discopotato03

Wasn't there a change in the long side pipe diameter with the later version of the Blitz return flow kit ? I'm not sure if it makes any difference but there does seem to be inconstant results with these IC kits . Also that above mentioned Hypergear turbo looks interesting , are we allowed to know how its wheel diametres differe from a GT3076R ? Cheers A .

Can you buy a 2.5L R32 and put the turbo gear in that ? Or just buy a GTS25T. The biggest problem for an RB20 block is the bore size , this limits the chamber diameter and that limits the valve size . RB20 valve sizes are inadequate for 2.3-2.4 litres and there is nothing economically viable you can do about it . Painted into a corner you can't get out of , this is literally why a big bore (86mm) RB24 or RB25 will always make better power than a stroked RB20 . BTW there was actually a big bore RB24 which I think had the RB20 stroke crank with slightly longer rods . It may have been a pov pak third world carby option . A .

IMO the Dash 9s are purpose built to do a good job on a fairly std GTR . I don't think anything is going to boost like standard R34 turbos and pull well over 7000 revs . 2568ccs isn't a whole lot for 1500 kilos of GTR and the roads to big power is breathing better at higher revs . The cost is boost lag because bigger is generally heavier and needs greater gas speed to overcome the inertia . Everyones idea of adequate performance is different , usable performance probably doesn't involve 7000 plus revs in a street car . The killer of adequate imo is numbers because everyone seems to think if you haven't got 400 at the bags you haven't got a life . V8ers with longer arms than legs think like this . Voy oight . A .

Big centre section turbo with T series turbine , R series compressor , for an RB25 . The "Z" was just HKSs way of saying ball bearings . Many went with a GT3582R if they wanted a biggish turbo for a T3 mounting flange . You also have IW option with a GT3582R . A .

Looking closer all that's of any interest in the GTW turbos is the smallest one with the 76mm 58T 9 bladed compressor in the T04E compressor housing . If it found its way onto a GT30 turbine in the GT25 sized BB cartridge (GT2554R-GT3582R family) it may have its uses . I think the GT29xxR series is a case of why bother without an IW turbine housing . A .

I found cleaning all the earth points in the engine bay made a difference to my S2 33 . Also the voltage regs don't last forever . I got caught out a while back and had to have my OE alternator rebuilt . The reg is the same as those on early Falcon Mitsi alternators - EA EB from memory . I don't think the OE R33 alt is listed in Australian parts catalogs but long time auto sparkys can usually work it out . My car shows around 14V at the battery and a little higher at the alternator so good enough for me ATM .

When its all said and done an RB20 is a stage 5 L20A , same bore and stroke but twice as many valves and cams . Hard to think of any I6 with 330cc cylinders that was a power house . The 25s simply got more inches . A .

Yep IW drying up from Garrett but Hypergear may come to the party with a T3 flanged suitable IW turbine housing for these Garretts if asked nicely . A .

I found a GTX parts list and these details were included . GTX2967R with 56.6mm 84T turbine GTX2971R with 56.6mm 84T turbine GTX2971R with 56.6mm 90T turbine GTX2976R with 56.6mm 90T turbine . If you had a HKS GT2835 Pro turbine housing the first two could probably bolt to an RB exhaust manifold . A .

Yes an interesting result . What I think upsets perceptions is todays use of E70 / E85 and what that allows you to do timing wise . People do get higher numbers with ethanol like my 271 wheel wasps when I ran the GTRS . To put that into perspective I think Micko had 270 odd with his GTX3071R when running 98 PULP , open to correction if that number is wrong . I noticed that Checkbuzz (Sp ?) got a little over 300 wheel wasps out of his 3076R 52T 0.82AR so maybe in some niches the old GT comp jobs do alright . Anyway it could be possible that like the older GT3071R the GTX3067R isn't a perfect animal , both are GT28 turbo upgrades and its possible that the cropped GT30 turbine is a better compromise in this area . Many felt that HKS had it right with the GT2835 Pro S and Garrett seemingly hasn't really been able to get equal results . All that really stopped them was the lack of a T3 flanged IW turbine housing for the cropped GT30 turbine . I think they are doing the larger (90) trim size version of this cropped turbine for the new GTX2971R but not sure about a T3 IW housing to suit . Bottom line is that you picked up 500 revs which is significant and another getting rare T3 IW GT30 turbine housing . Cheers A .

