discopotato03

Or just run a Garrett GT4088R which has a real Garrett high temp material spec TS T4 flanged turbine housing . One actually designed for its turbine as well . They really are a better match of wheel to housing on both sides and more thought has gone into the wheel trims too . GT/X35xxR anythings are Garrett bastard bitzer turbos , wrong housings for both wheels and a stupidly large turbine trim . They are a legacy of Garrett trying to have something along the lines of the HKS spec GT3240 without the legal issues back then . You can do better . A .

ALWAYS remove the flywheel and crank pulley and replace the crankshaft seals because they are a PITA to do in situ particularly the rear one . I always try to use genuine Nissan Japan ones as they are made to a standard rather than a price . I don't go with fancy timing belts so a genuine Nissan Japan one is what I would use . Mine has a non genuine one and it makes more noise than the one it replaced and I wished I bought a genuine one . I'd also take a close look at any turbo water lines and hoses that run behind the head because they are a pain to get at when the engines in . A .

Long short a mineral oil with the lest friction modifiers additive package . Cheaper Castrol in whitish grey bottle is fine . If really keen change it and filter after the first test drive . As above go find the longest mountain to climb and drive up it at low/medium revs and WOT .WOT gives the best cylinder filling and highest cylinder pressure to get behind the rings and push them out against the cylinder walls . Its the extra pressure the rings exert on the bores that allows the cross hatching to wear a working surface on the faces of the rings and bores . Turbo engines are easier if anything to run in because you have a physical pump to raise cylinder pressures and get the rings pushing out onto the roughened up (honed) bores . It really doesn't take very long to get a working surface on the crankshaft bearings if the block and crank journals are to spec . At 400 I call my engines run in enough for a dose of good mineral oil and after 2000 more its over to what ever I intend to run the thing on . Never ever had a problem with a freshened engine that was honed or bored and honed properly meaning round parallel cylinders and always used chrome rings . A .

Why not just go to a turbo parts supplier and get a new one , can't be that expensive surely ?

Oil cooler thermostats have a shuttle valve that opens one port gradually whilst closing another . They are designed to fail safe and not starve the engine of oil . The oil is stored in the sump so you couldn't dump freezing oil into the engine regardless . Generally cars that have OE oil coolers and thermostats set them to around 100C but they begin to open closer to 90 . Manufacturers do these things for good reasons its not just a guess . Can you imagine a situation where some overkiller decided to run a huge oil cooler with no thermostat and a heavy weight oil because they think thick is good . The whole reason to have an OE style oil cooler system is so you can run oil that works properly in normal driving conditions but not have excessive heat kill it when the engines worked hard for any length of time . These days manufacturers are specifying lighter oils to reduce drag in engines with close tolerances - emissions fuel consumption etc . These engines don't really like higher viscosity oils if they don't get them hot enough to flow easily . The answer in a high performance or turbo engine is to add a thermostatically controlled oil cooler to prevent the oil getting too hot and too thin to protect the engines bearings etc . Or the cheap way is to have an oil to cooling water heat exchanger like RB turbo engines do and have a reasonably high capacity radiator . One last thing , real good oils cost big bux and when you run them too cool they absorb more gunk that can only be removed by draining it out the sump plug hole . This is going to cost a fortune for no positive gain - anywhere . High capacity radiators and oil coolers are good things but only if they keep the fluids in their correct temperature ranges ie neither to cool or too hot . A .

Urban myth on oil temperature , it run fine at 90-100C . 60C is really low and you will be losing to cool oil drag . Also as was mentioned this is not hot enough to boil off condensation or combustion products that get past the piston rings . A .

I think you'll find that they do but it isn't necessarily on the radiator itself . Pressurised cooling systems work better because the higher than normal pressure raises the coolants boiling temperature .

From what I've seen the Japanese don't use tube made to imperial dimensions so often if you have a Jap "3 inch" exhaust its more like 80mm , 3" converts to 76.2mm . I'm just trying to remember if its pipe or tube thats measured in OD because the other is ID . I think the Japanese 2.25 inch comes out at 60mm rather than the imperial 57.15mm . 3 1/2 inces converts to 88.9mm so I imagine in metric its 90mm .

There is a bit of a following in the US of Shell Rotella T 5W40 synthetic oil . They like it because it appears to work and is not real expensive for what it is . The only real question is getting someone to confirm its specified as a "hard use" oil and not just one for turbo diesels . A .

