discopotato03

I ended up with the Meterman 38XR and will get the RS232 cable and disk in the near future . A fellow I know who used to work with industrial scales has a Fluke 225 which I think is no longer available . If he ever gets sick of it ... Cheers A .

Hi all , I think the Meterman 38XR through Dick smiths is about as close as I can get to the wish list . It does the min/average/max thing and duty cycle though only 1-90 % which I suppose is ok . It comes with a temp adapter and K type thermocouple plus the hanging magnetic base strap gadget . If I had to guess I'd say the distributors are reluctant to go much over $200 retail and thats why some very capable units from Extech and Protek which would probably retail for ~ 250 don't make it out here . Mores the pity . Cheers A .

I think that was a typo , (1-4 , 2-3) . There are some 4cyl twin scroll manifolds with a single wastegate but to have any hope of it working the division has to go all the way to the face of the wastegate valve , even this is not perfect because the divider must not touch the valve or it may not seal shut . If it was me with twins I reckon it'd be hard to resist the temptation to stay with integral wastegates because your getting twice the valve area . Also having the front and rear three cylinders isolated means that turbine inlet pressure will be lower and controlling the gates becomes easier because of it . Whats a pair of 2530 IW turbos good for on a well set up engine , 600 odd Hp ? Maybe 450-500 if grafted onto an RB25DET ? Cheers A .

I think running twin parallel turbos on an I6 and having a "balance tube" between the two manifolds is a stupid thing to do . One of the greatest advantages of having parallel twins is keeping the 123 456 exhaust events seperated . You keep the exhaust "putts" further (engine cycle wise) apart in seperate manifolds so that each cylinder blows down through each turbine housing and the pressure falls in each much faster before the next exhaust event . To be isolated eack turbo or manifold has to have its own wastegate and not share the exhaust pressure rise from the adjacent manifold . If you cross connect the exhaust manifolds its the same as having a single turbo single scroll turbine housing . This system falls down because since every cylinder is venting into one passage (housing) there never is a low pressure period so you lose a significant amount of exhaust energy merely fighting a path from one end of each manifold leg to the turbine housing . Reversion is another significant negative . My 2c spent .

Had a look at Dick Smiths site and they carry the Fluke 115 for $268 . It does just about everything (inc 20a current) except duty cycle but Jaycar have a kit thats supposed to measure that . My friend reckons measuring injector duty cycle is not always straightforward because of electrical noise ? Anyhow if duty cycle can be measured by other means such as a cheap kick around the garage meter then this one will probably do the trick . Thoughts ? Cheers Adrian .

You could always buy/build the Jaycar kit unit . It works off injector duty cycle which is a far better signal than a map sensor . Have a read of what SK did with his Stagea . Cheers A .

Great , thanks for that . A friend reckons Dick Smiths used to do them as well but that'd be too easy . BTW he showed me an interesting gadget he has thats a steel base with a tree of arms and a couple of thumb screw clamps to hold PCB's . On one branch has a magnifying glass to get up close to the board when soldering things . Feature wise I don't mind spending a little extra to get what I need because it saves buying twice . Thanks again , cheers Adrian .

Heller44 can you tell me who the distributor for Protek multimeters is . All I can find is blurb for the 506 model so possibly the 6800 one is not available here - bugger ... Cheers A .

Actually I think I may have found the answer . Protek make "6800 80,000 Count DMM" . This does duty cycle/frequency and the min/average/max readings that I really need (I think RS232 as well) . Its not a Fluke and costs nothing like a 189 but I think it does what I want at a much lower cost . The Jaycar cattledog does show a Protec 50 something so I'll ask if they can supply a 6800 . Thoughts ? Cheers Adrian .

I don't have a name , most people with those are trying to screw 300 Kw out of their engine and it sounds like the 0.68 GT2835 Pro S turbine housing is a bit restrictive for that power figure . Cheers A .

Everyone I've spoken to prefers the 0.87 A/R turbine housing on an RB25DET . I don't know for sure but I suspect the 0.68 was intended for RB20's and 0.87 for RB25's in that GT2835 Pro S range . Cheers A .

