discopotato03

I agree about the 30/35 size , but as I've said in the past I'd like to see a G28 as well because gut feeling is that a smidge more turbine than the G25 with a couple of compressor options is probably going to cover much of the hot roady needs . If Garrett really does want volume sales they really need T3 and T4 turbine housings because for many 3" V band isn't an option . I'd like to see a G28 or G30 become the modern GT3076R T3 Integral Wastegate replacement . A .

Has anyone seen any details about the T4 twin scroll integral waste gate housings that are said to be available for these G turbos . A .

Out of curiosity how does the GT3584RS stack up against the above mentioned turbos ? Not sure if they are available in a proper T4 twin scroll turbine housing though . Cheers A .

Sacrificing CR is a way of saying no we haven't found a workable method of stopping our forced lump from detonating . I'm not sure what range of compression ratios you talking about and I sense that you are not very aware of what factors affect measured CR .

Wow , all I can say is calculators don't build engines for manufacturers or race teams . There are some very simplistic ideas being promoted here based on guestimations being pushed as fact . All I can say is that very few engine are ever anything like 100% volumetrically efficient and trying to add a bar of pressure to a compression ratio is hmm - maybe optimistic . Way too many factors shoot that one down in a screaming heap . My take is that detonation is a factor of heat and pressure , whatever starts an unplanned combustion event . With static compression ratios , many things have run very high ratios but it is hard to argue that it slows down the way an engine revs . If you don't think so go search for some data on compression pressures vs combustion pressures . Fact . What higher static compression ratios do for you is increase the dynamic or actual compression ratio at less than full throttle . ANY restriction in an inlet tract will limit how much air a cylinder can inhale and if it aint full when the valves are ALL closed good luck getting the measured or "static" compression ratio . Then you can throw in hot cams that open inlets earlier and close exhausts later , and generally increase the overlap valve timing , and you start loosing trapping efficiency . The less there is to compress means you get a lower dynamic or effective CR . Hot cams are designed to allow an engine to rev higher , to make more power at higher revs . Don't ever lose sight of the fact that all you have to charge an NA engines cylinders is atmospheric pressure - period . Real word an engine CANNOT suck air in , all it can do is create an area of lower than atmospheric pressure into which the greater 1 bar at sea level can push itself into .

Hi all , I need an RB25 Neo turbo cylinder head complete with standard valves and cams . Cam covers and a CAS would be handy but not essential . I prefer unmolested and don't mind freshening it up . Cheers from Adrian in Sydney .

Interesting point about the firing order difference between an inline 6 and 4 cylinders . The four having a flat plane crank will be different to the usual I6 having 120 degree phased crank pins . I know of flat plane V8 cranks but I've never heard of a flat plane I6 crank . My guess is that most RBs , because of their capacity and being dimensionally based on the RB20 block , are a little short in their strokes and rod lengths . The RB30 is a big departure because being 3/4 of an inch taller block wise allowed a longer stroke and rod length . Also being approximately 3L the cylinder size is very similar to many 2L four cylinders . A .

Well if the G30 is going to be how some here expect it to be then I can only hope there will be a G28 , or a least a G28 turbine option . Sort of like a 6758 wheel size wise but less bulky .

I agree , the people at Evom are saying that the G30 may be released in 2019 possibly at Sema . I reckon they could have sold many more G30s than G42s but they obviously decided to cater to the drag fraternity .

I'll reserve judgement until the G30 and 35 are released and the market gets to test them . Garrett is obviously putting them up against the older GT versions and the market will soon know if they aren't much if any better . I'm most interested in the G30 and how it goes response wise compared to the GT3076R/GTX3071R . I'd like to see a bit less inertia and a bit better wheel efficiencies , in other words same power as a GTX3071R with better spool . A .

I reading a few claims at various sites that Garrett may have the G30 on show at SEMA . Anyone know anything about this ? A .

