M@&k

Hi all, Have pulled together some info from the RB25 dyno results thread. Only considered some of the more common turbo options (for more data points), and have focussed on those which are internally gated. Turbos looked at were: HKS GT-RS HKS 2835 Pro S Hypergear SS1PU GT3071 Was originally going to do 3076 as well, but didn't find a whole heap of examples where internal gate was still used. Have put together two plots. One shows peak power vs boost, and the other shows some dyno curves. Dyno curves are approximate, as I only read off a handful of points from posted images. Also recorded a bunch of dyno curves in km/hr but cbf trying to convert as not aware of different drive ratios between RB25 variants (e.g. Stag vs Skyline). Might dig some more in the info later to see if any other trends (e.g. for intercooler types), but nothing was immediately obvious. Some observations from myself: You're not going to see benefits of the bigger turbos (e.g. 3071) unless you push higher than 16 psi. Those with cams seem to be consistently at the top of the range. i.e. cams are good. Best results were had with Neo engines, but also some strangely poor results with GT-RS. SS1PU looks very good, shame there wasn't more results. Strongest mid range from 2835 Pro S Some possible conclusions: If you only want to run 16psi, stick with GT-RS (GT28) sized turbos. If you want max mid range (3-5,000rpm) smaller turbine is better. GT3071 really shines > 5,000 rpm, and needs boost. No groundbreaking insights here. There's obviously a heap of other factors that come into play too, but hopefully is of some interest.

Don't know too much about the HTA turbos to be honest. Might need to look into that. Also agree that Hypergear has been getting some great results from his SS1PU turbos. I guess I've been looking at Garrett because there is more data available. Just irritates me I can't find something between the two standard turbine ARs. If only the HKS Pro S was available at a realistic price, it would be a done deal. Also have been pulling together some info from the dyno results thread comparing some of the more common IWG turbo options. Will probably post in new thread when I get my sht together.

Looking for 260+rwkW. Basically what I'm searching for is the next step up from a GT-RS. The GTX3067 in 0.63 AR (as per Disco's advice) seems to be the next logical step up, and hoping it won't give away too much response from the 2871-52T of the GT-RS given the newer tech and slightly smaller dia GTX wheel. Another idea I was kicking around was to try and replicate the HKS 2835 Pro S: Use a 3071-WG CHRA (the cropped GT30 turbine), but replace the compressor with GTX67 Get the ATP T25-EWG-44 turbine housing in T3 footprint - it's based on GT30 housing and available to suit cropped turbine. + external wastegate etc. But it seems like too much of a gamble given the effort that would be involved. Not to mention the negative feedback generally surrounding these components. Anyway, it sounds like the way forward is to get the 0.63 AR housing and enlarge the wastegate port. Thanks everyone for their input. Cheers, Mark.

Thanks Disco. After much reading today, I'm starting to agree. My initial excitement over these housings is waning rapidly. Looks like if I want to try something a bit different, it's best with the 0.63 AR GT30 housing. Then at least if there's trouble with it, can at least swap out for the 0.82 version without having to change the dump again. Thanks all for the input.

I've been trying to find some results of people using these housings. Found some comments on Zilvia.net about the ATP T25-EWG-44 housing saying it was crap, which supports comments earlier in this thread. Link is below for those interested, but be warned that you will have to wade through 24 pages of SR20 babble: http://zilvia.net/f/tech-talk/432611-new-garrett-gtx2867r.html Still looking to see if there is any other info on the Cosworth type IWG housing...

Yeah, this is exactly my point. What did HKS do with the GT-RS (and other) housings to avoid boost control issues, when the Garrett GT30 0.63 AR seems to be generally considered a no no even though it should be less restrictive than the GT28...? Is it simply down to the size of the wastegate port?

That's an interesting point you raise about the smaller turbines Scott. Some time ago was comparing GTX2867 with 0.82 AR and GTX3067 0.63 AR. Supposedly they flow the same (which seems to be supported by Garrett turbine maps on their site), but someone, (I think Lithium?) said that the GTX3067 is a better match and hence more efficient. Trying to find a T3 housing for the GTX28 is a pain too. Wolverine, all input is welcome. Kind of like the idea of being a test pilot. Would be all worth it if it turns out to be a good combo. Obviously don't want to throw money away, but in this case I feel that the the risk (boost control) is a known, so can take steps to avoid it. At worst, might learn something. A questions that just struck me, how come boost control in the GT30 0.63 AR seems to be an issue, but not for the GT-RS (2871) which I also thought had a smallish AR? Just because the compressor flows less?

The plot thickens... look forward to hearing more on this. Hehe. Even if I did go external would plumb it back. It's going to be predominately a road car so avoiding unwanted attention is a priority. What are the chances of getting an engineering certificate for an external gate set up? Yeah the flange is a concern. Haven't seen one off the shelf, but was planning to talk to my mechanic who's pretty nifty at fabricating manifolds and the like. Plan is to get the "big can" actuator, which is 18 psi I believe. Good food for thought re: external gate. Maybe I really should be looking at a housing with a more standard outlet. That way if (when) I decide to upgrade again later, can get a larger housing to bolt up rather than having to make a new dump pipe again.

As much as I'd like to go external gate, it's most likely overkill for what I'm after. Looking at mods in your sig Scotty, I think we're playing in different leagues, haha. Part of the reason for the GTX3067 was to try and get GT3071 like peak power (260kW+), but with full boost by no later than 3,500rpm. And to try something new. But yeah paranoid about boost control with the 0.63. Not sure if you guys saw, but pic below is of the wastegate port on the Cosworth housing. That's a US Quarter Dollar (24mm dia) he's holding. Port looks decent sized to my eyes. Based on the comments, I think I need to do more research. Last thing I want to do is have this (Cosworth) housing be more restrictive than the little Garrett, or worse, crack and fail on me. If the design is good, but ATP castings are crap, maybe I need to look at getting a second hand OEM Cosworth housing from somewhere... Will definitely post up results when done, but to be honest probably isn't going to be until early-mid next year. Appreciate the input lads.

