discopotato03

If everybody keeps holding their breath they'll have more than blue balls . A .

Interesting reads at GTR Life though the suggested Garrett tech time line was wrong . HKS was marketing GT BB Garrett cartridge turbos a bit before 2000 and they go back to the early 90s , a spin off from Garrett's competition BB turbos . Again interesting but shooting with a modern 3.8L V6 is a bit different to a 2.5-3L RB 6 , I know R35s are heavier but the capacity to weight ratio is better than 89-01 era GTRs . I noticed that they are using 0.63 AR housings and comparing the GTX76 to the HTA76 and not surprisingly the HTA spins up earlier . The HTA wheel is slightly smaller and is very likely lighter so inertia has to play its part . Back in the day HKS used to sell twin GT3037 kits for earlier GTRs and they specified 52 trim GT compressors as well . You'd think having slightly less compressor capacity in a TT app would pay off spool wise and if you get a wide enough power range starting early enough it can be better than outright top end . My gut feeling is that the HTA76 is a better match for the GT30 turbine than the GTX76 , both seem to need higher boost levels to make strong numbers but I think the HTA makes more efficient use of its turbine power/exhaust flow . It's probably closer to a "TR3076R" than the GTX76 is just without exotic turbines and housing materials . I also think marketing and hype is something Garrett went looking for with the GTX3076R . I guess they can boast that it makes virtually GT3582R power in the same sized package as a GT3076R though the only difference externally is the compressor housing . I think they were aiming to downsize the GTX turbos in comparison to the GT versions for same or better capacity . It's hard to argue that a smaller lighter billet comp unit is a bad thing . Obviously FP has chosen to develop wheels that squeeze the most out of GT30 turbines which were high speed units to start with . Getting the balance of high speed performance with good spool would take time but I think they nailed it here with that turbine . We know they can or did do 71 and 73mm versions but not much info seems to be available on how they compare to their own 76mm version let alone the GT/GTX ones . Lastly price and availability is an issue because FP is on the other side of the world where Garrett is off the shelf here . In a perfect world FP would sell compressor and housing kits to a few trusted turbo mobs here so you could have local support and fast repairs etc . A .

This time around trying PS2 in 255 40 17 . I don't think they'll last very well but I want extra grip . A .

There's an old thread here "Hks Gtrs RB20" from 2008 about a fella that was getting 18 pounds of boost from his engine at around 4100 revs . In those days people seemed to like HKS 2530s and 2535s on RB20s . If you want to spend money Garrett has updated their GT28 BB range with GTX compressors so a GTX2860R or GTX2863R should give you a lighter more efficient compressor wheel than the GT series ones . A .

I have a HKS GTRS looking for a home if interested . It got me 271 at the wheels on E70 on a 33 25T engine . Somewhere back in the mists Roy spoke about RB20s with these turbo's on them and I don't think the result was bad though I can't quote numbers . The advantage with these turbos is they just about fall onto an RB20 or 25 like std dump standard mount flange and standard inlet hose . I can't remember what revs these wake up at on an RB20 but I think it would be doing something under 4000 . Garrett sells cartridges for them if it got tired down the track . I don't have water and oil lines but they aren't hard to organise , cheers Adrian .

The proper twin scroll Garrett housings have the same sized volute passages but they increase in area before the inlet ports on T4 flanged ones . A bit more exotic but have you considered the HTA variants like the 3582HTA or even a 3076HTA ? A .

I run E42 because I don't think higher percentages do much for you in a street car , I think round the burbs E70 E85 gives woeful consumption though injector design comes into it . Actually I surprised myself and got just over 500 kays from my previous two tankfulls so between 740 side feeds my tuning and that brew it can be done . It should get better with more modern injectors where mixtures closer to 1 Lambda or at times slightly above are supposed to be the go at light loads . Scotty IMO there are two useful features in those GTt rails , they take 14mm injectors and fuel enters and leaves in the right places . The ok factor is the OE reg and the useless factor is they don't fit . An aluminium rail that takes 14mm injectors and has fuel entering and leaving where the Neo does is good and if it bolts on it ticks all the boxes . Most people may like the front and rear plumbing , it may only be Nissan and me that don't . It shouldn't be too hard to to weld a couple of adapters on the rail to take 90 degree 8mm barb fittings and then you have an alloy rail that fits and plumbs like OE . Minus reg . To fit that use the EFI Hardware adapter or weld a cross piece on top drilled and tapped to fit it .

Not sure . A Nismo GTR one falls in gives enough extra flow and won't fry the wiring . Expensive but straightforward . Other option is external inline boost pump . A .

