Finally received ours today. Should get to the dyno later this week. Meanwhile, a few notes after unboxing.

- We ordered two of the .5L plenum spacers. The fasteners included with the spacers are too short.
You'll need to purchase seven 6m x 1.0 x 45mm SHCS to add one spacer. Use three of the included 35mm bolts from the spacer for the "short" holes.

Mcmaster 91290A204

- The quality of the casting leaves something to be desired. Not nearly as nice as the OEM Mazda manifold but a far better configuration of course. Of particular concern is the critical transition of the bell mouths to the port runner.
It appears to be a seam area which gets manually ground down. The result is a somewhat misshapen, lumpy transition there. A few minutes with a grinder and some sand paper will help. Miscellaneous bumps and burps otherwise.
As it's pre injector, don't worry too much about making it too smooth.

-The tapped holes for the TB flange are not blind. They are drilled through to the plenum meaning they will need to be sealed. Blue loctite or silicone on the threads should suffice

-The manifold ships with a phenolic resin manifold-head gasket. Our experience with gaskets made of this material is that they do reduce heatsoak but will eventually cold form (sag). It might take a year or two but you may eventually
have manifold bolts backing out or breaking as well as induction leaks. For this reason, we'll stick with the OEM manifold gasket.

- There were some decisions made as to the shape and angle of the runners that could be improved upon but we are guessing it will still outperform the square top handily. Dyno time!

Like most Skunk2 products, some sound conceptual work affected by sometimes indifferent production engineering and process control. Like the TB, consider the manifold a DIY project starter kit.

 

Let's try to keep this thread informative and on topic please.

 

......or I will unleash the ban hammer of thor with great vengeance and fury

 

Look forward to dyno results. How do you intend to play with plenum volume? One spacer at a time? Really curious how much of a difference they will make.

 

My thoughts exactly on the casting.

Question on the Phenolic gasket. Is that gasket the same as the Hondata brand? As in the same issues?

Thanks I look forward to your Dyno results.

 

As the needed fasteners weren't included we have to wait for those to arrive. The spacers are 17.5mm thick BTW. So the 45mm bolt then needs to be 60mm, which we also ordered. That will allow us to stack spacers.

Protocol will obviously be tune for no spacers first, add spacer and see if it then needs fuel anywhere. Repeat with second spacer.
Current plan is thus

Snoopy: Forged, blueprinted but otherwise stock NB2,header, CAI, MS2, pump gas. This engine represent probably 90% of the folks that will be interested in any manifold.
Taxi: Full whammy 2.0L with medium big cams, 11.0:1, internal coated all the things, +2 CNC head, E85. header, MS3. This represents just short of an "all of it" N/A build. Only needs bigger cams to go over 200whp me thinks. Same motor we made 200whp on ITB's a few years ago.
Bullet: Forged, blueprinted 10.0:1 but otherwise stock NB1 engine with TSE EFR6258, 3" exhaust and E85. Again, not nearly an "all of it" build but representative of what most Miata owners with F/I might build.

At some point early 2018 we'll stick the manifold on Vegas which is a full whammy, coated, 9.0:1, +2 CNC, cammed nutball motor with the same TSE EFR6258. Part of me wants to stick an EFR 6758 and just once, drive it with way over 400whp and the Quaife sequential.

Skunk2 gasket is black, Hondata blue. I think the Hondata is a different material and that's what we saw cold form after a few years. Thus why we no longer offer the Hondata gaskets.

 

Thank you. I have the Hondata on my car right now. I didn't remember what color it was. I guess I will be changing back to the stock gasket when I put on the new manifold.

 

Inspect it first. If you can, check the perimeter of each port, above and below the manifold flange, to see if it's migrating out. Might be OK, might not.

___

On a separate note, we have the added test variable of the Skunk2 TB. In the past we A/B tested on a stock engine and found no gains below OEM redline of 7000. On a forged engine spun to 8k we saw small gains with header, programmable ECU whatnot. 2whp over a stock TB on non-port matched square top. For this test we'll run a square top that's been port matched to a Skunk2 TB. Our reasoning is that is the best an OEM manifold is going to flow. A non port matched square top with OEM TB might be a few hp less but that is a specific A/B we have not run.

The Skunk2 will be run with an OEM TB and Skunk2 TB. So we should have three different plots for Snoopy. So many different configs to consider.

 

Thanks for doing this and making the data available once you get the results!

 

Thank you and we all look forward to seeing how this flows on the dyno at different RPM's vs the flattop.

Even though it's lighter what is your speculation on issues arising from it hanging off the block without a support?

 

We have no speculation on that. We'll see if it breaks.

 

 

Subbed .. any plans to test it with the Skunk2 TB as well ?

 

Yes, see post #8.

 

Subscribed for curiosity.

 

Awesome, this is going to be a really interesting test. Im pretty sure the Skunk IM will have gains on the topend, but itll be interesting to see if it loses torque down low to the squaretop. I think if I end up buying one Ill have to take out the porting tools and smooth out the casting flaws a little bit.

Also I can attest to the Hondata gaskets deforming. I had one years ago and it didnt even last a year before it lost its shape and created a IM leak at the head ports. When I took it off you could tell it just couldnt handle the heat whatsoever.

 

 

More install fun

-As noted in another thread, one corner of the manifold flange needs to be cut off to clear the pulse damper on the OEM NB2 fuel rail. Not a big deal but it won't mate to a BP05 once that's done.

- Because of the aforementioned runner shapes, reaching the flange bolts near #4 cylinder is very difficult. Like pulling the alternator and maybe pulling the starter depending on the tools you have and personal flexibility. It is not a quick install. Because we thought the install would be simpler, we're doing it on the shop floor. If you have a hoist, pulling the RF wheel might make reaching those rear flange bolts a bit easier and put your upper body in a position to generate some torque.

Overall, the plenum is simply lower than it needs to be. There are no native packaging constraints that require it to be that low. Affect flow and makes it a minor bitch to install. Looks cool though. The rough design we have had laying around for years places the plenum right under the hood. We never make ours so that's academic, but illustrates there is more than one way to configure it. Just the same, we're eager to get it on the dyno. Losing another day futzing around with the install ..

 

More difficult than on the squaretop?

 

Sub'd.