discopotato03

That GT2871R still uses the 54mm NS111 turbine which could be getting a little small for 2.5L . ATP are also doing what they call 3071 waste gated turbos which is a poor description really . What they are is the same core as a HKS GT2835 , the same compressor wheel (GT35 compressor = 71mm) as the GT2871R but different turbine . Turbine is an 84 or 90 trim in 56.6mm and is actually a ground down (by Garrett) GT30 turbine . Maybe you should ask ATP if they will sell you the GT3071 waste gated version with the .63 T3 style exhaust housing so it will bolt up . Another option is to use the HKS .68 or 87 T3 flanged waste gated housings on a GT30R or propper GT3071R . If using ext gate you could lock the integral gate shut . This is an expensive way to do it but should bolt up and allow a little more potential .

Interesting Joel , I want to use a higher CR like 9.0 and am curious to see what sort of timing such an engine uses . I'm aiming to use a GT30R or at least a GT30 turbine to minimise exhaust restriction so as to not resort to low timing numbers on boost to prevent detonation . what do your timing figures look like Joel ? Thanks A .

That figure of 426hp was with a GT28RS and ATP's own custom exhaust housing . The particular housing is a hybrid , it looks like a 5 bolt Garrett on the outside but internally its more like a GT30 style . It also used an external waste gate , a lot of effort was expended to make the EXHAUST side wok well . I wonder what Enthalpy from Honda-Tech.com thought when he read this ..........................

What ATP calls a GT3071R dosen't have a HKS equivalent . It's a GT30 turbine with a 71mm compressor . What HKS calls a GTRS has a GT28 turbine and the same 71mm compressor . The same core in ATP speak is GT2871R . The 71mm compressor wheels are GT35 series in Garrett speak . Thats why when you get the 35 on the end of GT2835 . So as to not confuse , the HKS 2835's use a ground down or factory cropped GT30 turbine from memory 56.6mm in 84 and 90 trim . These are as large as Garrett go with turbines in GT28 style integrally gated exhaust housings . ATP are also selling these now . For reference : Compressors GT40 = 82 mm GT37 = 76.2mm GT35 = 71.1mm GT30 = 60.1mm

You'r better off with a GTRS (HKS) or a GT2871R (Garrett and cheaper ) .

The point I'm making is that just because HKS don't sell it any more dosen't mean it CAN'T be bought off Garrett or some supplier of . Give me an example of a HKS turbo that can't be replicated and I'll show you how it can . 2540's and 3240's could be a challenge but better things are available anyway .

I am trying to find pictures of the exhaust housings of these turbos , particularly the 3037 Pro S . They are available from HKS in .68 , .87AR and T3 mounting flange . The exhaust outlet is called GT Pro and may be the same pattern as the turbos on RB20/25's . If anyone has any details or pics of these housings could they let me know . Brett tells me they are only available through HKS and cost around $800 . Could be a way to go for bolt on to RB's with GT30R turbo . Thanks A .

I don't know anything about this one . Can someone tell me the specs like bore , stroke , journal sizes , rod length , gudgeon pin diameter and block height . If it has a forged steel crank and suitable dimensions it may be useful .

Could you please measure the back diameter of the compressor wheel , need to know if there 76 or 82mm . Some say the compressor cover is .50 TO4E . Cheers A .

High rpm engines do really need higher rate springs to avoid valve bounce . Were you thinking of doing the RB24 conversion ?

Think again , ALL R33/34 RB25DET's came from Nissan with a Ceramic turbined Hitachi Ball Bearing turbo .

Roy I think the most success comes from extra lift rather than duration . Back in my Mini days I read David Vizards books which go into a lot of theory about heads and cam profiles . My interpretation is that generally the greatest port restriction is the valves themselves . Four valve heads breathe better than two valve ones because of the increased valve area . In standard form cams for four valve heads are pretty soft because they have extra valve area and tame profiles give good spread of torque over a wide rev range . With cam lift obviously a high lift cam has more average off the seat valve lift than a cam with the same timing but less lift . Full lift is only for a very short time so average lift probably dictates how well it all breathes . I see long period cams as a means of extending an engines rev range upwards , the higher it revs the less time is available to charge the cylinders on the induction stroke so holding the valves open longer means better filling . Ultimately long period cams have more overlap which leads to reversion at low revs and means rough running . The trapping efficiency is not there with longer period cam profiles . It is there with shorter duration profiles and the extra lift (average lift) from faster opening valves gives good breathing and good operating characteristics as well . There are people around like Ivan Tigh who can weld up some production cams and regrind them to suit custom needs , its an expensive process but may result in the ultimate short duration high lift RB cams . Cheers A .

