I would love to see this setup with a squaretop as well. It would be interesting to see the gains past 5500 rpm since that seems to be where the squaretop really shines.

"Conservative" were my instructions, since this is more of a streetable track car than a trackable street car. Wanted to make sure the tune would be safe on pump gas (including CA91) while heatsoaking everything under track conditions. When I fiddle with things over the summer I may even work on flattening out the torque curve a little to make 3rd gear easier to manage.

I'm interested too! However, I already have more power than I can realistically use right now based on my setup and my (limited) skill. Power-adders are going to be pretty far down my list of things to do for the foreseeable future. My next set of tires will be 225s, we'll see how much that helps putting the power down. Next frontier will probably be aero, but I have a lot of learning to do before I can make good use of the additional capability.

You are reasonable. You will live a long and prosperous life.

Really similar. About 4 degrees less at 160, at 220 I'm at 14 degrees, but only drop to 13 at 240 vs. your 11 a 250. Definitely splitting hairs at that point.

This looks like a nice graph! I am just surprised I can hit the same 175ftlbs at 3200 rpm with my stock 1.6 and TD04L-13T. But I get blown out of the water after that. Really drives home how well these things spin up for being such "big" turbos!

Thanks, my 250 kpa zone is really there only as a safe retarded buffer, so i dont blow up if i suddenly have a major boost spike.

My thread (https://www.miataturbo.net/dynos-tim...unk-2-a-99000/) already proves the gains found with a Flat Top. It then goes on to show the substantial improvement with a Skunk2 and the 0.5L spacer. Extrapolating from my results with a GT2560 turbo and FM hot side, This car should make 330hp all day long.

Very nice.

For Science, I would be willing to loan my port matched Squaretop (to Skunk2 TB) to see what happens to the dyno plot, if you want to do some more pulls and see what that investment will net you.

In your esteemed opinion how much midrange do you think you'd lose compared to the VICS, or would it be negligible compared to the gains up top? I've currently got a VICS inlet on, and a squaretop sat gathering dust in the garage - for primarily a street car which will sit at the midrange area not way up top is it worth swapping over?

Yeah Ken Hill already has this well documented guys. Look at his thread. Surrender your cats.

Ken's very helpful thread is VTCS vs. Squaretop, not VICS. Other threads have been a lot less conclusive - VICS seems to give a bit more midrange than a squaretop, but drops off a bit at the top end (but not as badly as the VTCS).

I know that Savington has built customer cars with both VICS and Squaretop manifolds - and in my hazy memory said that sometimes on a street car there are situations where the VICS may be preferable..

The only reason I use a VICS manifold in certain builds is to tamp down on high-RPM power for specific race classes (ST4 or Supermiata S1). In those classes, it is easy to select the "right" combination of parts and end up with a car that refuses to make less than 240-250whp, even at low boost. The EFR's turbine is so efficient (compared to the common Garrett T25/T28 turbine configs) that any decrease in intake restriction will result in a system flow increase, even without increasing the measured boost level. By using the "wrong" parts (VICS manifold), I can maintain similar mid-range torque and tamp down on top-end flow, effectively avoiding those issues.

In cars that jump between race classes, I can then just turn up the boost and blow 300whp through a VICS at 2-3psi more than it would take to make that power on a squaretop, because the EFR's high-PR compressor efficiency lets me do that too.

On my own 450whp street car, I used a Squaretop.

IOW, I use the VICS manifold as a built-in power restrictor. If you don't want to restrict power, don't use one ;)

Great explanation, thanks. Guess that's another job that needs to be added to the list then :)

So, about my offer ... :)

I call shenanigans

Sorry for the delayed reply, been neck-deep in work.

Mobius, thank you for your generous offer. However, at this point I'll have to pass in the name of marital harmony. Going to try and keep my time in the garage to a minimum this summer.

That being said, if I recall your motor is largely similar to mine (+1 CNC head, 8.6:1 pistons, etc.) save for the intake manifold. I'd be willing to share dyno time for science and we could do same-day runs once build v.3.0 is up and running.

We'll see what the future holds, but at this points I don't have any plans. Sure, there are lots of things I could do, but if I'm going to spend more time/money on more power I want to make sure I can use it. That means 1). driver mod and 2). aero come first.

Do you find that the VICS makes more torque down low or is that just poppycock?

I think Ken's test is the best one I've seen so far, and he showed the Squaretop picking up a bunch of mid-range over a VCTS. The VICS makes more midrange too, but not enough to be better.

If it is better, we're talking 3-5tq at most, and for that small gain, you give up power starting at 5500. It's a stupid tradeoff IMO. If you want the "best" manifold, full stop, you buy a Squaretop (or you deal with a Junk2 and its fitment/reliability issues and add plenum spacers).

If you have VTCS and are going through the trouble of changing manifolds, get a squaretop or S2 like Andrew said.

If you're fully broke and insist on changing the intake, VICS offers significant gains over VTCS. But with squaretops going for well under $300 these days, it's silly to spend $100 on a VICS.

Our setups are quite similar except you have vics and 8.6:1 pistons, while I have squaretop and 10:1 stock pistons. I don't yet have a full 3" exhaust either.

Not sure when I'm going to be running boost again, little things I want from Andrew like a radiator and an intercooler are out of stock with no ETA. There are workarounds I suppose if I get to where I'm ready to drop the engine in.