At the moment an R33 GTR pump , my tuner reckons EV14s like higher base pressures than other types and the problem is that when the pressure goes up the volume comes down . A .

The most down time on a daily driver . For the record I found pics at GTR.co.uk of a GTT with an RSP fuel rail on it but who RSP is fk knows . It has what looks like a flat section of aluminium welded to the top of the rail up front and two sets of holes to fit the standard FPR . They've used the front one so that it clears the GReddy plenum section . It also looks like it has a banjo fuel fitting in the back of the rail . For some reason I can't post links at the moment so search "RB25DET Skyline GTS- GTT owners POST your engine spec-power!!!" . Go the page 4 of this thread and scroll down to the pics of the GTT engine bay , look closely at the pretty blue fuel rail . This is a thread started in 2007 and Lithium was there too . Just on the XR6T rails , they have the feeds on the side not the top . A .

Well I look at it like this , others obviously don't mind having the fuel lines fittings project straight out of the rails ends but if anything were to hit them they'd break off . By strike I mean if you crash the thing and stuff wants to wrap itself around the front of the engine . Steel lines tend to bend rather than break where with aluminium it's the other way round . Manufacturers always do things for a reason and long short avoiding law suits is one of them . It makes sense to have rail inlets/outlets on the tops of fuel rails particularly at the front (RB) so any vapour escapes from the highest point - like cooling systems are supposed to . All I want to do differently is have the inlet and outlet on top and facing along the rail because I think they would be better protected . More stealth because they link up with the existing hard lines round the front of the inlet manifold . A black or silver rail won't look out of place if the front plug isn't blue purple gold etc . Actually I have to look at pics of XR6T aftermarket rails because some of them I think have inlets on top or bottom rather than the ends of the rail . Also I mentioned Plazmamans R33 rail because it uses three mounting points , others may as well . The reg , once people start using high volume fuel pumps standard regulators often can't control fuel pressure at idle and light loads because the bypass hole in it is too small . Throw in the fuel pump rewire so it runs flat out all the time and you can see why the small hole can't cope . Then it screws up the tuning because you don't have a constant fuel pressure head over manifold pressure . Search overreaching FPR . This has nothing to do with the reg being able to flow enough fuel at high engine loads because that's not when the problem occurs . I mentioned Sard and Tomei remote regs because they could fit down where the damper is in the return line behind the filter where the lines met at a right angle - like those regs inlets/outlets . Scotty I don't have a problem with silicon or braided fluid lines done properly . I also don't have a problem with aftermarket systems but I prefer them to slot in like the manufacturer would have had it . Do you sell genuine Sard or Tomie FPRs ? Cheers A .

Scotty I didn't ask you for EFI Hardware's adapter but if you got one in I'll gladly pay for it and postage and your fee . I don't care about the money because it's the result I want or the least compromise anyway . The bottom line is this . The best way to mount the Neo rail is to use its whole inlet manifold or take the lower R33 manifold to a fabricator and get them to weld mounts on like the 34 version has . You also end up with the short comings of the standard regs limited bypass capacity . The simplest way to go top feed is to use any aftermarket rail you like and screw barbed fittings into it back and front . It's also the most obviously non standard because Nissan doesn't do it like that and especially not with a reducer and an adapter . Some manufacturers like Toyota have banjos screwed into aluminium fuel rails but not with the aftermarket 3/4 16 UNF thread fittings . I don't think there are banjo fittings available with 5/16 or 8mm barbs and a 3/4 16 UNF bolt . It's probably simpler to screw blanking plugs into the ends of the aftermarket rail and fit 90 degree barbed fittings to the top of the rail back and front where the standard ones would be . Now for those that think I'm pedantic . I am a qualified Fitter Machinist by trade and though I've been out of that trade for 25 years I know how systems are planned out by mechanical engineers and manufactured by companies who put their head on the block public liability wise . This is fuel system stuff and if it f**ks up you have a flammable liquid under pressure spraying around an engine bay with coils and alternators only too happy to light it up . I couldn't give a rats what race teams do to race cars because they are not registered or insured to drive on public roads . They also have a fire service on hand to hose away the mess when things go bang . A .

Just on regs you could surface mount a Honda style FPR across the rail because they don't have the barrel shaped section that projects through the mounting flange like Nissan ones do . They have a groove in them to take an O ring . The drama you always end up with is standard regs tie you to the standard bleed port and it isn't always enough with higher volume pumps . I'm not sure if it's possible to have what I want because no matter which way you do it the look is not exactly stealthy . I did look into Sard and Tomei remote regs because they could probably mount where R33s have the fuel damper so out of the way . And avoid fakes . I am curious to know if Plazmamans R33 top feed rail works with the standard upper plenum thought it may need shorter mounting pillars . Amongst R33 rails theirs is one that uses all three mounting points too . A .