I like the Mobil 1 Racing 4T bike oils because of their high ZDDP content . I think sport bikes work their lube oil harder than cars do and are currently less under the greenie microscope .

With external wastegates there is always the opportunity to adapt GT28 flanged GT30 turbine housings , the hassle is moving the turbo out further and altering plumbing to suit . Also search the Mafias threads/posts because he claimed to have I think ~ 320 Kw with a 56T GT3037/GT3076R in a 0.63 IW GT30 housing . He used WMI which can be arguably simpler than high Ethanol content fuels . A .

You could just pull your existing or get a new pump and remove its impeller and refit it . I think overall the standard mechanical fan is a good thing , needs no electricity to run and pulls lots of air all the time . Simple reliable effective . I know people have a thing about elec fans but when they're not running it means less air through the radiator core . By the time they start the system is at a higher temp than it would have been if the std mechanical one was in place and then its a tail chase to get it back down again. I can see some merit in an electric water pump but I'm still uncomfortable with the idea of trying to control water temp with varying pump speed . I don't see major probs with the std cooling system if its in good condition - for road use . A seperate thermostatically controlled oil cooler would be better than the water cooling systems heat exchanger idea . A .

This was the kind of result I was hoping to see on an RB25DET with the 52 compressor trim GT3037/GT3076R - and with the 0.63 AR turbine housing . Corky Bell said years ago that you can't have good response down low and that meaty top end with the one turbine housing . You have to make your own decision on which compromise you want , mine will be the one that suits what I do with my car most of the time which is not using the meaty top end so much . Possibly the saddest thing is that Garrett unlike HKS never made a 0.73 AR GT30 turbine housing and the one HKS do make has a GT28 flange and no integral wastegate . Right at the bleeding edge the 56 trim GT37 compressor in the 0.60 AR T04E housing can churn enough air for about 540 Hp but I doubt you'd get near that without the 1.06 AR turbine housing and a pretty big exhaust . Besides I reckon it would be laggy on an RB25DET . Personally I don't think much of the 71.1mm or GT35 compressor wheel teamed up with the GT30 turbine . This is not to say they are an unworkable combination but I don't think there is anything brilliant they can do given a choice of turbos . Someone here said differently but I have never seen a GT3071R with a port shrouded compressor housing , they normally have a plain snout 0.50 AR T04E housing ant I've never seen a port shrouded 0.50 E one . The GT37 52T compressor is the one HKS specified when they though things could get laggy . It was an option for SRs and in twin form on RB26s . I don't see the point of having compressor capacity you don't intend to use so for all round IMO the 52T GT37 compressor looks pretty good on an RB25 . At least with these the worst you may have to do is change turbine housings if its too laggy or the top end not to your liking . Turbos aside you can do things like headwork and bump the CR a little to give it a bit more low down engine only torque . If I was rebuilding one I'd use the Neo head and pistons to suit because I think the more compact chambers was probably aimed at better lean running detonation resistance . Bit more timing bit better burning bit closer to the boost threshold etc etc . Its all fine till the wheels spin then the AWDs eat you ... A .

I think the first thing to consider is what fits because I'm under the impression that VCT RB25s use a different water pump to the fixed cam timing ones . Check it out , cheers A .

