy to pay what you ask, consider it sold, just need you to send your account details:)

Joel, I dont know - hasnt been on a dyno, just street tuned.