discopotato03

In real terms most of what a GT4088R has is larger than a ball bearing T04R (T04Z) . The actual center section is supposed to be the same size and the main difference bearing housing wise is that Garrett re machine the turbine end to take a T Series turbines housing with its crab plate mounting system . To mount GT Series turbine housing that bearing housing normally has four ears and bolts through them into the bearing housing . Turbine wise the "Z" has a T04 P trim or I think 74 odd mm 76 trim . The GT4088R is 77mm 78 trim GT wheel Compressors , 84.4mm 63 trim R wheel vs 88mm 52 trim C117 . The trim of the 88's compressor is smaller than the smaller diameter R wheel but it has more blades to work with . The other thing is that in non HKS form the T04Z uses a T04S sized compressor housing where the GT4088R goes up a backplate and housing size to GT40 . I think what Garrett wanted from the GT4088R was good response and low restriction on the exhaust side . GT40 turbines and their matching housings are a size up from T04 P stuff and dimensionally more like TA45 gear only lighter and better aero wise . The 88's turbine is actually smaller at 78T than the diesel spec GT40 one which is 84T . It their native turbine housings (T4 international flanged twin scroll) they blow the doors off any T04 P trim system . The real difference between the GT4088R and any other GT40 turbo is that C117 compressor wheel , you only have to look at its compressor map to see why . So I'm told the secret to getting the most out of a GT4088R is to NOT use the smallest turbine housing made for it (0.84 A/R) , they seem to prefer the 1.06 A/R one and make good power at lower boost levels than they do with the 84 or 94 housings . They also seem to like a really well developed split pulsed exhaust manifold and a waste gate on each side . The T04Z and plain bearing T04R are really just a T04 60-1 turbo with the R wheel substituted and the backplate/compressor housing machined to suit . Thats why thay have that iron backplate instead of a lighter aluminium one . HKS went to a bit more trouble with housings for their version of the Z turbo because they obviously thought it was a bit lacking with generic Garrett housings on it . With the GT4094R Garrett used a 94mm GT compressor in an otherwise std GT4088R , again IMO too much compressor load for the turbine to drive and too much wheel size for a GT40's diffuser diameter and a GT40 compressor housing . Rob must have his reasons for using one and its possibly that the 88R's compressor won't push as much air as he wants ATM . Possibly a GT4294R turbo with a turbine trim size like the 88R's 78T would have been better because from memory they are 84T and thats not the best thing for response in a turbo of that size on a three litre engine . Garrett is a large group of companies world wide and the gears turn slowly with new developments - market driven . I think a lot of their turbos response issues could be solved if they offered a few trim sizes in the GT range , they have started with the GT4088R and the three GT37R diesel turbos but we need that 78T size in GT30/GT35/GT42 turbo ranges as well . Some say that the GT4094R is a step backwards because they speced the 77mm GT40 78T turbine to drive that 88mm C117 compressor then go stick a 94mm compressor on the other end of it . A bit like having a diff ratio set up for a cars power and mass and then hooking up a loaded trailer to it . Anyway I reckon a properly set up GT4088R is a better thing than a T04Z but they cost more to set up properly . The Z turbo tends to be a bit easier to get response from (for less money) but doesn't give the same overall result even if their maximums can be similar . It sounds like HKS housings get the most from the Z turbo but your'e spending big money again . Super power with good response is rarely ever cheap , A .