Bosch do a shorty EV14 extended nose injector - 0280158211 . Supposed to be rated ~ 485cc at 3 bar . Or there was I believe a JDM S15 SR20DET side feed injector that is interchangeable and slightly bigger than R33 std injectors . The above mentioned Bosch ones have 10 holes and possibly twin spray pattern as well . My understanding is that the greater the number of holes they have in the tip the better fuel atomisation will be . Also the closer you can size an injector to your realistic power output the better off you are , as in accurate fuel control engine response and fuel consumption .

I agree Garrett has the potential to do great things with the G series . I'm thinking the compressors and turbines wouldn't have to be a whole lot bigger to put them in the power range that the fast road market is really interested in . If they keep the same frame size and have housings similar to the G25s , in for example a G28/G30 series , then we can have efficient responsive turbos . Keeping them compact and having reliable hot sides is where they could have it over the EFRs .

I can't remember which way round it works , as in plumbing the swirl pots lower fitting to the bottom radiator hose or to the fitting pressed into the back of the blocks thermostat "bowl" . I tend to think that the way to go is behind the thermostat rather than in front like Nissan has it standard . While I'm here if anyone has that fitting that presses into the block from a Neo turbo engine I'm prepared to pay well for a good used one . Neo Ts are about 10mm here where the R33 and Neo NA are 8mm . Cheers A .

It occurs to me that Garrett are taking a long time to bring larger versions of this G Series to the market . Its time they got their finger out in my opinion and had a look at bringing out the next turbine size up in the G series .

Would it be possible to see a pic of an RB spec Mitsubishi Alternator next to the LS Mitsy one please . I'm very interested in this kit but just curious to see if the LS one is larger in diameter compared to the Nissan supplied one . Mine would be for an R33 spec RB25DET . Thanks in advance , cheers Adrian .

I agree with this . I think you need to consider what people have achieved with the standard Neo turbo cams . Its great to theorise about valve lift but that's only one part of the camshaft story . 252 Neo Poncams are still going to have too much overlap for an engine you want to make good part throttle power with IMO . If it were me , and I wanted your preferences and had coin to spend , I'd consider using slightly oversized valves to make it breathe better and be nice all round . If you want to see things from a factory perspective you could look at 1JZ vs 2JZ turbo cams because its sort of similar deal to 25DET vs 30DET . I haven't done this but I'm pretty sure 2JZ turbo cams don't look anything like Neo T Poncams - even the 252 9.15 ones .

I think you'll find that GTSS and 2859Rs have cartridges with the same part number so the compressors should be the same . Turbine is just a cropped NS111 . Some time back Garrett wouldn't sell the cartridge on its own . If your sick turbo has a good compressor and housing you should be able to get it rebuilt . From memory Garrett did a turbo called GT2854R which uses the same turbine as the GTSS/GT2859R . Someone who can get that cartridge should be able to use your compressor and housing on that to create the same thing - provided you comp and housing are good .