Some examples of lower capacity compressors were done by Mitsubishi but in some model Garretts you have a choice of trim sizes , you don't always have to go for the highest capacity one . In their later models you don't get too much say but there is a large range with small jumps for the GT28 series using GT or GTX compressors . Slowly more pics and details are filtering out on the GTW turbos and I have a bad feeling that they are larger BB and plain bearing cartridges going off the pics . The larger centre section looks like the one used in the BB T04/60-1 and T04Z units . The turbine dimensions look like (from memory) T04 in N o and P trims and the smaller ones some other T series offering . The compressor backplate looks like machined aluminium not the ring type adapters used in GT25 based BB cartridges ie GT2554R - to GT3582R . The 9 bladed billet compressors are a step in the right direction and lets hope they make similar things available for the GT30 and GT35 based BB turbos . Where abouts is the results of the 0.63 AR GTX3067R ? A .

I haven't yet seen the 63 3067R results so busy ATM . All I know about SR heads these days is low port high port - and a little about the GTiR variation . What I do know is that sometimes using a lower max flow compressor for a given turbine size can give good results especially with low to mid range power in mind . I believe it comes back to having equal pressures across the cylinder head (inlet and exhaust) when running in the most useful part of the rev range . Gotta run cheers A .

A few things to consider Firstly the turbo (turbine housing) has to fit your manifold/engine so John West any that don't . Secondly Garrett do use the same turbine housing castings at times for a few different sized turbines ie up until recently GT30 and GT35 turbines in differently profiled common housings . Mostly GT28 turbine sized turbos don't bolt up to RB manifolds unless they are unique HKS hybrid housings with T3 flanges , Garrett pretty much used T2 flanges on GT28 turbos/housings . Garrett is obviously making a range of turbine housing ARs to give users a bit of flexibility with different capacity engines . For example if you had a 13-1600cc engine and you wanted to use a TS housing then 0.61AR probably isn't unreasonable . You'd think its small for a 2-2.5L engines but even so on a low revving diseasel application maybe fine . For petrol a bit small IMO . Most people agree that comparing single and twin scroll ARs is a head flick , the whole point of twin scrolls is to halve the number of exhaust "putts" into each side to make the engine scavange better and reduce exhaust reversion . I believe that when the engines loaded up and high in its rev range the total flow capacity of the turbine/housing combination is more important and the overlapping exhaust pulses get so close together that the TS advantage tapers off . In the heavy duty engine world , most big automotive diesels , the housings are sized to give the best performance and efficiencies under full load because that's where they spend much of their time . Different with a road car engine because you mostly can't use its performance potential for more than short bursts and stay legal speed wise . In some ways having a wide rev range shows up the limitations of centrifugal turbochargers because its difficult to make them work effectively across the whole speed range of your average petrol engine . Twin scroll turbocharging adds another dimension of complexity (manifold/turbine housing/wastegating) but done properly can help widen the forced engines power range over single scroll setups . I believe done properly it achieves this by improving the engines performance off boost and allows better efficiencies up high if the turbine/housing/gates are sized to suit the users top end wants . Everybody's wants are different so each has to define from the outset close to what they want to achieve . Personally I think GT28 gear is a tad limiting for any single turbo RB except maybe a mild RB20 , twins and 26s are a different story . I think you can do better for an RB25 and we'll soon know if the 0.63AR single scroll housing on a GTX3067R is responsive enough for even a conservative RB25 . I have read that Garrett wants to do larger AR housings for GT28 turbos but I reckon there are limits to how high a capacity compressor a GT28 turbine can drive regardless of how big the 28 housing gets . People reckon the 56T 71mm GT compressor was getting laggy with the 28 turbine and I don't think the situation gets much if any better with the GTX67 or GTX71mm compressors . Borg Warner has shown that turbines can get larger in relation to compressors if they have less mass/inertia but that means using expensive exotic materials and Garrett doesn't seem to be interested in going there . Hope this helps cheers A .

The $64 question is will they still do T3 flanged IW turbine housings because that's what suits most modest roadies . I couldn't give a rats about V band mounts etc , if it ain't got a workable IW option shove it where the sun doesn't shine . BW doesn't limit their units to external gates . The smallest GTW unit could be interesting particularly if it gets the usual GT30 turbine somewhere down the track . From memory it has a 9 bladed 76mm compressor in a modest trim size . A .