I'm trying to view it all from a dynamic or actual compression ratio point of view . Obviously ITB's give a far faster pressure rise into the cylinders (off boost) so the dynamic or real world CR gets to be closer to the measured or static CR . I already own an R33 RB26 head and complete inlet so it's just the means to get it on an RB25DET that I need . Personally I don't like shim under bucket valve trains and since I don't have the need to rev the piss bags out of my car the hydraulic system is fine . Also I have an ex Woolaf R33 25 head thats been ported/OS exhaust valves/Poncams . Also I'm staying with a single turbo and either a std manifold or the HKS one thats kicking around here . The 33 26 head is staying in storage in case the RB30 ever happens but thats not likley . I'd like to know more about the differences underneath RB25/RB26 inlet manifolds . By what was mentioned above it sounds like the oil/water heat exchanger is different between R33 RB25DET and RB26 , does this mean that the 33 25 one fouls on the 26 type IAC or its chamber or the AAV valve or plumbing ? I bought all my RB26 stuff from Doughboy some years back and I'm pretty sure there was an RB26 heat exchanger thrown in but don't know if its R32 or R33 era GTR type . Can I assume that if RIPS modified RB25 lower manifold/adapter places the throttle assemblies in the same place that the RB26's inner manifold section does that basically all the R33 RB26 bits bolt up around it ie the oil cooler/inlet air ducting down to the intercooler etc ? Also from pics I've seen of the RIPS creation they weld on an RB26 top water outlet which places the hose fitting I suppose where it would be on a GTR , and handily right out of the way of the RB25's cam change actuator solenoid valve . Fingers crossed an R33 GTR top hose completes the picture . I really have to say the engineer that decided RB26 heads had to have different stud patterns should be shot . Nissan could have sold a lot more spares to many more people if they'd been the same . Yes I get the picture with power vs throttle response down low , I think if the tuning was right and an educated foot was pushing on the go pedal you shouldn't lose much if any over a GTR because the GTR is heavier and its static CR lower . If anyone has some answers please sound off ! Cheers and thanks , Adrian .

For people who have converted RB25DET's to individual throttles , did this make a huge difference to how your engine drives ? Also question for RB26 people , RIPS in NZ said when they make their RB25 conversion lower manifold to take the GTR throttles and plenum chamber they don't use the air by-pass valve . By this I assume they mean the cold start air by-pass valve - he said with the engine management systems they use they don't need it . I'm curious to know if RB26 people have removed it and had no issues . Lastly I need to know if R33 RB26 idle air control and TPS units are compatible with R33 GTS25T computers - PFC in my case . Cheers A .

Yeah well it must make you wonder if some loose canon will cut lose with the hardware and put a hole in you . What are the firearms laws like over there . Just don't forget where the best lil "sirens" AND steaks come from . Cheers from Oz .

Personally I prefer to use a Garrett made turbocharger because if you pick the right ones they work better than a pile of parts put together by a reseller . Garrett often make available compressor and turbine maps but they mean zip it the wheels aren't used in their native Garrett housings . Accurate turbine maps need a set pair of compressor and housing to mean anything because how the comp end loads up the turbine has a lot of say in its performance . It would be good to know what you're intending to use for an exhaust manifold because that sets the flange size and single/twin scroll options . GT series turbines and compressor wheels are mostly better things than their older T series cousins because they tend to be lighter and slightly smaller in diameter for the same gas flow . Once you get into GT35R's (GT3582R's) you tend to be stuck with single scroll T3 flanged turbine housing though Turbonetic make a "F1-35R" based on a larger center section and T4 flanged twin scroll turbine housings . For someone in the States you could speak to Geoff Raicer of Full Race Motorsport because he's put a bit of time into turbos and manifolds for Nissan RB26's , not cheap but I believe the results are real good . Cheers A .

