discopotato03

Where everyone seems to fail dismally is that they attemp to control ENGINE temperature with electric fan/s rather than radiator temperature . The water thermostat is there to regulate engine water jacket temperature so provided the radiator contains a reserve of cooler water the system will work . If you don't want to have a ridiculous tail chase situation then the rad temp ideally should be lower than the water thermostats opening temp . Provided the water thermostat works properly the rad water temp could be 30 degrees and the the engine water jacket temp should be whatever the water thermostat regulates it to be . If you don't believe me drive your car around in near zero ambient temps with a mechanical fan and see what the gauge shows . If you were going to track your car then I don't see any reason why you wouldn't run the coolong fans flat out for the hard and cool down laps . Some of the rally people I knew had their factory fans (east west engine) run flat out any time the ignition was turned on , these did few road miles and never wore their fans out . The factory mechanical fan works because it pulls a considerable volume of air through the core all the time . IMO the value in elec fans is that they don't have to operate when there is sufficient airflow through the radiator to keep its temp low . In warm climates and round the burbs situations the elec fans probably have to work as well as the mechanical one to achieve the same thing . I think the simplest situation is to use the std viscous hub and maybe a higher capacity radiator but don't overkill on the core . Imo the single row core with the longest single tubes gives the best heat transfer for the thickness of the core . Multiple rows of tubes are a joke because each successive one cops the pre heated air from the one in front of it so the more rows the less heat transfer available . Also where there are gaps between rows there is no heat transfer from tubes to gills/fins so wasted space . Another 2c , cheers A .

Am in the process of e mailing Rob with the same question , possibly not economic to send one to NZ from Australia depending on the cost there . A .

I don't know about that , it just seems logical to make the turbo/s capable of pumping just about enough air to reach the power ask . There is never a guarantee that your engine can actually make the power you want but if the turbo/s are sized correctly it means you have to look at other things . Same old same old , make the engine breathe well and use conservative turbo size and boost levels . Thats my theory anyway . A .

Hi Rob , can you give us any more details or even pics without giving any secrets away ? I like the idea of a modified primary RB25 inlet manifold section that mounts the throttlebodies etc just like the inner RB26 section does . Can you tell me if R33 GTR IAC and TPS is electrically compatible with 96 S2 R33 GTS25T loom etc ? Computer is PFC BTW . I have all the R33 GTR inlet manifold system and if I can run it with the 25's rail and Nismo side feeds thats real good news . Thanks for your input , cheers Adrian in Sydney .

I'm not at home ATM so can't quote formulas to run the corrected pounds of air calcs . I think the important bit is that there is a standard temperature that air needs to be at to be able to measure its weight or mass . The way I look at it is that temperature very much affects airs density and density is directly related to it's mass . If it makes any difference , and I'm no fluid dynamics expert , I also tried years ago to work out air flow through engines in order to be able to spec the perfect turbo to a given engine . The trouble is that it's difficult to be exacting with any given engines volumetric efficiency let alone the temperature changes between the air filter and the inlet valves . 1001 variables and so many numbers entered into the formulas with fingers crossed - using "The Force" if you like . It doesn't promise an accurate answer and turbos are neither cheap or easy to R and R . In the end I chose to look at how many pounds of air it takes to make X amount of horsepower and work that number into potential compressor maps . Lets just say you want say 600 horsepower and want to explore twins for an RB26 , you have to be realistic about power goals here too . The figure I see bandied about is that it takes 10 lbs of air to make ~ 110 Hp and I tame it down to 10 to the 100 so as not to be at the ragged bleeding edge of compressor maps . So I'd think of it as 60 lbs of air for 600 Hp and halve that because I'm looking at two compressor sections . A significant thing to remember (IMO) is that the part of the map with the area of highest adiabatic efficiency (thermal efficiency) really needs to correspond with the air flow rate at the torque peak ideally . Generally an engines torque peak is at its point of highest volumetric efficiency so having the coolest on boost charge temperature should be of most benefit in this area . I used to see people going cross eyed crunching numbers and planning to have this highest compressor efficiency occur at peak power air flow rates . I think all they achieved was using compressor sections way to big for the application . One of Corky's quotes I like is that turbos make torque and that makes fun . There is one thing that you cannot forget about when trying to size turbos - the turbine side . It doesn't matter how well or badly the compressor section is suited to the engine because it has to vent it's exhaust gasses through the turbine ends . If you get the hot side wrong it either won't drive the compressors properly or will choke the engine under load . My 2c burnt , cheers A .