Hi machg , that is an old world non water cooled Garrett T3 cartridge and typical of what you'd expect to find on an early 80's era Nissan . If your going to put it on a rotary engine I strongly suggest you fit a much larger A/R exhaust housing because rotarys HATE backpressure and the L20ET Nissan housing would really strangle it . BTW Nissan was using off the shelf Garrett T3 cartridges and getting turbine and compressor housings made for them . Thats why the comp housing has Nissan on it and the cartridges ID tag "Garrett USA" . Also to set the record straight that series of T3 used the small type T3 turbine not the larger one normally found in USDM T3 based turbos ie Buick Grand National . If you want to measure its OD should be around 59mm whereas the USDM one was around 64mm . Nissan used their unique version of the T3 flanged T3 turbine housings in A/R ratios ranging from 0.36 - 0.48 - 0.63 . Off the top of my head I think Z18ET's used the .36 or .48 , FJ20ET's the .48 or .63 and RB30ET's the .63 . I'm not sure about L20ET and L28ET but I'd reckon they would have had the .36 and the .63 . The L20ET would have been hard to excite given its small capacity cylinders and rather agricultural exhaust manifold . Also most turbo engines of the era had pretty tame (low) static compression ratios because few had intercoolers and manufacturers were struggling to meet NOx emissions caused by higher CR's and combustion temps . I'd be sticking an RB20 BB turbo on one of those for a cheap solution , same capacity engine in fact same bore and stroke I think . If you can measure the OD of your compressor which should be ~ 60.1mm and the inducer diametre I should be able to tell you the comp wheel trim - and possibly its part number . Cheers A .

Yep have their 07 cattledog and have been looking into them . These Jaycar kits are aimed at an 86 Subie RX turbo not the R33 . It doesn't have a PFC/Datalogit option so I'm going to have to find other ways to alter fueling/timimg/boost with the std brain . I'm not much of an electrician but I want to learn something along the way so hopefully my kits won't look like over done toast ! I guess I should buy a decent meter and just accept good ones cost good money . The reason I need that above mentioned feature is to find std AFM output voltages (min/average/max) and recreate them with non std AFM's or bypasses . All still cheaper than stand alone aftermarket management (not chained to shitfull MAP sensing) and can be moved from car to car . Cheers A .

Thanks James will look into those . Its maddening that so few multi meters have that high/av/low feature . Cheers Adrian .

Hi all , this question is aimed at the hard core electronics people here . I want to build some of Jaycars automotive electronics kits for a turbo car and need a digital multi meter . It obviously needs do the usual volts/amps/ohms and also duty cycle frequency and possibly 20a current measurement . The biggie seems to getting one that has the high/average/low feature to for example measure airflow metre voltage range without killing yourself (eyes on DMM not road) . I've had a read through Autospeeds articles and JE thinks that this feature is very useful . So without tearing up the best part of a grand on say a Fluke 189 what is available that does all the essential things when playing with automotive electronics and the usuals for building kits ? Cheers A .

Just for the record whats the go with these new GT2535's ? I'm pretty sure the HKS spec Garrett one is out of production and has been for a while . I think they had a non GT compressor altered to give ~ 69mm 56T dimensions . If someone has made up a GT2871R with the Nissan/Garrett style compressor cover its not really the same thing . Cheers A .

They are laggy because depending on which way you look at it either the compressor is too big for the turbine or the turbine too small for the compressor . The result is the same and altering the number of turbos has no effect on the missmatch . Cheers A .

The facts about Garretts "GT2540 and GT2540R" . The one known as the HKS option GT2540 is real flop . In todays Garret speak it would be called a GT2876R because it used the high performance GT28 NS111 turbine (same as GT2530/GT2860RS/GT-RS/GT2871R's) and a 76mm compressor . The unusual feature is that its 76mm OD compressor is 6/12 blade but its not a GT (Garrett Technology) series compressor . What they used is a T04E compressor in I think 46 trim . The problem is that they have way too much compressor capacity for the turbine to drive so the turbine is struggling to motorvate the porky comp . Its all bad really because the turbine can't spin up very easily and so you get slip losses through the turbine housing . By this I mean the engines trying its best to force the exhaust gasses through but the slow turning turbine blades cause exhaust restriction/reversion etc etc . They always seem lazy to get going and they will be restrictive on the turbine side even when they get some turbine revs up . The "GT2540R" is a Garrett marketed option and even worse that the HKS spec version . Its basically the same thing cartridge wise BUT its compressor is a 76mm 48 trim 7/14 blade T04S series compressor . This wheel has more blades and a slightly larger trim than the HKS version does so its stepping further in the wrong direction . Unlike HKS Garrett don't have a T3 flanged integral wastegate GT28 exhaust housing so they won't bolt up to an RB20/25 . The bottom line is that both versions give poor results and you can do better , HKS eventually got the message and opted for the GT-RS which is a GT2871R 52 trim cartridge with housings to suit specific apps ie RB20/25 or SR20 . I wouldn't personally pay 1500 for either version and the only thing thats of any use in a good set up is the HKS T3 flanged T28 exhaust housing . The rest can go out with the John West rejects IMO . I guess if you have the dough a GT-RS kit is good because they throw in everything except the mechanic , the GCG Hi Flow is good because its effectively a std turbo as far as bolting it in goes . Another option is using a GT2871R 48T cartridge to Hi Flow the std RB25 turbo housings but this would mean plumbing alterations (oil/water) to suit the Garrett cartridge . Your call .

