discopotato03

Hi all , I'm curious to know what you gain and lose in an R33 spec RB25DET with these cams . I've had them for a long time and can't remember what it was like to tune a car for road with standard cams . Earlier on I had a PFC/Z32 and 740 Nismos and GTRS dryer where as now doing a bit better in those areas . Even so I just wonder what you lose in idle quality and drivability right down low . I know that 256 degree cams aren't exactly wild but the standard ones are from memory 240 and I image timed to have a bit less overlap . Also I'm curious to know if moving the cam timing around does anything for Poncams , exhaust is easy enough and inlet apparently with a bit of mucking around . Gotta run cheers A . Cheers A .

Yes , in with a gut full of GTX Diesel and the pretty much normal idle is back within 200 odd km . Didn't like the sound of those flush additives . A .

Hi all , I have an idle issue that comes and goes - mostly stays but occasionally rights itself . Moving timing mixtures around achieved zip but still have the irregular idle and occasional high idle and or stalling issues hot . Got sick of this and had the engine leak down tested which showed air leaking out the exhaust . The fact that the idle comes good some times must mean that it doesn't have a major valve or seat issue because they don't fix themselves . SK has suggested a sticking hydraulic bucket and given the costs of removing/rebuilding heads checking no 2's exhaust side buckets seems logical . Is this not an unknown problem for a 20 yr 163K old 33 25 engine ? I don't like the sound of engine oil flushes but the thought of a couple of short runs with high detergent diesel engine oils may be ok . Thoughts ? Cheers A .

Tech Edge WB3A2 . Problem found today , leak down test shows 80 on no 2 and the rest 160 . On no 2 most out exhaust but some via crank case . Bugger . A .

50/50 E70/P98 so ~ E35 . Will get the fuel pressure checked tomorrow . Moving fuel and timing settings around doesn't seem to help . A .

S2 GTS25T map sensed has chuggy weak idle and from time to time fixes itself up . 20 yrs old and not sure what to look for ie if there is something obscure these cars do at this age , 162K btw . All cooling hoses rad pump and belts etc just replaced . Had a sticky around the IAC solenoid and hoses all seems ok . Going in Tuesday for compression and if necessary leak down tests . Had EV14 conversion in recent past but problem didn't change . Had Splitfires and new OE coil loom a while back . Been running 33 GTR fuel pump for some time but not sure if it could be the issue . Doesn't falter otherwise drives fine though can be prone to revs dropping far enough to stall occasionally . Any suggestions , cheers A .

I reckon the best replacements based on standard sized RB26 compressor and turbine housings is the -9 turbos . They may not have fancy CNC'd compressor wheels in them but they appear to work very well in a 2568cc 1500Kg GTR . They are not a ring in but a dialed in unit so a result is not a fingers crossed guess .

If you really want a fresh HKS GT2530 make sure the compressor wheel isn't damaged and preferably the compressor housing too . If the one you're considering is for an RB20 or 25 it will have an integral wastegate T3 flanged turbine housing so it can make any GT28BB based turbo bolt to your factory exhaust manifold . Having said that there are limits to what sort of power you can get from even the best GT28xxR turbo particularly on an RB25DET . If you expect an easy 260+ RWKW on petrol you probably really need a GT30 based turbo in a Garrett . GT3076R or GTX3071R would get you there easily with the supporting mods . GT2530s and similar are better suited to mild 2L 4s . A .

Really all the system you're talking about does is help out when the engine is stone cold or nearly . When it heats up and closes only the actual idle control valve does anything . Your call but I reckon if it aint broke don't fix it . Your alternate engine management system won't care but the standard one probably will if you ever had to refit it . A .