Ring Jim Berry and ask him about those , I believe it's what I had before I had one of his custom clutches fitted . Don't quote me but I think there was some mention of the pressure plates cover not being as good as the OEM R33 GTS25T one . Worth the call , cheers A .

I think 600Kw at the crank let alone the wheels is an unrealistic goal to have in the first place . If you want to have a usable rev range with that sort of output I think even 3 litres (200 odd Cu ?) is a bit lacking . Having telephone number outputs is one thing and being able to do something useful with it , let alone affording it , is another . I don't think 600 hp at the crankshaft is unrealistic in a track RB30 but I don't think it'd be a nice drive on the street . A while back it was mentioned to me by possibly SK that RB30's can be stroked usefully to about 3.2-3.3L and compared to some of the zillion dollar mods people do at times it may not be as expensive ($/Kw) as many think . Std bore/stroke RB26's revved to 11 may be one thing but the budget must be horrendous . IMO need more cubes , do any of the later 3.5L V6's have any hope of going into an R32/3/4 ? A .

I can't agree with you there . Garretts own GT30 and GT35 (small frame GT BB versions) maps show you that the flow rates are similar between the GT30 turbine in their 1.06 A/R turbine housing and the GT35 turbine in their bored out 0.82 A/R GT30 turbine housing . The links to the turbine maps . http://www.turbobygarrett.com/turbobygarre...amp;3turb_e.jpg http://www.turbobygarrett.com/turbobygarre...8-allturb_e.jpg It looks to me like the GT30 turbine in the 1.06 housing size has less restriction in the lower pressure ratio zone than the GT35 has in the 0.82 housing . The fact that the three lines in the 35's map are a gentle curve rather than a sharp rise to a point and flat lining tells me that the GT35 turbine is too big for the GT30 family turbine housings . Purpose built (OEM) GT35 turbine based turbos use GT40 family turbine housings and not surprisingly their GT40 compressors live in GT40 compressor housings . Cheers A .

A "GT2835R" IS a GT3071R , same family of turbine , same family compressor wheels . The only reason HKS get this cartridge to work better than Garrett does is because they use GT30 based turbine housings in the six cylinder versions . If Garrett profiled their GT30 housings to suit the cropped GT30 turbine they would have a very useful unit . A .

No I actually wanted the details of the N1 turbo because it is a GT2556R not a GT2560R . Garrett do make a generic GT2556R turbo/cartridge and I want to know if it's the same cartridge/compressor wheel . Cheers A .

Does anyone have the ID tag details of the R34 GTR N1 turbos ? I believe they are an RB26 specific Garrett GT2556R and I'm interested to know which compressor wheel they have . I believe the unit part number is 702987-7 . Cheers A .

A while back someone here , Lithium ? , made up a Hi Flow using a Garrett GT2871R (48 comp trim) cartridge in re profiled I think RB25 turbos housings . I think his was in an R33 GTS25T and from memory he said it was very smooth power wise with a bit more everywhere . Something like this should be more than capable of making 300 hp on an RB20DET and it uses housings intended for an RB engine . Ask him , cheers A .

Your calls but I would avoid the GT3082 like the plague - unless you can get the 50 trim compressor version which was the HKS spec one "GT3040" . I cannot for the life of me see anything desirable about having a compressor wheel that's simply too big/much for the turbine to drive . The reason why they are lazy turbos is because they need a lot more exhaust gas energy (read higher WOT engine revs) to get them going . I reckon if you need the sort of airflow that the 82mm GT40 compressor can pump then at least give it the GT35 turbine to drive it with . I think its hard to go past a GT3076R on an RB25DET size wise , even these can be borderline laggy on the street but at least they are a reasonable wheel match and they are more than capable of frying road rubber . There is no way I would accept a GT3082R for price reasons , I have and would not hesitate to pay more for the GT3076R knowing that it will give a better overall result and that's what makes you like driving your car on the street . I know people think that HKS spec Garrett GT BB turbos have some sort of magic breathed into them but that's just garbage . What they did was have Garrett play around with wheel sizes and trims to optimize compressors to turbines so that they give good results on performance petrol engines . By good performance I mean a turbo that spools up and makes good engine torque over a reasonably wide range . If you actually look at their spec turbos they often have a more minimalist approach particularly with compressor trims - look at these : GT3071R - HKS 48/52/56T - Garrett 56T only . (HKS incorrectly called these GT2835 but they use a cropped GT30 turbine) GT3076R - HKS 48/52/56T - Garrett 56T only . GT3082R - HKS 50T - Garrett 56T only . GT3540R - HKS 54T - Garrett 56T only . (HKS call their version GT3240 but the turbine is a cropped GT35 one) Remember the pretty blue "Power and Response" tag ? Its because they aimed to make torque which is the thing that shoves you in the back . I think GT3582R's are a real bitzer in that both ends don't use appropriate housings for their wheels , GT35 turbine in a GT30 turbine housing and GT40 compressor in a T04S compressor housing . I reckon it was all aimed at using biggish wheels in a small compact cartridge and ditto for the housings themselves . I reckon its why you can sometimes achieve similar or better results using older T series BB turbos like the large frame BB T04 60-1 turbo . These use a T04 P trim turbine in a T04 turbine housing and a 76mm (3") T04 60-1 compressor in a T04S comp housing designed for a 76mm T04S compressor . Everything pretty much matches and you get 1001 T04 turbine housings in single/twin entry and T3/T4 mount flanges . Years ago I saw someone that used a plain bearing P/60-1 turbo on a hotted up (head/cam/injectors) RB30ET Commode Door and he tore up the pavement everywhere on 10 pounds of boost . 1.00 AR TS T3 flanged T4 hsg BTW . My bottom line for a street RB25 powered RWD car is a GT3076R , more than that equals more lag and you are beyond traction anyway . A .

