discopotato03

Really good thread people , also pleased to see a workshop with principles . Am going to start a thread on RB30 pistons as its O/T here . Cheers A .

Were you thinking of doing a detailed write up of the RB20DET wiring into HR30 ? I'd really like to know the finer details ie speed input , tacho probs etc . Thanks A .

B Man , simple test will tell the story . Run two boost gauges , one recording inlet manifold pressure the other exhaust manifold pressure . I bet I know which goes higher . Cheers A .

SK , does this also work for the 26/30 single turbo RB30 . Thanks A .

I'm pretty sure its a 56 trim GT40 compressor wheel .

Czy18e , I think its a bit like changing your final drive ratio from 4.1 to 3.1 and expecting the same acceleration . Same torque pushing greater load giving lazy acceleration . The principle of leverage ie the greater the radius the greater the torque for a given input works with radial inflow turbines as well . Does anyone know if Garretts GT3040R is available in 50 compressor trim ? I really would like to see back to back tests with the GT30R (3037) 56 trim and both GT3040's ie Garrett's 56 trim and HKS's 50 trim . I'm sure the turbine inlet pressure vs boost pressure would be equal with the 30R , higher with the 56T 3040 and a little better with the 50T HKS version .

DR30 struts also have 100mm spaced caliper mount ears . My plan is to find hubs with a different offset (inwards) redrill the stud holes (4) fit over hub and mount calipers .

Machg , mine will be an RB26/30 using a single turbo . My interest in the RB20 electrics is because its that loom I'll use with an Apexi PFC . RSX 84 does the R32 GTR/GTST booster go straight in or need mods ? Thanks A . P.S sorry earlier on , I gather by ignition you meant ignition on power supply . I re- read and I sounded a bit intense , cheers A .

Skyrine Dave I would be very suspicious of a flush 4 bolt exhaust housing , does not sound like propper GT style housing . If its a bastardised Euro flange T4 housing it will cost you performance . RS500 tried it and flicked it for the genuine housing , went MUCH better . All the ext gate GT housings should have the extended 4 bolt connical discharge plus the volute and nozzle shape are made to suit the paddle bladed UHP turbine . Cheers A .

There is a chance that Nissan developed optimal cam profiles and timing . In the cam charts I've seen the lobe center angles were different for the R34 .

I think the engine dyno train of thought is a valid one . Being able to repeat the same conditions over and over would have to be invaluable . I reckon on the strip there are too many variables beyond the drivers control .

GT3540R part no is 714568-0002 for .82AR exhaust housing version . The 1.06 housing version is -0001 . Cheers A .

Ok back again . Before I start remember these are my interpretations based on my research . With modern designs there will be a trim size (area of the inducer divided by the area of the exducer or major diameter of the compressor wheel) that gives the greatest pumping efficiency for that series of wheel . Going up or down in trim size goes away from ideal but may suit air flow capacity for particular applications . For example the old T3 wheels ranged in trim from 35 to 65 with the most efficient being around 50/55 trims . Plain bearing 3" or 76mm TO4S wheels from memory range from I think 48 to 60 trim or possibly 63 trim as Chris said . Their design application was Diesel engines which at the time required large volumes of air but not at high (by todays standards) pressure ratios or boost pressure . There are dozens of different varietys of TO4E wheels but again the highest efficiencies are at about 50 trim . Most of the variations seem to revolve around small trim differences and differing tip heights . Some of the early ones have cropped inducer blades I think to cope with centrifugal forces at high rpms . Both six and seven bladed TO4E's are made including the 57 trim Garrett motorsport special for the Group A Sierra . All the BCI-18C GT wheels are six bladed and up till recently were the ones specifically designed to work with the GTBB turbines and bearing cartrige . The 3" or 76mm versions (GT37 series) I've only heard of in 48/52/56 trims with 56 giving best efficiencies . The 82mm (GT40 series) I've seen in 50/52/56 trim . HKS's GT3040 has the 50 trim and I'd say this was done because they found the GT30 turbine a tad small so the smaller trim lesser but adequate flowing compressor needed less power to drive therefore less slip losses at the turbine and better spool qualities . I have no idea why Garrett do their version with the 56 trim compressor , maybe it suits some other application . What I would not do is put a .63 GT housing on the back of it to force it into boost on a 2.5 to 3L engine , even the best wheels will surge . Neither small or large housings can help it much because its not causing the problem . I have seen the results of some tests in the US (not by Garrett) comparing the GT3540R and 3040R . These were on 2L 4's with the 3540 giving more power , better transient response and lower turbine inlet pressure . Also not surprisingly it extended the rev range up as well . Where I fit into this is whether the 3540R will give me the response I want . If it won't the GT30R is probably too small though with a large exhaust housing at least it wont choke to death . Garrett do for HKS a GT3240 which has a GT32 turbine (whatever that is) that size wise fits in between the GT30 and 35 turbines . I've not been able to find out if Garrett use this turbine with GT40 compressors without the HKS price tag or if a housing is available with the T3 flange . Lastly to rpt the question , is anyone using the GT3540R (with the six blade BCI-18 compressor with a .82AR exhaust housing) on a RB30DET ? Result ? Cheers A .

