LaurelPWR

Thanks for the post man. I'm only really after HKS 256/264 cam results though... I have poncams now and theres literally hundreds of poncam results around the net. Is your turbo internal gate?

Here's another very similar result:

Better pic of the dyno without the power figures cut off...

Another set of old results from the RB25 dyno thread that look quite promising for poncam-like response with a decent top end for the given turbo/boost and fuel. Starting to think I I may be able to realise my girl [emoji848]

What do you think Lith, can I keep my current response and get some small gains with the hks drop ins?

These results from the RB25 dyno thread are pretty decent as far as response is concerned and that's a pretty decent top end figure too for that boost level on only 23psi & p98 fuel [emoji848] looks very poncam-like. I guess hub dyno results are a little stretched tho..

Very interested to see what you get out of those [emoji848]

Ok thanks mate You have Pm

I'm open to any and all brands if I can retain VCT and keep my current responsiveness !!!!! Please feel free to school me (:

Hey guys. Apologies in advance for the age old topic and question, but I'm having a very hard time finding any of the old threads and results on SAU about this and other skyline forums aren't much help either. Even google search results aren't yielding any solid information. What I want to know is, how do the rb25 s1/2 HKS 256 8.8 / 264 9.0 "drop in" cams compare to Tomei 256 8.5 / 256 8.5 pon cams as far as boost response is concerned ?? I currently use the poncams and I'm wondering if I install a set of the hks or even just a hks exhaust cam, can I gain a little more mid range and peak without loosing any response... The only sort of info I have been finding is people speculating about a set up they "know of" or "a mates car used these and made heaps of power"... Obviously a before and after dyno comparison on a same car, same dyno & same day with the two different brand of cams would be ideal but I highly doubt that info is out there.. My set up is s1 rb25 with HKS 2835 pro S .87a/r internally gated on e85 making 470whp on 24psi Any links of help is greatly appreciated lads [emoji1365]

Anyone taken the plunge yet?

I'll have a before and after dyno result in the next months but unfortunately won't be a straight up comparison between the 45mm and 49mm throttles as I'm also installing a crank trigger kit, r35 coil kit, 1000cc injectors and re tuning with a new link G4+ instead of the power fc but will be the same turbo set up so might still be relevant enough for some [emoji848]

There's some old videos and articles around of jap built gtr's doing 8 sec 1/4 passes with itbs so I would assume they can support anything one can throw at them.. Also, a google search shows results of 1000hp cars running itbs so I guess it's all about how much you want to spend for your personal goals and desires which is pretty much the outcome with all these sorts of questions...

Sorry mate...my bad. LOCATED GOLD COAST WILL POST ANYWHERE AT YOUR EXPENSE.

Good morning lads. Would anyone be interested in a brand new: Garrett Ni-Resist Turbine Housing, T3 GT30R Series, Split Pulse/Twin Scroll, V-Band (3.0" Discharge), 1.01a/r Turbine housing... Suits the Garrett GT3071R (60mm/84 Trim only), GT3076R, GT3082R, GTX3071R, GTX3067R. Also comes with V-Band clamp, locking plates, bolts and a T3 mounting gasket. Reason for sell is because I need a t4 flange housing [emoji57] It's never been run or used but had been test fitted to a brand new hta3076. $800

^^49mm bored out throttles with new 49mm oversize butterfly's, cnc port matched nismo plenum & cnc cut plate to match the new centres of the throttle bores that will be welded to the rb25 runners ^^finished cnc machine work inside the nismo plenum. The origional ID's inside the nismo plenum runners are 43mm from the bell mouths all the way to the last 10mm before the throttle, then it tapers to 45mm. I've had the runners cut to 46mm from the bell mouths, but then started the taper from halfway along the runner which tapers out to 49mm to match the throttles.

