discopotato03

Guys when I had the FJT in the Bluebird years ago I had to bridge out two wires close to the ECU to stop it rev cutting early . If anyones interested I could dig the loom out and have a look . Cheers A .

With a small enough turbine housing thats entitrely possible and .58's are around , HKS option a .61 for the TO4Z .

HKS do kits for R32/33/34 2WD but can't find details of turbine housing ARR . Nengun I think are advertising kits for RB's but won't let me in with Yahoo E mail . The HKS USA site shows an SR20DET doing 300.6 TQ and Hp at the treads which sounds about the go . Yeah I know another SR 2L ally 4 . Im outa here guys the trouble n strife and th tin lids are out and home brew awaits ! Chow for now , A .

Gary I'll look into that , a lot of people would be very inerested in an 86ARR T3 flanged exhaust housing for that turbine . I'll be back , A .

O/T guys but you could rate the GT-RS (esentially badge engineered Garrett GT2871R 52T with T3 flange and Skyline specific dump pattern) as ~ 420Hp compressor and 330 Hp turbine side . That exhaust housing is only .64ARR so 300Kw of exhaust flow ? That GCG Hi Flow would be very cost effective particularly as you already have the R34 Neo type exhaust housing , one out one in and no orphan bits needed . Will look dead stock and is rebuildable . How easy is that . Cheers A .

I think you'll find the Skyline model specific GT-RS has a custom HKS exhaust housing that takes the standard dump pipe or after market equal . Its supposed to be a bolt on/in kit . Cheers A .

The RB 26 Inlet manifold won't bolt to the R32 RB25 head , RB26 head is different on both sides to the other RB twin cam heads and more trouble than its worth to graft its manifold onto the 25 head . 26 head is the go if you can get one , all you have to worry about then is the stud pattern being wrong for RB20/25 single turbo exhaust manifolds . I'd like to strangle HKS for not making the manifold to suit the RB20/25 and 26 pattern as the 26 cast version is very hard to get . Cheers A .

Go with what makes you happy but remember the Garrett GT3040R (56T only) will have the exhaust restriction of a GT30R and a slight lack of turbine power to drive an 82mm GT40R compressor . HKS speced their 3040 with a 50 trim compressor because they knew the size mismatch was not ideal . I'd rather use a larger turbine housing on a GT30R (the real GT30R) . Many are finding that cutting down on the turbine inlet pressure uncorks the exhaust side with noticeable benefits . A good example is the VG30 housing on the RB25 turbos or Hi flows . Some of the American turbo mobs tend to agree that limiting a turbo by compressor flow rather than turbine flow works out well as is less damaging to the engine . Cheers A .

SLY33 the 46 trim 76.2mm compressor is a TO4E in the HKS GT2540 . I have seen an RB26 specific 2540 in bits and can well understandy why . 1) TO4E wheel older aero tech than BCI-18 series used in the GT-RS (GT2871 52T) 2) 76.2mm wheel way too big for a GT25 compressor cover . 3) Big diametre small trim wheels have more innertia than next size down ie 52T 71mm better than 46T 76.2mm . Any TO4E size wheel overwhelms a 53.8mm GT turbine . Not enough turbine energy to drive them and not enough exhaust flow ability even if it could . HKS's GT2540 has been with us for ages and was really a stop gap between the 2530 and 2835 series . It was spec'd early in the days of GT turbines when there was not the full range of GT (BCI-18) compressor wheels available to hang off them . This is why we also get ratshit TO4S compressors on GT turbines , neither these or TO4E wheels are high speed wheels and don't compliment the high speed turbine . Cheers A .

Mine used to do silly things untill I removed the disabled adapter harness for the Jap turbo timer .

Check the specs of HR31's . What did that Z31 RB20DET thing use ? Cheers A .

I think Sydneykid said if your engine is into boost at freeway cruise speeds , like every time you breath on the pedal for a hill , the consumption will be poor . Cubes may have found by using the larger turbine housing the boost threshold is higher and exhaust restriction lower . If the final drive was raised to 3.7/3.9 the car could use the extra torque it makes at lower revs to get better mileage . O/T but notice how the R34 GTt uses propper variable cam timing and makes good torque even with the larger turbine housing . The effective or dynamic CR is probably better that the GTS25T at the low end so does not need the early onset of boost to get it going . Has anyone compared consumption on a 33 and a 34 ? I'd like to know what the aftermarket VCT does to a GTR from a power and consumption point of view . Cheers A .

I think its how your engine makes its torque that has a lot to do with fuel consumption . Others on this site have said power from aditional airflow is the go rather than extra boost . My idea is to have a reasonably healthy compression ratio (~8.8/9.0) , a head and valve train that breaths well without long duration wide overlap cams . A turbo with efficient wheels and a very good balance of turbine to compressor . I believe the road to good power and fuel consumption is a state of tune that gives good part throttle torque particularly off boost - in other words you don't need to go chasing revs and boost to get it to go . I think we can safely say that engine management/cams/turbos and pump fuel has reached the stage where you can have a decent compromise for the road . In my book things that hurt reasonable consumption are : 1) Gutless low CR ie under 8.0 2) Long period cams with lots of overlap - lack of cylinder trapping efficiency and reversion . 3) I'll start a fire here , cams as above with single throttle plenum manifolds promote pressure fluctuation in the plenum enhancing reversion . 4) Turbos that allow much higher exhaust manifold pressure compared to inlet manifold pressure under boost . It takes crank energy to force exhaust out through restrictions . Fuel energy generated crank power that could have been used to drive us down the road . Exhaust reversal back to the chambers because of restrictions , polutes preheats and drops the fuels effective octane rating meaning less ignition advance can be used - hurts consumption . 5) Tuning - the method of load sensing and the flexibility of the computer itself is very important . I'll be going with hotwire AFM's because they have the best handle on air temperature vs density , I think MAP's a bit crude . So that leaves me with either std retuned ECU or Apexi PFC , PFC all the way . Lack of experience of the person tuning it - this hurts at the pump big time . My opinions only , feel free to change them . Cheers A .

