discopotato03

Yes you want to know the EGT out of the engine not the turbo for the reading to have any real significance . If it is the washer type thermocouple you may be able to fit it behind a turbine housing mounting nut though put another washer between it and the nut . Is the oxygen sensor in the exhaust manifold or turbine housing with RB engines ? Cheers A .

You will find turbo engines that need high boost pressure to achieve the desired horsepower are going to need high fuel rail pressure just to keep the head of pressure over manifold pressure . I think you can do better than that turbo for the power , something with better exhaust flow through the turbine side would help . That 90T turbine in the "overbored" GT28 turbine housing is known to perform poorly and the .64AR ratio is going to choke the living shite out of it . The propper Garrett GT3071R with the full sized (and unmolested) 60 x 55mm 84 trim turbine in a REAL GT30 turbine housing works much better . The above thing may have an integral wastegate but the other compromises (T28 flange and butchered GT28 housing) just don't work well enough . Sorry to be negative but I think the GT3071R "Wastegated" creates too many other issues and fixing them is not cost effective . Cheers A .

L S , won't bolt up .

Need the numbers off its ID tag .

That is HKS's Skyline (RB20/25) specific GT2530 . It should have a T3 mount flange and the std single turbo Skyline type dump pipe mounting flange , also note the divider between the turbine and wastegate outlets . The compressor cover is a modified TO4B .60AR Garrett , they've machined off the snout and made their own up and bolted it on with the four hex head bolts . It would be interesting to see it with the snout removed . I think HKS did this snout mod because most TO4B covers had a 2.75 or 3" inlet boss and they wanted to have the boss OD down to typical T3 size - 60mm or 2.35" . Cheers A .

The real Garrett GT30R unit number 700382-12 CHRA no 700177-0007 uses a .60AR ratio port shrouded TO4E compressor cover . If you machined up the conical section and located it with roll pins it would work like the HKS type cover . It uses the SAME identical centre section inc turbine and compressor as HKS's GT3037 in 56 compressor trim . You can buy HKS exhaust housings and fit them if they suit your application . Neither the real Garrett marketed GT30R (GT3076R) or HKS's GT3037 use the .70 AR ratio TO4S comp cover . These are reserved for the lag city 76mm TO4S compressor wheels or the 82mm GT40 compressors in the case of GT3040's (Garretts or HKS's version) or Garretts GT3540R (GT3582R) or HKS's GT3240 . Cheers .

I have no idea why the confused icon is in above post - not my doing ...

Cubes I would have thought 13:1 was a smidge rich for light load AFR , I'm sure RB's could easily deal with more like 14 - 14.5:1 and maybe even a little more light load advance - depending on what your running . 11.8 to 12:1 particularly at around atmospheric manifold pressure I think is way too rich and you may find more torque with less fuel and how ever much advance it can take without detonation . The tuners I used to talk to said they would not go beyond about 12.8:1 AFR because they believed the extra fuel didn't achieve anything worthwhile . Some suggested filthy rich mixtures can promote detonation so said don't do it . My own experience is that really rich mixtures only served to lighten the wallet . Often my best gains were from being right on top of the ignition timing and running conservative mixtures ie between 14.7 and 12.5:1 . I know that aeons ago it used to be said that putting a little extra fuel through an engine just to cool it was a good idea but the mass of the fuel in the inlet charge at around 1/14 will have very limited cooling ability . I believe that small throttle openings pull down the effective CR enough so that reasonably lean mixtures can be used with a fair bit of advance to light the fire early and get some heat and pressure into the cylinders at that all important 20 or so degrees after top dead centre . It sounds logical to me that this is the way to get the most economical use of the fuel and air for part throttle torque . Its also been suggested to me that taller rear gears will make for less revs at the same road speed so with a little more throttle opening you may lift the dynamic compression enough to make a difference in torque so a little better economy - for an RB30 in a GTST with std gearing ? Just my thoughts - open to other views . Cheers A .

