juggernaut1

Not a direct back to back but i went from 3071 to 3076 52 trim on my SR with larger dump/exhaust and made identical peak (~ 290rwkw) but the 3076 52 trim actually had reasonably more mid range than the 3071 - possibly due in part to the larger dump. HOWEVER, shortly after the new setup was installed I noticed that my Hypertune intake had a crack in it (for the 2nd time). It is possible the car was tuned with the crack when the 3076 went on as there were no tell tail signs anything was up as the crack was underneath so was not obvious and did not have a high idle speed. I only found out one day when I happend to put my hand underneath the intake and my fingers were being sucked onto the intake at idle. Funnily enough it would still fry the tyres in 1 and 2nd from around 3500rpm even with the crack and leaking boost. In finalising I want to say Peter at Hypertune has come to the party and is supplying me with a brand new plenum to refit at no cost.

One common theme I noted from the specs of these 3 GTX turbo's is that they run a slightly larger exducer than previous models, but run comparatively more inducer size....i.e. these 3 GTX turbos all have 58 trim comp wheels - up from 56 trim. 3071 model now also has a .6 comp cover - previously .5 comp cover

I have a reasonably responsive modified s15 and have also bought a 2010 G6E turbo (old mans XR6T). Both are great cars. For the street I prefer the G6E - peak torque at 2000rpm combined with a 6 speed semi auto makes for an easy reasonably quick cruiser - and I don't have to change gears (or I can use the manual mode) - just nail the throttle. For fun the S15 is great - once you get traction.

Because the v8 is gutless (OK has more progressive torque curve ) and thefore easier to drive on the limit. Have a look at the recent time attack. The Fernandes Falcon supercar had the V8 ripped out and the turbo 6 put in. It was slower than the v8 Commodore supercar. Fernandes said it produced too much power/torque and was a handfull - couldn't get traction in 4th gear....and that the v8 was an easier car to drive because of its more progressive nature. So not only is torque important - but the way its delivered. Link to results - note the Falcon was nearly 1 sec slower than the Mal Rose Commodore. http://www.natsoft.com.au/cgi-bin/results..../2010.EAST.S2.Y Also note the 1st 6 positions were filled by 4 cylinders or rotaries - probably becuase they are a bit "softer" when coming onto boost when on the limit.

IMO in order to gain a benefit out of these short runner intake manifolds you will need to spin more rpm. Generalising.....if you are going to drive it in the stock rpm band then stick to the stock manifold for the best overall power/torque curve.

But the boost curve of a Precision Turbo is rock solid table flat .

Just as I thought...thanks for that.

Thats generally been my understanding - the greater the intake temp exceeds the ambient temp the greater the correction (inflates power) and vica versa (deflates power). So there is no correction where intake temp and ambient temp are the same.

and another example http://www.xtremefordtuning.com.au//images...0F6%20Boost.jpg

PJ can you speculate what the intake temp of minus 77 might have on power? Where was the intake probe.......Antartica!! Is it possible to post up a graph in rpm? Cheers

Refer to the HKS website - the 52 trim 3076 is available in 2.75 non-surge or 4 inch surge.....from memory the bigger 4 inch surge was rated at slightly more power - a difference that might be carried across to the 56 trim 3076. Edit, Here's the link - you will note the 4 inch cover is rated at 10hp more that the 2.75 inch cover in both the 52 trim and 56 trim. http://www.hksusa.com/categories/more.asp?id=1092

I use a 100 cell CES racecat - 5 inch body 3.5 inch in and out. Usual impecable quality.

Ummm..... I think your looking at my power curve.....the other curve is the boost curve.

Haha...I'm not even going to ask for AFR's .....there probably in litres per 100klm's Lol. I'm running 1.2 bar springs (the old gates had 1 bar springs) Running a 3 port Mac valve as the boost controller which is controlled by the Autronic. However, the way the Mac valve is plumbed is what I believe is "unconventional". Both the top and bottom ports of the gates are plumbed back into the same port on the Mac valve (using a tee). I guess there must be a restrictor in one of the lines somewhere. This to me could be one of the causes for my falling boost...I'm not sure? This plumbing was carried over from the original setup which was done by the original tuner. I was speaking to Jeff at C-Red about this boost control side of things who suggested we plumb the gates using a conventional method ....i.e. not using the same mac valve port for the top and bottom ports of the gates. Failing this we may need to use a dedicated boost controller becuase, due to the size of the gates when combined, a small movement in both gates makes a big difference to the boost (read sensitive). In his view a dedicated boost controller will be more precise. I have a Blitz ID3 dual solenoid bost controller at home so this may be worth trying if the conventionally plumbed mac valve does not work.

