juggernaut1

Interestingly, I been having email discussions on the 3071 vs 3076 albeit in a twinscroll configuration with Geoff Raicer of Full-Race fame. Essentially, it comes down to whether the engine in question can swallow the airflow afforded by the 3076 compressor. Some engines just can't make efficient use of the airflow of the bigger compressor due to basic head design and set-up. An indication of this is that the 3076 will only have the same or marginally more power than the 3071. Another point raised by Geoff is that while the spool difference between the two might only be 100 - 150 rpm (in a twin scroll ATP .78 a/r ex housing) the 3071 is the more responsive of the two. I wonder how much the port shrouded compressor cover of the 3076 hurts it's efficiency.

no way.......NS members are way too astute than to buy a 2876 - thats only something a skyline driver would buy

Just installing a tube and fine ARE cooler at the moment. Chose ARE mainly because of the end tank designs which are said distribute more evenly through the cooler. I also had mine spec'd with a venturi plate on the intake side. This also helps airflow into the cooler tubes as tube and fin cores have raised tubes by design.

I think you will find that the Jap oil cooler kits with thermostat don't shut down supply to the cooler completely when cold (for example Greddy) - they just limit the flow through the cooler when cold and allow more flow when hot. In this way you're nice hot engine isn't going to get a big hit of cold oil from the cooler if it had a thermostat that shut down oil supply to the cooler completely.

Really - I have one and give my 200sx a belting for 30 mins at a time at Barbagello for 4 sessions each time I go and no probs. I know some removed the tranny support becuase it needs to be ground out to fit the CES which would cause it to crack as it is supporting the front half of the exhaust system. The only thing thats cracking are my discs.

Just to confirm aren't you running some sort of GCG housing on the cropped 3071R or am I mistaken. Good result nevertheless.

Personally, I would take a leaf out of CES's book rather than HKS. I've seen back to back dyno tests of a CES twin dump vs HKS merge dump on a 2871R on a SR20 and the CES lost nothing at any stage and gain more hp from 5500 onwards. CES make GT35 twin dumps for the falcon XR 6's so see if you can locate some pic's and note the way they have done it and apply similar principles. In the main you should concentrate on reducing turbulence caused by the wastegate gases and CES does this by keeping the wastegate gases separate for as long as possible by merging them back into the main pipe at a shallow angle as it goes under the vehicle.

Have you considered the Hermholtz reasonance theory when designing your manifold - here's an overview plucked from a US thread in relation to the sr20. Long runners make more "midrange" as Def says, "focused powerband" because of: http://en.wikipedia.org/wiki/Helmholtz_resonance This is the key here. The long runners make more airflow available to each cylinder... but ONLY During a very specific, narrow, RPM Range... depending on the size and shape of the runners. the SR20 intake runners get a mid-range bump in the 4500-5500 RPM range.. and thats about it... Anything ABOVE or UNDER that RPM range will suffer, because hermholtz also works backwards, subtracting available airflow from each cylinder, anytime its not in its peak operating range. So VE will ramp up quickly just into boost coming out of the 3000-3500RPM range, right in peak VE range thanks to hermholtz resonance theory (4500-5500RPM) at which point the vehicle has gained more and more acceleration due to this design, but as you pass 6000RPM hermholtz ruins your top end VE... killing torque.. and thus power... but the SR20's stock turbo starts running on the bleeding edge after that spot anyways... so VE is dropping but so is flow through the turbine and compressor... the turbo has to flow less now because it moves less air through the motor at the same boost, because of hermholtz, this complements the stock turbo perfectly since by lowering its flow at high RPMS it can level off without overworking itself. so the drop in torque is barelly noted on the stock setup (after hermholtz is removed, at high RPMS), but the loss of the long runner intake IS noted because of the huge dip in mid-range you lose by not having hermholtz there anymore. This is what our thread op has experienced. And as mentioned, cams are a huge factor here. They allow the motor to breath after hermholtz has been removed, taking advantage of a shorter runner intake manifold, the way the stock one cannot do, at all. Sure you can slap on a bigger turbo and bigger cams and keep the stock intake... but its a huge waste, you will be fighting hermholtz right when your large(er) than stock turbo comes on boost... this is why we change the stock intake. it isnt about volume or flow (although those help) its about getting rid of the hermholtz problem when it becomes a problem. It also depends on application, a longer runner intake may help the turbo get moving, as VE is punched right when it comes on boost briefly (obviously depending on the size of the turbo) so the car feels like it responds quicker... and it does... but overall power is lacking compared to others with the same setup because you are always going to feel that drop in torque after hermholtz starts robbing you, no matter how big your cams or turbo is.

Definately port match the turbo to your manifold to reduce any turbulence at the flange as it enters the housing which would reduce gas speed, particularly on low boost and transition to boost (i.e. offboost conditions). Refer following comment from Kyle (6boost) on a recent discussion article on this forum re aftermarket manifolds. I realise your car isn't a 700 evo engine but the same principles apply. After that there's always extrude honing your manifold and turbine housing. "(we were testing outlet shapes and sizes, and for a 700+hp car, the small hole was just too restrictive), and the red line was after 40min work with the die grinder to port match the manifold from a round hole to the same rectangle as the turbo. The results?? 380rpm faster spool, 40hp at all 4 wheels on the same boost,"

OK I'm back in the Towering Inferno called my office - false alarm. Thanks for that Disco but was chasing hard and fast data. I'm currently putting together a Tial housed GTRS and was thinking ahead if that didn't satisfy my needs whether I bore out the Tial housing and slot in cropped 3071. It could be a cheap swap. But then I've wasted the housing if it turns out to be a dog. I guess the Tial housing is a different ball game compared to the standard Garrett offering in any case.