No that one and the other similar one at turbobygarrett are the ones to avoid . The real one you can see at - Garrett GT3071R : atpturbo.com . The Garrett exhaust housings are shown up top where the rest are some of ATP's alternatives . The top ones are genuine GT Garrett . As I've said in the past the propper one has a GT30 turbine and GT30 turbine housing . The simple way to check is does it have a T28 flange and integral watsegate ? No deal . Does it have a T3 flange and .63 or .82 or 1.06 cast in the exshaust housing - in the ball park . If the housing has .64 or .86 cast into it its a GT28 housing so a dodgy . Acid test . Check the ID tag on the turbos bearing housing . It must say 700177-0023 or -5023 . If it says another number after the "-" ie 700177-XXXX its not the genuine article . Don't let any turbo shop tell you its not available either . At risk of sounding like a walking ad for GCG turbos try them if you have no luck . I know Brett deals with Garrett overseas so would track one down if you were having trouble finding one . If he could not find one he would probably make one up to suit your needs . Cheers A .

Actually my bad , Garrett do make a T3 flanged .63 ratio GT30 housing but trials of this combination in the US showed up poor results . It worked better on smaller comp trim GT3037's ie 52T and the propper GT3071R . Cheers A .

I don't know of any .63AR ratio housing for the GT30R but it would be a bit small (as in lacking gas flow capacity) for the compressors performance potential . Realistically you should be thinking of the .82 AR ratio Garrett housing or HKS's .87AR ratio GT30 housing as minimums for that compressor and power output . Cheers A .

The HKS GT3037 Pro S integral gate turbos are available in .68 and .87 AR ratio turbine housings . Garrett is supposed to be releasing .82 AR ratio integral gate housings for their GT30R and GT35R turbos in T3 flange ATM . The "right" GT30R Garrett has the same cartridge as HKS's GT3037 56T . Its unit number is 700382-12 - cheaper than a 3037 for essentially same thing . The common CHRA or cartridge part no is 700177-0007 or -5007 if you want to check . The GT30R mentioned above will support 300Kw (400Hp) if everything else is suitable . The GT35R is more of a 600+Hp turbo in large (1.06AR) turbine housing form . Cheers A .

Yes well unfortunately a GT2871R won't bolt up . One last time , IMO the 48 comp trim version of that turbo is the one to have . It can make 39lbs of airflow . If you want it to have a T3 flange you need a HKS exhaust housing . The Garrett marketed GT2871R 52T will not have the exact same characteristics as the HKS one because its modelled off their SR20 S13-15 specific turbo not HKS's RB20/25 specific turbo which uses different compressor and turbine housings to either the SR20 2871R or Garretts generic GT2871R . You may need to consider a slightly taller ratio final drive as the one to suit the std RB20 may be a little short for the RB24 . Your call . Cheers A .

A proper GT30R unit number 700382-12 would work better with that .82AR turbine housing . GT3040's particularly the Garrett marketed one's are laggy because the GT40 compressor is too big for the GT30 turbine . A better compressor match is the GT37 series wheels used in HKS's GT3037 and that above mentioned Garrett marketed GT30R . In fact that GT30R uses the identical cartridge (CHRA) as HKS's GT3037 56 trim . Many turbo shops try to say that GT30R 700382-12 is not available in Australia which is B/S , I know Brett from GCG can get them as no doubt others in Aus can if they try . Garrett at Chippingnorton may not stock them but not all Garrett turbos here have to be sourced through Jeffs joint . Cheers A .

