discopotato03

S15 turbos are a modified Garrett GTBB , 2 x 360 deg annular contact BB's . The CHRA is very similar to the Garrett GT28 "320 hp" turbo with minor differences in the compressor wheel to improve response and efficiency . With the right housings they could work similar to 2510's . The turbine is not the same one used on GT2530's , 28RS's etc so don't know what the engine rev potential would be in the higher boost ranges . I believe RB26's need compressor covers with the two mount holes for that water/oil plumbing gadget . Unless they are a give away something designed for the RB26 would be easier to bolt up . You can buy from Garrett a BB GT28 thats in theory identical to the HKS GT2530's so new for less than the HKS tag . I think those open bladed NS111 turbines are worth the effort on an integral gate setup . I'd reckon a fiddle with the cam timing could offset the trivial amountof lag these turbos give over the std bush bearing T28's .

I can't see it happening , but it would be interesting to see what a seriously modified RB20 could do set up for a maximum spread of torque . By that I mean short timed high lift cams , optimum cam timing , 9 to 1 CR and current type turbos ie GTSS or GT28RS with 10 lbs of boost . Correct me if I'm wrong but it seems SR20DET's towards the end (S15's) got more sophisticated engine management , and the Garrett GTBB turbo is a far cry from the RB's ceramic sputnick turbocharger . This may be a little off topic but I think its fair to compare the R32GTST to the S13 with the early fixed valve train and the bush bearing T25G turbo . I believe these were both on sale in Japan in 1989 so its relivant to the era . I have not owned either but have been in both and the R32 was a much more complete package in bog std state . The RB20 was very smooth and progressive in other words easy to drive . This feeling of it won't go down low is silly , what two liter engine thats designed to rev does ? Can you really expect them to pull like a Masey Furgeson (Farm Tractor) at low revs and keep it up to the redline ? I cant comment on drag race engines because they don't interest me , smooth controllable power curves do . I hate engines where the power all comes in with a bang at half rev range and is impossible to control . Gary would probably tell you that average power is far superior to top end because of the effect on handling . In my biased opinion the R32 is a better balenced car with a quite reasonable power curve . The S13 did not have that nice feel and roll free handling poise - probably because of the different weight balence and strut front suspension . The SR20 did not have that "I want to rev forever" feel that is nice in a sports type car . It did not have the feeling that it could be changed down two gears at a time to power out of sharp tight up hill curves from a reasonable clip . There are definatly times when using another thousand revs (or two or three) are preferable to an up change on twisty roads . The SR20 was not a smooth engine when pushed which I put down to heavier pistons and longer stroke . I think the SR20 was a bean counters jack of all trades , I think the RB series sixes were a more sporting oriented engine and this shows up in the cylinder heads - the twin cam ones anyway .

Hello Gary , if you have the time can we please have a brief run down on the efforts taken to morph an SR20 into a race engine . I believe its truly a case of engineering over design- but on a moonshot budget . To get the same power out of an N/A RB20 surely would cost peanuts by comparison . Cheers A .

I think an RB20 would stand up to harder use than an SR20 and keep coming back for more . Correct me if I'm wrong but an R32GTST would weigh more than the S13's and is probably a better handling car . The valve train on SR20's is not intended for high rpm use , Nissan went through LOTS of engine development with SR20's for the 2 litre super tourers . From memory the head was turned 180 degrees , the cams reversed , special brackets made to stop the rockers going postal . The bore stroke and rod stroke ratios were nothing like the production engines . There was not much Nissan about the finished block either . Possibly the question being raised is how each engine performs in standard tune . The SR20 having larger pots (capacity wise) may feel a bit more willing at low revs , but a bit further up I reckon the RB would anihilate it . With the smaller pots the RB20 may have more to loose with back yard tuners and their "she's sick mart" ways of doing things . My money would be with the RB20 out of these two every time . Cheers A .

