discopotato03

I believe its to do with very little blow by ie keeping the expanding gasses in the cylinder rather than escaping into the crank case . If they reduce oil contamination in the cylinder it can help maintain the fuels octane rating . Cheers A .

I got JE VG30 Pistons and the gapless rings for mine , I wanted 87.5mm and 22mm gudgeon pins but mainly the higher compression ratio ie up round 8.8 - 9 to 1 . I don't know what clearence is recommended for these as the build is not too soon . Fingers crossed those Sealed Power rings will pay off . Cheers A .

The cartridges in the S15 GT28BB's would probably work OK but the housings differ from RB26 specific turbos to suit the single SR20 application . I prefer the larger single for cost and complexity reasons but if I had to use twin GT28's I would use those with the more open bladed turbines . The compressors on those S15 GTBB's are a specific type for the OEM but are available as replacement cartridges .

They don't look good on paper because of the size difference of turbine to compressor ie 60mm to 82mm = almost 27% , 15-20% is preferable . At least the 50 trim of the compressor helps . I don't think you mentioned anything about AFM size/exhaust manifold type or if high performance cams are used . There are lots of options ie the cast HKS exhaust manifold/external gate teamed with the larger 1.06 ARR turbine housing . I would check for pressure drop across the intercooler as well . The RB25 top end if its std may be lacking in the breathing dept so porting/cams/springs or the best option RB26 top end may pay off . If your looking for a bolt on turbo solution I guess the XR6T's version of the GT3540R could do but its asking the turbo to do all the work probably with a highish boost threshold . Cheers A .

Lithium its going to come back to what you think feels good . If you want a punchy power curve where it all comes in with a rush at 3000 use a GT2871R/GTRS because thats what it can do . When it spools up and the engines torque can double in 500 revs thats what appeals to some . I prefer to muck around with the engine management to enhance the low down (off boost) torque and throttle response to get all the engines capable of giving . Depending on engine capacity and the weight its expexted to pull , where in the rev range the turbo enhances torque is important . If your car had say an RB20DET it needs to be biased toward the lower end because its no torque demon at low revs and R33's are no feather weight . Having 2.5 litres means a bit more torque at low revs so the turbos useful range can move up the engines rev range . If it had an RB30DET/VG30DET it can go even higher because the off boost torque is heaps (particularly if the compression ratio is in the 8.5 - 9.0 range) . If you want the most flexibility go for a larger engine in a slightly lesser state of tune , thats what I aim to do .

I know the difference - the hole through it is 7mm to suit the GT BB turbine shaft . The original is 6.35mm (1/4") to suit the bush bearing shaft . The fact that they have seven full and seven splitter blades is significant when you consider virtually all Garretts (post 1990 CAD designed) compressors use six of each . If you put them next to one another (a T04S and a BCI 18 compressor) and look closely they really are worlds apart . Start at the exducer tips , their angle is far closer to vertical than modern designs . The angle of attack of the blades is more toward the wheels axis than later types . What is really is obvious is the blades thickness on the old T04S wheels . The effort has gone into making newer designs slice easily through the air at low rpm (less energy needed by the turbine to accelerate it to boost threshold revs) , make it mechanically stronger to withstand the centrifugal forces of high rpm , make it an efficient pump which equates to less heat or density change on the way through . Keeping the mass to a minimum helps reduce the innertia of the turbos rotating assembly . In todays world I doubt any engine manufacturer could afford to ignore the benefits of modern turbocharging as response/power/fuel consumption/bulk/weight are all directly tied to it . Cheers A . Cheers A .

Cubes the turbine the highflow uses is I think the 76 trim TA34 ("stage 3" in turbonetics speak) which from memory is 64-65mm so larger than the GT30 turbines major diameter (60mm) . We both know which the better turbine is though . Just on those Hi Flows , I believe they can use any of the T3/T31/TA34/T4B,E bush bearing type compressor and turbines . Garrett are supposed to make all the GTBB type wheels (both sides) in bush bearing style that could be used if you can get them cheaply and easily . So if you could find a GT35 compressor and GT30 turbine and fit it into the Hitachi bearing housing with the XTR (Turbonetics?) BB conversion bingo - one GT3071R that falls onto an RB25 and suits all the plumbing requirements for oil water air and exhaust . It can be that easy , the real question is can it be done economically enough to market it successfully . Maybe we shall see ahh GCG ? Cheers A .