RB25DET with a HKS GT2835 Pro S spooling at 4000 rpm ? Gotta be something wrong there . A few people using that turbo in .68AR turbine housing form on their 33's say they work very well . As for the GT3071R someone on this board has one on an RB20DET and they're not unhappy . I get the feeling that your concerned about the torque characteristics that your engine has or that you want it to have . Putting a maximum KW figure on your build and trying to size a turbo around that figure can be very hit and miss as a wide variety of turbos can potentially achieve 250 Kw . If you really are only going to use it on the street I think you should aim for useful torque in the range that you drive it most of the time . Honestly there are no bragging rights in a street car that doesn't work too well when driven in a socially acceptable manner . My gut feeling is that trying to get a broad torque spread on an RB20 based engine is a big ask . This is because they don't have the capacity to make good strong torque without some boost . If you size the turbo to make boost at lowish revs it will run out of gas flow potential somewhere in the upper mid range . I think SK mentioned that RB24's with maximum effort porting and valve sizes fall short of what 2.4 litres really needs so its pointless erring on the large side turbo wise . To make the most effective use of the flow potential it has I would probably aim for something either GT2860R based (meaning the better GT28 turbine and one of the 60mm diametre compressors) or some kind of hybrid with a slightly larger turbine and a compressor with just enough capacity to make acceptable airflow . Its hard for me to say use turbo X because the result may feel great to me and terrible to you . If you really can't make your mind up the safest bets would probably be HKS's GT2530 or the GCG Hi Flow . Both are better than the std RB20 ceramic BB turbo and once you get a result you will know if its enough for your tastes . If the 2530 isn't enough there's not a whole lot you can do with it where as with the Hi flow you can play with the three different AR ratio turbine housings and a couple of Skyline type compressor covers to "tune" it a little gas flow wise . I know of a couple of R33 owners who really like the R33 Hi Flow so if you can find someone whose done it to show you the result it would help . It won't be exactly the same as an RB24 in an R32GTST but it will give you an idea . Cheers A .

Not really because a .63 AR GT30 housing is considerably larger than a .63 AR GT28 housing would be if it existed - closest in GT28 is .64 AR . When you go up a family in turbines ie GT28 to GT30 the matching family of housing is also larger overall - internally and externally . Remember that a GT3071R is using a 71mm compressor rather than the higher pumping capacity 76mm wheels that GT30xx turbos usually have , so this means that the smaller AR housing (for a GT30 turbine) combination stays in sync with the compressor/housing flow wise . I can't speak for Brett but if you buy a hybrid turbo from them this generally means you buy one turbochargers worth of parts so no unused bits to pay for , you should confirm this with him though . Lastly you are not stuck with that Nissan/Garrett compressor cover either as you could option a .60AR TO4B truck style cover or even a 50AR TO4E cover and backplate . Cheers A .

All sorts of DR30 odds and ends . Will have a look over the week end .

A bit of confusion about GT28 and GT30 turbines . Its easy to think that GT2835's are GT28 turbine based but the only thing that is optionally GT28 is the turbine housing and flange . Turbine dimensions : GT28 76 Trim = 53.8mm major diametre by 47mm minor or outlet diametre . GT30 56.6mm = 56.6mm by 51.6mm 84 trim or 56.6mm by 53.8mm 90 trim . GT30 60mm = 60mm by 55mm 84 trim . GT28 turbines should use GT28 exhaust housings and GT30 turbines should use GT30 turbine housings . When HKS had the GT2835 series made they wanted a bolt on option for SR20's which have T25/28 flanged exhaust manifolds . Cheap easy solution was to bore Garretts GT28 housings out to suit the ground down or cropped 56.6mm GT30 turbine so the turbo would bolt up and retain the integral waste gate . It was a flop because turbine housings are designed around a specific outer or major turbine diametre and boring them larger than intended screws up the nozzle angle and shape . HKS had their own non gated housings made up for this turbine in T25/28 and T3 flange but they are GT30 turbine based housings so they don't have the GT28 overbored housing issues . They also have their own GT Pro T3 flanged integral gate housings for this turbine . Garretts GT3071R (the real one cartridge no 700177-0023) uses the standard sized 60mm GT30 turbine which luckily was not offered in bored out GT28 housings . Don't be scared by the "GT30" part of GT3071R because its compressor is the same family as the GT2835 series . Garrett calls the GT35 compressor 71 as in 71mm OD so in HKS speak a "GT3071R" would be a GT3035 ie GT30 turbine with GT35 compressor . People automatically think all "GT30R" turbos are laggy but this is mainly because most GT30 turbine based turbos use compressors of larger diametre ie 76mm OD (GT37 series or dinosaur TO4S series) or even 82mm which is the GT40 series . As the compressor OD drops so does the load on the turbine so the 71mm or GT35 compressors are easy for them to drive . A large trim compressor demands more turbine power than a smaller trim so if you can use them you get even better transient response and lower boost threshold . As I've said in the past I'd get the mid or 52 compressor trim GT2871R refitted with a GT30 turbine/housing because it gets you the Nissan/Garrett style compressor cover . ATP turbo in the US are now selling a split pulse T3 flanged turbine housing for the GT30 based turbos plus Garrett make an open type .63AR one as well . Cheers A .