Boost graph: Points of interest: boost graph in KPa! starts making positive boost at approx 2300rpm approx 21.6 psi by 3750 approx peak boost of 23 psi at about 5000rpm then starts dropping. different hp compared to graph posted above - not sure whether ran more boost to achieve above graph. doesn't make 1.6 bar of boost at 3600rpm as previously advised - but see above comment.

Now I don't have an R33, but I just fitted a 3.5 inch CES custom exhaust to my s15. I thoroughly recommend it as it is not loud nor drony. I previously had their 3 inch system on my s15 which they claimed had legal db's and I can honestly say there 3.5 inch system is NO louder even with a 100 cpi cat. It has a large oval mid muffler and large oval twin tip muffler (with twin 2.5 inch dual skin perforated outlets) which are custom made at CES. It cost me $1600 plus freight. Now that might be a little more than your willing to spend but...but what extra price do you put on a drone free and reasonably quiet exhaust? I live in Perth and the exhaust was custom made at CES in QLD and yet despite this it's a beautifull fit even though the car was not there...tucks up nice and close to the body. Also has twin tips as I wasn't keen on the cannon style to which Trevor at CES advised it would be slightly louder with the cannon. Can snap some pics if you want to get an idea of the quality and fit.

Uranium?

Disco Yes this is the surge ported 52 trim 3076. We had slight surging issues with the previous 3071 setup when it was boosting. So I went with the surge ported version of the 3076 just to be sure I didn't have surging issues...probably just as well I did. Not to mention the surge ported version was rated at slightly more hp than the non surge ported version. Yes I am also using the S15 low port head with has been subject to JHH engineering work...including clover leaf combustion chamber, porting and polishing and larger ex valves only. VCT was attempted to be retained for additional mid range torque and to spool the turbo earlier. The VCT kicks in at 1500rpm and comes off at 7000rpm. Standard I think it comes on at 1000 and switches off at 5000 rpm or thereabouts. PS I see BMW is now ditching the twin turbo setup (was it a compound setup?) on the 135i inline 6 and going to a single twin scroll turbo.

Yes, a 3076 52 trim turbo is slightly bigger than the 3071 56 trim. Your right though, I can't conclusively say what did what....I don't even know what boost it was running on the dyno yet apart from that I was told it made 1.6 bar at 3600rpm. All I do know is that I'm running a slightly bigger turbo and the car is definately more responsive throughout with the changes and the tune. Perhaps this turbo is just more efficient at whatever boost it is running compared to the 3071?

Tomei 260/260 hydro cams....still using variable cam timing.

.78 ex hsg

I was told it made 1.6 bar (23psi) at 3600rpm....which sounds plausable judging by the torque curve....which is awesome for a 3076 on a stock stroke SR I'd like to see the boost graph though.

The old cat was a Metal Cat 4inch body with 3inch in and out. The old exhaust was a CES 3 inch exhaust from the cat back. The previous dump was a full-race motorsports dump with custom lower pipe. No boost controller alterations Yes I believe the larger 3.5 inch dump straight off the back of the turbo and introducing the gate pipes back into the exhaust just before the cat are can be attributable for the extra responsiveness. Josh at C-Red did an awesome job of the fabrication work - fitting a 3.5 inch dump and twin 44mm gate tubes in an SR engine bay is no mean feat. The 3.5 inch CES exhaust is also pure quality. In fact I would also suggest its no louder than their 3 inch system even with the 100cpi cat. The mufflers are 2 x large custom made in house at CES.

My previous setup copped the following upgrades: 3076 52 trim (replaced the 3071 56 trim); Extrude honed exhaust housing; 3.5 inch C-Red custom dump and custom CES exhaust (replaced 3 inch ex) Tial MVR wastegates smaller (replaced Tial 44 wastegates) 100 cpi cat with 5 inch body 3.5 inch in and out; Gate dump merged back into exhaust just before the cat (previously merged just before it went under the car); BP98 retune by Sean at Allstargarage. Unfortunately I don't have back to back dyno's on the same dyno as the retune was done by a different tuner. Will post up the boost graph when received. Initial driving impressions - this feels more responsive than the previous 3071 setup. Peak hp is achieved at around 6350 rpm. I suspect the boost control is a little wonky judging by the torque and hp graphs. links to other threads: Dyno's http://www.skylinesaustralia.com/forums/Sr...l=my+sr20+build Build Pics etc http://www.skylinesaustralia.com/forums/Sr...l=my+sr20+build

My bad. Agreed