The real engine management "leckies" would know for sure but my research leads me to believe that the peak and hold circuitry is different to the saturated system . PH injectors I believe tend to be low resistance high current ones where saturated ones tend to be high resistance low current . I've been told the quick dirty method of running high current injectors in a saturated system is to splice in the resistors but you don't have the peak and drop current to snap open and hold the pintle pin like a PH system does . I did actually speak to Ray Hall and his response is that the V44 is aimed at a price sensitive market segment and I gather to be price competitive had to sacrifice the peak and hold injector drivers and go with the more common trend towards saturated injectors . Please do NOT make the blind assumption that I'm saying the product is cheap and nasty , the trouble is that so many buy everything on price and if it was made in Xxxxx and sold for $4.99 lots'd buy it . Something I did read in Honda circles is that someone out there is making good reliable 1000cc saturated injectors and apparently they at times work allegedly better than existing PH ones . My problem was that getting "affordable" hose barb/tail saturated injectors is not too easy where PH or high current ones are easy and cheap . No good for a wire in V44 though . My answer could be to use Mazda Rotary turbo O ring injectors and machine shallow rings into them for the short length of rubber fuel hose to bite into under the clamp . If I could buy a V44 with PH drivers/circuitry I'd do that so Guilt - spill the beans . Cheers , Adrian .

For my own interest I'll ask people I know who do engine machine work , they have to know because the cutting tips on machine tools don't tell fibs . You would be able to tell by running a file over a non critical bit if it's iron or steel . A .

Are you sure ? I don't think I've ever seen a production engine block made of any grade of steel , they have always been aluminium with liners or iron . A steel block would be very expensive as well as very heavy and Ford aren't really into expensive and heavy . Cheers A . BTW the only GT2860R family turbos I'd bother using on a four litre six are the GT2860RS's , they have the largest 0.86 A/R GT28 turbine housings (which are not huge either) and std they have T04B compressor housings . Personally I wouldn't bother with twins unless you can't get a decent TS exhaust manifold . On an engine that size even ball bearings aren't so critical because there is more than enough exhaust gas flow to drive adequate turbos into boost . Later bush/plate bearing center section turbos are a lot better than the old (ancient) T3/T04 centres meaning more reliable . Your call , cheers A .

I think I'm going to go with the RIPS modified RB25 lower manifold to run the GTR throttles and plenum chamber . Robs wants $125NZ to supply the lower 25 manifold section and it's probably not economic to buy/post one over - or is it ? If anyone in Sydney can sell me an R33 RB25DET S2 unmodified (non port matched) lower manifold section cheaply please let me know . Also for the record are the gaskets in RB26 manifold sections reasonably easy to get ? Cheers Adrian .

Hi Fine Line , thats my theory as well with my RB25 - so much tied up in the head . My modified head isn't on yet and it has OS exhaust valves as in larger but not enough to need the seats to be changed . For cost reasons I stayed hydraulic and got R33 RB25 poncams for it . With skimming the CR should rise to a bit over 9:1 . The exhaust manifold I'm thinking of running is the cast HKS one and hanging a GT3076R off that . My goal is to have a very streetable 280+ Kw and if keen enough may get RIPS modded lower inlet manifold and mount RB26 multi throttles on it for snappy throttle response . It's the torque and response I'd like in a reasonably free reving RB25 . Cheers A .

I wanted to cover all the bases so I bought my Datalogit with their USB converter cable , and through E Bay a Dell Latitude D610M for under $400 . It has a real serial port and it's now set up to dual boot Win XP or Windows 7 . The Tech Edge WB3A2 I have can use either as well , serial via its RJ45 socket or USB through a std square socket . I actually screwed up here because the Tech Edge uses its RJ45 socket to plug the LCD display in , they kindly sent me an RJ45 splitter with steering diodes in it so I can connect the display and serial cable through the one socket on the controller box . Serial comms work quite reliably its just that Lap Top manufacturers have tried hard to get rid of the serial interface because most home users don't need it . Universal Serial Bus was never quite as universal as is should be and not surprisingly a lot of scientific test equipment demands a serial interface . In the end I think most people buy an older lap top with a real serial port and use that for car stuff . I particularly like the Dell D610M because its fine to surf the net or whatever and can talk to your Datalogit through a cheap reliable easy to get serial cable . Other than that get the Datalogit people to send you their USB converter cable . A .

