discopotato03

HKS GT2535 is getting real long in the tooth nowdays , came out in the very early 1990s . In the day the best thing about them was that they were a bolt on manifold and dump wise for an RB20/25DET . It used one of very few turbine housings that had a T3 mounting flange and the same dump pipe flange pattern as the original equipment ball bearing turbos on R32/33/34 RB20s and 25s . These days most people hi flow the std BB turbos with a different cartridge (centre section inc wheels) and reprofile the std housings to suit slightly larger compressor and turbine wheels . Either way the GT28 sized turbines are a bit small , and the HKS turbine housing is small AR wise for an RB25 anyway . Later HKS made what they called a "GTRS" which is similar to a GT2535 but with a slightly larger compressor wheel . Probably a better thing but still limiting on a RB25 , mine made 271 RWKW on E70 . An easy slight upgrade if all you want is 250-260 kw and gets rid of the std ceramic turbine issues .

Interested in 25 Neo engine .

What HKS called back in the day (think 1990 odd) a GT2530 is what Garrett had renamed a GT2860R series turbocharger . The GT25 part of the number meant "GT25 series" ball bearing centre section and 30 meant the ~ 60mm OD compressor wheel from memory in 63 trim . In Garrett speak the GT28 is for the turbine used , and the 60 means ~ 60mm OD compressor wheel . Again , back in the day HKS had Garrett develop and manufacture specific application turbochargers and patented them . In other words you could only buy them from HKS , Garrett couldn't sell them to the public for a number of years . Often HKS also had their own turbine and compressor housings made . This is why you could for example buy a HKS GT ProS 2835 or 3037 and get them with T3 flanged integral wastegate turbine housings . The market had to wait for Garrett to make T3 flanged GT30 and GT35 wastegated turbine housings so you could easily mount these turbos to T3 exhaust manifolds on ie L28ET FJ20ET RB20 and 25 DET . For the record Garrett develop that style of turbine house as an OE app for the Ford XR6T's GT3582R . Actually we are in exactly the same situation today with G Series turbos , IMO these turbos are unusable for most because of the lack of T3/T4 flanged turbine housings and in some cases integral wastegates . If you could buy G30's/G35's with T3 and T4 IW turbine housings you could throw all the GT/GTX30s and 35's in a big dumpster bin . And thanks Geoff , yep I narrowed the era down to around 2015/16 for the 8mm cartridge change . Older Garrett catalogues didn't mention the new part numbers . I couldn't get their version 5 which I think was the one just before the GTX2 range was released .

Sorry folks , yes OT but I'll be brief . I think that there has been a change in turbine shaft diameter to 8mm in all if not most of the Garrett GT BB range . Obviously this means a change in the ball bearing assembly itself to take a larger diameter shaft . I suspect they may have standardised on a bearing assembly same or similar to the G series one , this would make economic sense . Not 100% sure but I think this change goes back at least to 2016 possibly in the GTX Gen 2/ GTX3584RS era . I'd say this is the reason for the part number change and you'd think these newer turbo cartridges (centre housing rotating assemblies) would be interchangeable with the earlier ones . Again sorry this post OT but something I wasn't aware of . Cheers DP03 .

Garrett GT2859R is Garrett Pn 707160-9 = -9 = GT-SS . All one and the same thing . RB26 twin specific turbocharger .

Fair enough , I'll get back to Leigh at HKB electronics and mention this . BTW I've just fitted the 140a LS1 Mitsy alternator and the voltage at idle can still fall below 14v , I believe this is due to alternator voltage compensation at running temps . I've watched the idle voltage drop and rise sitting at lights and driving along in warm weather . Ideally I want about 14.7v cold and around 14.3 at running temp . Its actually interesting to read what's happened over the last 20 years with alternator voltage regulation . Voltage deliberately reduced to drop idle load emissions and fuel consumption . One mob reckons some cars are deliberately regulated low which reduces battery voltage and then alternator voltage ramped up to around 15v under extended braking to - emulate a regen brake . Anyway I want what keep my battery right up and 14+ into coils injectors and fuel pumps won't hurt either . Thanks and cheers from Adrian .

