discopotato03

It would just look like a std IW GT3071R but with the B cover on it , in fact if you used the B housing and adapter ring off a GT2871R 56T it would all bolt togeter with factory parts and no cartridge alterations . Thinking about it you could vew this 2nd variation as a scaled down XR6T style GT3582R - because they use the next size down comp housing ie T04E instead of the usual T04S . Don't quote me but I seem to remember reading about B covers on 3071R's I think on EJ turbo engines . Most Rex engines (all single scroll ones) have a dogs breakfast header system and it can make healthy turbos laggy on them , possibly the smaller housing brings the air speed up a little faster for a given flow rate and helps pull the bottom end up . As per HKS , they DID have 52 and 48T compressor options on 2835's and 3037's - just not in their Pro S turbos . What both types of Pro S's did get was a custom port shrouded comp housing and that makes a difference if the comp trim is big and the turbine housing A/R is a bit limited . The full height compressor blades can cycle air out the ports so unload the wheel a little and not over feed the engine to the point of surge . Cost would come ito it too . The possibilities .

To be sure if you can post pics of your turbo (front/back/side/ID Tag) I should be able to identify it for you - well at least which series anyway . There is a lot of variation in what gets called "T04S" or "T04R" . Normally T04"S" means the 3" or ~ 76mm 7/14 blade T04S series compressor and T04S 0.70 A/R comp housing on the front of a garden variety T4 cartridge . T04R as in what HKS used to sell as a T04R turbo just had the "R" or 84mm 63T BCI-8D compressor wheel fited to a T04S turbocharger . I think HKS may have been cropping the T04 P trim turbine at one stage but thats nothing any reasonable turbo mob couldn't do . I used to have a couple of pics of the HKS spec TA45S and if I can find them I'll post them . A .

It's not real hard to do , whip off the comp housing and jamb nut and pull the turbine out . Replace with a GT30 one , balance it and bolt on the GT30 housing . Whenever I asked he said you're only paying for one turbo just not sure if he's charging for the balance . The T04B comp housing is a bit smaller than the T04E one so probably won't need the spacer to get the comp housing off the exhaust manifold . http://www.turbobygarrett.com/turbobygarre...R_472560_15.htm http://www.turbobygarrett.com/turbobygarre...071R_turb_e.jpg

I reckon if I was doing a 3071R now I'd be asking Brett to grab a GT2871R 52T and swap in a GT30 turbine and bolt the 82 IW turbine housing over the end of it . A bit more compact with the T04B compressor housing , a bit more responsive with the 52T compressor and low pressure with the 82 housing . Not the cheapest option nor an off the shelf one . A .

The thing is that the waste gate is regulated by boost pressure not exhaust manifold pressure and a waste gate would only begin to regulate gas speed once the target boost pressure was approached . I can see scenerios where people could put an 18-20 pound spring in a big external wastegate and wonder why the turbine inlet pressure went stratospheric . It's because until the gate cracks open (signalled by boost pressure only) it achieves SFA so not a very effective exhaust manifold pressure relief valve . Corky mentions exhaust pressure signals to operate wastegates and I think he even said don't laugh because it's not as silly as it sounds . If you did this with an exhaust side restricted turbocharger the rise into boost would be pretty lazy dependant on what spring load the gate had . If a turbocharger is properly sized let the wastegate regulate air pressure and the lack of restriction regulate exhaust gas pressure . Most diseasel turbochargers are big on the hot side and not so much on the cold side , they do this because they want low turbine inlet pressure and don't need huge compressors (in comparison to their turbines) to make their peak power . Atmittedly their CR's are pretty high and they make reasonable torque at very low revs . A .

Just some turbine maps comparing what can be done with the two sizes in GT28BB vs the three for GT30BB turbos . The two turbochargers I looked at were the GT2871R 52T in 0.86 A/R turbine housing form and the GT3071R in 0.63 A/R form . The corrected mass flow is quite similar and the two compressors are same family just in different trims ie 52 for this 2871R and 56 for the 3071R . http://www.turbobygarrett.com/turbobygarre...7_1_turbo_e.gif http://www.turbobygarrett.com/turbobygarre...071R_turb_e.jpg Not that it's possible to buy a GT28 BB IW turbine housing in T3 flange 0.86 A/R but if you could I think you'd make better power with a GT2871R 48 or 52T than a GT3071R in 0.63 A/R form . The point I'm making is that small turbine housings are not the best way to get the most from any turbine and if you read into the old bibles they usually say a more modest turbine in a medium to large housing (for that turbine) gives better results . I look at the power range suggested at the GT3071R page on Garretts site (300-460) as basically telling us what this turbo is capable of given the spred of exhaust gas flow for the three turbine housing sizes . The real turbo engineers tend to tell you that small AR housings are not flash because they don't have enough volume for the expanding gasses to impart their thermally excited energies into the turbine blades . From memory the term they use is expansion ratio and in a small housing you'd think it would be low . Anyway this is not getting anyone anywhere . Bottom line is if you want to push a mechanically bog stock engine with this turbo then sure use a 0.63 A/R housing . IMO if you are prepared to go inside the engine and remove some of its physical exhaust restrictions so that it can make more power (and increased exhaust flows) the 82 housing will better deal with the increase in flow ie not become the next restriction downstream . I also think the 3071R's 56T compressor is too much for a GT30 UHP turbine in a 63 housing , the next sized down turbine (GT28 NS111 in 76T) in an 86 housing gives about the same flow and people don't complain about how GTRS's (2871R 52T) work on RB25's - would be even better in a 0.86 A/R housing . Anyhow I've been there before with the GT2860RS 0.86 A/R on a 2L four and it was really good . A .