The 2540R will always be last - bar none except some lousy backyard hybrids . The 2871R would be next - good response but a 53.8mm turbine is getting a little small for 2.5L once it starts to rev . For a lowish boost application it could work ok - note Garrett unfortunately don't make a T3 flanged .86ARR integrally wastegated exhaust housing which is the minimum needed for 2.5L and that turbine . The GT3071R would have to be the pick of the three and with its GT30 turbine has lots of turbine housing options in T28 and T3 mounting flange patterns . If its the 4-7000 rpm band your interested in GT30R is worth considering as well . Its larger higher flowing (and modern/efficient) compressor will do it better up high than the GT3071R . Its the choise you need to make based on what the car is used for most of the time . If you dont want to upgrade computer and fuel systems its pointless having more airflow than the std components can support . If however you intend to make serious power and live within the 4-7 rev range the higher airflow is needed . My choise in your situation would be a GT30R (700382-12) with one of the HKS T3 flanged integral gate turbine housings in .68 ARR for response or .87 ARR for a bit less restriction up high . I would do the fuel pump , PFC ECU , and injectors in that order first because I use my car for every day transport and it has to be useable and reliable after each mod . Cheers A .

Sorry doesn't work like that . Small diametre turbines have short blades (hub to tip) so don't want to know about generating enough shaft torque to drive large diametre compressors untill the exhaust gas speed is very high , high enough to create pumping losses and thermal melt down . Just as you wouldn't use a short crow bar to lever a large rock why use short turbine blades to lever a large compressor . This is why its absolutely critical not to overdo the compressors flow capacity . Big compressors want to move lots of air and its the resistance of moving the airs mass , not the compressor wheels mass , that creates resistance to it turning . Remember its the TURBINE thats fighting this resistance to turning and if its wearing short blades all its doing is promoting turbo (turbine ) lag . Theres two ways to fix this 1) drop in a smaller compressor that works well within the shaft power limits of the turbine or 2) use a larger diametre turbine better equipt (greater mechanical advantage from its longer levers or in this case blades) to muscle the large compressor and its high mass flow . Now getting back to that GT2540R and its dinosaur T04S compressor wheel . There is a rule stating that the more in number and thicker the blades are the less the pumping efficiency will be . These wheels are not a high pressure ratio item and this can be seen in their maps . The island of highest efficiency is cut off at the 1 bar line rather than being a complete island above it . They are designed to move a large volume of air at lowish shaft speed (living within the reliable limit of bush bearings) up to about 1 bar of positive pressure (15lbs boost) . When current (1976) they were teamed up with T04 turbines that were large heavy thick bladed relatively low speed turbines and bolted to diesel engines . Now jump forward 20 years to the point when some cork head decides to fit it on the end of a light weight high speed small medium sized turbine supported by ball bearings . The old bull T04S neither knows or cares that its not a T04 turbine driving it and basically says wake me up when ya get the lead out . the best results will always come from the most modern wheels and a similar diametre on the turbine and compressor . An old rule of thumb was keep them within 15% of each other in the bush bearing days , 15-20% is not unreasonable with modern turbos . The 2540R is gettting up towards 30% which is a bit much AND has a totally inappropriate wheel design . You can do much better than this . Cheers A .

From the HKS USA site the GT3240 (GT5982R in new speak) is a tad smaller in the turbine dimensions ie 58.7 x 54mm vs 60 x 55mm for your GT3037S . The compressor the former uses is an 82mm 54 trim GT40 series wheel . How they come up with the 580 PS power rating beats me . Also note that its sold with a .87 ARR T28 flanged exhaust housing . You may be better off looking at the HKS version of the GT3040 which has the same turbine as your 3037S and a smaller (50 vs 54) trim 82mm GT40 compressor . Its still not a good match in my opinion but looks better on paper than the 3240 and has a few more turbine housing options . What turbine housing does your 3037S have ? Cheers A .