Actually both use the Garrett 71mm GT35 BCI 18 series compressors in 52 trim though optional on 2835's 48 and 56 trims . Main difference is the turbine , GT-RS is the fancy name for a Garrett GT2871R with the middle or 52 trim compressor . All 3 2871 cartridges use the 53.8mm GT28 turbine in 76 trim (NS111 type) . Also avail in 48 and 56 trims . HKS GT2835 and some Garrett GT3071R's (WG type) same cartridges use a 56.6mm cropped GT30 UHP turbine . The theory is larger turbine makes for better "balance" of compressor to turbine size ratio . Make careful note that HKS generally stick to smaller trim compressors than Garrett do - the result is better response or lower boost threshold if you like . As for the 400PS , the GT-RS would be on its knees from a turbine inlet (back) pressure point of view . PM me if you want all the numbers n bits n pieces . Cheers A .

My understanding is that long duration cams help to extend an engines rev range upwards . As revs rise there is less and less time to charge and vent the cylinders so opening the valves earlier and closing them later in the cycle gives more time to breathe and vent . Trouble is you get cranky characteristics because the valves are open too long in the scheme of things at lower revs and this reduces trapping efficiency . The fuel air charge is difficult to compress in the chamber if the valve/s are not seated . Until the right air speed is reached you get reversals in both ports and that "cammy" effect with long period profiles . When the right speed is reached air, which has mass , flows in the right direction ie in inlet and out exhaust valves without the reversion . Higher lift cams obviously open or lift the valves further off their seats to let the charge in . When a cams profile is changed so that there is more lift for the same duration the lift curve obviously changes . For the same amount of camshaft rotation in degrees (from when the valve just starts to open) the higher lift version will have the valve further off its seat righ through its lift phase ie not just at full lift . A valve further open gives greater flow potential to fill the cylinder , I'm told generally the valve is the greatest restriction to port flow . I believe high lift is the way to go but the valve train has to be able to support it . Standard springs are likely to coil bind with high lift profiles so cost and effort to fit better ones is involved . Direct cam lobe on bucket valve trains are good at handling the loads up to a point but extremes go beyond the material limitations of standard valves/springs/collets/buckets eventually . RB heads I believe need some fettling around the sides of the bucket or lifter bores to clear the extended noses of high lift cams . This is hardly a bolt on type mod so goes against what the Japs can do and afford given that labor charges over there are huge . It seems the long period cams are used with less than ultimate lift so that they can be fitted to a standard head and valve train - bolt on/in mod . These types of cams will increase breathing potential but move the usable rev range upwards - provided they don't valve bounce and loose the valves sealing ability . I like the idea of shorter duration high lift cams as the breathing ability is there without the reversion dramas , meaning high flowing port but with good trapping efficiency through limited valve open timing . I doubt anyone is gonna make me a 256 deg 11mm lift cam so the Tomei Pro Cam at I think 260 and ~ 11mm will have to do . Hard on the valve train but easy on the bottom end I suppose . Good oils should make it reliable I hope . Cheers A , open to ideas/opinions . Always check piston to valve clearance .

When is this due in Sinn City ? Cheers A .

Its difficult to tell what kind of bearing system that thing uses , I'd like to think if they're throwing good money and technology at it it has balls . VATN or variable area turbine nozzle was the original name for this concept . It works by the lobes or vanes moving to vary the effective area radius ratio but at the nozzle . The theory is that there is no waste ie no wasted exhaust gas energy being by passed to control the turbine speed . Its supposed to be able to make the ARR so big that total control is possible and turbine inlet pressure minimal at all times . The potential problem of having boost nearly all the time is present so intelligent electronic boost control will be a must . In the past the hurdle with VATN was reliability of the movable vanes given petrol engine exhaust temperatures . Any garbage in the exhaust gas has the potential to screw it up . I'd say the corrosive nature of out outgoing high sulphur ULP was holding things up a bit as well . Porsche given the market its aimed at (price range) can probably well afford to use this kind of technology to keep performance up into the nothing politically incorrect comes out the pipe future . A pitty our pollies don't fit the same criteria at either end .... Cheers A .

The thing I'd like to know is if this 5% Ethanol will be the future standard . If its the case I guess we'll need to tune performance engines to suit . 100 octane fuel sounds good but will it have the anti nock properties we want ? I am naturally suspicious as well because the oil companys love to charge more for big bling numbers . High octane fuels should be the future because performance emissions and consumption benefits are too good to pass up IMO . Cheers A

Finally got pics of the wheels . Compressor looks a little like a big trim GT wheel though the splitter blades sit a bit lower . The turbine looks a lot like a TO4 P trim . Cheers A .

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Guys the main difference between a 2510 and a 2530 is the turbine itself , the 2530 uses the more open bladed 76T NS111 turbine where the 2510 uses the more oem style turbine found in the response over flow type turbos . I'm not sure if its economically feasible to rebuild it as a 2530 unless you have the turbine and Skyline specific exhausting from one . Probably easier and cheaper to buy a 2nd hand 2530 and bolt it on . Cheers A .

www.turbobuick.com - boost vs back pressure Works for me .

For those who like the theory side of forced induction this ones a good read . TurboBuick.com - Boost vs back pressure . Looks into cams and turbos and cross over . Don't go there if you're tired or under the weather . Cheers A .