If you mean the old HKS RB26 kit , split pulse single low cast manifold , the turbo should be a "TA"45S so the next size up from T04B/E/S . A .

I have an early copy of Turbochargers by Hugh Macinnes as well , the 6/76 edition . Some of these old bibles are great reading but don't forget that forced induction went through a revolution in the 1980's with turbochargers creeping into Formula One , Indi Cars and the ferocious rally era eg Group B . The "pressure balance" is always going to be there with reciprocating popet valved piston engines because they are expected to make usable power over a reasonably wide range . In an ideal world all engines would have lower exhaust manifold pressure than inlet manifold pressure because that is what would be best at drawing most or preferably ALL of the spent gasses from the cylinders at the end of the exhaust stroke . If in an NA engine you can develop low enough EMP then the engine will scavange really well - low enough to help draw the cool clean inlet charge into the cylinders in the valve overlap phase . If the inlet system breathes well enough its possible to achieve 100% volumetric efficiency which means the cylinder is fully charged - sort of like if there was nothing on top of the block with the piston at BDC on the inlet stroke . Actually I do remember reading aeons ago about F1 engines reaching something incredible line 120% VE but F1 engines are supposed tro be the pinacle of automotive engineering . Back to using a radial inflow turbine powered rotary air pump . You won't get too close to what can be achieved in extreme NA form with turbochargers because of the nossles and turbines in the exhaust tract/s . A turbine housing by definition is a collector that collects exhaust gasses from all the cylinders and accelerates them into the turbines blades via its nossle/s . This is the place to make or break a turbo engine package because there is a choice of turbine efficiency or the engines volumetric efficiency . Manufacturers of production vehicles want the turbine to spin up quickly low in the engines rev range because it's early boost thats makes usable torque at "civilised" engine revs . In the past manufacturers weren't using all the available technologies because they wanted it on the cheap . Back soon .

If anyone has an R33 RB25 DET PFC open at the moment can you post a pick of what the Commander socket looks like from the inside . I chased up Cubes pics from the fried days but can't pick out the socket from his pics . Cheers and thanks , Adrian DP03 .

Cubes I reckon a lot of the boost control problems stem from higher than necessary pressure between the exhaust ports and the turbine . If the pressure gets high enough it will muscle the flat valve open purely because its higher than the combination of the inlet manifold pressure and the actuators spring . In this situation it's trying to act as a pressure relief valve rather than a device to regulate turbine (and therefore compressor) speed . A wastegate actuator tries to regulate turbine speed by acting on boost pressure in the inlet side , provided the hot side pressure is not too far above the cold side pressure it should stay in regulation . I would have thought that an RB30 is more than capable of making low to mid range torque with little or any boost low down , in fact I reckon with a bit less turbine housing restriction it would make similar to what it does now without boost so you could move the turbos speed range a bit higher in the engines speed range without losing a whole lot . A larger turbine housing will make for better off boost performance IMO because the engine should be acting like a more efficient air pump . Back to the maps , Garrett quote Hp figures for their turbos based on air flow performance . They don't say anything about how the range of turbine housing sizes affects Hp - though people should be able to work that out just by looking at the turbine flow maps and noting what the lines indicating each size show by comparison . Have a look at the GT30 turbine maps and note what the flow differences are for .63 .82 and 1.06 sizes , ~ 20 , ~ 23.5 , ~ 26.5 corrected lbs/minute gas flow . So obviously the larger the housing size the less pressure exists inside it for a given exhaust gas flow rate . If the gas velocity is reasonable then yes the wastegate will work as intended , it should also be able to keep the turbine "windmilling" fast enough - lets face it BB cartridges were designed to have a lot less oil sheer drag than bush bearing ones . Reading between the lines I'd say you can forget about getting anywhere near a turbochargers air flow/horsepower potential without its largest available turbine housing size . The compressor may attempt to cram it in but the spent gasses also have to escape and they all have to go through the turbine or wastegate . A small ratio housing with a bionic actuator can't work because as soon as the elevated exhaust side pressure forces the gate open the compressor speed doesn't increase so boost pressure has to drop . Creep I suppose you call it . I agree it is a juggling effort to balance turbine response against exhaust gas flow but the engine likes it when the restrictions are low . I remember when they were first playing with GT4088R's in the US (admittedly in twin scroll form) every time they went up in turbine housing size they found they could make the same power with less boost pressure - basically if you get get the bad stuff out quickly/efficiently the effort to get the new stuff in is far easier . Makes sense to me . Back to the GT3071R , I was just looking at the maps for them and the comp one shows around 46-47 lbs flow capacity so easily enough for 450 engine horse power . I know of examples in the US of built up SR20's cranking 450 Hp/400 lbs torque so the turbo obviously can do it provided the engine is modified to handle the gas flow requirements . These engines had a lot of head work and reasonably healthy cams in them so its not just a bolt this turbo on a tune with a big fuel system scenerio . If you want it all you must have the head reworked and do the camshafts as well . My own RB25 is std mechanically and the Sin Kid head is almost finished , it will have Poncams and the static CR up around 9.2-9.3 in an effort to make the engine a bit more grunty down low and at small throttle openings . I want my engine to stand on its own two feet and not need boost (or exhaust restriction) at low revs . I want it to feel like a larger capacity N/A engine and also don't want it to jump into boost at any great rate - don't need the "rush" . Out of time , have a date with a long string of shipping containers , cheers A . Actually have an interesting link to an Aussie fella that does well rallying Rexes and his ideas on turbo dump pipes http://www.msengineering.com.au/exhaustsystems.html