I reckon the Jaycar Digital Fuel Adjuster kit is pretty cheap if you can build it yourself though like any intercepter will run into RR if pushed . PFC falls in - just about and tune to hearts content . Cheers A .

The whole "Hi Flow" issue is a huge snake pit , for the uninitiated there's a few things that you need to understand before you go for the tools/wallet/seller . Its very difficult (at times impossible) to find a turbocharger that will bolt up to an essentially std engine and give all the nice low down production style characteristics with more of the same from the mid range up . To expect to do so is unrealistic , the manufacturers go to a lot of trouble to make production cars easy to drive in the 1-3500 rev range because thats where the majority of them spend most of their time . "Hi Flow" turbos have two major problems being fitting convenience and cost , actually another is dependent on the supplier knowing what works and what engines actually like/need . If the turbo won't bolt up its useless and IMO things like T28/T3 adapter plates particularly on an I6 are worthless . Too many manifold runners to merge into a single T28 turbine housing inlet . All sorts of silly things have been done with non native turbine housings where the priority was just getting the thing to bolt up to the exhaust manifold . The turbine and its housing must be a workable combination or the whole effort will be compromised and sometimes pointless . Its absolutely wrong to think that that any turbo is better than no turbo . So firstly the exhaust housing has to fit the desired exhaust manifold and the outlet the exhaust pipe . Secondly the housing has to be a workable match with its turbine wheel/shaft . Thirdly the compressor housing has to clear the exhaust manifold and everything else in the general vicinity , and have enough room for its inlet/outlet plumbing . Fourth , the compressor needs to be one thats capable of being driven properly by the turbine so it provides enough wind without placing any extra avoidable drive loads on the turbine . In a perfect world a Hi Flow turbo will fit exactly the same as the std one does with all the std plumbing fittings for exhaust in/out - oil in/out - water in/out - air in/out . Cost , no properly designed and manufactured turbocharger is cheap . Someone somewhere had to pay to for it . The materials used in petrol engine turbos has to have high temperature resistant properties to be long term reliable and these are not cheap . Often OEM turbos use unique parts ie not from a generic range of components so to make incremental alterations is not possible without custom castings ie HKS's exhaust housings / compressor housings . Anything not made in quantities particularly for high volume OEM apps is going to be expensive . This is part of the reason why turbo kits from the aftermarket like again HKS are expensive , they had to do all the costly development work so that the performance result is there and that the kit fits together quickly and easily . Enter the backyard Hi Flow turbo . This is a very grey area where the turbo is often a bitzer and alterations were made purely to 1) make it bolt together and 2) bolt to the engine . Almost always the compromises to get it on the donk damage its real world performance because the cost of doing it properly is beyond what a backyardies mates will pay . Gotta train to catch , cheers A .

Dynamic or effective compression ratio is determined by many things though the free flow abilities of the inlet tract and the trapping efficiency of the cam timing have I think the most say . If you have any notable pressure drop in the inlet system ie poor filter/s or inadequate throttle/s porting valve size etc then cylinder filling won't be the best . Long duration cams open the inlet valves earlier and close the exhausts later so generally the overlap period is longer and trapping efficiency less - at lower revs anyway . This because gas has mass and the faster it goes the less it wants to stop and go backwards (reversion) , ever seen a big cammed N/A engine "come up" on its cams and take off ? Thats because now the gasses have enough velocity to travel in the intended direction . So worst case scenerio poor inlet tract and long cams means low effective compression pressure . On N/A high performance engines higher static or measured compression ratios are used to raise the dynamic (effective) CR when the trapping efficiency is low because of long duration cams used to allow the engine to breathe at high revs . Turbo engines are different because the compressor supplying air a greater pressure than the atmospheric gives us better cylinder filling so the effective CR is higher than the measured or static CR . Personally I think cams that give more valve lift and modest duration is the way to have the engine breathe and have high trapping efficiency . The BUT is that the whole exhaust side has to be low restriction from the exhaust valves south so as to not create high turbine inlet pressure . My old broken wheel (twin scroll turbo system) has a large say in this and if you can keep the turbine inlet pressure down , trapping efficiency up you have modest boost pressure/lots of airflow/good turbine response and much more controllable power delivery . Systems like this seem to make a lot of torque over a fairly wide range and don't need horrendous rev ceilings to achieve it . BTW I was talking about a single twin scroll system earlier but much the same is achieved with parallel twins . Cheers A .

