I was reading up about turbos and i came across this http://www.homemadeturbo.com/tech_projects/itb/ . I might be attempting this on my turbo 2gnt. My idea was to buy an obx intake manifold, chop it right before the injector bores, mount the itb's to that, trim the runners on coming off of the obx plenum and use that to mount to the outside of the tb's and run your intercooler pipes to. Mount of the map sensor shouldnt be a problem since its going to be MS'ed. The only thing i am somewhat worried about is either tryin to get our stock TPS & IAC to work on there or somehow use the gsxr's. Elaborate on my thoughts people! All comments, ideas & opinions are welcome!

upon further observation... clearance will def. be an issue! I might have to fab something up instead of using the obx manifold.

Check out Neons.org sometime and drop ITB in the search. They do some crazy things to the 420a over there.

They also have front mounted intakes, so they have a bit more room to work with. You can definitely get some ideas over there. You might also Google ITB setups. Lots of good info out there. TVRs running 8 of them on MS, TODA makes a set up for the RSX, and there are a couple other vendors I've found. Even though you don't have to mount your stock MAP to use with MS, you're still going to need a way to equalize the vac readings through use of a vacuum tree of some sort. Interesting project. Get to it!

I was contemplating the benefits of this setup..... doesnt really seem to have many! Since i am already forcing air into the motor(turbo) a regular intake with a large throttle body should get the job done with a lot less hassle. I think i am still going to attempt it since i have never seen it done on a 2gnt. This might be a little off topic but... whats so bad about the obx intake manifold? Did anyone ever have it flowbenched in comparison to a stocker? Seems like an alright design for a turbo app., short runner length large plenum and it accepts a large throttlebody. I dont see any reason why it would not perform well. I have heard complaints about the runners not matching up neatly to the intake ports on the head and placement of the map sensor but thats nothing some minor fabrication cant fix. I want reasons why the obx manifold is crap, not opinions. Has anyone ever dyno'ed a turbo 420a before and after install of it? Im not being argumentative... i just want facts about it (performance wise).

come on guys!!! lets get technical in this mofo

Originally posted by taclipse
come on guys!!! lets get technical in this mofo

:wary Where have you been, son? I'm all over ITB discussion, as are, I would imagine, at least a couple other people on this forum, but you turned this thread into an OBX manifold discussion. :twitch

Originally posted by taclipse
Whats so bad about the obx intake manifold?

Aside from the fact that it's known to be of questionable build quality and offers negligible gains for it's better-than-$200 asking price on eBay, and Concept Illusions has to modify it before they can sell it? I guess there's nothing wrong with it. :rolleyes

Originally posted by taclipse
Did anyone ever have it flowbenched in comparison to a stocker?

Concept Illusions markets this manifold as being a 70% increase in volumetric efficiency over stock. I would think, making a claim like that, they'd have some research numbers to back up such a statement. Why don't you give them a call and inquire as to these claims? (snicker)

Originally posted by taclipse
Seems like an alright design for a turbo app., short runner length large plenum and it accepts a large throttlebody.

Those are, as you stated, ideal qualities for a turbo manifold, however what do you think about spending more than $200 bones on a manifold that has been known to require porting and modification right out of the box after purchasing something marketed as a direct bolt-on? Did you do any research on this forum about what others have said about this subject in the past? I'm not gonna lie, there's a lot of shit talking to be found, but I didn't come across anyone saying anything positive about this that wasn't in I-actually-bought-this-damn-thing-so-I'm-gonna-look-at-the-bright-side-of-life tone of voice. Think about it this way: OBX markets this manifold as being specifically made for this application, yet they neglect to install a MAP sensor port? How do you test this product on a car without the MAP sensor? You don't. You make something, put it on a flow bench (maybe) pat yourself on the back that it flows some air and doesn't leak much, then you peddle it to kids on eBay who don't know any better and want something pretty under their hood.

Originally posted by taclipse
I have heard complaints about the runners not matching up neatly to the intake ports on the head and placement of the map sensor but thats nothing some minor fabrication cant fix.

Hey! Maybe you did some research after all! Way to go. It is appreciated. Maybe that's why you didn't get flamed and people just ignored this thread once it turned into another OBX manifold discussion. Minor fabrication isn't really a problem, I think it's more that the product does not provide the gains it promises and there are better ways to get more power out of your intake than with this thing. People are just tired of hearing about it, I guess.

Originally posted by taclipse
I want reasons why the obx manifold is crap, not opinions.

You just said you were familiar with them! To recap:

• Fitment issues
  
• Sketchy build quality
  
• Price
  
• Vendor reputation
  
• Negligible gains
  

You have to keep in mind that people on this forum know where the problems are with the stock manifold and in what areas it needs to be improved, so they know what is and what is not needed for this application. Simply put, for the money, the OBX intake manifold and the vendors who sell it do not make available any form of documentation or evidence that the claims made to sell it are justified, the manufacturer has a reputation for selling cheaply-made knock-offs on eBay, the amount of fabrication that *might* be required to one of these things before installation (since build quality is known to be inconsistent at best) is unacceptable for a product of this nature, if anyone who bought one did do before and after dyno runs showing impressive gains with this installation, they haven't said anything, and most of the comments in support of this prouct are on par with those defensive remarks made by people who bought one of those "performance chips" on eBay as well. That should tell you something.

Originally posted by taclipse
Im not being argumentative... i just want facts about it (performance wise).

I will give you a very hot tip. Somewhere on this board, Matt Duncan is discussing (or was) building of a custom intake manifold for a turbocharged MSnS'd 2GNT. He posted looking for an intake manifold flange and went from there. Matt is a smart guy who knows what he's talking about and, even better still, he's in the zone right now brainstorming how he wants to go about addressing known issues with the stocker in his new design. You might want to find his thread about the intake manifold as well as other threads about the stocker and become familiar with what improvements need to be made to the OEM piece so that you can get a better understanding of what needs to be done so that you can possibly contribute some fresh ideas from outside the box. All the fun, in this community, comes from the custome shit.

Now, as for ITB set ups, why do you say they aren't worth the effort? Understandably, installation on a turbocharged car presents unique issues, but what reasons can you share with everyone as to why this wouldn't be a good idea on a normally aspirated car?

(I'd go on, but damn. I'm tired of typing!) :order

:) atleast you put me on the right track! I dont post much on this forum (as you can see) and whenever i use the search function i end up with 19 pages of complete garbage or biased opinions. I dont feel like filtering that information to find Mr. Duncan's thread. Thats one of the reason im not very post happy on here! I have lots of ideas floating around in my head and they are all somewhat intake related, I didnt feel like cluttering the board more than it is with small questions. Im not really worried about the claims by the manufacturer or advertiser's. I think this manifold would be a good building block for improvement (ie:velocity stacks) and would work as a good cheap starting point. I'd rather post on here and get opinions from the forum members rather than contacting the company directly, not to mention last time i tried to email obx w/ some questions i got a poorly written response back. I also never doubted ITB's on an NA car, If you read above i stated turbo car.

Matt's (XtremeRS) intake manifold thread:
http://forums.2gnt.com/dcboard.php?az=show_mesg&forum=5&topic_id=99380&mesg_id=99380&page=2

some discussion on ITB and the issues:
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=32&topic_id=428

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=32&topic_id=3

My project...that's been on the back burner for some time now. Maybe if I decide to go MSnS I'll get back into it.
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=32&topic_id=888&mode=full

EDIT

I have updated the upper manifold...it's bigger now.