I don't believe I'm reading this , if feeler gauges are good enough to set ancient contact points they're plenty good enough to gap a spark plug . Feeler gauges are a glorified go/no go gauge and repeatable accuracy gapping spark plugs is childs play . We are talking to the thou or 0.0254 of a mm . Simply open the gap up a tad with a small flat blade screwdriver , insert the appropriate feeler gauge finger and gently tap the outer electrode till it closes up on the feeler gauge leaving a neat fit - bingo 1.1mm or 0.0433" (tad over 43 thou) gap . Plenty of people have opened up the gap on std plugs or closed up wide gap ones if they couldn't buy the manufacturers set gap . A .

With the water feed through the lower section of the manifold it's debatable it you'd achieve anything unless you had an RB26 manifold and used those insulators between the inner manifold section and the throttle bodies . Most people I know reckon warm air at low engine speeds is good for vaporising fuel and at higher engine speeds the air is moving too fast to absorb any significant heat . Jury still out cheers A .

Yes it doesn't look completely standard but in my case it should look a little less lethal without the "EGR Valve" on it . I was thinking of making a heat shield for it out of that quilted aluminium blanket material which Ford use at times . I must also hunt around at Pick and Payless to see if there are any factory heat shields that could be convinced to fit . I don't suppose the XR6T's have a heat shield on the turbine housing do they ? Yes will fit new studs as in the modified head will probably go on at the same time so easy to fit them beforehand . I really like the idea of RIPS modded inlet manifold to take the GTR ITB's but thats going to have to wait for the time being . Have to organise the pipes and a GTR front mount , maybe 33 GTR drivers side plumbing will fit . Cheers A .

Thanks for the pics , I'm also considering reducing the inlet pipe down to around 80mm and hopefully into a standard airbox . Just on this why does everyone say that it's virtually impossible to use them with a GT3076R ? I think the few R33's using this manifold I've seen (eyes and pics) have GT3582R's or GT3082R's meaning they use the larger T04S comp housing . I was hoping that the HKS manifold having the dryer a bit further south may leave extra space to plumb in the AFM and factory airbox . The 76R's air outlet is 2"/51mm as well so the duct to the intercooler could be a bit smaller than the T04S's 2.25"/57mm one . From memory these manifolds were designed to mount a T04E turbo and the turbine housing would have been effectively a little different and the turbos centre housing a little longer moving the comp housing further forward . Cheers A .

Well you should be able to tell me if the turbo misses everything or if any alterations were needed . Do you have any pics of the turbo fitted up ? Unless anyone knows I must ask GCG if the gated and non gated GT30 turbine housings are based on the same center and mount flange dimensions . Cheers , Adrian .

I'm curious to know if anyone is running a Garrett GT3076R (GT30 IW turbine housing) on the HKS cast low mount exhaust manifold . I know with a GT3082R on the HKS manifold mods are needed to make the compressor housing miss the engine mount or bracket and I'm hoping the GT3076R's comp housing being a little more compact will miss everything . Another thing I'm hoping is that the HKS manifold mounting the turbo a bit lower and further back will make it possible to plumb into the std airbox via a std or Z32 AFM . Anyone been here , cheers Adrian .

A bit more . http://forums.nicoclub.com/zerothread?id=179864 A .

I did get RIPS to E mail me pics of his modified RB25 inner manifold section with the RB26 TB's and plenum bolted to an engine and it looks the part . Rob mentioned that they don't use the air bypass on their engines and I've asked for details but not gotten a reply . I gather he means the cold start heated extra air bypass valve and I'm not sure why they wouldn't use it . Can anyone familiar with R33 RB25 and R33 RB26 inlet manifolds add anything about this ? Also for the 20th time can anyone confirm if an R33 GTR's IAC solenoid is electrically compatible with an R33GTS25T (S2) loom and PFC . Cheers A .