Oh right, so the ATP external wastegate jobby is no good eh. To be honest I know sweet FA about external gates. Sounded good on paper...

Thanks for the input lads. Wolverine, guess I've been a bit worried about the response of the 0.82 housing. But equally concerned about boost control with the 0.63 as you've highlighted. Was kind of hoping the 0.72 Cosworth would be a good balance. Admittedly have maybe been a bit hung up on trying something different, e.g. like with the GTX3067. Scotty, didn't realise ATP housings were crap too. Cheers for the heads up. Read about the AVO / Sonic housings, but not ATP. So it really does seem the Garrett 5-bolt outlet housings are the only viable IWG option?

Hi guys, I've been looking into T3 turbine housings for the GT30 series turbos (specifically the GTX3067) which will fit to the standard manifold. Response has been high on my priorities, so the 0.63 IWG housing was originally considered, although was always a bit concerned about boost control. Always thought it would be nice to find a turbine housing which sat between the 0.63 AR and 0.82 AR housings commonly used. I was pleasantly surprised to have stumbled upon a couple of options which might do the trick. First one is the Cosworth 3-bolt outlet IWG housing (first pic below): http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-HSG-075&Category_Code=GTH Seems to have a really decent sized wastegate port too: http://www.turbobricks.org/forums/showthread.php?t=103756 This housing is stated as having a 0.72 A/R, so sits nicely between the two "normal" housings. Seems to me like it could be a good balance between response, top end and also boost control. Downside is I would have to go with a less common outlet flange. Second option, is this housing which has an external wastegate flange (second pic below): http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-HSG-043&Category_Code=GTH Quoted from ATP website: "Special turbine housing, T25-EWG-44, T25 inlet flanged, GT28 style 5-bolt outlet. External gated (44mm flanged), flows like a full T3. Available for GT28RS/71R/76R, full size 60mm GT3071R/GT3076R/GT3082R turbine wheel and Stage III (76 trim) turbine wheel. Allows full T3 flow but on T25 flanged manifold. Only available in .72 A/R. .72 A/R is built to GT30 geometry so this A/R is comparable to one that is right in between a .63 and .82 A/R GT30R housing." Note that although it's listed as T25 it can be optioned with T3 inlet. Also interesting here is that this can be gotten in form which fits the cropped GT3071-WG turbo, so may be a decent option to get HKS 2835 Pro S type performance at half the cost? Overall second option is less appealing to me because it's another step away from stock looking, plus more expensive due to cost of wastegate and extra plumbing of dump. Wondering if anyone has had any experience with either of these (especially Cosworth one)? Or even just thoughts on how these might perform would be very welcome? Hoping the collective intelligence of SAU might shine some light on this. Cheers, Mark.

Reason for sale? Willing to sell without rail?

Mine made 184kW after the tune (not sure what it was before tbh). Only mods are pod, exhaust from turbo back, and R34 SMIC, 9psi. So pretty much in line with yours really. Oh, also seem to be getting much better fuel economy now. A welcome side benefit.

I really like your rear wing. Nice wheels too by the way, looks like it means business.

I was looking into the same fitment for mine. Read a number of posts that the 9.5 +30 will touch the suspension at full lock. I guess you can drive around it, but it was enough to turn me away from the idea. I ended up going 9 +20 front, and 10 +38 rear (XD9s), and although is good fitment with no hassle, sometimes wish I went with 9.5 +22 all round. Also for what it's worth, I don't think that the 235 is that stretched on a 9.5. In fact I quite like the shape of the sidewall you get with that fitment. Anyway, whatever you go with, make sure you post up pics in the fitment thread once done, so we can admire.

What are the offsets? Should be stamped on the back of the rim if you don't know off the top of your head.

I had a photo of this (the one in your signature) on my desktop for a while. Great car! Now I just need to justify to myself that I can afford to buy it... Any photo's of the interior?

What is said negotiable price good sir? Also, any pics?

A friend of mine imported her 300zx through J-Spec. She was after a specific model (had to be 4-seater, twin-turbo, and specific colours) so was hard to find. He didn't pressure her into buying something she didn't want even though it was taking a long time to find something. I remember he also gave good opinions on what was worth considering or not. All round I'd say it was a thumbs up. At least based on my once-off second hand experience...

Pics of the interior and engine bay would really help the ad in my opinion. Oh, and posting a price doesn't hurt either.

18x10 +30 will foul on the inside (rim against upright at full lock). I believe 18x9.5 +30 also fouls on the inside at full lock, but have seen some guys run it.

R33 GTST Work XD9 18x9 +30 - Federal 595 235/40 18x10 +38 - Federal 595 265/35 Certainly fills the guards better than previous wheels I had, but not as close to the lip as I'd hoped. Probably could fit another 10mm poke on each corner without any drama. I had all the guards rolled in preparation, but in hindsight, probably not needed. I reckon these offsets in the XD9s are good if you're looking for minimal hassle in fitment, but definitely not as tough as f +20 / r +18 (which most guys have). At least I have an excuse to start saving for a set of Meister S1Rs

Also keen to see results. How did you go fitting up dump etc? Did it end up sitting in the standard position?

Found it: http://www.skylinesaustralia.com/forums/topic/401848-trying-to-fit-my-dream-wheels-te37/page__view__findpost__p__6393854 You can see in one of the photo's how they used the tab to hold in the liner. Personally I would prefer to keep my liners when I roll. This looks like an option, but would be keen to hear others thoughts too.