Trust GReaddy do a couple of adapters to mount the factory style reg , search Trust GReddy Fuel Pressure Regulator Union adapter M16 . A .

I have seen one review of a GTX3067R replacing a GT3071R in 0.63 housings and it spooled slightly earlier than the GT3071R . To be fair these turbos use different compressor housings , T04E 0.50 AR for the 71R and T04B 0.60 AR and port shrouded for the X67R . A .

It's not about getting enough out of 740s , it's about how well they tune up and other people can fill you in on that topic . Aside from that side feed injectors are a right royal pain in the ass , a pain to get out of the rail compared to top feeds and tech wise they are a generation behind . A "factory" style top feed rail is held down by two or three bolts and disconnecting fuel is as complex as a couple of screw clamps . I think some people have the notion that Bosch EV14 injectors are a balls to the wall moon shot product which is strange because they were designed to be an OE injector - NOT a motorsport component . If you don't believe me go check the flow rates of the unmolested ones and note that they don't have Bosch Motorsport part numbers . The highest flowing OE ones I know of are 550cc with a Ford Motorsport part number . Meanwhile back at the rail , complicating shit - hardly . Take a rectangular block of aluminium and drill three holes in it , tap two for the fastening screws . The GTt fitting is about 22mm deep . Take a piece of aluminium rod and drill/tap it to take a suitable 90 barbed fitting . Weld both to the rail with the front on e crosswise . Fit end plugs back and front . Assemble as if it were a factory top feed fuel rail . Late edit , does any Nissan using this style reg have an aluminium fuel rail because if one did you could cut that section out/off and weld it on yer Skyline rail . A .

Couldn't edit above post for some silly reason . Early in that post I mentioned the EFI Hardware adapter which allows you to use the standard FPR on the front of a rail with the -8AN ORB thread form . You wouldn't need this if the reg was mounted on top of the rail . IMO it's using bling or any fittings on the front and back of these aftermarket rails that makes them stand out as being so different from an OE system . Scotty I'm curious to know if you would be prepared to make fittings and weld them to an aftermarket rail to mimic what Nissan did on R34GTTs , if it was a direct changeover with a set of EV14s I think that's as easy as a stealth conversion gets to be on an R33 spec RB25DET . Maybe a group buy would be the way to see if enough people are interested ? Cheers A .

As is known people have been doing top feed injector conversions on Nissan engines that had side feed ones for ages . If you don't mind how it looks anyone's cheap rail and fittings can clamp top feeds on the manifold and then it's just a case of who's pretty fuel pressure reg you want to use . I like stealth because I don't want people asking what's that glitzy looking thing doing there . So , the factory update on R34GTts was to flick the side feed idea and use a different rail and top feed injectors . Nissan changed too many things with the upper and lower inlet manifold halves to interchange the bottom half - bastards . Also the R34 fuel rail mounts in a totally different way to R33s so while it's not impossible it's not exactly straightforward . I think the perfect way would be to make an aftermarket rail that's effectively a GTt one but which mounts on the R33 spec manifold . I did a lot of searching yesterday to see what makes it easy to mount the Nissan fuel pressure regulator on aftermarket rails and it comes down to Injection Hardware's conversion kit and a rail with the right female thread to take it . Not all rail ends are made the same and they can use different fitting styles . Most now use parallel threads because tapered ones can be a pain to make seal and sealants tapes etc can end up in places that clog injectors . A common thread form used in the US anyway is called -8AN ORB and that takes a bit of explaining . Firstly "-8" is not a thread size it's a hose bore size and it this case it's 1/2 inch . With dash number sizes think each increment is about 1/16 of an inch so -8 is 8/16 meaning 1/2 inch . Now many fuel rail extrusions are 1/2 inch bore so they need to have a parallel thread to take a fitting with a 1/2 inch bore to suit the rails passage . What they came up with is 3/4 inch by 16 threads per inch (TPI) thread form known as AN or literally Army/Navy - mill spec . A parallel thread butting up against a shoulder isn't going to seal fluid under pressure reliably so there are a couple fixes for this . The easiest way is to use a soft crush waster like aluminium to form a seal between the rails end and the threaded fitting . A better way from an engineering point of view is to use an O ring and have a bevel cut into the rail for it to seal on . If you look back at the -8AN ORB moniker the ORB bit means o ring boss . Meanwhile back at the GTt fuel rail , Nissan mount their FPR on top at the front directly opposite the No 1 injector on a tubular standoff so it doesn't project into the passage . The regs' outlet points back along the top of the rail . The fuel supply (inlet) enters the rail down the back at the top and the external tube runs also forward along the top where both tubes meet and hang a left in front of the inlet manifold's no 1 leg . I think the ideal way to have an aftermarket rail would be to mount the standard regulator on top at the front and the inlet also on top down the back like Nissan does . It would be simple to have a block section at the front drilled to take the std FPR and a threaded boss down the back to take a simple right angled barb fitting for the rails inlet . A couple of plain bungs to seal the extruded rails passage ends and Bob yer uncle . If keen you could have a brace of two to support the supply tube running down the back of the rail . Just on this I was searching so many RB25 rail pics I came across some of rails with the supply tube separate from the rail and they may have been on S1 RB25 NA engines , on S2 GTS25Ts it's physically joined to the rail . If you look at the S2 lower manifold there are a couple unused bosses on the cast in upper water log and I think these have threaded holes to mount this early style tube . A rail made like this should be able to use most of the engines original fuel system plumbing and if it was pained in a gold colour may be mistaken for a factory one . Thoughts ? Cheers Adrian .