I would not loose any sleep . Garrett do two CHRA's very similar to the 2530 , one is from the GT28RS (better 60mm compressor) and one called the GTR upgrade CHRA . In fact garrett do a similar if not identical turbo to the 2530 for direct fitment to the RB26 . The GTRS is only badge engineering on a 2871R (see ATP Turbo.com) both are streets ahead of the HKS GT2540 which was garbage anyway . Any one with tap into HKS will find they had an exclusive tie with Garrett to produce certain combinations of compressor and turbines . This would have had a sunset clause and competition issues would have stuffed it for HKS . So you'll find all these things being sold round the world by Garrett (who makes them anyway) for less than HKS thievery . Cheers A .

Can we have some pics of your turbos exhaust housing / dump pipe please . Thanks A .

I think you'll find most competition oriented devices have side effects on road cars . I've never run multiplate clutches but have asked those who have on competition cars . Until recently I thought they were all about multiple small diameter friction plates to increase grip and reduce innertia or the flywheel effect . Another advantage of the things is the multiple plates have their own hubs on the gearboxes input shaft sharing the load , compared to a single plate single hub . By the sounds of things the down side of using them in road cars is cost and the rattle that the drive plate makes at idle . Sydneykid did mention recently that one of the aftermarket Jap mobs was doing one that didn't rattle so it must have some kind of pre-load spring . I know of at least one import GTR that had its removed for a more conventional clutch because its a road car . Cheers A .

Actually Pat it works the other way . The thermal mass of the bearing housing is quite small and with water in it it never gets red hot . With todays iron alloys the heat to the bearing housing is not a problem . Its keeping the oil temperature below the cooking temperature that is the issue . The exact reason why car manufacturers do it is so that turbo engines can be shut down like any other engine and not have heat related turbo failures . Manufacturers put long waranty periods on new cars and todays drivers don't want to be bothered with tiresome idle down antics . Another thing to think about is todays lean burn engines exhaust gas temperatures are highest in highway cruise mode . Full load and boost EGT's are significantly lower .

Affordable longer studs are standard on the R31 GTS and not very expensive , for really long studsyou may need to look into Nizmo bits but very expensive . I wasn't looking but would not like to crash a car with wheel spacers and get caught , Insurance will wipe its hands and the relivant Traffic authority will throw the book at you . Definately not a legal mod and easy to spot if you know what to look for . The right wheels are out there and give handling advantages over incorrect offsets and excess negative camber . Up to you .

Thanks ookami , off topic I know but I need to see one as the T3 flanged GT3037 Pro S probably uses a similar integral gate version of the housing and dump . I've been told that on race cars the water cooling is sometimes deleted to reduce complexity and long term reliability devices are not needed .

Water has a high thermal mass - it takes a lot of energy to boil it . If the turbos bearing housing can be kept at or below 100deg C the lubricating oil flowing through it will not burn or solidify killing the bearings . This is most likely to happen when the engine is shut down hot , the bearing core hanging off a potentially red hot exhaust manifold and turbine housing can roast any oil present . Contrary to popular belief many OEM water cooled turbos don't have water pumped through them but have one water fitting higher than the other to allow thermosyphoning . It does not take much water volume to maintain a safe temperature in the turbos water jacket for the 3-5 min after shut down that is critical . When I fitted the GT28RS to my old FJ20 I used the blocks drain plug hole for the water inlet and drilled / tapped the head behind the thermostat for the hot water outlet . After shut down you could hear water boiling in the turbo , the bubbles rising up the high pipe , out through the thermostat and rad cap into the overflow recovery bottle . Obviously the boiling water was being replaced by cooler water lower in the cooling system untill the bearing housing got down to or below 100 C . I think all turbo SR's and RB's had factory water cooled turbos so the inlet and outlet should be there . If you can use it because its cheaper than fried turbos . Can you post pics of the exhaust housing side of your turbo please , I'd like to see what sort of dump pipe pattern the HKS GT Pro housings use . Thanks A .

Always dramas putting big boots on strut cars with zero scrub geometry . Have you noticed that most late model cars have rims with deep hub sections and spokes that come out a long way before joining up at the outer part of the rim section . Z32's , some R32's and S14/15's had fairly unique wheels to cope with this style geometry and wider four piston brake calipers . There is some serious grip to be had with 205 tyres though , need the right tyres and suspension . I'm using custom wound 185 in/lb front springs and HDT V8 spec Bilsteins front with 195 in/lb rears and std spec Bilsteins plus std roll bars . My caster rods have nolathane front bushes and front strut spherical joint tops . Next mod will be adjustable caster rods and just about as much positive caster as I can get . Cars of the R30 era dont use much caster (compared to current cars) and what tends to happen in hard cornering is this . For a car set up with static negative camber the body rolls away from the inner radius but the camber remains negative meaning the contact patch of the tyre is reduced to the inner part of the tread . The extra positive caster changes the camber from negative to positive on the inside wheel and puts more of the tyre square to the ground . This gives more cornering grip better turn in and more selt straightening . The only disadvantage is higher steering effort but pwr steer handles it ok . Cheers A .

