discopotato03

No progress ATM , job change in the pipe so larger fish to fry . A .

So tired ATM , too tired to search propeller head stuff but yeah I noticed the 9 bladed compressors and thought hmm HTAish . Now that Garrett are into machined wheels they can carve all sorts of things up easily enough but it would be good to see a few more modern turbines in their mix . Other players in the aftermarket have put up things that are easily better than some Garrett products and maybe market pressure has got them off their butts . Have to love the WWW for showing up the good the bad and the ugly . A .

VG33 is a SOHC 2 valve V6 from memory with hemi style heads . Not quite like RB/VG/VQ . A .

Yes higher poundage inlet valve springs because you have boost pressure behind the inlet valves acting on the whole area of the backs of the valves . You don't have combustion pressure on the chamber side of them as soon as they close . More boost means greater heat and pressure and the hot/exhaust side is the half to worry about to avoid reversions and detonation . A dedicated turbocharged race engine has to be reliable when running in a supercharged state for long periods of time . OE road turbo engines are designed to use the "power boost" to get up to speed or climb the odd hill for short periods of time . Interesting actually , restricted rally engines are often thought to have small compressor sides compared to the turbine side . This is because they are rev limited by the restrictor so have no use for large compressor wheels . The turbines are big in relation to the compressor because they have to have a survivable pressure and heat balance across the engine ie hot side vs cold side . To make any engine survive a lot of boost for any significant length of time you need to increase the flow capacity of the hot side . Things like porting/exhaust valve size/manifolds/turbos with larger hot sides eg GT3576R/very low restriction hot side . Actual engine cooling is important because you have to reject more heat developed by higher power outputs . Effective oil cooling / charge cooling / water cooling would be a real good idea . The burning question is how long do you expect to be using high boost performance ? A .

My last post must've got lost . The guts of it was that this turbo is a hybrid of the GT2867R and I reckon most of its dialling in would have been based on GT28 hot side development . That means a 53.8mm GT28 turbine in a 0.64AR GT28 T2 flanged turbine housing . We already know that older GT series compressors ie the 71mm ones easily take that hot side combination to the limit and beyond . It was known decades ago that the cropped GT30 turbines in HKS turbine housings out performed the GT28 based versions - search HKS 2835 Pro S results to see the performance difference . I think what a lot of people are missing here is that the GT30/0.63AR hot side combination is clearly better than the GT28/0.64AR one which is why you'd expect a GTX2867R to perform better in GT30/0.63AR format . I also think it doesn't matter a rats arse what happens with GT3076Rs/GTX3071Rs/GTX3076Rs because they are significantly different to a GTX3067R and the sort of potential you can screw out of post 300 RWKW turbochargers . I wouldn't expect to see 300 plus wheel wasps with a GTX3067R on an RB25DET even with E85 and for that reason I don't think its mandatory to have a 0.82 housing on it - because its unlikely to ever see the exhaust throughput that a 300 plus RWKW Skyline would have . I think of all the things you could potentially do the 0.63IW turbine housing stands the best chance of getting you what you want . All else being equal it will bolt in and increase the gas speed through the turbine blades for any given engine speed and load . Assuming you have a gas tight system beyond the turbocharger and no glaring exhaust restrictions down stream of it there is no reason to expect to see less than about 270-280 RWKWs IMO on a healthy factory RB25DET . I got to 271 wheel wasps with a HKS GT2871 52T in their unique T3 flanged 0.64AR GT28 turbine housing and obviously the only reason it didn't detonate to death was the E70 it was burning . Your turbo in 0.63 form is an upgrade on a HKS GTRS in every way meaning a more efficient compressor end and a higher flowing hot side , these alone should get you at least as much as I had IMO without needing 70% ethanol content fuel . I'm sure I remember people with HKS2835 Pro S's getting into this area without ethanol . A .

What I am saying is that the compressor has to spin fast enough early enough in the engines rev range to get a pressure head (boost) on the inlet side . I look at an accelerating engine as an expanding volume from the compressors perspective and you may have a situation where the turbo is playing catch up and not getting any worthwhile pressure up until mid range revs . Then up high it falls off capacity wise . The way to increase the compressors speed in relation to engine revs , and load , is to put more energy into the turbine and that usually means a smaller turbine housing . I think you really need to search for other peoples experiences with that GTX3067R and don't be too concerned if most of them involve 2ish litre four cylinder engines . These engines usually make less torque at the same revs than an RB25 and with your turbo in the 0.63 housing they are making good all round power . I think its absolutely wrong to make the global assumption that the GT30 turbine 0.63AR turbine housing combination is an epic fail in any and every instance . Granted some GT30s have higher capacity compressors than others at high flow rates small turbine housings will become the limiting factor turbocharger wise . This time round you have to look at turbine speed and exhaust flow rates with the smallest lowest maxing compressor option in the GT30R family to keep things in perspective . Really this turbo should be viewed as a modified GTX2867R with a bit more hot side potential (flow) than the GT28 turbine/0.64AR GT 28 turbine housing can give . If you research GT28 turbos with the larger (for GT28) turbine housing ie 0.86AR the result wasn't always good . I'd say Garrett went looking for the extra flow with a different larger turbine and it worked with what is considered to be the smallest of the GT 30 housings . I think the best way to look at it is that the 30/0.63 is larger and higher flowing than the 28/0.64 and that's why the 3067 version works better in your instance than a 2867 would . Out of time but I think 0.63IW is the answer . A .