There are a couple of ways to reduce the manifold or turbine inlet pressure but none are exactly cheap/easy . Increasing the exducer size or trim is one way but you need to find/buy/fit . Increasing the turbines exducer tip height makes for a wider nozzle passage but still find/buy/fit . A lower number of turbine blades is another because you open up the gaps between the blades . Provided the turbine housing casting is beefy enough you can extrude hone the internal volute passage . Not always but usually this housing size problem arises when an OEM turbo has a unique application specific casting shape and was only available in one size . Generally provided the exhaust manifold has a reasonably common mounting pattern alternatives can be found . Do you have a specific example of a housing that you'd like better flow through ? A .

And they work real well with E85 in the US so I imagine here as well . Now Did I mention the steak knives and to ask for chips with them . Guilt we need you here for part of the year if possible , cheers A .

I think in simple terms make the compresor just a tad over the airflow requirements and match the turbine and its housing to the compressors air output . I think better to have a balanced match of compressor and turbine than compromising turbine size to wind the thing up . If the balance is right and its still laggy I think it's trying to tell you that its overall size is too big . In a way I see sizing turbos a bit like sizing cams in an NA motor , go too big and lose the bottom end torque . I suppose falling off the boost range is a bit like falling below a given cams power range . I think in the end the trick is making forced induction boost torque and I wish people would forget all about Kw and Hp numbers . Those dyno graphs with the Hp/Kw lines like the side of Mt Everest mean jack to me , the torque plateau is everything . To each their own , cheers A .

One of these days someone'l strap on a GT4088R (which you can buy locally) and they will be the "new" gun turbo for that power range . The switched on Americans absolutely love them because they are very resposive and provided the engine is up to it make the power standing on their ear . Magic combination of housings/wheels/trims BUT must be used only in twin scroll form with the proper matching turbine housings . If you ever get to hold one of these 88Rs in your hands you'd think hmm , big (T4) mount flange but not that much larger overall than a GT3582R with a 1.06 A/R turbine housing . Normal in/out comp housing fittings meaning none of that GT42R bulk or odd truck connections . They were designed to be a performance petrol turbo so have no diesel engine ancestry . One day , cheers A .

Can we take it as granted that an R33 fuel tank system is sealed well enough not to let any significant amount of atmospheric water in ? It will be interesting to see what additions the General puts in their flex fueled Commode door's fuel system - if we ever get beyond the "its here next year" thing . E85 also has to be much more widely available than one servo and the oil co's will fight tooth and nail to keep it out . A .

Personally I think it's difficult to put a Km number on when to dump the first lot of oil , I reckon 1000 Km is a little high if you've run it in properly . Putting around like grandma simply doesn't work because without some engine load you don't get high enough combustion pressure behind the compression rings to push them out against the cylinder walls while they have that rough honed finish . Really having a turbo engine means you can achieve higher cylinder pressures so its easier to bed the rings in with a bit of boost . I can't for the life of me work out why people think ahh ya can't run it on boost and must drive to Perth and back on 2% throttle and it's essential to have a tail wind . I just finished running in my dinosaur Subaru EA82T engine and it doesn't blow any smoke ever or use any oil - at all . It was actually a less than perfect situation because the builder put Elf semi synthetic 10W50 oil in it and I didn't realise this for a couple of days . Myself and a mechanic friend spent time loading this thing up (WOT and the full 6 lb farts worth of std boost) between 2500 and 4500 revs and I did my best to drive it up the longest steepest hills I could find at WOT . At 800 k's I changed the oil to Mobil 1 Racing 4T 15W50 which is bike oil and it runs fine . People absolutely have to understand that newly honed cylinder walls have rough peaks and they are intended to "wear" or bed the compression rings in . If you putt the thing around and waste those sharp peaks the rings may never bed in and seal properly . The only way to rectify that sitiation is re hone the bores and start again . As for the oil I think a lot of the warm up urban myths come from using yester years honey like dino oils ie 20W50 . A good synthetic pours cold like water by comparison so its got to get around the engine faster at start up and lubricate properly to begin with . I'm not suggesting that people flog cold engines but if you had to I think a good synthetic would be kinder to the engine . Your calls , cheers A .