Upon closer inspection the supplied datalogit plugs seem to have the plastic pegs in the wrong place , they look like generic 6 pin din plugs but with only 5 pins . The PFC unit and the Apexi Commander must have a slightly different version of a "Din Plug" system because their plugs have the plastic peg offset downwards towards the dimple that lines up with the small square hole at the base of the socket . BINGO - just sussed it out ! Whilst glancing at my old dinosaur laptop I spied a "Din" socket on the back of it . Methinks I wonder if the Datalogit plug or the supplied extension cable fits in there - which of course they didn't ... Then brain drops into gear and remembers that computers don't use Din sockets - they use PS2 sockets . I just happened to have an old PS2/USB adapter plug within reach and gess what , it fits the lap tops port and looks just like the Apexi Commanders plug - only 6 pins instead of 5 . The burning question seems to be why would FC Datalogit supply the gear with Din plugs when the Power FC's socket and the Commanders male plug are PS2 plugs - minus one pine ie 5 ? I really hope someone thats been around these Apexi Power FC's , like Paul33 , can shed some light on this issue . Lastly one for the computer hardware nuts , is there such a thing as a 6 pin Din/PS2 adapter plug available because that would adapt me from PS2 to Din and solve the problem . I should NOT have to break the plastic lugs from the Datalogit plugs to make them work , they should be the correct type . The silence is deffening , cheers Adrian . http://www.accesscomms.com.au/reference/ou...lugsminidin.htm PS Have a look at plugs C and D - note the lug in the middle of the plug diagrams . This is why the "5 Pin mini DIN" wont fit in a "6 pin mini DIN socket even without the 6th pin . http://en.wikipedia.org/wiki/Mini-DIN_connector 5 pin and 6 pin . The size and the offset of the "middle" peg .

No one has any answers to this ? Has anyone else bought a new Datalogit recently ? A .

So , it's interesting that someone tried the 0.82 A/R IW turbine housing on a GT3071R - and on an RB25 as well . It sounds like the pay off is less exhaust restriction so a bit more engine torque low down . I reckon the lower gas speed through the turbine housing means it's easier for it to make the right angle turn and flow out through the gates port when the flat valve opens . I know exactly what you mean when you say there's always some power there - but over 2K revs . This is pretty much what my old FJ20ET did with the larger of the two available turbine housings (0.86A/R vs 0.64) on my GT2860RS - only it started to go positive pressure wise at about 1700 + . The term I coined and Joel will rember it is the "windmill effect" , basically I think well matched BB turbos idle or windmill fairly fast compared to bush bearing ones so rapid transients (accelerations/decelerations) are possible at low engine revs . I think it's possible that the turbo can pump slightly more air into the engine , even at less than ambient inlet manifold pressure , than atmospheric pressure can do by itself . If you managed to log your AFM voltages before and after you changed the housing size it would tell the story . Also by having wide open throttle at lowish revs means the available pressure can more completly charge the cylinders , the turbine housing being less restrictive means the exhaust gasses are more likely to go south rather than have partial reversions into the cylinders . Best mean torque ignition timing at this stage probably means more efficient use of the air and fuel and less chance of detonation . I know Joel won't necessarily agree with me here but I think he could achieve similar gains if he swapped his 0.82 A/R GT30 turbine housing for a 1.06 A/R one . Actually I think the difference would be slightly less on an RB30 in an R32 because the rod stroke/bore stroke difference and the lighter car . Also turbo wise his GT3076R's port shrouded compressor housing would tend to mask any negative effects of a housing thats possibly a little small for a 3 liter engine . I doubt HKS would have gone to the expense of fitting a custom port shrouded comp cover to their GT2835 pro S turbos , there must have been enough gain to justify the cost of having such a comp housing cast and machined . A short time back I was looking into Garretts bush bearing GT3571 turbos and I think I found a pic of one with a port shrouded T04E housing on it , from memory it has the slightly different series housing too - BSK1 ? Cheers A .