If you're getting 250 at the wheels then I wouldn't think you are getting all that the GTX67mm compressor can give . Assuming there are no other issues such as tuning or tuning around detonation for some obscure reason I think you can do better . I'd have to search around again but I think you are the only one that ever used the 0.82AR housing on that turbo , most went with the 0.63AR version or some T3 nock off type housing . It really sounds to me like your turbine isn't spinning its compressor fast enough to make it work properly . Maybe a problem is that the 67s unique 10 blade count needs more revs to make it pump enough volume compared to most GTX wheels with 11 blades . I have to wonder if Garrett was trying hard to get the best balance of compressor vs turbine performance in the GTX2867R and you'd have to assume they were struggling with hot side flow in a 0.64AR GT28 based turbocharger . Generally less compressor blades means more revs to pump the same volume and higher turbine speed means less resistance to exhaust flow up to a point . It may not sound like a big change shoving a GT30 turbine up GTX67s ring but is a major change and one that I reckon needs consideration to make sure it spins 67 fast enough to do the job . The only GT30 turbine housing that was ever remotely going to make a 30 turbine perform like a 28 turbine in a 0.64 GT 28 housing is the 0.63 one . Really turbochargers have to be looked at as a system not just a folk law sized turbine housing with a hair dryer clamped on one side . I also doubt your intercooler is a major restriction but if you want to see then try measuring boost pressure before and after the core itself . A .

I would lean towards getting the turbocharger right , I use the same IC and my at the time GTRS on its knees made 271 at the bags . Back then the tuner said boost pressure fell from 17 to 14 indicating that it was choking on the hot side . A .

Michelin Pilot Sport 3 reasonable , Pilot Super Sport noticeably better , Pilot sport 2 better again but not as long lasting . A .

Wolverines thoughts actually and I think he went in Micks car . He went through the GTRS 2835 Pro 3076R and 3082R on his own cars . A .

IMO the whole point of having plain buckets is to allow the use of more aggressive lift ramp on the cams . The idea being beater breathing through the valve opening further rather than longer . Longer period or duration cams IMO are better suited to engines turning higher revs all the time and may not play nice even in an RB30 around town . I think cams need to be chosen with CR in mind and the inlet manifold/throttles style too . Single throttle inlets will make longer cammed engines grumpy because of the pressure fluctuations in the common plenum chamber , not as bad with ITBs because the throttle plates tend to block the reversions . Your call but as mentioned less duration even at the same valve lift would be easier to live with . A .

I think at that stage the 7163 was still in the development phase and early proto types were different to the production version . Only guessing but I suspect that mixed flow turbine and final compressor dimensions were being dialled in for Indy Car engines . A .

I like the idea of Scottys external gates mounted on the turbine housing . IW will work with a 0.82 Garrett housing and either a GT3076R or GTX3071R . People say the GTX3071 is a tad less responsive than a GT3076R and a mid trim 76R should be slightly better responding than the usual larger comp trim version . Any of these turbos should romp in 270-280 at the bags its just that some will give slightly better transients than others . Take your pick , cheers A .

I think a GT3582R will be quite laggy on an RB25 with the std CR on your 93 octane . In the US with things like the 3076 and 3582 HTAs available I think you can do better . With non standard manifolds the EFRs are probably better again particularly on pump gas because their turbines tend to be larger in relation to their compressors than most other turbo suppliers . You should be able to get 500 from a 7064 or a 7670 with better turbine response/transients than most other makes . Having less inertia and exhaust restriction is the go IMO . A .

The 48T was the smallest and the 52 the mid trim . Too busy with other things like working all round the clock and Saturday Sunday are just another day . When I can get enough days off together it'll eventually go to Insight for a change of injectors rail reg and a tune . I recently changed back to EFlex because the altered E85 made my car grumpy and gave poor fuel consumption - no matter how I tuned it . Plus I was paying 116.9L for E70 and its closer to home . United is near work but if I changed jobs its a 90 min round trip to replentish my stash - screw that . Getting ~ 400/tank mostly round town . What I can say for sure is that this 52T is not laggy with a 0.82 IW housing , the engine itself could make a little more bottom end torque but its 148K old now and probably getting tired . 18 year old car with turbo tech that's older than that . A .

