the spacing isnt different, the flange is just upsidedown

 

Crappy cell phone pics...







Hard to see in pics...but it looks a lot bigger.

Will do volume test tomorrow, taking care of "honey dos" right now.

 

well what do you know?! no crap it was bigger.

 

WOW AWESOME, It actually looks like a quality piece. I was a bit worried about how the casting inside would looks because it is essentially a knock off mani, but it looks good in there. How is the angle from the flange, dose it curve upwards at all. Or do we need to make angled cuts and weld the flange on at an angle so that we have access to under the mani once its bolted to the head?
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Now I'm gonna feel bad. I'm getting a sweet new mani with EWG soon and will most likely do this and I'm going to want to take my head apart and port it. Or I could just port it before I put my engine back together. Baddass topend with stock bottom end trying for 300

 

your rods will bend first.

 

Please measure the manifold volume with plenum only (if possible), and plenum plus runners. Runner volume matters.

 

stupid question probably that i couldnt find the answer to: Why don't people swap bpt or
b6t intake manifolds? Seems they'd work well since they're designed for turbo applications... are they not bolt-on?

 

IIRC the TB would be on the other side.

 

Surprising results.

OEM:

13.5" runners
1.15L plenum

Blox:

7.5" runners
1.35L plenum


I'm still going to fab it up, but it may not be the solution we were looking for. Either way it's still nearly 20% bigger (had problems getting the throat of the Blox to fill with water since due to it's girth).

There will also be some block-off plates needed for the Honda IAT sensor spot and the IAC etc.

 

it's better than stock, and I betcha it'll be a really good compromise for power throughout the entire powerband.

 

Can you give us an estimate of the difference in the runners?? Average diameter of both would be good; avg diameter and volume of both would be great!

 

Diameter is probably port diameter. Overall volume of the manifold is pretty similar when factoring in the runner volume. I don't understand why you guys are bonering over these manifolds. They're not optimal for turboing with the plenum size.

 

The blox IM is pretty much a copy of the ITR (intergra Type-R) IM which has a 8,400 redline...and take to boosting great on those motors. It also is a compromise between an extra top-end manifold and something that wont kill spool and mid-range power. plus it's cheap. I dont want a manifold that kill spool yet nets me gains at 6-7K if I can get one that doesnt affect spool and gives extra power from 4-7K.

Plenum size isn't everything, too big and they kill velocity and hurt the flow. A 20% increase in plenum volume coupled with a 50% short runner should prove a good manifold for our motors...just wait.

like I said, my plenum I built was 3.2L, had 6" runners and my peak torque was 7200K

 

Like Brain has reiterated many times these manifolds are known to make good power on boosted b18s and they should help make power in the rpm range we want. It seems like a good affordable option to replace the oem manifold. Sure it's not perfect but I imagine it's going to be a whole lot better than stock.

 

So what's up with the aebs manifolds. I've read a comment that they are supposed to flow as much or more than the itr and skunk two. I can pick one up for pretty cheap. It's cheaper new than the blox. I just want to make sure this isn't getting into ebay tacotaco territory.

 

Did you post that dyno? I'd like to see how spool was vs top end

 

yeah, but I also blew my motor during these pulls:



so I'll never really know until viperormiata finally gets it done.

 

Brain's right...it's still a definite improvement, just not quite the 100%-of-displacement plenum volume I was hoping for. I felt like I wasn't getting the bag spread all the way out with the Blox...and was surprised at the volume of the stocker. That bitch is looong.

The blox plenum is not only larger, but has a much greater cross-sectional area (and shorter cylinder. The runners are grouped closer for more even distribution. Where the stocker looks like a corridor with four hallways to the right, the Blox looks more like a half-spider, large center with angle appendages. My engineering sense tells me it's much more conducive to higher mass flow rates.

I'm starting to take a look at where the runners match up, and how long I'd like to make them. If anyone has a good idea what the powerband design is for the OEM piece I'd be interested, but I'm assuming 3000-6000rpm from dyno plots.

My target for this exercise is broad power from 4000-7000rpm.

The Skunk2 claims power from 5000-8200rpm.

Based on all of this I'm going to shoot a little shorter than the middle so it feels like it still wants to keep pulling at redline.

What do you guys think of a 10" runner?


Also, there is almost no way to get the throttle body at the stock location. The OEM runners actually angle down where I want to cut them, and the Blox runners curve up about like a *****. I'm hoping to keep everything out of the way, and occupy pretty much the space of the OEM runners, with the plenum and throttle body just lower than OEM. This would make it easy to just cut out a straight section of your coldside piping coming up behind the radiator.

Next problem is the angle of the throttle body. The Blox is completely perpendicular. We could machine an angled plate and get back to the Miata angle, but I'd prefer just to do a custom elbow since I want to go to a larger throttle body anyhow.

After that we've gotta plug a few sensor ports, although I'm tempted to see if I can get the Miata harness and MS to run a Honda IAC valve. This manifold has the air passageways for this cast in, and we might as well take advantage of this.


I hope to get my assignments done quickly today and be home this afternoon cutting and grinding. Will try to find an aluminum welder locally.

If I can get this done soon enough and solve some of the issues I ship it to Phil to do a dyno run with. First issue for me is a throttle body. Off the honda-tech I go...

 

I cut mine here:



just before they angle down...I'm wondering if you shouldn't do the same. That's about 3" from flange to flange.

it's also short enough so you can go back in and clean up the joints:




Probably have no issues getting MS to run the honda idle valve.