No , only the 9RS got the turbo with the Titanium Aluminide turbine and Magnesium compressor wheel . Can't remember what the part numbers are but the second version of that turbo is better because it has a "Super Back" compressor wheel while the earlier ones are flat back and can fail if pushed hard . All Evo 9s used a turbo centre housing with a larger integral compressor housing back plate and its matching compressor housing uses a larger diameter diffuser section . I believe the Evo8 MRs and all 9s used a revised 10.5cm turbine housing with a mirror imaged "D" shaped waste gate outlet that was supposed to flow better than the twin holes and flat valves that say an Evo 6 10.5cm turbine housing has . I think the later ones were supposed to be less likely to crack than the early 6 style ones . Lots of detail things changed from Evo 8 to Evo 9 engines and it was aimed at having a bit more low down torque with better consumption and emissions . The 9s were reasonably heavy for a 2L car and a combination of different head/variable inlet cam timing/turbo changes/more boost/closer ratio six speed box made a better overall system than earlier Evos had . Also each 4G63T from about E6 on had better rods and pistons to cope with the boost increases , from memory 9s had something like 18 lbs boost std and the 10s about 21 pounds . Also MiVec was more than just the variable inlet cam timing , revised (enlarged) cooling passages between the head and block - and the heads deck was thicker . They use motorbike sized spark plugs and improved coolant flow around the hot sides of the chambers and exhaust ports supposedly made them a little more detonation resistant . In the US most people don't play with anything less than an Evo 9 based turbo because you get better housings which get the most out of std or larger wheels . Those 9RS turbos come on a little earlier and have a bit better transient response because of the lighter wheels less inertia to overcome . The TiAl turbines with fail at high boost levels because the bonding between the wheel and shaft can only take so much loading . Probably smart to run std Evo 9 boost levels with them which is quick enough on the street I reckon . A couple of years back an Aussie won in class a Pikes Peak event with a very well put together standard sized Evo 8 turbo , the proof of the pudding is the run times not the boost or kilowatt numbers . Just my 2c , cheers A .

The reason that the bypass valve is bolted to the water log is so it never cools down and closes off completely unless the engines coolant is actually cold . The idea is that if the coolant is warm it partially closes and doesn't have the engine racing if it isn't quite cold . The system actually works quite well so unless its in the way why remove it . A .

That air valve your talking about is a dumb device that is generally fed power from the fuel pump power circuit . That way it won't heat up and open unless the engine/fuel pump is actually running . If it was simply wired to the ignition circuit it would heat up and close before the engine was even started if you didn't crank it . Having that valve means the idle speed control valve doesn't have to be that big that it can pass enough air on its own to keep a stone cold engine running . If it was it would need very fine electrical control to accurately control engine speed . To a degree the smaller the idle air control valve is the easier it is to regulate it . If the factory knew how to do this better with the technology of the day they would have done it . Today its all done with electric throttle/s so the earlier bypass systems aren't needed . That water log you mean carries all the engine coolant out of the head and ducts it to the top hoses water outlet .

Personally I would stay with Garrett GT or GTX units , eg a GTX3071R should put you in the power range you mentioned .

No they are actually better things than the bellows type ones with the braided wire outer covering . The braided ones don't like really high temps and the word on the street is that they expand inwards creating flow restrictions . With the spring loaded "cup" joints the only things that can fail are the carbon ring or the two bolts and springs but I've never seen the fasteners or springs give up . The other thing is that they are really simple to take apart and the usually the only consumable part is that carbon ring - which if in fair condition goes straight back in . I had to insist the exhaust place that made my system fit one but it was well worth it . Truck exhausts sometimes use these kind of joints so big bore parts shouldn't be hard to get . Some better exhaust places may even have the press dies to make them . The obnoxious hum/buzz/drone in aftermarket exhausts is often the exhaust pipe and mufflers vibrating/resonating particularly if the engines torque reaction is being restricted by 3 or 4 metres of big bore tube . The engine and gearbox mounts are there to dampen engine/trans NVH , but hang a long rigid tube off something solid like a manifold and or a turbo and you can expect noise and vibration issues . My old Subaru RX Turbo had a 3" dump pipe and 2 1/2" behind the middle muffler , think 1800cc flat four with small port prehistoric heads and a little GT2554R turbocharger . In legal rally trim (Grp A cams/pistons/computer/exhaust) these engines put out a great snappin 190 hp at the flywheel . Really that exhaust was too big for what I was doing but with straight through mufflers and one of these joints in the factory position it was NOT noisy - at all . I'm not saying that these joints are a magic bullet but together with big can area straight through mufflers (no baffles) you can have an exhaust that doesn't wake the dead or irritate your cars passengers . A .