The no1 enemy is exhaust gas over temp generally caused by restrictions on the hot side . If you take most of the restrictions out of the exhaust side the detonation demon is easier to cope with . Everyone likes to think that high charge temps are mainly caused by elevated inlet air temps but reversion sends post combustion gasses back into the chambers and this is very likely to be at higher temps than post compressor air . If you need mega revs out of a compressor then chances are that the exhaust gas velocity required to drive the turbine at that speed comes at the price of elevated turbine inlet pressure .

I gather what you want to know is which (GT3071R/GT3076R) will make the 270 Kw/360 Hp with best response . The first aspect is what can you afford to spend because either can get you there , arguably the GT3071R would be more responsive in its best configuration which is twin scroll and external gate . The bottom line is having an equal pressure balance across the engine and its not possible to achieve this and have responsive power delivery (throttle/boost response) with a single scroll system . When you collect all of an engines exhaust putts and merge them before a single turbos turbine nozzle you create an area of high pressure for the cylinders to vent into . The problem is that the exhaust manifold pressure ends up being high when it should be low (at the exhaust ports) and low when it should be high (at the turbine nozzle) . With a true twin scroll system each turbine nozzle only see's an exhaust putt half as often so it gets twice the time for its exhausting cylinder to blow down through the nozzle , also on an I6 there are only 3 cylinders connected to each half of a divided manifold so the chances of cross contamination is far less . This is the way to reverse the situation and have low pressure when it should be low (at the exhaust ports) and high pressure when it should be high at the turbine nozzles . Low pressure for the cylinders to vent into and high pressure across the turbine nozzle to accelerate the gasses into the turbine blades . Venting into an area of low pressure means much more of the exhaust gases thermally driven expansion energy (high velocity) is available to power the turbine . Its the low energy loss communication between the exhaust valves and the turbine blades that does the trick . You can sort of have low energy loss venting the cylinders into a large A/R single nozzle turbine housing but having the volute and nozzle that big makes for lower gas velocity into the turbine blades and lazy turbine response . Turbo wise the real GT3071R is a good thing in twin scroll form though not so responsive in single scroll form . This is because the GT30 turbine is reasonably large for the 71mm 56T compressor and its a juggle to make it spin the compressor fast enough to make the "wind" without compromising exhaust flow and ever increasing turbine inlet pressure . Single scroll turbochargers are very sensitive to turbine housing A/R ratio where twin scroll ones are not . The real GT3076R has a fair bit larger compressor (76.2 vs 71.1mm) and in 56T is borderline missmatch particularly with the smaller available A/R GT30 turbine housings . Its cartridge was originally a HKS spec Garrett one and it was intended to be used with large ratio HKS turbine housings ie 3037 56T 0.87 A/R , GT3037S 56T 1.01 A/R or 1.12 A/R . with the base model GT3037 the comp trims go 48/52/56 and turbine housing A/R's 0.61/0.73/0.87 . I don't think there's any cheap easy way to get a responsive 270Kw though efficient intercooling and headwork/cams should enhance whatever you go with on an RB25DET . Some say the RB25 GCG Hi Flow with the VG30 turbine housing can get within reach but the other engine enhancements are probably a big part of getting there . Cheers .

Exactly Dale , the smart people in the US usually opt for a GT2860RS on Audis . As for that intercooler , IMO you could just about remove the top third because I don't think it would achieve a whole lot .

Hi all , no time ATM but back later on . The thing to remember firstly is how much charge air the engine in question can swallow . The right capacity compressor can supply the required air flow by mass (lbs/min) and not too much more . Any more is a waste and critical turbine shaft power is wasted powering a larger compressor and its extra capacity may not have been of any use anyway . Result = lag and added turbine inlet pressure (backpressure) for zip . Pumping capacity will vary with a compressors trim size and a large trim ie 56T 71mm compressor may have the same approx maximum as say a 76mm 48T wheel but the maps will look different and 101 things like housing style A/R etc all play their part . Compressor surge is not a factor of exducer tips going supersonic , thats a sign of the compressor being spun beyond its mechanical speed limit . More later cheers A .