I prefer to look at the number of corrected pounds of air that the compressor is pumping , if anything the lower the boost pressure is for a given air flow rate the less the outlet air temp tends to be . For what ever reasons the real GT3071R didn't end up being the more responsive little brother to the GT3076R that many of thought it would be . I think Garrett attempted to make a production version of their competition spec TR30R turbo and it didn't really work out because unlike the TR30R's 60mm NS111 turbine (in 73 or 76 trim) the 60mm GT30 turbine is 84 trim and 10 bladed instead of 9 . It makes life hard trying to get more or I should say earlier response with a big trim turbine by using a smaller A/R turbine housing , I reckon what happens is that the smaller volume volute passage gets the gas speed up and the larger aspect ratio exducer side loses much of it . HKS seemed to get around this best by using the cropped version of the GT30 turbine in a GT30 based turbine housing with the GT2835 series turbos - not the GT28 turbine housing versions of them . Out of this I think they got a bit higher shaft (compressor) speed without necessarily using small ratio turbine housings . Garrett chose to only use these cartridges in GT28 turbine housings for their marketed range and we know they're a POS turbo in that form . If they'd given us the 60mm NS111 turbine from the TR30R and profiled their GT30 turbine housings to match then the "GT3071R" would have been a more responsive and successful turbo IMO . The TR30R turbos had either a 76.2 or a 69.something mm compressor wheels in a couple of trim sizes . The largest comp option that I've seen a map for is dimensionally similar to the GT3076R's 76.2mm 56T wheel but it is of a different family and if I remember correctly is 5/5 bladed rather than 6/6 like most GT series wheels . A .

If you want the most out of that turbo you HAVE to run the the largest 1.06 A/R ratio turbine housing . Others with these turbos on twin cam RB30's for some reason fear turbine lag with this housing and I can't understand why . Some have said that these engines are a bit laggy with a 1.06 turbine housing on a GT3582R but thats largly because the GT35 turbine is 8mm larger on the OD and a fair bit larger on exducer size than the GT30 turbine . I know 8mm doesn't sound like much but do the area of a circle calcs and you soon work out the difference is significant . I can't tell you what the boost threshold difference is between a 1.06 A/R GT3076R and a 1.06 A/R GT3582R but the wheels are larger and heaver in the latters case . The other thing is that the GT30 turbine has been designed to work with a GT30 turbine housing as a matching pair , everything I see points to the GT3582R's using a bored out GT30 turbine housing so not exactly an ideal situation . Real GT35 turbine housings from the diesel world start at about .96 I think A/R with the twin entry T3 like Euro T4 flange and grow to about 1.17 + A/R with the large T4 international TS flange on turbos like the GT3576 . If I wanted a reasonably free reving RB30 twin cam and 320 + Kw I would have no hesitation at all in running the big housing on a GT3076R , big engine with big exhaust flow requirement needs a bigish turbine housing to cope with it . I'm not so sure the GT3076R is a "low boost turbo" because it wears a T04E compressor housing . I don't think the beginnings of gas flow restriction start with the compressor housing , I reckon its all in the turbine housing . The fact that they come std with a port shrouded compressor housing shows that Garrett knows the compressor will potentially surge with small and possibly medium sized turbine housings . Both wheels in the over the counter GT3076R are big on trim size - 84 for the turbine and 56 for the compressor and this is not something added to give stellar turbine response . It's done to maximise gas throughput for the basic size of each wheel . If really serious with three litres forget all about these small frame GT BB turbos , step up to a split pulsed T4 flange manifold with two external gates and bolt on a GT4088R . Arguably one of the best dedicated petrol engine performance turbos Garrett ever made . Your calls , cheers A .