Starting another thread on aftermarket top feed rails for R33 GTS25Ts . Scotty not totally given up but done properly an aftermarket rail would be easier . A .

It's old news in the Mitsy world but Hi Flowing their TD05 16Gs with the 18 and 20G versions of that compressor family tends to make them increasingly laggy . If you search you could find out which Mitsubishi turbos had 18 and 20G compressors standard - turbine wise . In Evo terms Mitsy went to a lot of trouble to make the engine package work and up to Evo 9 never used larger compressors as original equipment . They actually went slightly smaller in couple of models to make them spool earlier , think one version was called 15GK2 in the TME E6s . Long short the 16G6 compressor is a good match for the TD05 turbine and makes for a balanced turbocharger wheel size wise . A .

Yep I tend to think an aluminium rail in natural finish or matt/flat black would be alright provided the fittings aren't some silly nail polish colour . It seems the -8AN (3/4 x16) parallel thread is a defacto standard and seals with an O ring on a bevel in the ends of most aftermarket rails . I reckon if the EFI Hardware adapter parked a standard or equivalent reg on the front of a plain rail it shouldn't attract too much attention and at least put the return line where it's supposed to be . A .

Not impossible to get the Neo rail on but probably more stuffing around than its worth . If you look at the R33 RB25 lower manifold the side feed rail mounts at three points sort of below the rail . The GTt one mounts above the rail on the cast in water passage . The 33 manifold has similar mounting points for something else but they are closer together than the GTTs ones . You could weld mounting pads to the lower manifold if it was off but most don't feel like removing it and it becomes a unique part . If keen you could cut and weld different mounts on the GTT fuel rail but it's cad plated and could peel off inside and leave bare steel which isn't flash . EFI Hardware advertises an adapter system that screws into the front of aftermarket rails to take the Nissan style rail mount reg so if it fits ARTs rail that makes life very easy . I think the rail has to have "machined O ring port" threaded sections back and front for this adapter to fit but I don't know enough about aftermarket rails to know if they are all like this . I can lay my hands on a Nismo adjustable FPR and I'd like to know if their bypass port is any larger than the standard one . A .

Long short I have Arts rail and collars and a set of short ID850 injectors which are the same length as the Xspurt 740s he used . After exploring most options I don't think the R34 GTt fuel rail is worth the trouble it'd take to get it to fit the R33s lower manifold . So the last piece of the puzzle is the pressure reg and I don't like the look of the aftermarket ones . The most OE looking thing I can think of is the Nismo type B universal one that uses tubes both sides rather than the flange system OE rail mounted ones use . The universal reg looks it's based on the Z32 300ZX one and has its own two bolt bracket as part of the unit . Maybe it can be mounted on the bracket above and to the right of the std FPR or to the bolt on the front of the No 1 inlet runner . A .

Turns out that the flange and bolt pattern is different R33 to R34 RB25DET . A .

A Neo turbo is basically like any other RB25 Hitachi but usually with the larger OP6 turbine housing . Tao could tell you but the Hitachi centre housing is of similar dimensions to the old Garrett T3/T4 water cooled bearing housing and from memory the water banjo thread size is the same . The Garrett centre needs a Garrett T3 sized aluminium compressor back plate and the Hitachi compressor housings are almost the same sise where they clamp on . The Hitachi back plate is part of the centre housing casting . Minor machining lets the Hitachi turbine housing fit the Garrett style centre housing . Long short if you can find a serviceable RB25 Hitachi turbo use that with your turbine housing if it's the larger one . A .