My RB20 W/ RB26 ITB's thread

Post by **sci2000tech** » Sun May 10, 2009 4:12 pm

So since there is a lot of discussion about ITB's going on lately, I figured I would make a thread documenting my project.

Rather than making an adapter plate to mount the ITB's directly to the head, I decided to cut my factory intake so I could use the stock fuel rail and have longer runners.

I started by ordering a stock RB26 pletnum, planning to go with a single TB. After doing some research on ITB's, I picked up a set of RB26 ITB's and matching metal gaskets from Ricky @ Rawbrokerage.com.

First step was to get 1/2" flanges cut to match the gaskets. I'll get picks of the flanges up as soon as I can.

Then we mocked everything up in the car to find out where to cut the factory lower runners.

The water neck on the manifold had to be cut to clear the flange. We are also going to have to cut the thermostat housing as it sits too high, and will hit the flange. Probably going with AN fittings for the water necks and radiator.

So this is where we are now....

I am just waiting on the ARP studs(M8X1.25 - 3") so we can bolt the flanges/ITB's/Pletnum together and tack weld it to the RB20 runners to do a final fitment check before we weld it all up.

Worst case scenario, if the ITB's don't work out, I can just get shorter studs and weld a single TB to the front.

_______________________________________

Here are the flanges welded on, and ported to match the manifold:

The porting we had to do to make everything match up:

___________________________________________________

Arp studs installed (M8 x 1.25 - 2.9" long)

With ITB's on..

Everything bolted together.

Here's a close up of the throttle linkage.

Factory RB20 TPS bolts right up to the RB26 pully.

______________________________________________________

Everything welded in place.

________________________________________________________

After powder coating.

_________________________________________________________

OEM water neck.

After some modification.

And how it sits now.

_________________________________________________________

And thats how she sits today, just waiting for a tune.

Modified by sci2000tech at 2:10 AM 1/31/2010
Modified by sci2000tech at 2:14 AM 1/31/2010

Post by **neonbomb** » Sun May 10, 2009 5:19 pm

Very nice

Keep us updated

Post by **Carl H** » Sun May 10, 2009 5:37 pm

very nice...i like where you're going with this, please keep us updated.too bad you dont have a stock setup to do a before and after with the setup.

Post by **sci2000tech** » Sun May 10, 2009 9:57 pm

Carl H wrote:very nice...i like where you're going with this, please keep us updated.too bad you dont have a stock setup to do a before and after with the setup.

Yea, I haven't run the car with this turbo setup yet, so it will be difficult to tell what gains are attributed to the ITB's as opposed to the new turbo set up.

I do have a stock motorset sitting in my garage though. I picked up whats left of the full race s14.5 that Forrest drove, and I was going to drop in the stock rb20 until I get better at driving. If I do this, I can swap the ITB's on and do a dyno before and after to see what gains, if any, are to be had.

I won't feel so bad if I hit a wall at the track in this one. Also has tubbed fenders and a full cage

Post by **GTRs13** » Mon May 11, 2009 6:10 am

What kind of fitment is the cut lower manifold, to the ITB connection that I assume you are going to weld?

As in, you have no flange. You are welding straight to the ITB assembly?

Post by **sci2000tech** » Mon May 11, 2009 8:11 am

No, I had flanges cut to match the ITB gaskets. The ITB's/pletnum will bolt up to the flanges.

They don't line up 100%, but its close enough where we can just do a bit of porting. The flanges are at my welders house, so i'll get some pics the next time I'm over there(once the studs come in the mail).

Post by **Kalypso** » Mon May 11, 2009 8:18 am

you could slice off a little more

Post by **Kansei240sx** » Mon May 11, 2009 12:47 pm

I've seen this done on an RB25 that was over in Japan and worked out real well. When the power levels get going really high always make sure that cylinder 5 and 6 get that special no lean treatment!

I hope this works out really well, it'll give me an alternative method for the RB20 swaps i end up doing. This is cool!

Post by **sci2000tech** » Wed May 27, 2009 12:29 pm

Update!

Got the flanges on and all welded up by Adam from Streetorstrip concept.

Here are the flanges

All welded up...

A close up of the welds.

Since the flanges didn't line up 100%, we had to do some porting.

With the ARP studs on(M8 x 1.25 - 2.9" long)

ITB's slip right on...

The studs are the perfect length, allowing just enough space for the gaskets/washers.

Bottom view all bolted together.

Top view

A close up of the throttle linkage

Luckily, the RB20 TPS bolted right up to the RB26 linkage. One less thing to worry about.

And how it sits with the ugly, stock fuel rail.

I stll need to figure out the coolant lines, and then it's off to get powdercoated before I throw it on the engine.

Post by **Sil240** » Wed May 27, 2009 2:19 pm

VERY NIIIIICE!!!

Post by **mattblancarte** » Wed May 27, 2009 2:26 pm

The welds on the flange look awesome!

Post by **yotik** » Thu May 28, 2009 1:51 am

Post by **Neejay** » Thu May 28, 2009 4:33 am

Damn that's nice!

Post by **Kansei240sx** » Thu May 28, 2009 2:14 pm

What kind of welder did he use? That is very pro, i like that setup!

Post by **rbsileighty** » Fri May 29, 2009 8:27 am

Very nice bud! Very similar to the concept I had in my head actually...

What's the rest of the engine like (cams etc?)... just concerned about the runner length being so short if you're running aggressive cams or aftermarket exh mani. Can't wait to see a dyno graph! When you get a chance would you mind measuring the runner length?

Keep up the good work!!!