I reckon most will say that all else being equal the 0.63 will bring the turbo on a little sooner . But they're are not real big for a GT30 and some consider them (0.63 turbine housing) marginal on an RB25 . My gut feeling is that those type B 260 Tomei Poncams are costing you part throttle and low to mid range torque . The only person I've spoken to about these was Wolverine , he had or has them in a Neo era Stag and found they cost valuable poke in the normal drive type engine speed ranges . Personally I don't like any RB25 Poncam , I dug up a timing numbers a while back and it seems Tomei gave them a little more duration timing but shit loads more overlap timing compared to the factory cams . Something like double the overlap timing . My finding in a 33 spec RB25 is that they gave a slightly more throaty idle and made surprisingly more low note exhaust boom noise . I reckon I lost the low to medium nice part throttle torque and when it did get going typically on an RB25 at around 3500 revs it came on quickly . Its not impossible that Tomei set them up to lose down low so that when they came on it was with a noticeable rush . Hectic stuff for the kool dudes . Factories rarely if ever set cams up to work like this because it not what 80% of people like or will tolerate . As I mentioned if you want to bring everything in 500 revs earlier then refitting the factory cams should help because they designed them to work more in the rev range you want it to . Some people like to think putting bigger cams in a bigger engine is a must but I doubt very much Nissan would have used cams set up anything like RB25 Poncams . Now to VL Turbos - manual ones anyway . Gearing wise they were nothing like R33 or R34 turbo Skylines including the GTRs . VLTs had a wider ratio gearbox with something like a 3.58 first . The diff ratio was I think 3.45 . They had a pretty soft cam and small - like RB20 bore inlet manifold runners . Static compression ratio was about 7.8 to 1 . Actually gearing wise a VLT was more like the four cylinder S chassis cars except the gearbox ratios were still wider and the diff ratio taller . If it was easy to do a 3.9 or 3.7 from an S14 or 15 could be handy but you need to think about the Skyline boxes taller 1st 2nd 3rd ratios as in hill starts and getting it off the line . Anyway an RB30 with a Neo turbo head and inlet manifold should not be lacking poke provided the static compression ratio is at least 9 to 1 . Cams with a lot of overlap timing will cost you in the every day drive rev ranges because you lose trapping efficiency in the cylinders , meaning there is less air to compress and compression pressure will be down compared to what factory cams will give . Please don't quote me but "if" I remember correctly standard RB25T cams have something like almost zero degrees of overlap timing with the actuator switched off . On I think is around 20 degrees . Again from memory Poncams were more like 20 degrees switched off and 40 switched on . There is a thread here that I quoted the standard R33 and R34T timing numbers and the three RB25 Poncam ones ie R33 and R34 A and B . A .

Rather than changing turbine housings I'd give the standard cams another go . Stao once told me that he never liked Poncams and found they lost down low and increased turbo lag and didn't do that much up high .

According to Garretts cattledog there are or will be T4 twin scroll integral gate turbine housings available for the G series . If you buy or make a twin entry T3 to T4 adapter plate you may get one on a Skyline manifold . If Garrett are smart they'll make T3 flanged housings available , like EFR did .

I'd be putting the standard RB25DET Neo inlet manifold back on it . The runners are reasonably long and Nissan downsized them compared to the R33 spec inlet manifold obviously to increase air speed into the inlet ports . A lot of people seem to think that fitting the short runner ie Freddy etc style inlet manifolds to any RB25 costs it torque and throttle response in the lower to mid range .

Interesting - thanks for that . I think we can safely say that either of these G25s could do a lot better than a GTRS on an RB25 particularly in the upper turbine housing sizes . The $64 question is what happens to turbo response with big housings on G25s . I know its early days but the T25 or V band mount option is going to be a deal breaker for some . At least EFR offers a T3 mount plus integral waste gate on their B2 (I think it is) frame turbos . I did search to see what was available in 3" V band to T3 adapters - but they won't be a compact arrangement . Having stainless steel means at least fabricating changes is a bit easier . Given the release time on the G series Garrett is taking a long time to get them out there - and even longer to release info on the slightly larger versions supposedly in the pipe . I'm hanging out to see what the next turbine size up is capable of - and I'm guessing it won't have to be very much larger to be just what many roadies want for a street RB25 . EFR chose 58mm for their medium sized B1 units , if Garrett does something similar then they should be able to achieve GT30-GT35 type performance with hopefully better turbo response than either of these . Time will tell . A .

Well that's subjective really . If these things flow in the real world as well as Garrets claims then they could turn up on all sorts of things . Note the clockwise and reverse variants which you'd think were aimed at TT V bank engines .

Same here I used a piece of good quality EFI hose . For the record I would have used a couple of OE quality EFI hose clamps as well . You can get at the mongrel on an R33 by removing the three bolt IAC housing and some of the wiring loom brackets in that area . A .