Hi all , I went to plug the new Datalogit kit int my PFC and find that it wont plug in . The male plugs on the extension cable and the black box have plastic guide pegs that are too long/wide to fit in the PFC boxes socket . The Apexi Commander's plug fits fine and when compared the difference is very obvious . Surely to christ I'm not expected to break the plastic pegs out of these male plugs to get them to fit the PFC's socket ? I have a home made extension cable made from a 6 pin din plug that's had the 6th pin and the plastic peg removed and yes I made sure it haden't lost any pins in the PFC's socket . Does everyone attack these male plugs or is it just mine that have a problem . Cheers A .

Yes digging deep into the testicular fortitude account . A friend of mine gets to work on competition quads at a place near Peakhurst I think . They play all kinds of weird bike engine things but get right into EMS's FI etc . If modern bikes are anything to go by you could just about lose the front wheels ... A .

I was under the impression that R34 RB25's had a second "fly by wire butterfy" to do the traction control thing - sort of pre purely ECU conrtolled throttle . I had wondered if Nissan were struggling to get enough grunt to keep people happy with N/A variants of the R34 so were trying to get their inlet manifolds to flow a bit better . What I'm thinking about is the possibility of using the "Twin Inlet" plemum top on a turbo engine to get a bit better air distribution than a single "hole" to feed 6 cylinders . I had wondered if the chamber was divided into two and seperate throttles used how much better it would be . Cheers A .

Engines with long cams tend to prefer twin scroll turbine housings on turbochargers to get around the reversion issues long duration wide overlap profiles give . With the righ combination of bits I reckon you can get the power without the 10G rev ceiling and it may be worth looking into high lift profiles with a bit less duration and overlap . My guess would be a GT3071R but with a non standard and reprofiled GT32 turbine housing which I think you can get in 0.78 A/R . The twin scrolling allows you to have the larger A/R ratio and less restriction (potential reversion issues) with no real lag penalty if everythings sized about right . You generally get to up the ignition timing because reversion/pollution/preheating is less so the detonation threshold is higher . Depending on what octane fuel you can run you may not have to drop the static CR that low , if the engine is not expected to have torque at low revs there is less time at higher revs for the end gasses to auto ignite . Ethanol fuels are supposed to make for lower peak combustion pressure but higher average pressure so if the rules allow ... Just my 5 cents , cheers A .

Hi all , I was looking at a section of an R34 engine manual and I noticed that it mentioned the "Y" shaped gadget for the inlet on RB20 and RB25DE engines . It makes me wonder if this would work better distribution wise on an RB25DET . How common are the bolt patterns between R33 and R34 RB25's - between the upper and lower halves of the inlet manifold ? Also is the idle bypass housing the same ? Cheers A .

Do the R32 RB25DE's use top feed injectors ? Someone did tell me that the top and R33 side feed rails are interchangable with the top feed ones . I think the Nismo SF 555's or 740's are high resistance saturated injectors so not sure what you'd do with an R32 . A .

Fuel rail and fastenings but not injectors . A .

From another site , it's supposed to be the first servo on the left hand side past the Mechano set (intersection of Hume Hwy/Liverpool Rd and Woodville Rd) heading south . I believe it's locked and you need to go inside and see Sid who will check your car out for it . I'd just like to be able to get it in my fuel containers so hopefully that won't be a problem . I can understand servo owners being a bit concerned about letting people toss it in the tanks of cars not specifically designed to run it . In proper fuel containers it should be ok and relieve them of any legal dramas . Cheers A .

Hi all , just heard mention of E85 being sold at some servo on the Hume Hwy near Woodville road ? Sydney that is . Does anyone know where it is ? Cheers A .

Yes right you are , the details are at the bottom of the page in the link I posted above . Cheers A .

I guess it would depend on who supplied it and if they cut costs by not using a genuine Garrett GT35 turbine housing . I think one mob in the States may have been machining the "ears" off Garrett housings to form a V band flange . Also you see them on US sites with what looks like T3 flanged TB31 turbine housings on them . I would always prefer a Garrett housing designed for the turbine size and family used . A .