About the only thing the TR30 turbine shared roughly was the exducer diameter at ~ 60mm . Turbine housings were also unique as were the style of compressor wheel screwed on the other end . The GT30 UHP turbine , like most in that family , were designed for diesel applications and partly the reason why the trim size is 84 . HKS merely asked Garrett to cast them in higher temp materials and fit a shaft to suit the GT25BB centre sections . As for the smaller NS111 turbine , I always thought it looked like a development of the one used in the GTiRs T28 turbo . They were 10 bladed and used a larger 79 trim size from memory , both the car and the turbo were a flop effectively . Everyone including Garretts engineers know they can do better than the GT30 UHP but I reckon they only ever will for an OE high volume app where someone else is paying the development costs . BW seems to have the best all round turbines ATM so if Garrett is serious about being competitive the materials have to change . A .

Geoff has anyone back to backed a 7163 and a 7064 on the same engine ? I'm guessing differences would be the mixed flow turbine but more significantly the larger series housings on the 7064 . A .

Yep I was having starting issues and got sick of the increased consumption . My local EFlex servo is getting cheap ATM so that's what I'll stock up on . Starts are much better but need to get finger out and retune the cold and hot starts because they've gotten really rich . $1.16.9/L acceptable , cheers A .

My car doesn't seem to like the later E85 either , it acts like its running slightly lean and is more difficult to start - consumption noticeably worse . I'm going back to EFlex for a while to see if it improves things . A .

Yep I think so too . I suppose a GT35 turbine at 68mm isn't that much smaller than the EFR 70 mm one but running either to the limit would be a challenge on the factory manifold . A .

What do people think would be the practical limit EFR wise on the std 25 exhaust manifold , I guess a 7064 or a 7670 would be the go with an IWG turbine housing . I like the idea of the higher flowing hot sides allowing good power on PULP and while twin scroll systems are nice its further than some people want to go on a roadie . A .

What the machine shop does is hone inside the big end of the rods with the caps bolted on and torqued up . The rod and cap mating surfaces can be faced to close the bore up slightly so when honed it is perfectly round in a "fitted" state . A .

I agree with Lithium on the "full" GT30 based turbos . The GT28 based ones of which the GTRS was probably best will make reasonable low to mid range torque but the exhaust flow isn't there . Cropped GT30 was a HKS tweener idea that in my opinion only ever worked in their turbine housings . Things like 2535 and GTRS will always be better than the standard ceramic Hitachi so if that's the ask then they have their place on very mild engines . There probably isn't an ideal turbo that goes as close to bolting on as say a GT3076R (dimensionally) or a GTX3067R and the 2835 Pro S is effectively dead . I think the thing most people really want is strong part throttle torque and RB25s lack what RB30s have by 500ccs and 500 revs . An RB25 is easily good enough at 3000 plus but some want more at part throttle between 2-3000 . So without a capacity increase you have to compromise and sadly the conservative one means strangling the hot side . In a perfect world R33s would have had an RB30 and probably 3.9 or 3.7 rear gears . They would have been a nicer overall package I suppose like a VLT (torque wise) but with a better head and you'd think an SMIC and higher CR . I wonder how soft turbo wise they would have gone to get 206Kw from an RB30DET , probably the GTt turbo and intercooler and 4 pounds of boost . I still haven't seen any 0.63AR IW GTX3067R results on an RB25 but in this day an age that's as conservative as I'd go with a new turbocharger . If you don't drive in slow traffic everyday then I think a 0.82 AR GT30 like a 76R or GTX71R is the go because they suit an RB25 from 25-2700 revs up if tuned properly preferably with modern injectors . Personally I think R33 gearing is a tad short to be a relaxing cruiser but it had to be that way to get some go out of a nearly 1400 kilo car with a tiny ceramic turbine .

I'm thinking better torque timing in the spool phase but injector performance would play a part here . A big old world injector won't react or probably atomize as well as a modern one so being rich here is probably safer overall .

Maybe the theory of "under octane" ULP in the E85 is not a theory and they prefer to use a more highly refined dino like 98ULP . I think ultimately E85 or similar is only ever going to get mainstream acceptance when you can prove to people that it works consumption wise , and to achieve that you need engines with high compression ratios . How you get around NOx emissions I don't know but I have read that direct injection engines gain more from evaporative in cylinder cooling so the higher a fuels octane the better assuming it doesn't get harder to light off like high octane petrol does . A .