His quote was , "The GT3040 has poor turbine efficiency because the compressor wheel is too big . I (he) would not use it on anything" At times he's backed up his views with experience gained on their gasflow test stands so I take him at his word . I don't know about new TO4S wheels either , I do know the better E wheels and ALL BCI-18 wheels use six full and splitter blades . Ages ago I put some time into comparing TO4S and BCI-18 wheels (covers off) and there are major differences . If you look at the exducer blades and the rest of the blade you will notice a much better angle of attack on the BCI-18's . The root of the blade is a better shape too . The blades are thinner than TO4S ones , they were designed to be a higher speed wheel with less mass and somehow greater mechanical strength (able to withstand higher rpm without flying to bits) . The original TO4S wheels were not designed for high rpms or pressure ratios . They were intended to be used with large heavy TO4 and TA45 turbines that could flow lots of exhaust gas without lots of revs . I believe the GT turbines teamed with GT wheels of similar OD's can move lots of gass with higher rpm's , less innertial lag and compact overall dimensions . Oops gotta run (work) To Be Continued tomorrow . Cheers A .

Cameron I looked into that one too , my Garrett contact (in US) said he would not put that on anything because of the difference in turbine vs compressor diameter ie 60mm and 82mm . In his opinion the extra work the turbine is asked to do to drive the GT40 compressor costs it turbine efficiency (slip losses at the turbine) . These are his opinions so I'm not desputing anyone elses choise . Its a shame the Garrett PDF cattledog does not show the GT3040R so we could see the turbine efficiency graph . It does show the GT35R (GT3540R) and the turbine efficiency is I think 74% which is quite high . Its a pity Garrett don't do a larger trim GT30 compressor to use with the GT35 turbine , I believe it would work like a GT28RS scaled up 50% . Cheers A .

Sounds like a very mixed up description . TO4B .50 AR comp covers are thin on the ground and too small anyway , rarely will you hear of a TO4B comp wheel described by its trim number . They normally are given a letter ie S trim , V trim , H trim . If its got eight blades its lag then surge city . If you must use TO4B wheels use only the six blade versions ie H trim . It sounds more like a T3/TO4E hybrid to me . With the turbine side look to see what kind of exhaust housing it has . If its a Nissan / Garrett T3 ie Z-18T or FJ20ET don't touch it with a barge poll , these used a turbine with a smaller major diameter than the Ford style T3 . They cannot develop the shaft torque required to drive TO4B/E compressors . OEM Garrett used TBO3 turbine sides for ther own TA34's wich is the correct name for the T3/TO4E factory hybrid . The TA34 turbines are the ones everyone loves to call Sierra Dash 1/2/3 or Turbonetics stage 1/2/3 . In a propper Garrett "Five Bolt" exhaust housing they work reasonably well . You will note that the TA34 turbos did not use large trim TO4E comp wheels ie 50/54/57/60 trims because they knew they were light on turbine power . I once saw lists of 40 and 46 trim versions . Fred from Turbo Logic (Port Kembla) said he used to sell smaller trim versions of these to the RB20 brigade and they boosted from 1800 to I think 7000 . There is a .58AR turbine housing version which should be a torque animal and a .63 AR version with the largest turbine trim . If its none of these I'd reckon that someone is selling you their problem . Be VERY wary of Joe petrol head's custom job . I can't say that everything Garrett's ever made is brilliant but at least they try with propper test facilities . The biggest drama is that lots of parts interchange but only the CORRECT combination gives a worthwhile result . I believe this is why there are no spares available for the GTBB turbos . Why would anyone pay squillions for HKS spec Garrett GTBB's if they could assemble there own .