Hi Lithium , I was comparing the maps as to where the surge line is to the left and the flow limit is to the right along the 1 Bar (14.7 psi) line indicated by the 2 pressure ratio scale up the left hand side of the map . Sure the 3071R's compressor wheel is a higher pressure ratio wheel compared to the T04S wheel in the 2540R , but its also far lighter , has less and thinner while being mechanically stronger blades . Where the later smaller diametre GT compressors win is that they can be spun faster to generate the same airflow wth even less heat in the inlet charge than the older T04B/E/S compressors . Also while the 50ARR T04E compressor housing (cover) std on the 3071R is not the biggest dickest of the Garrett world it does the job and is easier to fit in todays compact engine bays . The great galoot of a T04S compressor housing is more difficult to plumb and hard to justify in this air flow range - unless of course its owner and followers gather around it can in hand for the ooh ahh hymn . Ill have a look at the map for the 2871R which uses the same family of compressor (71.1mm GT35) but in a smaller family housing and see if its any better . As for cost it only hurts once , but if the result of the cheap job steams you for ever after the difference will seem trivial . Cheers A .

Actually the power rack (Bluebird) is much more robust than the locally made manual piece of crap . I would go so far as to say with non std wheel off sets and lots of positive caster the steering gets real heavy . Just had a thought if you use Bluebird power assist bits you may need to shorten the steering arms to retain enough steering arc , My Bbd had std arms and the full lock was a bit average . The tubular section of the power rack is longer than the std one so it runs out of travel a little sooner . I may take it to Just Jap and compare it to S13/14/15/R32GTST racks . Yes FJ20ET's go onto Bluebird X members , The Jap SSS 910 X member and Gazell FJT brackets virtually bolt together , got a pair of those too . Cheers A .

Yes an important point , fitting a non native turbo can add up quite a bit . The cost of the GCG Hi Flow is hard to beat considering it slots straight in and costs zip if you do the spannering yourself . I would insist on the VG30 housing though . If you must fit one of the Garrett GT BB's there are better ones than that "2540R" dinosaur that ATP sell . Have a look at the turbine and compressor maps for the GT3071R and GT30R , much better . You could even ask Brett (GCG Turbos) if the Hitachi housings (std RB25DET or VG30DET) can be profile machined to fit the GT3071R cartridge (now re named GT6071R by Garrett for its 60mm turbine and 71mm compressor) . Doing it this way gets you more modern wheels than the Hi Flow which may be cheaper and needs the same amount of machine work , it would also bolt straight back in . Custom water and oil feeds/drains would be needed and cost a bit more . Cheers A .

You pick it wreackers usually have some MR30's kicking around - try them . The early 82 models have the best head with the heart shaped chambers and minus the cast in exhaust port liners . The exhaust ports are sort of rectangular rather than round as is the exhaust manifold . Don't quote me but the cast in number at the front of the head (near side) may be N42 . This is the best std version .

Yes keep us posted as I have the 910SSS X member and power rack which my FJT Bluebird used . You need to get a matching set as Bluebirds have different rack mounts for manual and power racks . I'm not certain but I think the 280ZX used a very similar power rack . S12 Gazels are also from the same era so check them out as well . With Bluebird bits you may need to cut and shut the control arms so that the roll bar and radius rod links bolt up .

Before I do Garrett list another 2860 turbo part no 707160-7 cartridge no 446179-54 which looks very similar if not identical to HKS's GT-SS . Both the 707160-5 and -7 variants look to have RB26 specific housings and note the divider in the exhaust housing outlets . The turbine inlets are more square in shape compared to most generic GT28 housings I suppose to match the RB26 exhaust manifold outlets . We need Garrett to list compressor tip heights to identify the specific wheels . As Arnie said ..... Cheers A .

An interesting read . Just so all can see , if anyone has a HKS GT-SS turbo can they post some pics of the turbine side at the exhaust outlet . The turbines these use are not as open in the blade form as the 76 trim NS111 (53.85mm) GT 28 turbine . I believe that a compromise exists with low spool or boost threshold in one hand and high exhaust gas flow (for its size) in the other . I don't believe its possible to have a low boost threshold and high end performance AND headroom for future mods . If you tie yourself into small turbos you will limit the engines power potential by restricting exhaust flow out and airflow in - no free ride here . If it were me whatever turbo I chose would have the higher flowing turbine as the first consideration . Crudely speaking the turbine housing is there to gather and accelerate the exhaust gasses through the turbine blades and duct them into the exhaust pipe . The area radius ratio size is varied to "tune" the gas speed for a given turbine size . The smaller they are the less maximim flow they have . This is why I prefer turbos that enhance exhaust gas flow and if anything are limited by compressor capacity . Its interesting to look at the variations in the GT28 series (now called 28XXR series) particularly that 2860 707160-5 . I think I looked at it once to see if it had the same 60mm compressor as the (old speak GT28RS) as they are both 62 trim , but I think the cartridge numbers were different possibly because of different tip heights . If I had a clean sheet for all round twins for an RB26 it would have the GT28RS cartridge with slightly smaller .58 ARR exhaust housings for slightly better response than HKS GT2530's . With what is available I would take a close look at the 2860 707160-5 . I'll get an e-mail off to my contacts to see if any difference is significant . Cheers A .

