Skunk2 vs Square/Flat Top Intake Manifold - Dyno Results
 

There have been a few discussions recently surrounding the Skunk2 manifold and in a nut shell (feel free to correct) it's been a great competitor to the Square-top. Coming in at a similar price point, often less, I'd say it's an excellent contribution to the aftermarket support these cars have. We've shipped over 100 of these manifolds and decided it was time to fill the gaps in the results that have been posted. We're blessed to have a community that is so result driven and kudos to the guys who have also shared their findings: FM, 949 and anyone else who might have been overlooked.

Skunk2 vs Square-Top (Naturally aspirated/Same Calibration) 949 results:
Square-Top: 150.41/123.19
Skunk2: 154.71/123.29

Skunk2 vs VTCS (Turbocharged/Unknown modification to boost or calibration) FM results:
VICS: 318.5/280.2
Skunk2: 350.8/278

Skunk2 vs Square-Top (Turbocharged/Same Calibration) Fab9 results:
Square-Top: 341.8/295.4
Skunk2: 341.8/298.8

Darby continued to up the boost by 3-4 psi and was able to knock out some pretty serious numbers with an end result of 365/309 on the Skunk2 manifold but this was done after changes were made in the calibration.

Plenum spacer? We're installing one Saturday and will test again, identical boost levels and calibrations.

Bottom line: You decide, but it's my interpretation that your decision can be made easily with the information we've been able to put together here.

• VTCS or USDM intake manifold owner (naturally aspirated) MAYBE: Buy yourself a S2 intake, you'll pick up numbers either way. If you're running any sort of FI you'll apparently see tremendous gains.
• VTCS or USDM intake manifold owner (forced induction) ABSOLUTE YES: This seems like a no brainer, tremendous gains and it's a quick way to clean up your engine bay for internet fame. It's also nearly the same price of sourcing a EDM Square-Top.
• Square-Top owner (naturally aspirated) MAYBE: Your call if a few ponies is worth the coin but you aren't at risk of losing anything.

Stay tuned for plenum spacer results. Cheers guys.

The dyno operator and tuner was A Star Fabrication just up the road from us. This isn't the best representation of the plot but you can see the square top results blend right along side the S2. We will try to update the thread with a better screen shot after we play with spacers.

https://farm5.staticflickr.com/4647/...e694c95e_z.jpg

Props for the post.

It should also be noted that some people were experiencing fitment issues with fuel rails. Someone will post the correct info or correct me, I can't seem to remember off the top of my head. Was it return-less NB guys? There is also a relocation of the TB inlet location, people with rigid charge pipes or reroute could have fitment issues they didn't have before.

Again, just something to keep in mind for a bottom line decision.

is the bright red plot the square or skunk2?

Just popping in to say I can confirm the NB1 rail with the 90-93 FPR flipped over fits better than it does on a VCTS, VICS or Square top.

Peak numbers say only half of the story. Yay for collecting all data points, nay for not adding plots

All of the plots are there, outside of FM and 949's findings. Like I said, I didn't personally operate the dyno and the plot lines are graphed so thick it's difficult to decipher one from the other but they are illustrated. That being said, they are so in line with the square top that you can't see much of a difference.

I'm working with them to get a different line thickness.

Thanks for doing the test. Subbed for spacer results.

By changes in calibration you mean changes to the tune? Fuel and/or timing?

Yes, just swapped it and ran it.

So what colors were what again? I about had a stroke trying to figure it out. Then there was that huge blob in the middle?

I think tuning for intake changes would depend on competency of the tuner. Ideally, the fuel and spark would be updated for the new intake to extract the best power curve for each. If tuning for the new intake manifold is going to produce inconsistent results (due to an inconsistent tuner) then just leave it be.

So it's basically the same as a squaretop to within a tenth of a horsepower. Amazing.

Still, if you don't already have a squaretop, junk2 is actually not a bad value proposition.

I still don't see any reason for existing Squaretop owners to go out and "upgrade" though.

There is none.

I can't say there are pressing needs to upgrade here but I'll cover a couple of the advantages that one might find useful.
1. It's new
2. It can be taken apart for port/polish work to be done easily
3. It looks nicer

Completely agree. But for the sake of being on the same page with everyone the calibration was untouched. I'm sure there were improvements to be made.

You're telling me, I'm awaiting cleaner lines - sorry guys. The bottom line is, minimal improvements were achieved with just the swap and then with 3psi she seems to be touching the efficiency pocket of that turbocharger.

I gotta say I like the look of the manifold on a table but when its installed in the car I think its odd, maybe just because of how far out it pushes out. I'm not sure if that's just my OCD wanting the distance from end of manifold to spark plug holes to be the same on both the intake and exhaust side, or maybe its because I think it looks out of place in a Miata. That might be due to years of seeing non S2 manifolds in them. Nice that it performs well, and will be an alternative to the JDM manifold when they run out or if importing them becomes harder. Any competition in the market is good. But for me, since I already own a Squaretop, I'm going to port that to match my S2 TB and install it. If I didn't already own a square top, I'd probably just get this because i guess I wouldn't even need to match it to the TB

Bright red is S2.

I’m still trying to decide which manifold for myN/a car.. I may go with flat top to keep some midrange since it’s a street car.