Fatz you do have a couple of options here , first is to replace the .50 ARR comp cover with the larger .70 ARR T04E cover and keep the backplate . Second is to use the larger series T04S cover and backplate (adapter ring) which is what Garrett did with their GT3540R turbocharger . If your finances are limited go the larger ARR .70 "E" cover . If the sky is your limit go the "S" bits . Also remember that the T04S covers are quite large so make sure there's enough real estate where your turbo lives . Generally compressor covers are sized around airflow rates or speed . So for a given compressor wheel the larger the Area Radius Ratio the lower the gas speed will be and vice versa . Also the larger it is the less chance it will have of being a choke point at high wheel speeds . Someone did tell me that all else being equal going up in comp cover AR brings the boost on a little later and "hits" harder . With most Garrett turbos there is a set compressor wheel diameter for each wheel/cover family , ie 60mm wheels T3 covers , 71mm wheels T04B covers , 76mm wheels T04E covers , 82mm wheels T04S covers . In recent years Garrett started going up a size in cover with some of the GT BB series compressors . I think this is because the comp wheels are mechanically stronger , and and can still pump efficiently at much higher rpm's than the bush bearing has beens . This is a win win situation , the small high speed wheels are compact , cheap to produce and more importantly have less innertia so spool sooner . Examples of this are the little GT28RS (T04B comp cover) and some of the GT2835R series turbos with 71mm compressors and T04E covers . The Garrett people inthe US tell me that the up sized cover , and a little extra tip height on the wheel , gives extra pumping capacity and a few more points compressor efficiency . I can only think of two examples of Garrett turbos that went smaller in cover size , they are the HKS GT2540 and the Ford GT3540R . The 2540 is getting on and was probably an attempt to get a bit more flow and power out of a small series turbo , and a low mount compact (convienent) fit for GTR's . Its safe to say Ford was not looking for serious performance with the XR6T so a compact and probably cheaper adequate cover got the nod . You can bet they knew people would modify them for performance , so the limited cover capacity may have been intended to limit the performance with the std turbo but not affect the standard state of tune . Cheers A .

For outright performance the early high inlet port non VVT head is better . If you get them the GTiR head is the Rally homologation type , better valve train and inlet manifold .

What about using an R32 loom and sensors and an Apexi PFC.

Talk to a radiator specialist , they know which sensors fit what .

I have often thought a GTiR SR20DET could make a good conversion .

Is anyone using a system like this ? I was thinking along the lines of an A/C rad to cool the water , a Davis Craig booster to pump the water and an ARE ? heat exchanger . There does not seem to be many water set ups so I was wondering what you all think , water is rather heavy so is this likely to be a problem . Actually were the XR6T's intercooling problems solved this way ? Cheers A .

Cubes that exhaust housing looks very like some of the large series TO4's I've seen around . Sorry to be negative but the genuine GT35R turbine housings have a different shaped passage , to better suit the greater tip hight "paddle wheel" style GT turbines . RS500 had a post ages ago about the downside of using TO4 housings with GT series turbines . A fellow I know used to weld external gate fittings onto FJ20 and RB30ET exhaust manifolds so maybe this could be done to an RB20/25 exhaust manifold . Good luck anyway cheers A .

Ghostrider competition gearsets were available through Nismo (and others) , where 1st was in the 2.6 - 2.2 range and needed short (4.8 - 5.3) rear gears to work . Another thing to remember is that with short rear gear sets , the number of pinion teeth is less making the pinion smaller AND weaker . Give me a 37/10 or 39/10 pair anyday over a 37/9 or 35/8 .

Joel its not difficult to be confused with Garretts PDF . I think the maps of the GT32 and GT40 may be describing bush bearing turbos . In that list GT30R and GT35R , I think the "R" denotes GT series Ball Bearing CHRA . If you looked at the GT42 it shows the optional BB CHRA . With the comp covers the maps don't tell if they are TO4E or TO4S . I know for sure that Garrett did the E covers in .50/60/70 ARR's where the TO4S ARR's are all over the place with odd ball no's to suit diesel apps . The 50 E cover would not have any meat left over with an 82mm compressor in it . Ford would have looked into the maximum flow of the cover and probably decided it was enough for 240KW (crank) with effectivly the 4 psi that makes it to the inlet manifold . Brett tells me that 6psi leaves the compressor and 4psi leaves the intercooler . I reckon looking at the large 1.06 ARR turbine housing and adequate ? comp cover Ford were trying hard to have little restriction on the exhaust side , and just enough inlet flow to get the power rating . Garrett and Ford would have the compressor map for this combination but getting it out of them would be difficult . As an RB bolt on these should be pretty good , its just a pity Garrett haven't done the .82 turbine housings as well .

Cubes , would be very interested to see the compressor map of the GT40 comp in .50 E cover . Any chance of posting it ? Thanks A .

