virant's 2003 clunker
 

Hey,

Had a previous Miata build get stolen. Managed to track down the thieves and get it returned with at least usable parts. If someone is interested in this story, I'd be happy to post more details. Insurance company totalled it, I took the payment, stripped the car of relevant parts, got rid of it, then found a new Miata to buy.

The car as originally purchased:
https://cimg8.ibsrv.net/gimg/www.mia...74c4a99aa0.jpg

After this, I bought a hardtop because Pac NW, did some bodywork and cleanup of the car, which ended up with:
https://cimg5.ibsrv.net/gimg/www.mia...6b50609089.jpg
From here, I installed Xidas that I recovered from the old car, all new IL Rubber bushings, new alignment bolts/endlinks/etc. everywhere from SuperMiata, a MS3 pro ECU, AEM wideband, gauges, a SuperMiata rad and FM cooling shroud from the old car, FM front BBK from the old car, FM butterfly brace and associated hardware, and a HardDog Hardcore M2 rollbar.

After that, I proceeded to build the engine and throw on a 6758 with 14 psi. Enclosed is the initial dyno dynamics dyno results with a Skunk2 manifold, although I'll post a final dyno later. The interesting part to this is that 1 spacer at 14psi actually meets or beats the Squaretop at all RPMs. I was very surprised to see the low rpm behavior of the skunk2 with 1 spacer.

https://cimg8.ibsrv.net/gimg/www.mia...20a98a8c05.jpg

Interesting about the spacer, I haven't seen much data on it! Awesome to see those numbers on 14psi with a 6758, hoping for similar results in the spring

Interesting data point. Tested against the squaretop same day, tires, dyno, correction factor, etc?

We only tested N/A but it was back to back on the same day.

This is far from a standard engine. I'll be posting more details this weekend.

Everything was done within 2 hours of each other at the same place.

However, my setup is far from normal. I've dropped well into the five figures with you guys over the past six months as one example (Tell Ed I said hi and sorry for the headache with the boxmount bbk). I'll be posting more details in a post later this weekend. However, I will say we only saw this behavior occur at 14psi with my setup. We saw little to no benefit with 1 or 2 spacers when I was dyno'ing N/A (Actually, we saw negative benefit as area under the curve with 2 spacers N/A). I also suspect that with higher boost, the benefit of 2 spacers may become more apparent based on the behavior we observed with 1 spacer. However, 14psi and 1 spacer has me at 330whp, so I have my doubts on how much higher I can go psi-wise to prove this theory until I throw in the BMW tranny.

never assumed it was, I’m interested because I am just finishing up my full forged 1.8 and mild BP4W build with a 6758 and skunk2; seems like you’re working with a fairly similar build and am happy to see those numbers is all 🤷🏽‍♂️

Either way, following along 👍🏻

So squaretop dyno'd same day/conditions as Skunk variants?

And thanks for your business!

Thats 14psi directly on wastegate, no EBC or something else? I expect torque to be at least 500rpm sooner with that turbo, but it's pretty linear power after 4500rpm

Everything is done within 2 hours at the same tuner. It took me awhile to find a tuner who was willing to put up with some of my more inane requests for data.

14PSI off of a turbosmart wastegate, yes. No EBC yet, I am talking with the tuner as to how we can implement EBC best due to these results as we both had thought 14psi would be under 300rwhp and neither of us thought the skunk2 would react this way to the spacers under boost. As for the powerband, I'd be interested in further discussion about that at a later point. I suspect it is due to the engine which I built to spin all the way to 8k safely (Should've been 9k, but 949 no longer stocked the crank I needed when I needed it) and make power to 8k. I think that it is due to cams, but definitely worth discussion this weekend.

Your car is beautiful...

Your power production is outstanding at 14psi.

I'd like to see the flat tops curve on the same map as above.

Completely interested in the weekends discussion.
I'd also like to see the "prequel" with the original car.

One thing I don't agree with...

That car is NOT a "clunker"

Same as TNinja, I'd love to see the overlay with the squaretop runs taken the same day. If that's possible. TIA

Dig the fast back top and color!!!

I'll ask my dyno tuner when we figure out the path to take with EBC and get him to give me a dyno sheet of flat top, skunk2 w/spacer iwg, and skunk2 w/spacer ebc. However, I have a pdf of someone else doing the same thing of a flat top vs. skunk with spacer on these forums and got the same results I did. I have attached it, however, I was not able to find the thread it was from. Hopefully two people independently arriving at the same data point adds credence to this, @emilio700 .

Thank you.

Thanks. Not same day, correction factors didn't match so weather was different, but still useful info. I presume no other changes.

As I understand, this is correct. Trying to find that thread, only had the .pdf since I downloaded it to take a look and realized it was the same pattern I saw with the skunk2.

Another .pdf I ran across that I downloaded earlier from the same thread. It seems to support my psi theory. Still trying to find that thread.

Found the thread finally. Here you go, @emilio700 https://www.miataturbo.net/dynos-tim...unk-2-a-99000/

Back from a track day. Exhausted, but even at 7psi the car is insane.

Spool...

Current engine:
CNC SuperMiata VVT head, SUBs, supertech dual heavies, +1mm ss intake, +1mm inconel exhaust
Tomei VVT cams (Love these so much, their lift is just after when the BP head starts flowing decently)
FM Pistons (9.0 turbo 84mm)
Eagle rods (Shoulda been Carillos but Supermiata was out at the time I needed them)
SuperMiata oil pump
SuperMiata BHJ damper for now (Fluidampr soon)
Skunk2 mani w/spacer and TB
Kraken efr manifold, downpipe and full 3" exhaust
ID1050X, truck LS coils, 80psi returnless fuel to radium fuel rail
EFR 6758 with turbosmart IWG and BOV
Stock crank because SuperMiata didn't sell the moldex crank when I needed it


I'm open for ideas on why my spool is poor. My best guess is due to the powerband moving to the right. As it is, I have close to a 4k rpm powerband with the engine setup to go to 8k rpm, but I certainly wouldn't mind some lower range grunt. Any ideas based on the above engine list? Also, should I worry about spinning the above to 8k rpm? Heard some mixed information on this and was hoping for someone like @emilio700 to chime in.

What are the cam specs?

Sometimes altering the exhaust cam timing can have effects on boost threshold.
Usually you need to be on a dyno and try different settings on your car.
It's not a "one size fits all" thing, your set up might like something different than another.
Also need an adjustable exhaust cam gear for this.

Are you still on wastegate only?
If so I would not worry about anything else before getting EBC set up.
A stock waste gate has a "cracking" pressure where it starts to open much earlier than the "boost" setting it's set up for.
EBCs can delay this "cracking" big time. Lower boost threshold is result.

I would also want to see what pressure was in the exhaust manifold versus boost level.
I'm guessing your set up will have lower TIP than BOOST. This is why you are making serious power at 14 psi.
Besides the cam specs and timing (unknown right now) everything else looks like a strong 400+ hp recipe.
Wild cam profiles will push the effective power range to a higher RPM.

You probably just need EBC...
And Emilio is GOD on this type of stuff so listen to what he has to say.

Thanks! Good tips, yeah, I am only on an IWG. No EBC yet.

VVT cam specs are here: https://www.tomeiusa.com/_2003web-ca...cam_BP-ZE.html

Also, totally agree about Emilio. It's why I buy almost exclusively from SuperMiata.