I forgot to add Nissan main crank bearings are up to the task but the big ends can suffer . Most seem to use Nissan mains and Nizmo big ends or all ACL race series bearings . Again check this as I am no Swami Guru and get it wrong sometimes . Cheers A .

1FSTKR it all depends on the intended use of the engine and the budget you have . If this thing is a flat out drag engine it could just about use the T78 . If you look at Garys (SydneyKid) posts it appears there are two levels of build . 1) 450 odd ATW HP: Std RB30E block crank rods pistons water pump and maybe oil pump . RB30 water pumps are designed to move lots of water at relatively low revs , most are using RB26 pumps wich allow you to extend the rev range upwards without pump cavitation . The RB30 water pump is the cheapest new one but plenty of good 2nd hand RB26 ones around . All the R32 series and early R33 RB25 oil pumps fit the RB30 crank . I am using a good 2nd hand R32 RB26N1 pump , the only diff between this and std RB 26 is the relief valve spring tension . The RB30 is the only block without piston oil squirters - best solution is to ceramic coat your piston crowns . Using RB30E (NA) pistons with RB 4 valve heads gives around 8.2-8.3 CR , using RB30ET (Turbo) pistons from memory gives 6.8-7.0 CR . 4 valve heads are around 63-64cc chambers , the 2 valve heads were less and gave 9 and 7.8 CR . For engines in this power range 8.5-9.0 CR makes the engine crisper , (more torque off boost and better drivability and fuel consumption at part throttle) . Some say they're achieving this by using Arias forged high top pistons , others are using JE VG30DETT pistons (larger 22mm insted of 21mm gudgeon pins and + 1.5mm or 87.5) decking the block around 1mm to get approx 8.6 CR . More can be had by more decking plus a smidge off the piston up to around 9.0 CR . It is VERY important to achieve 25-40 thou piston to head clearence to get effective squish or quench to lessen the chance of detonation . 25-30 thou is considered very good . RB26 heads use larger diameter bolts so block holes to be re-drilled and tapped . RB26 440cc injectors supposed to be good for 400-420hp . Using cast Nissan pistons will require the timing and air fuel ratios be correct because if they are detonated they break ring lands . 2) The 900hp version needs good rods ie Carillo , better valves retainers springs cams rod bolts head fixings main cap studs and nuts and probably an O ringed block . I think all this is aimed at coping with higher rpms and power loads . Some are using 86.5mm pistons to leave a little more meat in the block . I have been advised not to use the RB26 N1 water pump as it is designed not to cavitate in constant high rev environments but does not move enough water at road speed revs to cool effectively . This is only a brief overview and I think it is correct but you need to be sure so double check . Hope this helps cheers A .

My RSX wears 15x7 and 15x8 Volks , these are very light for their size and help bring the unsprung weight down . Not sure how 11" rims would go on the back , will make tyres expensive (good ones ) . One thing to watch with semi trailing arm IRS is the camber and toe changes through its travel . If you can reduce the body roll to a minimum it helps . What rim diameter and rubber profile were you looking at ie 265 50 16 ?

I did try that once with eratic results . I'm not sure if the waste gate actuator is designed to run at lower that atmospheric pressure which you get in the inlet manifold at part throttle off boost . The danger is that the turbo could be running at higher boost than the manifold pressure indicates ie flow losses through intercoolers , leaks etc . Plenty of production cars can boost against a partly closed throttle so if the manifold pressure is below the actuators spring rate the turbo can be worked harder than intended . However if you take the signal from the turbos outlet you can be sure the pressure your regulating is what the compressor is putting out . Would I be right in assuming R32GTST's don't have electronic boost control and R33 GTS25T's do ? Cheers A .

RB31 power , my opinion only , I would drill and tap the RB 25 comp cover and use the compressor discharge pressure as the wastgate actuator signal source . Using inlet manifold pressure signal can make the wastegate do strange things like opening and closing very quickly . Those Hitachi turbos have enough problems with ceramic turbine failure (particularly with increased boost meaning higher shaft rpm's) so throwing extra transient loads on them only agravates the probs . My opinion only , not interested in turbo mods that could lead to failures , the cost and inconvienence is not worth it . Cheers A . P.S My prefference is the early RB25 turbo with the aluminium compressor wheel , seen too many shattered plastic ones .