Noise reduction is more important than ever with the laws being the way they are , which is why standard cars now sound like vacuum cleaners . That "soft joint" also takes a lot of load off your turbine housings bolts/studs and very likely the manifold itself . A .

No , the 3037 in HKS speak uses the same cartridge (centre section and wheels) as the Garrett marketed GT3076R - 76mm 52 trim compressor wheel . The 2835 in HKS speak uses a smaller diameter 71mm 56 trim compressor wheel . Really if you have a turbine housing from a HKS 3037 Pro S adding a Garrett GT3076R and its compressor housing basically gets you the full 3037 Pro S . Garrett sells the cartridge and compressor housing combo and if you want the complete unit the turbine housing is added to it . Garrett GT turbine housings are mostly made of the expensive Ni resist material and add considerably to the cost of a complete turbo . Also I don't know if its possible to machine a HKS Pro S turbine housing out to 3037/GT3076R turbine dimensions if your housing is from a 2835 Pro S . From memory HKS used the same T housing castings but offset machined the 3037 ones so they didn't break into the waste gates passage with the larger turbines profile . I remember looking at pics of the hot sides of GT Pro S 2835s and 3037s and the gap between the two outlets isn't very big nor very different from each other . A .

How does this ATR43G3SAT compare to a Garrett GT3076R in their 0.82 IW turbine housing . Mine is the 52T compressor version . A .

I'd be interested to know if the idling overheating happened over time or after changing some particular cooling system component . I don't think I could have resisted actually removing that water pump to eyeball it and the section of block behind it . Don't suppose it could be an N1 pump by any chance ? Can you tell from the outside ? Um , it does have standard pulleys ie not under driven ones ? Just a thought cheers A .

Mine is 3.5 to the back of the cat and 3 through two large strait through mufflers to atmosphere . One thing you can do is to put a "soft" part in the system to isolate engine vibration from the exhaust system . Most of you would have seen those spring loaded carbon ring and cup joints many transverse front wheel drive cars have . Because the across car engine rocks back and forth under acceleration (torque reaction) the exhaust can't be rigid or it'll act as a tie bar . This clever joint allows engine movement whilst staying sealed , it also isolates to a degree engine noise and vibration . Big diameter tube is very rigid and tents to transmit lots of vibration and noise into your cabin . I got my one off exhaust fitted with one of these spring loaded cup joints behind the cat and roughly where the gearbox exhaust hanger is . That way the front of the exhaust system is supported the length of the rigid engine and gearbox but allows movement south of there . A bit of mucking around but it does work . A .