In a perfect world there would be no pressure south of the turbine at all . Gas only wants to know about flowing from an area of higher pressure to an area of lower pressure so you want the pressure drop across the turbine in order to drive it . Cheers A .

What d'ya reckon Casper , with spiritual intervention a wing and some pink nail polish even a boat can fly ? Can we put Noas Ark plates on it ? Where do the oars go ?

RB25 and 26 blocks are the same height from crank centre to deck surface. The rods are the same centre to centre length but the gudgeon pin diametre is larger for RB26 . Logically if the rod length is the same and ditto for the block heights the RB26 pistons have a lower crown height to allow for the slightly longer stroke . It is common to see RB25DET's with RB26 cranks rods and pistons . If you can get the bits for the right money its a worthwhile upgrade , better components and slightly lower compression ratio . Any easy capacity increase is a big bonus especially if it does not weaken the bottom end . If possible I would do the crank nose mod or get a later big nose R33 RB26 crank to avoid any oil pump gear splitting issues . Cheers A .

There is a train of thought getting about that lower cylinder head water jacket temps give lower combustion chamber temps so a little less heat conducted to the charge air before (and after) the plug fires to help prevent the end gasses from auto igniting . My experience with low coolant temps was also lower running oil temperature and more drag - this was using good 20W50 mineral oils . So because the 20W50 runs cooler I use a 10W40 now in winter and the very low tech (Charade 2V G11) carby/points engine won't ping at all . With cooling systems , if they operate as the manufacturer intended , water temperature is regulated by the thermostat so low ambient temperature such as Tassie winter should not change this . I agree with Corky when he says if there is one major issue that is the stumbling point with high performance engines its the thermal one . To use all the advantages I would be looking for the coolest air to feed the system which helps charge density and detonation resistance . I don't think the lower (not necessarily lowest) viscosity oils are an issue provided they don't get too hot and cause low pressure dramas - which are easily solved with oil coolers . At the end of the day if you can get a few more degrees of full boost timing it can give good returns . The only disadvantage is lower heater performance but if its zero outside it should still prevent second belly button syndrome ... Food for thought cheers A .

If detonation is the issue can you run lower viscosity oils and lower coolant temps ? Can we assume your car has a cold air intake and filtration system thats up to the task . I would also be doing the exhaust manifold vs boost pressure test as this will show up any higher exhaust system pressures . Not all 3" systems or cats are created equal . You could also do a pressure test at the inlet manifold to see if theres any loss of pressure between here and the compressor outlet that would indicate a restriction or a leak . I would be wanting to know what the air/fuel ratios are under boost as well because filthy rich mixtures can create detonation issues and cost power . Cheers A .

Mafia's turbo was not a true GT30R in that it had a TO4S compressor instead of the propper 6/12 blade GT37 wheel that the "real" GT30R has . It also had the cropped turbine like the GT2835's use so lucked out both ways . As I keep saying the GT3040R is not very good compared to the alternatives , the propper GT30R turbo part number 700382-12 is a far better thing and will have less negative compromises . Honestly many people with RB25's tend to think even the GT30R is a little laggy on the street so either a "real" GT3071R or HKS GT3037 52 trim would be my choise . Your call .

Is it possible to have the comp cover outlet facing down instead of up ?