My views on variable cam timing . The idea of what I call opening the cams means moving one or both in the opposite direction to reduce valve overlap in the scavange phase . What this does is increase the cylinders "trapping efficiency" ie you cant lose compression pressure out of valves that are not open - in a healthy engine that is . High performance engines with fixed cam timing have to compromise ie something thats livable low down whilst breathing well enough in the middle and higher up . To have the best of both worlds you need very short overlap valve timing low down and increase it as the revs and load rise . This is part of the way the broaden an engines usefull power range by increasing the engines torque down low whilst having things sized to make it breath well in the mid to high rev ranges . I don't think this was Nissans intention with RB26's which is why they don't feel that torquey down low . I'm actually surprised the HKS VCT mod is not more popular and available from other suppliers . For whatever reasons Nissan didn't do much more development with the RB26 after R32s , they obviously didn't think it was worth their while to improve the head and valve train like they did with the RB25 Neo and Mitsy did with the MiVec 4G63T engines . In a perfect world RB26's would have VCT on one or both cams to compliment the ITBs and a properly developed TS single turbo - for a production type 225 Kw engine . Note the RB25 Neo had on paper almost R32 RB26 power levels and with the same inlet and a decent TS turbo it could have done better . Mitsy changed a few things on on the Evo 9 notably the larger TS turbine housing and larger diffuser size compressor housing . The real RS got a Titanium alloy turbine and a Megnesium alloy compressor wheel . The head had smaller diameter long reach spark plugs and improved cooling jackets around the hot side of the chambers and exhaust ports . Both aimed at detonation resistance so they could run from memory 19 pounds of boost std on less than ideal fuel . The combination of more detonation resistance/free breathing turbine housing/more boost/better cylinder trapping efficiency showed up as a broader spread of torque starting not very far up the rev range . People say you can run quite healthy cams in these engines and not cop the reversions grief fixed cam timing engines have when you do this to them . Anyway same deal as Nissan , car getting heavier with all the greenie mod cons whilst the engines capacity remained the same . Needed more low to mid range torque to haul the pork . Anyway with RB26's you have to strike a compromise because without VCT or capacity increases you won't get the wide spread of torque needed to drag around one and a half tonnes and have it feel good everywhere . My ideal would be std or mild cams to make it run nicely ie maybe 256s and GTSS type turbos to give it strong mid range torque . I don't give a rats ass about power numbers or how high it revs because high numbers and peaky power characteristics make a road car useless in my book . When the east coast speed limit is 110 and on expressways only where can you use peaky power ? If you build impractical states of tune whos fault is it when its a PITA to drive around town ? A .

Yep those old VG30 4 cam single turbos are old in the tooth nowdays . The other thing is that they use a slightly smaller compressor wheel than GTS25T/GTt so the best thing to do is use the OP6 turbine housing on an RB25s native turbocharger . Um , almost forgot , RB25 turbos have an anti reversion groove machined into the snout of the compressor housing and I don't think the VG30 turbos have it . Easy to duplicate in a lathe but why not just swap turbine housings and refit your turbo as per normal . A .

This question gets asked a lot . There is much mucking around to convert side feed to top feed and that comes at some cost . If you add this cost to whatever injector ie IDs you're looking at and the cost is comparable just go with direct fit side feeds like Nismos . They fit and work the same as standard ones and aside from colour look factory standard too . I think the only time I'd go to top feed was if I was going to run a GReady type inlet manifold and it was a permanent thing . Buy fit forget . A .

Yes I imagine a lot of trial and error goes on which would be expensive and time consuming . Yes and there always seems to be a process of learning about what doesn't want to work . A .

Hi all , recently I bought a 9RS turbo for the Lancer and I got the chance to look at a wide range of Mitsubishi turbines and compressors many of which were aftermarket . It was quite interesting to compare OE cast wheels like 15GK2s and 16/18/20G6s and even a few CNCd HTA wheels as well . I would like to have seen a GTX wheel to compare to the HTAs because some of the differences between the cast Mitsy wheels and HTAs look to be the hubs section . The billet wheels have less hub and more blade which may be part of the reason why some of these billet compressor wheels of similar diametres can have greater capacity than earlier cast ones . I remember reading that part of the compromise with cast compressor wheels is that they have to be easily and reliably removed from tkeir moulds and this could have performance limitations . It was pointed out to me that even GT compressors like the 71/76.2/82mm ones are sort of fat in the hub and this could be part of whats driving Garrett to make their GTX billet CNCd wheels . I do know that there are other differences like blade counts and that port shrouded compressor housings are more common on these units . Possibly one of the selling points of the GTX turbos is that they can run port shrouded comp housings and not get the jet turbine sounds which is better IMO . Also wheel development should be faster and cheaper when your residant computer geek can punch the numbers to get the machining center to carve out whatever you like . It would be a similar deal with housing profiles and when you already own extensive test rig equipment its all good . If only the turbines were as easy , cheers A .