From memory . HKS Pro S housings came in 0.68 or 0.87 AR ratios for the 2835 and 3037 turbos . IMO it isn't practical to change turbines in a 2835 cartridge , probably better off just using a GT3076R (Garrett speak for GT3037) in the GT30 spec HKS Pro S turbine housing . Generally the GT2835 Pro S turbos came with the 0.68AR turbine housings but the 0.87 version was an option . The cropped GT30 turbine in the "2835" turbos was a special by Garrett for HKS back around 1990 to try to squeeze a modified GT30 turbine into GT28 turbine housings . It was a failure which somehow made it to the market for RB26 and SR20 applications . Basically the nozzle angle in a GT28 turbine housing is all wrong for GT30 turbines - even cropped ones . HKS were the only ones to make GT30 turbine housings profile machined to suit the cropped GT30 turbine that did work . The GT Pro S turbine housings were for a time the ONLY T3 flanged GT30 integral waste gate housings available , later Garrett got around to making their own version but never machined to suit the cropped GT30 turbine . Also have to remember that the compressor wheel in the GT2835R is a 71mm 52 trim GT (Garrett Technology) family and not exactly a high volume wheel for say a 2.5 lire engine . To get the most out of it you need to spin it fairly fast and a GT30 turbine isn't going to want to do that without a smallish ratio turbine housing . This was why HKS opted for a custom Garrett version of the GT30 turbine , shorter blades and a bit less mass to spin the wheel up faster . Garrett tried the 71mm GT compressor wheel + GT30 turbine wheel combination in turbo called GT3071R . People tried them in GT30 0.63 and 0.82 AR Garrett turbine housings and many were never happy with either . I think the smaller housing brought it on a bit quick and made the compressor surge and the larger one seemed to add unacceptable lag . I reckon HKS knew all this and got around these issues with their unique turbine housings and port shrouded compressor housings . The situation is a bit different with GT3076Rs and GTX3071Rs , Garretts GT30 IW turbine housings work fine and the compressor housings sold with them are port shrouded as well . Garrett has never successfully bridged the gap between the GT28 NS111 turbine and their GT30 UHP turbine . The cropped GT30 was a band aid for specific HKS applications but not a real fix . Shortening the length of the blades really leaves you with too much wheel hub area and mass and it only kind of works in turbine housing made specifically to suit it . There are a few 60mm versions of the NS111 turbine but they were only ever used in competition turbos of the TR30R family which again are application specific and very very expensive . Also made of different materials not necessarily suitable for general aftermarket use . Basically dead end . IMO if you have a HKS GT30 Pro S turbine housing , and the unique dump pipe , get a GT3076R or GTX3071R cartridge compressor housing combination and fit them together . You should be able to sell the complete 2835 Pro S easily if its in good working order . I think trying to customise the 2835 could owe you a lot of money and net you a lack lustre result . Your call cheers A .

Close to 8 . I just found the contact through Ebay which from memory was Adrad and went with them . Good looking unit and came with a higher pressure cap which I don't want to use . I never had a cooling problem other than a pin hole leak in that back pipe junction . S2 GTS25T is now 20 yrs old and while the std rad looks ok its probably a time bomb . Basically doing all steel plastic and rubber coolant hoses/pipes in the bay plus pump , rad and OE thermostat . I'll be interested to see if the coolant temp stays closer to 76-78 degrees rather than 82-85 . A .

Old thread revamp . The thing is that the Garrett version of the GT3082R , once known as the GT3040R , use a larger trim version of the 82mm GT40 compressor than the HKS spec one did ie 56T for the Garrett marketed one and 50T for the HKS spec one . Both are made by Garrett but HKS paid for the development of their dialled in version and had exclusive rights to it for a few years . Imo any GT30 based turbo isn't exactly small for a 2 Litre four cylinder but with Garrett its a big jump down from GT30 to GT28 turbines and turbine housings . I believe the few band aids like the cropped GT30 turbine are a crock and only recently proper turbine housings appeared for them - but in limited applications ie no T3 flanged integral waste gate option . I reckon this is why people go to Hypergear and TD series turbos because they bridge the gap Garrett isn't willing to . For the record I had a HKS GTRS on my GTS25T and it made 271 RWKWs (E70 juice) on its knees and with falling boost pressure . A .

I now own a Koyo part no KL020442R and a good looking thing it is . Trouble with internet sites is getting a pic of something that actually is an R33 Skyline radiator . Even Kudos show a pic of something nothing like a Skyline part . Anyhow 53mm and everyone online and off reckons they fit fine with all standard hardware . A .

Actually I found an EBay add for the Koyo Type R020442 53mm from Punchbowl in Sydney . Not all Koyo R33 rads are the same but the claim is these go straight in with the factory shroud and fan . If I can cash n carry with the 2yr warranty probably way to go . Cheers A .

I figure my 20 year old OE radiator has done the job long enough . Looking at aftermarket and not interested in cheapies . From searching the PWR and Koyo all aluminium radiators look the part so what have people here found with them ? The ask is must be direct fit with standard fan and fan shroud . Thanks in advance cheers Adrian DP03 .