Long story short , I asked KB electronics to make an alternator voltage booster fuse replacement . They want to know why this fuse is 10a as in what else is wired into the alternator sense circuit that needs it . All I know is that this fuse is in the back fuse box near the battery . Any help appreciated , cheers Adrian .

All good , good to hear Corky is still around as well . And yep I remember hearing good things about that GT2554R on BP16s and 18s as well . At one stage I think I had a GT2554R kicking around in the cave somewhere . IMO you need turbos to wake reasonably early on pure street cars with reasonably small capacity engines . My understanding is that there is limited space in MX5 engine bays and those engines tend to work better in fairly mild states of tune . Anyhow if I find that 2554 I'll let you know . Cheers , Adrian .

If what you say is the case then Prospeed Racing doesn't know their stuff . Garrett Turbo 707160-5 is actually a GT2860R specifically with housings to suit twin aps on RB26's . It was intended to be a direct fit replacement for OE GTR twins . It's actually fairly similar to the once well know HKS specific Garrett GT2530 . GT2530 uses the same turbine as this 707160-5 making it also technically a GT2860R . There was a huge range of turbos in the GT25 and GT28 ball bearing range . Probably the "easiest" way to track them is by their cartridge , CHRA (centre housing rotating assembly) , numbers . For example the "GT2530" uses cartridge number 446179-21 where the 707160-5 uses cartridge number 446179-51 . AFAIK the 707170-5 was never OE on anything . Just to confuse things there was from memory one turbine size in the GT25BB family and two in the GT28BB family . Of the two in the GT28BB group there was also a cropped (ground down) special made for HKS . The higher performance GT28BB turbine was the 53.8mm OD NS111 turbine in 76 trim . Again from memory it fist came out in the HKS specific GT2530 , GT2535 and GT2540 . Later Garrett were able to market their own turbo variations with this turbine eg their GT2860R , GT2860R 707160-5 , GT28RS and the GT2871R family in 48/52/56 compressor trims . Actually the 52T version was originally the HKS specific "GTRS" . Anyway all this aside 707160-5 is RB26 specific so not really a good choice for a four pot single turbo application . I reckon this turbine wouldn't be terribly responsive on a 1600cc four . I think you would be better of with a generic GT25BB turbo if you really want something in this range . There should be lots of info on line about Garrett turbos on MX5/Miata BP16 engines . I remember ages ago reading about what Bell Engineering was doing with them in the states . I think the site was Turbo Miata or Flying Miata , something like that . A .

I bought the kit to fit the LS1 140a Mitsy alternator to my S2 GTS25T . Long story short can I fit a new output cable from the 8mm stud on the alternator directly to the forward stud on the inner side of the under bonnet fuse box . I was thinking of taping up the original 6mm eye fitting on the "alternator starter gearbox" loom and running a new cable as well rather than patching into the original loom . Also do I need to replace any major fuses to cope with the potentially higher output ? Thanks in advance , cheers from Adrian .

Hi all , I have a 1996 S2 GTS25T which has died after problems I believe with its immobiliser . I bought this car in about 2008 from the original owner who said it came here a year previously . I think the immobiliser may be a Brant and has the grey numeric key pad with white numbers that glow red . The keypad has often been difficult to operate and worse of late . For a week before the car died it would run ok then develop a brief miss and then start start to run lean . The temp fix was to pull over ignition off and restart . It has now died completely and refuses to start . Cranks fine but does not even try to fire . No red ignition lights . Usually when the 4 number code was entered I'd get a solid relay click and everything would power up . Now it sometimes gives a near silent click and no ignition lights . I'd really like to flick this system if only to get the car going again . I think what the installer has done is cut several wires just short of the plug on the back of the ignition switch and run extension wires to whatever relay box they used to immobilise the power systems . Would I be right in thinking that if I cut and re-join the factory wiring all should be good ? Cheers from Adrian .

I don't like guessing but if I had to I reckon this is partially the result of a bigish turbine housing on an around 54mm turbine . Yes it flows well but probably at the expense of turbine response down low . Also the standard twins basically achieve the same thing on an I6 as a twin scroll twin gated turbine housing . I don't think we will realise the true potential of these G Series turbos until Garrett or whoever starts making twin scroll turbine housings for them . V band is a bit nowhere for the mass market .

