LaurelPWR

http://www.performancebyie.com/blog/the-right-bellmouth/ Interesting read

They flow tested the otaku rb25 manifold ( no stacks) vs the greddy forward facing plenum.... There have been absolutely no flow tests done for the rb26 otaku manifolds vs oem or nismo or greddy.

I've been looking into one of these "billet" intake manifolds that have been doing the rounds from Otaku Garage and a few other lads who all get them through Alibaba I assume.... I wanted a nismo plenum but I can't justify $2k+ for a plenum.... Especially not when these are going for $700-$1k One particular seller is offering them much cheaper than others I've seen and is also offering an option of having velocity stacks inside the plenum. I'm only really interested in the rb26 individual throttle plenum as I run GTR throttles on my rb25. I'm aware hypertune, plasmaman and JUN all run internal trumpets in their plenums and thats enough for me to believe it's a good thing to have. I've been told by another seller who doesn't offer the stacks option that that are a hindrance to flow and performance inside a plenum.. What's your lads thoughts on all this? Stacks or no stacks?

Yo man any updates? Hope it's all going well (:

For what it's worth lads, I been chasing a gts-r manifold for a while now.... Getting over waiting as we all know how rare they are and people asking $2k+ for them when/if they do come up is a bit hard to swallow for something so old... CRG is fabbing up an R31House style manifold for me in a few weeks. It won't look as flashy because you'll see welds on the joins as it will be made from steam pipe instead of one piece stainless runners. But we had a good ten min chat on the phone yesterday about it and he's very confident he can replicate one! I'll probably make a new thread when I get it...

Oh okay man I'll send him a text and ask for some more info specs..

No man no more information was sent or received unfortunately [emoji17]

Where you located?

After I upgraded to a HKS gt-Rs, I was on the dyno converting my car to e85 and I looked at my curve vs some other gt-Rs results I had seen and I was underwhelmed in its response and ability to hold boost.... (Was using a blitz duel SBC for boost control at the time) SO, while on the dyno we measured back pressure directly behind the turbo in the o2 port and found it had 4psi of back pressure @ 20psi of boost. The steps I then took in the following months: I installed a turbosmart eboost2, deleted the 100cell "highflow" cat and upgraded my standard oem manifold to a HPI manifold. Then a re-tune! We picked up around 800-900rpm+ in boost response which resulted in more power earlier for a fatter midrange... There's a dyno below showing before and after. The BLUE line is before the upgrades and the RED line is the final tune after the upgrades. (Ignore the fact that the blue line makes slightly more peak at the top end as that run was only done for the printout to win a bet with a mate... It actually made 393.9whp peak before the upgrades..) All on an rb25 s1, pon cams, Ross forgies, gtr itbs, e85 etc.... HKS turbo had the standard HKS 14psi actuator on it...

What type of boost controller are you running? What's your exhaust system? Cats?

I may have one... What you wanna pay for one?

Sorry for any offence man, there was none intended... I'm extremely interested in your results a whole lot more so than others as I'm also putting a twin scroll rear housing onto a hta3076 on an rb25 and I'm having a very hard time choosing between the .83 & 1.01 a/r twin scroll housings... It seems your the only person to have actually done it so far on an rb25 and posted real results about it so I'm getting a little carried away with myself about what the possible issue could be in your setup... It's all very exciting indeed haha IMO First things first, instead of finding the "boost leak" you need to work out if the problem is actually a boost leak or a restriction or both or neither or shit intercooler or something else... Are you running a cat? And what boost control do you use?

Me and my bro would probably take 2 or 3 if it was to happen... Anyone else über keen?

Also forgot to ask earlier man, what's the specs of your full exhaust system/cat/mufflers etc.

I too have had struggles with traction so I added some micro flares, some 315/30/18 nitto nt01 semi slicks and re aligned the car to only .8° camber on both rears. I can't recommend the nt01 enough. Excellent grip even without a warm up. I also run my rear coilovers and sway bar on the softest settings. As far as your turbo/engine set up is concerned, have you read the thread about a hta3076 by 34GeeTeeTee on his rb25 Neo ? His engine set up is very similar to yours except single scroll not twin scroll but (absolutely no offence intended) his results are far more impressive than yours... Here's his dyno for before and after the turbo swap Blue line is gt3076 and red line is hta3076 Here the link to the thread: Forced Performance Hta Turbos There must be a restriction or boost leak somewhere in your system bro...

They showed some interest at first but It was too long between emails and they never replied after a while... I spoke to a guy two weeks ago who actually worked in the Gibson team on the cars and rb20 motors back then and he gave me some names to talk to if I was interested in the manifolds etc.. I don't see why we couldn't still get something happening if there was 10-20 people actually genuinely interested in this who have the money for it...

For sure man! Its a great result especially compared to the old gt3076... As far as boost leaks go, I spray soapy water all around the bay and use compressed air (30-35psi) through a 2-1/2 inch tapered pvc tap and pressurise my whole system to eliminate boost leaks! Works a treat and I very rarely have any leaks cos I do the test a few times a year or whenever I'm doing an intercooler flush or turbo inspection or swap etc... I would suggest vkadam does something similar to rule that out also..

Another plausible possibility for sure... I run my turbosmart eboost2 boost gauge source from the plenum and I have a separate Omori Boost gauge source from the compressor housing and there is a very slight (less then a full second) delay in me reaching my target boost at the plenum and the compressor spikes to 1psi higher at the same time. Correct me if I'm wrong but could another possibility be faulty/weak bov?

Thanks for your reply man [emoji4] What size a/r twin scroll rear housing did you end up using? And what manifold did you mate it with? What boost control are you running and what size gate? Sorry for 20 questions brother hahah

Well if anyone wants an autech manifold I have access to one for $300US plus shipping through a guy who has the rb20 autech motor...

The autech manifold appears to have the same flange as the r31 house in that pic and not a t25 flange as someone said earlier in the thread... Just out of curiosity, would anyone be chasing an autech manifold? AND What would people be willing to pay for one??

Awesome thanks for that man! They don't appear to be anywhere near as good as the Gts-r manifold.... They don't look tuned length or a decent merge

You wanna sell yours? [emoji12]

This is what I expected to see....

Yeah man I pmed you last week about yours... Have a look in your inbox brother