A few details are now creeping out . The GTX2971R looks like having the larger or 90 trim version of the cropped GT30 turbine which we know is a flop in GT28 turbine housings . Garrett has been said to have cast new turbine housings that better suit this and the normal 60mm 84T GT30 turbine and I think they are the new V band and twin scroll T3 flanged ones . Also there is info on the new GTW BB and bush bearing GTW units at ATP Turbos site . Cheers A .

The other option if you really like 7163s is to use a twin T3 to twin T4 adapter plate/spacer and a TS T4 housing on the 7163 . I guess it depends on the physical size of the turbo you prefer and how much top end you want . 7163 is obviously a bit more compact and lighter , and you'd think more linear in its boost characteristics . Geoff Raicer reckons they are the most responsive 500 CHP turbo out there so 400 should be easy if everything else is up to it . A .

They should all be using the same cartridge and wheels 446179-21 from memory . I seem to remember the KAI version having a port shrouded compressor housing so was likely a single turbo version . The main unique part today is the 60mm 63T compressor wheel and I think it was only ever used in 2530s and one other app I can't remember . You can turn any GT2860 with the same turbine into a 2530 if you have the original undamaged compressor wheel and housing . Swap the wheel in balance and bingo new guts . A .

I like Scotty's idea of the bend so that the vent paths area is large at the housing casting . I was always told that big is what flow paths have to be if the angles are compromised by packaging etc . A .

From the mechanics , regardless of what it says on the cans don't spray large amounts of any cleaner down an engines throat without having a few revs up to get it through the system . The last thing I'd do is spray into a cold silent engine . The drama is any gunge on the inlet system or valves or piston crows can come away and in a slow cranking cold engine can make a mess the plugs won't thank you for . And yes it's a drama if anything gets caught between the valves and seats and hydraulic lifters pump up . I'd start with a plug change cheers A.

That BB centre section was based on the GT25 plain bearing housing . GT25 housings are more compact than GT30 and yes getting at some of the bolt heads can be interesting . Most people working on them often have "special tools" or normal ones reshaped with a bit of heat . The next size up centre section is more like plain T3/T4 dimensions but they start in the GT37s etc . Gotta run cheers A .

With a bit of stuffing around a good turbo workshop should be able to make a pair of effectively 2530s (current terminology GT2860R 63T) using the "2510s" comp wheels , from memory "2510s" were just 2530s with smaller turbines . Gotta run cheers A .

There is a train of thought that "T3": twin scroll turbine housings don't quite do it as well as the T4 flanged ones even in the same AR size . If staying with the GTX3071 it may not be an issue given the limits of the compressor side but Geoff Raicer is probably the one to ask . A .

As has been mentioned there are supposed to be a few new offerings on the way from Garrett . The GTX2971R sounds interesting but the few details available only say the turbine is smaller than GT30 and larger than GT28 . Someone mentioned this turbine being smaller but slightly higher flowing than the GT30 so if its true then it must have less hub and more blade area . Also there is vague info about a couple of GTW , W for wide I think turbos is plain and ball bearing but there numbers must be using a different system to the usual turbine size plus compressor OD ie GT30 76mm R . The pics show 9 bladed billet compressors in either T04E or what looks like port shrouded T04S compressor housings . The turbine housings look like being V Band outlet and inlet in some cases and in a few closer spaced AR ratios . If people find our more can they post here for all to see . Cheers A .

I'd just do a quick clean up around the throat/seat area if keen . You can fit slightly oversized exhaust valves with a bit of machining on the existing valve seats . All RB25 and 26 twin cam heads are a tad down on exhaust valve size and if you re do the exhaust valve seats they can be done for the OS valves in one go . Ferrea and one of the other mobs do them but I don't have part numbers . I did this and had no power loss . The current trends with turbo engines is to do everything possible to free up the exhaust side so the engine runs more efficiently when on boost . There is a supposed valve head area ratio exhaust to inlet and I can't remember accurately the numbers but the RBs end up being a tad small in the calc . Doing this is a bit like having a very mild exhaust cam upgrade but no valve train geometry changes . Works for me , cheers A .

As long as the co pilot comes with a leather switch ......