Disco, Do you have any dyno results or can point me in the right direction regarding the cropped wheeled T2 flanged 3071. I cant find any and I see mixed comments regarding these turbos but never any dyno's (have also searched NS.com). The reason I ask is that someone I know (a tuner) raves about this turbo and uses one on a Drift Australia SR20 powered drift car in a .86 ex housing and makes very good reliable power - (2 years of drifting on stock bottom end). Further he has tuned a friends car (stock SR20 S15) with the cropped 3071 in .86 with Tomei 260/260 cams and engine management and runs 12.2 sec quarters. Gotta go the fire alarm has just gone off!!!!!

Yes they are nice http://www.tialmedia.com/graphics/SS%20housings/gt28%205.jpg

Found this link on power porting process of before and after hp figures done on a test mule RB30 engine when Specialised Power Porting was in its infancy. http://autospeed.com/cms/A_0622/printArticle.html

^^^^^ agreed but IMO the 6Boost manifolds has one of the best collectors in the business. Mercury Motorsport made 562 rwhp from their stock stroke sr20 with a 6 boost mani and GT35 turbo. This car also ran 10 sec quarters with manual box. My manifold is also unique in that it has been custom made to suit one of the new round collector v-band Tial cast stainless housings for my HKS GTRS turbo.

OK for what its worth 6Boost ex manifold and standard blacktop inlet manifold (SR20) before and after extrude honing at 28 inches. Please note that my mandate to Andrew Sanders re exhaust manifold was not to equalise flow as I didn't want to increase the volume too much in runners 2 & 3 and loose any response. And my mandate re the inlet manifold was to equalise flow - which is nearly perfect. Just an example of the benefits of extrude honing. 6 Boost Exhaust Manifold Before.............After 1 250............260 2 220............245 3 222............247 4 252............262 Standard SR 20 Blacktop Inlet Manifold Before.............After 1 254............300 2 257............306 3 270............306 4 254............300 For comparison sake I pasted this RB exhaust manifold flow data previously posted in this thread but Im not sure at what pressure the flow tests were done?

I have recently had my 6boost (SR20) ex manifold and stock SR20 inlet manifold honed by Andrew Sanders (along with my turbo compressor cover). I don't have the before/after flow results on me but will post up later for anyone interested in this process.

Part of your decision will come down to available space to fit the gate. The Tial gates are generally of a more compact design than the turbosmart items. The turbosmart pro-gate is 48mm and is a sizeable gate compared to the Tial 44. Your getting a 6Boost mani aren't you? I know Kyle recommends the Tials due to their compact design which generally allows the gate to be mounted straight off the manifold for better boost control rather than having a 90 degree bend off the manifold to the gate.

Disco, I thought the GT-RS had a 52 trim comp so it is equivalent to a GT2871R 52T....no?

Actually, I'm in Perth WA but frequent the US forums for info. Yeah dyojets probably read 10 - 15% higher than our Dynamics. That said I've also seen by brothers SS Commodore car read 500 rwhp on a dynamics in Sydney and 450 back here in Perth. So obviously calibration differences btw dyno's of the same ilk.

how come I get all the good jobs

See attached link of .64 2871R on stock bottom SR20 with 400whp. OK so its a 56 trim and it was on a dynojet with extrude honed stock exhaust manifold and exhaust housing. http://forums.freshalloy.com/showthread.ph...ight=JWT+S3%27s

The 52 trim 2871R (aka HKS GTRS) is spec'd with the .64 rear in standard form. However, if you went to someone like GCG or horsepower in a box you could probably spec it with the .86 rear. In all honesty if you were going the T2 .86 rear on a 2871R I would probably go with a 3071R (which is 56 trim comp) in T3 .63 rear with external gate as similar spool but much more top end. If internal gate is your thing as you probably know Garrett do the 3071R in a T2 footprint but it has the cropped turbine wheel - 56mm from memory (2871R has 53.5mm wheel). Whereas the proper T3 3071R has a 60mm turbine wheel. Please note I'm not an RB engine expert as I come from a SR engine background so read what you want from my suggestions. Late edit: just saw the link you posted it seems like the turbo it is a T3 housed 2871R. I can't help wonder whether the 52 trim comp might run out of puff tho'. For a 2.5 litre I would have thought the 56 trim comp might be better suited.

That looks to be the Garrett 2871R 52 trim (aka HKS GTRS) with T2 ex housing as used on SR20's. They're more efficient run at around 18 -20 psi.

For those of you who don't know what a TR30R looks like and/or interested in specs see the following link: http://forums.vwvortex.com/zerothread?id=2444259 Cheers

DP03 Don't they run restrictors in the WRC cars which is probably why hp is down realtive to the torque. I think they also run a round inlet on the turbine housing so throw in the cost of a new manifold as well.