Tell me if I'm wrong but is someone trying to cut and shut RB25 manifolds with GTR plenums ?

I was thinking along the lines of the GT3540R (a real one not the seven bladed TO4S piece of crap) and a REAL GT style .82AR exhaust housing . I would like to see positive pressure at a bit over 2000 and .8 to 1.0 Bar from 3000 to 6800 . So is anyone using the real one ?

Has anyone tried this combination that can me the result . Thanks A .

Sydney Suspensions previously known as Heasmans Princes Hwy Sydenham .

Have you ever noticed that these spaghetti leg fabed manifiolds (the locally made ones) look like a nest of snakes ? I have to wonder if the contorted angles that some of the tubes use when they reach the collector are much good . Some US designs merge the primaries into a single tube which then feeds the turbo , the WRC engines seem to do this too . At least then the primaries are facing the desired direction and not wasting gas velocily and heat energy trying to oxy the collector off . On a six cylinder engine I recon the split pulse (123,456) would be easier to produce (than spaghetti special) and give better response and less reversion , also access to the turbo is better . HKS do cast iron manifolds for RB20/25/26 (single turbo) which are along these lines and usually have provision for an external waste gate . If you can find one of these it would have the advantage of cast iron (less chance of cracking/warping) a guaranteed fit and the opportunity to use a higher performance waste gate system later if you need to . Also if you can do this part for reasonable money it has the potential to open a lot doors to future upgrades . Its no problem to make a cover plate for the external gate mount if you need to use an integral one for cost or cop reasons . You'll stand a better chance of convincing Joe average Wood Duck that its factory rather than the scaffold and ****y poo custom job . Just my two paseos worth , cheers A .

Fair enough , I just keep thinking that IGN PWR is available at the firewall connector . Mind you I have not got my hands on an R32 RB20 engine harness or wiring diagram to see how the R32's tic . I gather it all goes in with the MR30 X member and R32 brackets plus minor mods to gearbox mounts/tunnel hole . Is it a shit fight with the console ?

I don't really understand the ignition conection to computer problem , surely this is a plug that plugs into the ECU . The coil loom should plug via the ignitor to the engine harness to access the ECU . All the harness should need from the existing loom is power supply and signal access to ECU and FP relays . The FJ20 version also has the water tmp sender up the front of the engine and wired through the engine harness to the firewall connector . It also has signal feed to its unique idle air and EGR vacum pulse soleniods . The only other thing it has is FPR switched power to the cold start air regulator valve . All these things can be tapped into at the main engine harness connector on the firewall . All R30's I've seen have that connection and all engine controll wiring in a fuse/relay box next to the brake booster . What was in your car that required the alterations in the cabin area ? Cheers A .

I still think the complete 26 top end is the go . If you look at RB20/25/26 heads on the inlet side you'll find numerous detail changes to suit their application . I believe the bolt patterns are different because of access to the fasteners to assemble it all . As for inlet system development I'll bet any money that Nissan put more into developing the RB26 inlet (as a package) than GReady ever could . Cheers A .

Has anyone tried to use the aluminium RB26 engine mounting brackets ? They are light and strong but don't know if suitable for R30 install . Cheers A .