RBS14

I don't agree with you when you say they will be too small. if I had gone with 45's would you say they are too small? wooo hooo 2mm!

Deviouska has these same tb's on his sohc, and he's gotten great results. I'll side with him, instead of with someone (no just you) who hasn't done them on a ka.

Here's the bottom line:

-they will be an INCREDIBLE improvement over the stock manifold + intake piping.
-they were WAY cheaper than ANY other tb's I could have gone with.
-B series honda engines are completely different in design (rod/stroke ratio etc.) than ka's. Saying a B18 responded in X way from ITB's in no way means a ka will respond in the same way.

Mods: this is all in fun and games, please don't think it's a pissing contest and lock it.

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240sx2nr95

very cool! make sure and get some pics when installed!

-Dan

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z_boi

you just cant handle a turbo alex....really nice set up tho...

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radhaz

Great initiative! I'm looking forward to following the progress on this.

ledzeppelin240

Nice setup. It was mentioned that they work and the SOHC. The SOHC has a lower CFM than the DOHC. I thought that should be added in...

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Drunk Bastard

great job RBS14!!!!!!!1 I can't wait to see the follow ups on this project!!

sLiDewAys

Scott, looking good man, ghetto ITB set up is madd Santa cruz'ish. FHA SHOSKIE!!!

lol, but it looks really good man. i hope to see you and it arround sometime. later and wishes for the best

brandon

Rennen

Good job, nice to see you taking the first step and trying them out!


I am definitely interested to see how this goes since I will be trying a similar setup in the near future.

I may just suck at reading tonight but... how are you going to meter the air going through this whole mess, and what kind of ECU are you using. That is my main concern between the decision between ITBs/carbs.

-Matt

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RBS14

I'll be using a MegaSquirt standalone. It uses a map sensor, so it's perfect for ITB's.

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revat619

Scott, that's frickin awesome! Definitely keep us updated on the progress!

lookin good.

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kandyflip445

When you stick that on and are reving your engine, will it not eventually work the ITBs out of those rubber tubes? It is a great idea though. make sure to get a sound clip/vid.

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RBS14

no, it won't come apart. That's how they are from the factory on GSXR's, so I figure it'll work for me too.

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SR240DET

what are you using for your ignition system? megasquirt isnt compatable with our setup.... are you using EDIS? lemme know how that goes..

SilviaDriver

Yup. Different engines. Yours has more stroke which means faster pistons speeds. Which also means those ITBs will run out of breathe sooner.

BTW, every mm makes a difference. Did you know bores are measured to the 0.0001"? Does that make a difference? Yup. Bearings are measured to the 0.001"? Someone who says 1mm doesn't make a difference is not paying attention to the details. 45mm would still be too small for your KA.

RBS14

Yes, I am using EDIS with the ms.

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Andrew Bohan

fo sho, i was already researching it.

looks sick man. good luck with it.

nismo2491

I just want to say thats tight.

as far as them being too small I have no opinion or knowledge on that but for the sake of argument that 2 mm is a big difference:

area of a 43mm ITB: 1452.20 mm square

area of a 45mm ITB: 1590.43 mm square

thats almost 140square mm, which is a lot of space.

and for more infor 50mm is 1963.49 mm square almost 500 more square mm

let the math speak for itself but I'm sure there is big differences in airflow between all three. BUT at the same time I bring to light Car Craft magazines recent 454 shootout where the dynoed 2 very similarily set up (same cam profiles, same valves, same compression and combustion chamber size, same carb, etc), basically as close as you could get. they dynoed a small block 454 and a big block 454 and because of the smaller valves on the small block that kept up the velocity of the air the small block had more power all the way through the range, and more peak power. only at 3 points did the big block squeeze out a tad more power. so smaller is better sometimes.
KEvin

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YellwMonky

this has got to be one of the coolest things i've seen on this forum ! great job and keep us updated !! I'm very interested to see the results

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sideviewcivic

I got that issue. Great job on the ITBs man. I think your set up will work nicely since DOHCs generally fall out of the powerband past 6K unless you plan to do headwork and cams. If you get cams and headwork oh oh baby I wanna be there for dyno days!!!!

atom

Not necessarily.

Bigger displacement = use bigger throttle plate diameter
rev higher = use bigger TP diameter
Higher flowing head = use bigger TP diameter


So compared to Honda's, KA's rev much lower, have a worse head, but has .6 liters more displacement...........hard to say. But if I were to personally piece together my own setup I'd probably try the 46mm Busa throttles.

Also better throttle response = use smaller TP diameter so that's another thing to think about.

ootranceformeroo

Looks great scott! yeah for sure post pics and a possible vid when you get it installed on your car! Should be dope!

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Maeda

Damn thats weird.
Are you supposed to run 4 pipes out of the intercooler or what?
How does all the boost go into those seperate things?

Oh yah thats right there isn't any to speak of.

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S14DB

The RB26DETT uses ITB's...

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AKADriver

Yep! You can use ITBs with a MAF, too, Nissan, BMW, and Toyota have all done it successfully. You just need a plenum over the throttles.

projectRDM

I was expecting a nicely welded manifold, not a chop job with ITBs stuck on with rubber couplings. Although the idea is a good one, the execution leaves a lot to be desired. You could have easily welded the pieces together, then grinded and smoothed the beads down inside and out, even going as far to remove the casting marks to give it a production finish. Plus leaving all the OE flanges and extrusions for various parts that are no longer used makes it look very 'backyard' done.

Still curious to see the power gains up top, and the overall loss of lowend torque.

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Jeff240sx

JFC Russ! Everyone's "Get it welded because it looks like ass" is.. well.. stupid. The aluminum intake manifold and [I assume] aluminum throttle bodies need to be welded with an ac/dc tig, or heli-arc'd. Both of these require special welders with skill, which makes it expensive. I couldn't see him taking it somewhere and paying less than $200 to weld the TBs to the intake runners. And spending another $200 on what people have called un-proven would be a waste. Let him put the stuff on with silicone couplers, test it, if it doesn't work, he's only out a few hundred.. not nearing $1000.
-Jeff

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Maeda

I know. I'm not speaking out of ignorance (although sometimes its hard to tell with me), it's sarcasm. It's an ongiong joke I have with the poster.

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RBS14

well I'm glad you don't like it. But I sure do. Did you not read the part about them using couplers from the factory on GSXR's? maybe it's ghetto to you, but it's solid as a rock, so I don't see any reason to change it. What gain would there be from welding the ends of the runners together? They aren't going to flex at all now, so why do it? Casting marks on the inside are almost unnoticeable and VERY small. Not worth the work IMO. grinding down casting marks on the outside? how does that help performance? I don't care how it looks, just how it performs.

Also, welding the TB's to the manifold would cause quite a problem If I were ever to need to switch them out with different ones. If one gets damaged or the such, I would have to re-fabricate a whole new setup from the beginning.

I've done all of this thus far with a hack saw and hand files. I don't have any power tools, so I'm pretty happy with how it turned out with the tools I have used.

From what I've been told by people who have done it, low end torque loss is very minimal. The gain in top end will more than make up for any minimal low end losses.

Jeff: exactly!

John: I plan to do it with hopes and dreams fyi!

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sykikchimp

definately interesting. I don't think I've ever seen a DOHC with itb's..

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MakotoS13

i just thought of something. it looks nice and im sure gets lots of air in but i don't like the TB's not being physically mounted with something other than tubing.

i'd like to take this opportunity to retract my orginal enthusiasm.