Post by **maryjane** » Fri May 29, 2009 9:10 am

looking good! keep us updated on dyno numbers!

Post by **S133P3R** » Fri May 29, 2009 9:44 am

that ITB set-up looks killer, way to go on the custom work.

Post by **Chaos the Xile** » Fri May 29, 2009 11:04 am

where did you get the flanges for the stock intake at? where they one customs or part of the rb26 intake/itb assembly that you hacked and welded to the slock plenum??????

Post by **sci2000tech** » Fri May 29, 2009 4:01 pm

The welder is a Miller Syncrowave 250DX. I don't know much about welders, but this one is badass.

rbsileighty wrote:Very nice bud! Very similar to the concept I had in my head actually...

What's the rest of the engine like (cams etc?)... just concerned about the runner length being so short if you're running aggressive cams or aftermarket exh mani. Can't wait to see a dyno graph! When you get a chance would you mind measuring the runner length?

Keep up the good work!!!

The engine is internally stock for now. other than that:

6Boost t3 manifoldKKK K3T 3070MGA turbo(off a Blitz kit)HKS 50mm wastegateSard 550'sZ32 MAFSand of course, the ITB's

As far as the runners go, maybe someone can enlighten me as to how the length affects engine performance. It is a concept I never really understood. All I have been told is that the RB20 doesn't flow enough, and that ITB's/ shorter runners would actually hinder performance. I just don't understand how less restriction, is worse.

Regardless, just like the practicality of a twin turbo RB20, I have to find out for myself

I'll get the length of the runners once I grab the manifold from Adam. He's welding the coolant water neck right now, then we're done with the intake.

Chaos the Xile wrote:where did you get the flanges for the stock intake at? where they one customs or part of the rb26 intake/itb assembly that you hacked and welded to the slock plenum??????

The flanges were custom cut with a waterjet to match the ITB gaskets.

Here's what the intake looks like all welded up and bolted on(in horrible lighting)

I just want it to run again

Post by **rbsileighty** » Mon Jun 01, 2009 3:46 am

I have some books and such at home... the best I could find internet wise is this article... seems to be a fairly comprehensive writeup and well written. I've been on this forum before... think there is a guy who has RB26 ITB plates on his NA Soarer V8... that thing is nuts btw!!!

http://v8soarer.com/intakerunners/index.shtml

Let me know if you have any questions... hope this helps... keep up the good work!

Here's a decent calculator for running through some ideas... http://www.velocity-of-sound.c...1.htm

Post by **sci2000tech** » Fri Jun 26, 2009 10:02 am

^^^Thanks for the info, very interesting read.

I just picked up the runners and pletnum from powder coating.

I'll bolt it all up to the car and get pics this evening. Sunday it's off to Adams to get the coldpipe and W/G dump tube done.

Post by **Kalypso** » Fri Jun 26, 2009 12:09 pm

Post by **240daveTX** » Fri Jun 26, 2009 12:33 pm

+1 for another RB20 vert

Post by **sci2000tech** » Fri Jun 26, 2009 5:54 pm

Bam!

Post by **iceman.chris** » Fri Jun 26, 2009 11:06 pm

F*cking badass

Post by **Andyb2637** » Sat Jun 27, 2009 6:30 pm

youtube please

Post by **Fibre guy** » Mon Jun 29, 2009 4:14 pm

Final product looks good!

Post by **PorkChopExpress** » Mon Jun 29, 2009 5:03 pm

whats the usable limit of the stock rb26 intake? looks great btw.

Post by **black240jl** » Mon Jun 29, 2009 5:23 pm

make me one

Post by **sci2000tech** » Mon Jun 29, 2009 7:49 pm

PorkChopExpress wrote:whats the usable limit of the stock rb26 intake? looks great btw.

Not too sure, but I know it's more than my turbo can make.

The cool thing is, I can get a greddy intake if I have to and it will bolt right on.

black240jl wrote:make me one

I would if I could weld

Last time I talked to Adam, he said he wants to have the car present to ensure fitment. Unlike exhaust manifolds that are made on a jig, this was a one-off piece.

I'll talk to him and see if he is interested im making more.

If not, this thread was intended to be kind of a step by step how-to for others interested in having ITB's without an expensive CNC adapter.

If you can weld or know someone who can, then your set. The flanges can be cut to match an ITB gasket at your local waterjet. Or I can have some cut for you if you can't find someone local. Studs from ARP or any other bolt supplier. Ricky @ Rawbrokerage can hook you up with the ITB's and pletnum, and the rest you already have.

Thanks for the comments guys. Little by little she's getting there. We just finished up the coldpipe and w/g dump tube, so it's down tuning just after one more thing......

Wire tuck!

Then I'll get a video up so everyone can see the results.

My RB20 W/ RB26 ITB's thread

My RB20 W/ RB26 ITB's thread

Re: My RB20 W/ RB26 ITB's thread (sci2000tech)

Re: (Carl H)

Re: (sci2000tech)

Re: (GTRs13)

Re: (sci2000tech)

Re: (Kalypso123)

Re: (Kansei240sx)

Re: (Sil240)

Re: (mattblancarte)

Re: (sci2000tech)

Re: (Neejay)

Re: (rbsileighty)

FN-QR

Re: FN-QR (S133P3R)

Re: (rbsileighty)

Re: (sci2000tech)

Re: (rbsileighty)

Re: (sci2000tech)

Re: (sci2000tech)

Re: (240daveTX)

Re: (sci2000tech)

Re: (sci2000tech)

Re: (Fibre guy)

Re: (PorkChopExpress)

Re: (black240jl)

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums