discopotato03

Please excuse my ignorance but can't the Rbxx loom be spliced into the engine harness connector in the middle of the firewall ? This would be my plan . 1) Mount RB computer in std location and feed loom from engine bay to ECU and connect . 2) Plug RB loom plugs to engine sensors . 3) Cut plug off MR30 engine harness to graft onto RB loom to supply power and signal to EFI and Fuel Pump relays . Things I dont know about RB's are need speed sensor input ? need map sensor as well ? The FJ20's loom has a plug not too far from the main ECU interface . I'm not sure what its for or if RB20DET looms are like this . Appart from The RB ECU and loom to the firewall I would not expect to have to do any wiring inside the car . Are my ideas valid or have I missed something ? Cheers A .

Lots of lag and exhaust restrictive . Typical bush bearing TO4E/S T3 Hybrid . For what it is its not cheap . Only practical application is bolted to "She's fully sick bro" type car .

Sounds like a lot of money to spend on a road car . I'd have thought the std rods with good bolts and a bit of prep work should be able to take more power than most will have traction for , plus the price is good . I'll ask today if its possible to gas Nitride steel rods . Has anyone use oversized bolts in factory rods ? SK , when these rods let go which part throws in the towel ? Cheers A .

Fair enough , I can't understand why anyone would bother to build RB20/24's when RB25's are cheap to buy and have much more interchangability . But if it came that way......... Cheers A .

These GT30's you mention dont have it so bad because the larger (higher flowing turbine) is closer to the correct balence of exhaust gas flow vs compressor airflow . In a perfect turbo world your engine would have equal boost pressure and turbine inlet pressure (back pressure) across the cylinder head . This is difficult to achieve but the major advantage is beating exhaust gas reversion back into the cylinders when both (or all four) valves are open . When reversion happens (ie exhaust manifold pressure is higher than inlet manifold pressure) HOT spent gasses flow back into the cylinder to mix with the cooler inlet charge to pre heat it and polute it . The whole idea of efficient turbo compressors and intercoolers is to create airflow that is cool or dense which per unit volume gives a higher weight or mass of oxygen . If it gets pre heated again you've undone all the good work and are MUCH closer to piston crunching detonation . Spent exhaust gasses don't burn very well or contribute to power production either . Another downer is that if what power the engine developes is partially used to push the exhaust gasses out of the cylinder through restrictive manifolds/turbines/housings/exhaust pipes its less power to drive us down the road . The simplist way to look at it is forced induction tries to turn the engine into a larger capacity one with larger capacity exhaust flows . Back to the "GT30" . The honest retailers will tell you that there about 19 or 20 different turbo's using that UHP 84 trim GT30 turbine . If your curious like me and spent months digging up turbine and compressor flow maps you also would have noticed that identical turbine and housing combinations show different efficiency levels depending on what compressor and cover are hanging off the other end of the shaft . I put the question to a Garrett production engineer (and petrol head) I know of in the US why ? He said large capacity compressor wheels need lots of shaft torque to drive , they have more bite into the air they screw through . If the work needed to drive the compressor is realistically more than the turbine wants to give you get exhaust gas slip losses through the turbine . So with the turbine turning slower than the exhaust gas wants to flow to get through it (all in a vain attemp to drive that great galoot of a compressor) the restriction sets in and turbine inlet pressure climbs . Remember I said the more and thicker blades a compressor wheel has the lower its efficiency . Well these things as well as outdated blade shapes give a TO4S wheel more bite (and resistance to turning) than later designs . Most of you will have noticed that propper GT turbos claim quite high power outputs for their size particularly when compared to old TO4's . With todays modern turbos a lot of effort has gone into reducing markedly the rotating innertia of the turbines and compressors so that less exhaust gas energy is required to accelerate them . Their open blade forms make them highly efficient at higher rpm's than the old dinosaurs so they don't need to be physically huge to move lots of air and flow lots of exhaust . Compact is good in overcrowded engine bays . So we have light weight bits that are easy to accelerate and pump efficiently with low exhaust gas restriction . I'm sure the annular contact ball bearings were put there purely because Garrett knew the old bush bearings and thrust plate could never survive the extra rpm's , not reliably . I think the GT30/TSO4 was early in the days of the Garrett GTBB when most of the development was aimed at the turbine , later evolutions used superior compressors that pumped cooler air and required less shaft power to drive . They also work better at higher pressure ratios than earlier designs . Diesel engine designers are pushing for higher and higher boost all the time so compressor and turbine efficiency becomes more critical to the success of the package . Garrett has been developing better internals for turbos which should be appearing soon , first for diesels and eventually petrol engines . Hope some of this helps A .

Correct me if I'm wrong , the turbo you mention is called (by some) GT2540R . This monstrosity has a major imbalence along the same lines as HKS's GT2540 only worse . The drama (aside from the stone age wheel) is that the turbine is too small to power the compressor wheel . Is is imperative that the balence of compressor wheel to turbine wheel is close to ideal . The yanks made a rough rule of thumb that the major dia of the turbine should be within 15% of that on the compressor wheel , in the above case 48 trim TO4S= 76.2mm and 76 trim NS111 turbine = 53.8mm . In this case it comes to approx 71% . The real world experience of this is that you need higher exhaust gas speeds to drive the compressor into boost than would be the case with a properly speced turbo . So more revs to get it going and more exhaust restriction once it does . Hence lag in the first half of rev range and overheated detonation friendly EGT's in the second half . Talk to Brett from GCG , his customers are getting as much power with the GT28RS (60mm comp wheel in TO4B cover .86AR exhaust housing with same NS111 turbine) as those with the GT2540R . I see this happen all the time , people look at the compressors performance potential a judge the turbo by it . What people really really N E E D ! ! ! ! to do is look at the turbine and housing FIRST . This area is the main bottle neck and has to be sorted first . I realise its difficult and expensive to play with non std exhaust manifolds and or waste gates but if that what it takes do it . Am running out of time and fingers here but also note another rule of thumb . The more blades and thickness of blade section a compressor wheel has the lower its pumping efficiency . Any extra work a turbine has to do shows up as lag or to use the correct term boost threshold , transient response suffers making the engine feel like a choked up torqueless dog . chow A .

This is because only the REAL GT30's , GT35R's etc use the REAL GT compressor wheels . Turbo shops are only too willing to sell you the TO4S versions because they're cheaper and OEM on many DIESELS . Look at it this way HKS have NEVER used TO4S wheels in their range period . This is not to say that only HKS spec GARRETT GTBB's work , only that they don't like/want stone age compressor wheels either . As a point of interest TO4S wheels were available in the mid late 1970's , the BCI-18C (six bladed wheels) are about 15 years newer technology and also a generation later than the TO4E series . When the demand is high enough for the right turbos thats what the turbo shops will sell , till then find someone who will import them and reap the benefits .

Yeah same here , the FJ's a bit rattly but starts every time and only gets normal maint . Its often parked next to the good FJ but I'm determined to put my time and money into the "Masey Furgeson" and not be sidelined . LOL Cheers A . Roy would it be worth your while to buy an early RB25DE , fit DET pistons and sling it in ? Its a cheap way to get into an engine with more potential than an RB20 .

I started this thread so I'll put it to rest . My original drama with the RB30 DET was clearence of the inlet manifold and the throttle body facing the wrong way . I guessed wrongly that the RB26 head and inlet system would cost a motsa . Since the RB26/30 have the same bore size and coolant passages getting the 26 head on a 30 block is easy (don't forget larger dia head bolts) . So for what I consider very reasonable money I bought a complete RB26 head/inlet system . So in other words I have the best performing factory option which solves the above probs as well . If I had grafted the GTR inlet system onto an RB25 (R32) head along with the GTR cams and springs it would have cost more for less performance . Also not having a RB25 bottom end to trip over helps . Cheers A .

For a good read search Garrett_Cat 7 17 13

But then again an Audi RS6 would be nice ....................

SK do they have a prob with RB30DET's not being a factory option ? Most are probably not aware if it looks factory and evaprative , breather etc ancilliaries are connected and working . I doubt many engineers would witness the computer , if you tell them its factory that's what the report will state . Cheers A .

Go get em boyz , its about time we had good programable management based on OEM . Cheers A .

Phantom , it sounds like your GT3040 has the seven bladed TO4S compressor in it . I speak from time to time with a production engineer from Garrett (Calif) who also hapens to be a petrol head and hates the "S"wheels . I'm thinking of starting a list of known Garrett GTBB turbos and their part no's so that all can identify what they have or order what they want . Your RB30DET sounds exactly like what I want from mine . If this can be achieved with RB26 injectors I'll be rapt . I've also wondered how the GT30R would go with 3L and up to 1Bar . Does the waste gate adapter allow the gate to hold boost all the way up . Also is the use of externals defect territory in NSW / VIC / SA ? I would have thought if it had no leaks and merged before the cat and engineered the over zealous "Eco Nazis" have no say . Have fun A .

G'day SK , where would Negun be ? The Nizmo FPR . Are these rising rate (yuck) or constant rate as like std but adjustabe base rate . Does Negun whoever they are sell the Bosch 044 pump . Only ones I've seen go for about $450 , typical ? Cheers A .

Chris , I downloaded this Ok but winzip keeps telling me that it won't view properly . Then I get letters and numbers that don't make sense . Any idea what the problem is ? Thanks , A .

My parts collection has started . For those with RB's in R30's with std engine harness , was it difficult to interface . That large connector on the firewall , can the RB loom be modified to pick up power here and controll the relays etc etc . I was hoping to pinch an MR30 engine harness plug and rejig the RB loom to plug and play . Thanks , A .

SK are the compressor wheels on the "Hi-Flow" cores seven bladed , well seven full and seven splitter (lower) blades . If this is the case then the wheels must be TO4S and hardly a high performance item . Turbonetics and Innovative cores seem to be mainly old school turbos with the annular contact ball bearings using ceramic ball dividers . The results here in Australia have not been good due to bearing failures . It is wrong to believe that all the performace gains are from the bearing system . With Garretts GT series a lot of effort went into reducing the mass of the rotating assembly particularly the turbine . If you look at the turbines closely they use (mostly) less blades of thinner section and a greater tip height or B width . You could also call this the inducer section , some have described them as open or paddle shaped . Now take a look at its matching turbine housing from the cores side . The channel (nozzel) section that feeds into the turbine blades is generally far wider than T3/T4/std Hitachi (RB 20/25) turbine housings . Now turn it around and look down the turbine inlet (into the mounting flange) and note the cross sectional shape ot the passage . Most GT housings have a pronounced capital "O" shape though parallel vertical sides . Compare this to earlier housings with the narrower chanels and a more "V" shaped volute section . You don't have to be Einstein to see how Garrett has achieved quite high gas flows through compact turbines and housings . Both turbines and compressors are mechanically stronger meaning that they can withstand far higher rpm's without disintergrating . Also Ahh32 the GT2530 does not use the old school T3 compressor wheel . It is a 63 trim 60mm GT wheel . There are three very closely related wheels in this family . The best from an efficiency point of view is that on the GT28RS , 62 trim with slightly greater exducer tip height which gives a few points heigher efficiency in the TO4B cover . The Skyline GTR upgrade GT28 turbo uses a wheel fractionally smaller (inducer) compared to the 2530 . I think they are 47.2 , 47.5 , and 47.7mm . The HKS GT2530 has been around for a while and wheel development is an ongoing thing .

By all means have a lovely time with the calculator compressor flow maps and reams of paper . If you do some searches here under Hi-Flow turbos you should get a feel for what the guys are using . Chow A .

Fellas I'm no expert but most of the serious efforts I've seen used billet cams . Otherwise they got someone like Ivan Tigh to weld the lobes over the nose and re-grind a new profile . They specifically left the base circle alone so not to alter the geometry . In other words when the valves are closed the inverted buckets are where the designer intended them to be . I dont even want to think about these hydraulic bucket heads and non std base circle cams . Thankfully no sensible cam grinder would do this as they would realise the problems . It sounds like the only guaranteed result comes from aftermarket RB20 cams . If I'd gone to the effort and expense of buying/fitting RB26 cams that didn't work and were changed back , maybe the aftermarket items were not so expensive after all . Cheers A .

Angry , its no secret that old TO4B series compressor wheels are truly archaeic . The eight bladed versions are definately Diesel application . There are a couple of six bladed TO4B wheels that work HEAPS better in petrol applications . The most common one (maps anyway) is the H trim . These need less shaft (turbine) energy to spool up at lower exhaust gas speeds and are less prone to surge at higher engine and turbine speeds . You probably need to also look into the TBO3 and TA34 range of Garrett turbos . From memory the TA34's are a factory hybrid T3/TO4E with integral waste gates . They use different exhaust housings and turbines to the old Nissan/Garrett T3's . Fred from Turbo Logic once showed me one of these and claimed that the RB20 boys loved them . I once had lists of these from the net but threw it all away when I got the GT28RS . Honestly the BB turbos are way to go . Its living proof that turbos don't have to be physically huge to give breathtaking performance . Cheers A .

More HKS turbos . For those wanting an equally good turbo buy the Garrett GT28RS . Same turbine , nearly identical comp wheel (fractionally greater tip height) in TO4B cover . Unfortunatly its turbine housing is a .86AR (good) with the T28 flange (not so good) . It may be possible to order it without the turbine housing and buy the HKS .64AR T3 flange housing . HKS sells their housings separately , see Brett at GCG . ATP Turbo in the US also sell a turbo called GT2871R which surprisingly is nearly identical to the HKS GTRS , in fact it can be optioned with the same compressor . On the outside it looks the same as the GT28RS . Both of these turbos are really crying out for that .86 Ar turbine housing so it may be worth trying to adapt between the T3 flange (manifold) and T28 flange (turbine housing) . I used the GT28RS on an FJ20 2 litre with great success , positive pressure at 2000rpm and a linear rise to full boost at about 3800rpm . STD actuator is I think about .8 Bar . Buy Garrett , no glits no surcharge same quality . Cheers A .

I've not seen fuel line fittings on aftermarket rails . I have seen odd ball EFI hose sizes though , I think it was 7 or 7.5mm . A problem may exist in metric and imperial hose size . I suspect there's plenty of imperial hose on metric fittings . One example I know is that FJ20 hose tail injectors need the 7 or 7.5mm to seal properly under the clamps . I definately don't like rising rate fuel pressure regulators , to me this is a band aid for undersized injectors . Also running the system out of regulation (ie non constant head of fuel pressure over manifold pressure) creates tuning difficulties . In my opinion the use of factory style hose and fittings (of good quality in good condition and correct size)) should work . If the aftermarket rail has some extra function that works buy it . If not the only the factor of lightening your wallet will make it go any better . Cheers A .

This stuff about the GT3040's . Ages ago I went to the HKS USA site to look at turbo specs . Has anyone noticed that the HKS spec GT3040 uses a 50 trim GT40 82 mm compressor wheel ? This series of wheel was available in 50,52,56 trim which varies in not only air flow but in the shaft power required to drive it . HKS through Garrett Japan probably tried these and others to tune its performance to suit a specific requirement ie high performance petrol engines . Turbos of this size and larger eg GT3540R's are found in many Diesel applications . Remember Diesel engines gererally operate over a far narrower rev range than petrol and the exhaust gas temperatures (EGT's) are significantly lower . Much of Garretts bread and butter sales are OEM Diesel huffers . Ok so Roger Racer decides to open a turbo business selling the GTBB's . He can slap housings on diesel spec cores (CHRA or centre housing rotating assembly) to give (to some) acceptable results with these cores . BUT they will never be as good as a specifically designed unit . Firms like HKS have far greater resources to contract Garrett who specialise in this field . As I said before it is possible to get close to and sometimes identical combinations to HKS . I have not researched enough into GT3040R's and GT3540R's to see if Garrett sell a 50 Trim GT40 compressor with the GT30 or GT35 turbine . As for these high flows I can guarantee that putting the GT30 turbine in a housing designed for a low tip height small diameter ceramic turbine is a disaster . The nozzle shape and volute form are all wrong and turbine efficiency is up the creek . If you can't get the turbine / housing combination right nothing you can do with compressor will fix it . With the above mentioned Hi-Flow to a degree you are paying for the fitting convienence with excessive turbine inlet pressure heat and boost lag . RS500 got his 3040 working properly only after fitting a PROPPER GT30 style turbine housing made by Garrett for that turbine . Lastly HKS turbine housings . They did have some of their own made because there was no Garrett item to do the job , for example no OEM requirement for a GT30 turbine housing with a T25/28 mounting flange . Obviously Nissan were not about to use them as standard on SR20's or RB26's . Just for the record I think Brett sells these (GT30 .73AR T28 Flange) for probably half that mentioned above , but don't quote me . The crux of all this is no one wants to pay for the HKS tag . I point blank refuse . Take your time and do some research . Chow A .

SK , have you tried the GT30R as a single on an RB26/30DET . Could this combination be the perfect torque spread animal in the same vein as GT2530's on an RB26 ? Thanks A .