If you want to stay with the std RB20DET exhaust manifold it means using a turbocharger with a "T3" flange . From HKS it could be something like a GT2530 or GT2535 or GTRS which is a 52 compressor trim GT2871R . Just make sure you ask for the RB spec ones because they were also made with T2/25/28 (same) sized mounting flange on their turbine housings for CA18/SR20/RB26 . The RB20/25 specific GTRS also has a port shrouded compressor housing and the 2530 Kai may have it as well . Very important on a small capacity six . Most people find generic GT2871R's laggy because they usually get or opt for the largest (56T) compressor and IMO it's a bit much for the GT28 turbine to drive . Garrett make the GT2871R in 48/52/56 compressor trims . The GCG Hi Flow could probably get you there though be aware that the RB25DET's turbine housing looks virtually the same as the RB20's one but it is a little bit larger in its internal passage so starting with an RB25's turbo would be a better bet than an R32 RB20's one . I think the VG30 BB turbos turbine housing would be too big and laggy on an RB20 . GCG and some other mobs used to sell an aftermarket turbine housing with a T3 mounting flange and was set up to accept a Garrett ball bearing GT cartridge , the buyer option which one and it was profile machined to suit it's turbine . It also had the std RB20/25 dump flange pattern . It would be possible to fit the cartridge from a GT2860RS or GT2871R into one or possibly use an original RB25 one . It comes down to your priorities of how much to spend and how easy to fit up . A real GT3071R is going to be a bit bulky for a 300 Hp turbo and has the biggest chance of being laggy because it's GT30 turbine is designed for a fair bit higher power output - 300 Kw + . Maybe for starters you could try a std RB25 turbocharger with the RB20's wastegate actuator , just remember it still has the ceramic turbine and in some cases the composite compressor wheel so don't be greedy with boost or they die a quick death . It won't give you 225 Kw but it should be easy and reasonably cheap , they make ~ 185Kw on an R33 RB25DET . Options , cheers A .

I'll say this then I'm out because this could go nowhere forever . IMO torque is what drives you down the road and the more you have the better off you'll be to a point (traction) . I think it's brave to say that an engine that revs (as in picks up revs) faster makes for a better car . In the real world compromises have to be made and no one drives everywhere in 2nd gear at 4000 + revs . Money is always an issue to most mortals and chasing small changes in stroke length IMO is not worth the effort unless your hands are tied by class regs . If I was that way inclined I'd put any any extra money into RB25 head work and cams because I reckon that would work better than a de stroked one with a lesser CR . The theory around using a "decompression plate" on an archaeological find (Olden 202) was not a good one and while it got the static CR down it killed all the bottom end torque as well . The only reason CR's are lowered is to fight off detonation and there are better easier ways to do that anyway . While ever you have an engine that has to be run at part throttle it is stupid to have real low CR's , the fact that the engines throttled (strangled for want of a better term) means that the cylinder filling ability is lower so the "dynamic" or effective compression pressure will be as well . If you like having no torque and doughy throttle response this is the way to go about it . I really wish people could grasp the fact that if you make an engine breathe better by removing avoidable restrictions you can often make lots of power/torque without high boost pressure . "Big boost" makes for lots of problems so if you can make adequate power without it then you're not making problems that are difficult/expensive to solve . Your call .

From memory HKS T04S turbos were full T04's meaning they used a T4 turbine as well . T4 turbines were generally available in three trims N/O/P with the O and P trims (I think 69 and 76 trims) more common . The unique bit with HKS T04E's and S's was the turbine housing being "T3" flange and usually a smaller AR ratio . As was mentioned these will not be real responsive because the turbines are heavy and the bush bearing center section not as free spinning as a BB cartridge . GT30 BB series turbos like the GT3076R are more modern evolutions of the older T series turbos . A .

Cooling system pressure is usually regulated by the radiator cap . A .