*rb25de neo head

That's a matter of personal preference my dude. I personally love the snappy on/off throttle response I get from them. It was a nice upgrade from the forward facing "Greedy" plenum and also surprisingly increased boost response. Another thing is, I don't know any other car in the world running an old GT28/29 frame, internal gate turbo making the figures I make so I strongly believe they help me achieve that also. So yeah they have cost me a lot and continue to do so, but to me it's well worth it haha As far as room to work on them goes, well rb's are mounted north/south so naturally they would be a s h i t l o a d easier to work and because mine are in an s13, my strut towers are further away from the motor (s chassis McPherson strut VS unequal double A-arm R chassis) so I may have a little more room again to access them over a skyline. Then if I compare to the factory rb25 intake manifold... NO COMPETITION AT ALL haha You can't hardly access the injectors and a few other sensors on the factory long plenum because of its curl-over long runner design. Then add the fact that the throttle body sits smack bang in the middle of the plenum, feeds from the cooler cold pipe that goes up past the top of the turbo, over the rocker covers... just to chance plugs and coils you have to pull half the intake system off... Give me throttles over that any day haha. Easier, snappier, faster for a given purpose.

Yeah man I just received my 49mm throttles from them last night [emoji87][emoji12] They only offer a 48mm service though...they like to keep a minimum 1mm of housing "meat" between the inner bore wall and the shaft bearings on each end of each set of throttles...but after a long phone call explaining that there's other company's that offer 49mm service albeit for a higher cost, I convinced them to go to 49mm and they do it by moving the centre of the bore inwards .5mm to retain the 1mm of "meat" at the shaft bearings. I would post pics but I went and dropped them off at the machine shop with a nismo plenum to get the plenum cnc port matched to the throttles. I don't need the injector plate machined as I run the throttles on my rb25 using a custom made adapter that used cut and shut lower rb25 runners which are 50mm ID. Will be interesting...

The whole single throttle more power thing is a myth... I believe both single & itbs have their individual uses and purposes so it's not something that really can be compared. Not to mention there's the car in the article above built by Top Secret running itbs making well over 900hp... But anyways that's an argument that could go on and on hahahaha So yeah, aside from all that, I kinda just really wanted to know if anyone on here has actually done it.. I've always seen it as one of those glamorous mods that is there for the high end and elite types and big workshop builds.. Would be cool to hear from just a lad who decided to take the plunge on it. But as said above^ it's normally done with a whole host of other high end fruit so probably never going to see a before and after but it's worth a shot asking (:

Hey lads, As the title states, RB26 oversized 45-49mm throttle upgrade... The best known company that offers this service is NAPREC in Nagoya, Japan. I believe it's around $1.2k+postage and tax and also (if you use Streeter) Streeter's postage fees and commission etc. And that's just for the throttle machining and rebuilding and you have to supply your own set of throttles. Then you need the 50mm gaskets.. more $$ NAPREC link: http://www.naprec.co.jp/product/t001 There is also the Garage Ito option which is cheaper but still $1100+postage+gaskets etc. etc. and you still need the set of throttles to send them. Nengun link: https://www.nengun.com/garage-ito/rb26-big-throttle-body Interestingly enough, HyperTune now offer their itb intake manifolds with the 49mm oversize runner option to mate with NAPREC throttles. Both company's promote each other in regards to these products now too. NAPREC link for HyperTune plenum: www.naprec.co.jp/product/rb26dettサージタンク There's also this Facebook post I saw with what I assume is a customer of Top Secret and someone who has done the upgrade. I'm not 100% if these claims are of the oversized throttles and the plenum combo or just the 49mm runner plenum...Anyways he's claiming around a 40ps gain from the upgrade which I think (if at all true) is actually a pretty substantial gain for an intake mod... Here's the link: https://m.facebook.com/masahiro.takemura/posts/921436694600562 And a screen shot of the link: Some more screen shots of the products in question: So, has anyone on here actually done this mod or know of anyone with first hand experience on this and that has done the 49mm itb's ? Would love to hear and or see some graphs or real world results.

Yes let loose is the key words... 20-30psi should do [emoji1362]

I would assume they have plans for G30 sizes... Here's hoping these G25's do what is claimed... And If so, could it be too much to hope for a G30 type to produce 400-700hp [emoji848][emoji848]

[emoji848][emoji848]not bad at all... I would be willing to be the guinea pig and give it a go if i hadn't spent a heap on this new hta3076 twin scroll sitting here [emoji57]

I'm keen to see what pricing will be like....