Well we will have to agree to differ because as I said everything I've been taught about radiators intercoolers and oil coolers says the opposite . Next time you see an oil cooler catalog note they generally get taller as in add more tubes to increase the core area and flow area (tube number) . Cooling water radiators are a bit different because they have to be fitted in the available area and that includes plumbing as well . Anyone that took a thermostat out to increase cooling didn't understand that how water flows around a cylinder head is very important . The correct way to go about that is to remove the flat valve from the thermostats surrounding plate and refit it . Many moons ago some special tuning/competitions departments used to sell what they (in BMCs case) called a blanking plate which was a tubular device to replace the thermostat in old Cooper S race/rally engines . It ensured that the coolant flowed properly around and out of the thermostats end of the head casting . If maximum effort cooling is needed in competition apps and another I'll mention in a sec "split cooling" is used . This is where coolant flows in the top of the engine and through the head and down through the block passages and out the bottom to be returned to the radiator/s . The Locomotives we run around in at work have GE 7FDL V16s in them and the way to boost power reliably in them from in the 3s to 4400 gross Hp was to use the split cooling technique . Anyway getting back to radiator type cores . The tube design is very important because the idea is for the tube to absorb as much heat as possible from the fluid or gas running through them and the conduct it out to the fins or gills if you like . These days they virtually always use "turbulators" inside the tubes to break up whats called the boundary layer which wants to insulate inside of the tube from whatevers going through it . Aside from adding more internal surface area these turbulators encourage turbulent flow because this is what it takes to get the medium to expose most of its volume to the tube material so it can conduct the heat away . Now we know that turbulance doesn't do a whole lot for flow velocity but the whole point of the cooling core is to cool whilst posing the least flow restriction . So therefore more tubes or air paths means you have a better chance to make the air turbulent enough to give up the heat but overall not slow it down over less flow paths creating a pressure rise . I'm pretty sure Corky Bell mentions the correct way to increase an intercoolers capacity is to increase the number of tubes rather than increase the tubes lengths . Realy the GTRs intercooler tends to be different in the tanks to many aftermarket ones especially those that don't have a lot of tank depth . Also the intention was to have the turbos on one side of the engine and the throttles the other so its not hard to see why they are layed out the way they are . Anyhow to each their own and I'll continue to look for the elusive Trust turnflow kit or if I can find two suitable cores get one made . A .

GTSBoy everything I've been taught about radiators of any description is that the slower the air or fluid velocity through the tubes the better chance it has of rejecting heat because it spends more time exposed to the cooling air flowing over the outsides of the tubes and fins . I can't see how higher velocity meaning less time to cool can work better if everything else is the same core design wise . If you look at the tanks on that Trust IC they reduce in volume at the far ends so I'd say the idea was to attempt to even out the air speed along the length of the tanks . Anyway given a choice I think its the better compromise . Also , BTW , I think the old Supra ones are supposed to be poor flowing things because of the tube and tank design rather than their layout . Had they used that tube/tank design with lesser longer tubes they would have been totally useless IMO . A .

Interesting, I never realised the new GT-R uses a vertical flow intercooler design too, must be something in it. Yes there is "a lot" in it . More tubes has always been better than longer ones because more flow paths equals less resistance to flow . The cooling area ia about the same flow restriction is not . Also note the horizontal tanks mean you don't have the return pipe under/over your typical front mount return flow system to rob core area or add volume to the IC system . take a closer look at the OPs second picture and note that these vertical flow intercoolers are made from two cores fitted side by side . If we could come up with a couple of OE from something same sized cores the fab work wouldn't be real difficult to make the same sort of thing . If anyone has access to light truck wreckers can you please look at whats being used on some of the turbo diesel top mount units because good second hand cores "in parallel" may just be the ticket . I think a lot of the work in making custom aftermarket intercolers is punching the end plates and welding around each tube . More welds more time greater cost . To the OP can you please measure the vertical heights of the cores between the tanks and the overall width which we can half to determine the width of each core Trust used . Anyway there is a lot to like about this system and I think its as good as it gets whilst having standardish plumbing in the engine bay . It doesn't cause legal hassles going back in the inlet manifold side and if you can still get 250-300 Kw potential thats good enough for a few stealth bombers . Actually if hand made there may even be the opportunity to have a front mount that didn't need any bodywork cut which is the other 50% of the legal issue . A .

Well I think E36 M3s had a 300 Hp 3L all aluminium straight 6 twin cam with individual throttles and twin vanos/VCT . Not cheap but if you could source parts or a wrecked one everything should bolt/plug in . I remember SK saying that they have virtually 50 50 weight distribution front to back which keeps them light and they handle real well too . Keeping it in the family would be preferable but otherwise possibly a high CR NA RB26/30 ? A .

And the reason why it does is because in absolute pressure terms 0 doesn't change . Gauge pressure sets 0 at 100 kpa absolute but atmospheric pressure changes with weather and altitude . A .

I still like the idea of the Trust turn flow intercooler because the top and bottom tank system means the return pipe is much shorter - and also that the core has more tubes rather than longer ones .