Personally I think the only instance of a shorter stroke crankshaft in an RB25 being useful would be to increase it's rev potential or to possibly if legal suit a class/capacity limit . I reckon I'd do the cylinder capacity calcs because guestimate thinks you may be less than 2400cc . To seriously destroke an engine you have to look at the shorter stroke and possibly longer connecting rods to improve the bore/stroke AND rod/stroke ratios - if you want all the benefits available . I think destroking an engine to reduce the compression ratio is a bit out there somehow , I wouldn't be aiming for anything less than 8.5:1 in anything that saw much part throttle road type usage . The manufacturers had all sorts of reasons for using silly low 7.5 or 7.7:1 ratios in the late 70's to mid 80's era OEM turbo engines . It was the era of "power kerosene" octane ULP and turbochargers/engine management systems were crude by todays standards . They also hadn't gotten around to realising that intercoolers AND more sane 8-8.5 CR's gave much better overall results . Lastly having the piston further down the cylinder at top dead center is probably the worst way to reduce CR because the piston is further away from the heads quench pads so you may reduce the CR and raise the detonation threshold . Lose lose situation for no very good reason . Imo cheap and quite reasonable = ex VL RB30 , close to equal bore and stroke and good rod length to give very acceptable rod angularity . Arguably better than RB25 or 26 because can make the power with 20% less revs in some cases . Just my thoughts , cheers A .

I don't want to burst the bubble but resisting detonation is not just about low compression ratios , it is possible to have a low CR and have it detonate sooner boost pressure wise than another better set up slightly higher CR one . I think it's more about the effective combustion chamber and piston crown form allow the charge to burn , fuel octane plays its part as does charge temperature . There are two schools of thought on CR and boost , high CR/low boost and low CR/high boost . I would rather keep the compression ratio up and find ways to make the engine breath as well as possible so that you don't need high boost pressures to adequately charge your cylinders . I think it's a bad idea to use an RB20 in any form if it's in any way avoidable . They have small ports and valves and there isn't room in the chamber (for larger valves) or casting (for larger ports) to do anything significant with them . Any RB25 head including the R32 RB25DE one has a lot more valve and port area than you could ever get into any RB20 one . Stretched RB20's don't work in my book because when the head runs out of flow all the cubic inches in the world won't help . A .

The last pieces of my turbo are on order , the 0.82 housing and the large canister 14 lb actuator . I reckon 14 pounds should be a good starting point and with the 0.82 IW GT30 turbine housing should not be light switch anyway . I must remember to ask Michael to make sure the housing has the larger flat valve though I think all they do now don't they ? I suppose with the turbo mounted lower down on these HKS manifolds it's easier to get the water outlet line facing upwards and I wouldn't mind it going around the front of the engine RB26 style . Yes no one has ever seen the heat shield for those manifolds . I might try to get some of that aluminium "quilted" blanket material and make something out of that for the manifold and turbine housing . I don't suppose Ford had anything made for this style of housing and dump on XR6T's ? I'll duck into John Robinson Nissan at Rockdale tomorrow and order the exhaust manifold studs and the manifold gasket . My manifold has four good mounting studs for the turbo but I'll need that gasket as well . In time , cheers A .

From over the pond though this one doesn't have the proper GT turbine housing I reckon . http://forums.nicoclub.com/zerothread/4239...ernal-wastegate A . Noted the pantz party , LOL . But there's more , from the same site . This has some interesting stuff about Holset turbos on RB engines and an Apexi cast RB manifold I'd never seen before . On the second page there is a pic of an RB25 wearing an Apexi manifold with a HX35 , it also has a GReady type inlet and I noticed the TB indexed around I suppose to make the throttle cable reach it . http://nico.zeroforum.com/zerothread?id=306777&page=1 Just on the HKS manifold a few have been sold here and the "Kits" have been broken up at times . She'll want to strangle me but I don't suppose anyone is selling the adapter and waste gate to suit the cast low mount manifold ? A .

I gather it's the compressor housing that gets a bit cosy with the engine mount when using the HKS manifold . Yeah I figure it probably isn't any more trouble to plumb up a turbo on the HKS manifold than the std one since you have to make a dump and inlet pipe anyway . From what I remember of your car the turbo sits further back and almost below the manifold so a bit more stealth I suppose . Actually thinking about it your GT3082R has a larger T04S comp housing than my GT3076R's T04E one so may clear as is with a bit of luck . Was much removed from the mount or its bracket on your car ? I was intending to buy genuine manifold studs and gasket/s , if anyone has their part no's - thanks . Also is the space behind the turbine housing adequate to fit in an IW type dump pipe with a reasonable radius bend ? I was lucky and bought an S2 without anti stop brakes so I don't have the pump box and mass of pipes to worry about . Also have to think about heat shielding , did HKS originally sell those manifolds with heat shields ? Cheers , Adrian .

Komrad Git Toyavich , how much wodky to make my Lada him go likt zis ?