Coul this be an over compensation for the owners lack of masculinity ?

They most certainly are , identical core as GT35R or known by some as the GT3540R . 56 trim 82mm GT40 compressor , 84 trim 68mm GT35 turbine . The unique thing with this turbocharger (apart from the integral gate) is its .50AR TO4E comp cover , possibly optioned to feed 4L at low boost and have good response . For anyone interested GCG is tooling up to make a .63AR integral gate exhaust housing for GT35R's as part of a low boost kit in the wings . I will probably option mine with a .60 E comp cover and 82 or 1.06 turbine housing .

LOL no debate this time . I do prefer the HKS exhaust housings , they just need the T3 flange on more of them - the GT30 style ones I mean .

SteveL , what changes were made to the carrier or hemisphere ? offsets maybe ? The only special tools needed to change like carriers are a torque wrench , dial gauge and weight scale or experienced hand . Bearing blue is handy to check the contact patch but as I said the pinion height does not change . Ghostrider why would you want a 4.1 or 4.375 ? I would be more interested in a 3.7 especially with an RB30DET and stock gearbox ratios . If anyone wants to swap an open 3.7 for a 3.9 I'm listening , need to keep the uni flange though . Ghostrider I may know someone with a 4.375 open , PM if interested .

From memory the early (pre short nose) R200's are very similar in regard to how they fit the case or cast iron bit . The carrier bearing pre-load is set by select fit washers (same dia as outer race) on the outside of the bearings . If the later hemisphere (carrier) has the same offset width and crown wheel bolt pattern its pretty simple . If you change centers and retain the original crown wheel all that needs to be set is the carrier bearing preload and backlash for the crown/pinion teeth . The pinion has not been removed so its height has not changed . At some stage Nissan changed the crownwheel bolt diameter (I think about the time DR30's grew turbos) but this is not hard to get around . I have a master craftsman when it comes to Nissan Diffs , an old school mechanic not just a parts fitter . The old Nizmo cattledog shows a huge range of LSD's and all dimensions , Ill have a look in the next couple of days to see if the early centers (hemispheres) are dimensionally the same as S13-15 and R32 Skylines . The splines for the half shafts will need to be the same . I know R32 GTR's had 32 or 33 spline side gears whereas most R200's are 30 . Another odd ball is the R200 viscous center which has different length stub axles . Do some searches on R200 diffs , there's lots of info on US sites . I have an R200 LSD with a full set of active plates , in std form there was only one active set per side and thick spacers to fill the gap . Its not for sale yet but maybe at some later stage . To be continued .

All mine has is the two RS badges and the DOHC RS Turbo on the boot lid . Adequate . For eleven big ones you can have the keys .

I hate your posts Sam , I keep loosing sight of the text .................

I think its been said here before that RB S13's are no lighter than R32's and have cooling issues . If you can get one to replace the S13 , Nissan's done most of the work for you in a better handling and braking package . I'd put my money into an R32 if it was me .

Ghostrider , doing 180 on this and looking into GT3540R . I found out the BA Turbo does run TO4E 50AR comp cover but only pushes 6psi boost . I'm looking into the 60AR E cover to save some space over TSO4 covers . God knows which turbine housing , either .82 or 1.06 . It seems the 31 bottom end (87.5 bore) makes so much torque off boost that its not desirable to get much if any boost before 3200rpm . SK was telling me that this is low enough to do something on the expressways but not low enough to launch into boost at round town revs and speeds . I suspect this is why its important to get the static CR up to 9:1 . He was also saying most of the time the throttles are barely cracked open so with good tuning the consumption is very good . Cheers A .

If your getting good lighting fom the Tekamon's yours is the only one . I just had a thought , my inner lights have two adjusting bolts and they both make for up or down . If I screw them BOTH in or out the beams should move from side to side ...... :Oops: There may be a set of R30 camber adjustable strut tops up for grabs soon . Cheers A .

Chris I think you'll find ALL RB crankshafts are forged steel . I would always always go for the greater capacity . I think the RB26 head offers lots of advantages over built up 25's and often much cheaper , better cams , spings , inlet system and the shim type buckets - all std . HKS did make a cast split pulse T3 flanged exhaust manifold , with provision for an external waste gate , to suit the RB26 head . I understand they're not common but a few out there . Cheers A .