I think a lot of people don't really understand what that temperature sensor is intended to do . It was explained to me many years ago that when a turbo engine is worked hard for long periods of time in high gears eventually everything gets well and truly heat soaked . Teams found this out when running at high speed in tarmac rallies for extended periods of time . This was hard to simulate - everything reaching highest temperatures real world , but they found out the hard way with detonated pistons . Nissan is not stupid and would not use a water temp probe to measure rapid changes in air temperature . But if you think about it a water temp probe is an easy way of measuring the temperature of the inlet manifold that is being cooked up over time from sustained high load running .

Hi all , long long time since I've been in this thread . A while back now I gave up on Caltex EFlex and returned to 98 . The current plan when I can find time is to convert my R33's inlet manifold to the Neo T one and get into 3/4 length EV14 injectors . I want to try the split /twin spray ones that are supposed to spray at each inlet throat/valve rather than at the centre port divider . From previous research it seems that the highest flowing twin spray 3/4 length EV14's are from Ford Mustang Shelby GT500 models . AFAIK there are 500/550/630cc versions available and you'd think being emissions compliant cars that these injectors would atomise pretty well . Just on this the 2020 Shelby GT500 is getting a 5.2L intercooled supercharged 750 odd Hp V8 and it's retaining port fuel injection so there may be a larger split spray injector available soon . Anyhow I'm curious to know what sort of power people think a 630 to 650cc injector could make in an RB25 on E70/85 . Cheers from Adrian .

Hi all , old thread I know but I need some info on the injectors that will be in next years Ford Mustang Shelby GT500 . The engine is a 5.2L four cam supercharged V8 , named Predator , and surprisingly it will still have port fuel injection . The largest current GT500 Shelby V8 injectors I know of are 630cc/~60lb Bosch EV14 mid length - 0280 158 298 . I'm guessing that an around 750 Hp supercharged V8 would need 700 + cc injectors assuming they use one per cylinder . They should be interesting because anything that can meet current emissions regs would have to have good atomisation which could be difficult to achieve in a biggish injector . I have searched but not much info available that I could find . Thanks in advance , cheers from Adrian .

Hi all , just curious as to how people modified the R33 throttle body when fitting them to R34GTt inlet manifolds . Would be a straight bolt on but it has a vacuum port in the top of its mounting flange that actuated the charcoal canister valve . The 33s plenum has extra material to seal the back of it but the R34s plenum mount flange doesn't . I suppose the easy fix is to make up a thin spacer plate to seal this port or weld and face the R34s plenum mounting flange . Or is there an easier way ? Cheers , Adrian .

Hi GTSBoy , we are still struggling with these three pin hole plugs that go over the cold start spring and wax pellet piston thing . We made up a two pin tool and even extended its length for more leverage . All it did was bend the pins , these things are stupid tight . I have an R34 NA Neo IAC assembly as well as a complete Neo turbo inlet manifold . Neither of the plugs is even looking like moving . If you still have your tool could you post a pic of it please . Cheers from Adrian .

Hi all , I know this is an old thread but does anyone know how to get that cap out on the cold start piston side . We made a pin tool up but that cap is crazy tight . I'm reluctant to heat the casting up because of the seal that lives inside where the idle speed magnet solenoid gadget goes . Thanks in advance , cheers from Adrian .

Hi all , does anyone know if the ViPec R33 plug in ECU can control a Bosch 3 wire IAC valve . Thanks in advance , cheers Adrian .

I was just looking at the dimensional drawings at the ATP site , it appears that Garrett have used three slightly different compressor housings . The G25-550/660 and G30-660 use a 0.70 AR housing , the G30-770/900 and G35-900 a 0.72 housing , and the G35-1050 a 0.75 housing . From memory their diameter's are around 170 190 and 205mm . A

I'm curious to know what Gibson Motor sport ran on the Group A cars in the day .

I think I saw a post on Honda Tech saying something about Garrett altering the G30 turbine trim to be something like the NS111 60mm turbine . I'd have to check but I think they were 76 trim.

I'm really interested to see how the G30-660 will go on 2-2.5L 4s and 6s .

All I could find was this but there is nothing in it . https://www.atpturbo.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=tp&Category_Code=G30660