32/36 DGV Webers were available with a manual choke as well . The 2 Litre Escort version was an emissions version and not real good . Weber specialists should point you in the right direction .

Working the Indian Pacific home from Parkes in the early hours sorry .

Cubes yes , the GT30 housings will fit early and late cartridges as will any housing machined (profiled) to suit . Garrett often sells cartridges without exhaust housings so the end user can select one of several to suit his/her application . If you look in the old Garrett catalogue PDF the "GT3071R" (700177-23 CHRA No) is sold as a cartridge without compressor or exhaust housings but there are three variations of both turbine and compressor housings available . The integral gate HKS housings are the go and while expensive not as much as an aftermarket cast manifold and waste gate . GCG can get HKS housings (as I suppose HPIAB could) and if enough people were interested they could possibly market these with late "GT30R" turbochargers that will bolt up and take advantage of all the available technology . Cheers A .

Ah , I think you mean compressor wheel and that's how far back the BCI-8 series go .

Bass Junky , thats the "In a Box GT30R" is it ? Thats not what Garrett used to call their "GT30R" , now called the GT3076R . The cartridge in the picture shown has a 1976 era T04S compressor wheel and .70ARR T04S compressor cover . The most up to date "GT30R" uses the BCI-18 series compressor with six full and six splitter blades . It's lighter and stronger than the T04S wheel and capable of higher revs , it also requires less turbine generated torque to excite it meaning less slip losses and higher turbine efficiency . The current version's turbo part no is 700382-12 or cartridge (CHRA) no 700177-7 . It's usually sold with a port shrouded .60ARR T04E compressor cover as well . The seller is not going to like this but your turbo is a less costly item to source so easy to sell cheaply . Just the same as you would not swap your 90's era RB for an L series I would not swap an early 90's compressor for a mid 70's one . HKS knew the difference and that's why their 56 trim GT3037 series all use the 700177-7 cartridge . Cheers A .

Black32 only the name has changed , they've got a unified system at last . GT32's are all bush bearing except HKS's GT3240 which is another cropped bastardised turbine job . Don't mistake GT32 and GT35 compressor maps and look for the all important "R" for rolling element or ball bearing cartridge ie GT3076R . Cheers A .

No just a good race or rally fabricator who genuinely can weld and measure . I doubt anyone will look too close at a 20+ year old car , if its done properly it should look factory . Incidentally try running nolathane caster (radius rod) bushes and very little or no toe in . Mine has 6 deg positive caster , 1/2 neg camber and next time out from 1/16 toe to zero . Is feeling better .

Cubes the real GT3071R's CHRA number is 700177-23 with the 84 trim 60mm GT30 turbine. Its on that site under medium frame comparisons . An interesting thing to look at is the turbine efficiency of the more performance based turbo options . The GT2860RS (used to be called GT28RS) is 72% as is the GT3076R (GT30R in old speak or 700382-12 CHRA) . The GT3582R (old speak GT35R or GT3540R) is 70% . It starts to slip away with the 56 trim version of the GT2871R at 66% turbine efficiency and goes through the floor with those "other" GT3071R's that use the cropped (56.6mm vs the normal 60mm) GT30 turbine in the overbored GT28 exhaust housing . There's an even worse example in the GT2876R (old speak GT2540R Garret version) which uses the 76mm 48 trim T04S dinosaur compressor , around 60% turbine efficiency . The side note even says not recommended for performance engines as its not symmetrically sized ? When you can find them the Garrett engineers will tell you that high turbine efficiency is critical to make it work well . You may think the difference between 60 and 72% efficiency is trivial but in the real world its huge . When you consider the turbine and compressor pair major diametres a pattern begins to show . GT2860RS 53.8 x 60.1 10.4% GT3071R 60.0 x 71.1 15.6% GT3071R 56.6 x 71.1 20.4% GT3076R 60.0 x 76.2 21.3% GT3582R 68.0 x 82.0 17.1% GT28T04S 53.8 x 76.0 29.2% Generally the closer in size the pair are the greater the turbine efficiency . Cheers A .