Back in Winning Blue. Our 'new' Project Blue!

[ArmandH180]

Hey Brian! I just spent the last few hours reading this thread and trying to follow the progress. I just want to clarify where the motor stands at this point so I can make sure I'm following.

In review of your 2.5L current build is this correct?
Cold-air intake
2.0 intake manifold
2.5 head
12:1 pistons
"upgraded rods" with ARP bolts
Header (of continuously changing dimensions lol)

and are these correct assumptions?
Standard rod bearings
Standard 2.5L cam
Standard injectors
Standard fuel pump
91 octane

Anything else noteworthy on the motor?
Any plans to do larger midpipe and/or exhaust to accommodate this higher flow header?

I picked up a 2.5L long block for a steal in preparation for a build and swap at a later date. I'm debating on if I should go the direction of stick with "all motor" and do 11 or 12:1 pistons and just a cam OR go ridiculous with 9:1 pistons + cam + supercharger. Jury is still out but I'm very interested to see where you go with this project. Very happy to see that the results are aiming even higher than the advertised 195lb-ft on the 2.5L GWR store page.

On a side note I'm also the happy owner of an '06 winning blue (6spd). Soon to have the front bumper of a '13 though. Almost all the parts are in!

[Brian]

That list about right except I do have set of cam regrinds....but my suggestion is stay with the standard cams and I wish that I had stayed with the standard cams. I do have bigger injectors and upgraded fuel pump too so we have ability to go E85 if we want.

[ArmandH180]

Now when you say you would stay with "standard" cams do you mean the 2.0L or the 2.5L standard cams? I know Moto-east has a "stage 1.5" and a "stage 4" cam on their page that I'm looking into.

Do you believe you'll be staying with the same RoadsterSport midpipe and exhaust for the 2.5L or do you anticipate designing a larger one to go with the headers?

[Brian]

The 2.5 midpipe has plenty of flow, so no plans for changes there.

Having driven numerous versions of 2.5 my opinion is that street customers for 2.5 should stick with the stock 2.5 cams. The new ND Miata has low/midrange torque that earlier Miatas never had and you get to enjoy even more of that with 2.5 if you stick with the 2.5 cams, no point shifting the power up the rpm band unless it's a track car. Enjoy a Miata that has serious torque off the line from every stop light, it's a blast this way.

[ArmandH180]

Here is my current build plan for the 2.5 swap, looking for some feedback from you in particular, Brian.

I picked up an '09 tribute long block for $500 delivered
-> Use the 2.5L head and match the 2.0L intake ports
-> Massive balance shaft delete
-> Moto-East stg 1.5 cams
-> Carillo 2.5L Rods
-> CP 12:1 Pistons, std bore, high compression valve recess
-> Deatschwerks 265lph fuel pump
-> 500cc injectors
-> GWR 2.5L header (when it comes out)
-> GWR RoadsterSport Mid-pipe w/cat
-> GWR RoadsterSport II exhaust
-> Moto-east Cold Air Intake
-> Moto-east 93 octane tune

-> ARP head studs
-> ARP main studs
-> ARP rod bolts
-> GWR Engine drop brackets
-> GWR Short mounts for 2.5 conversion
-> V8R Drive Line Kit

I do tend to make my cars less daily-driver friendly even if they are daily driven. I have the Fidanza flywheel, Exedy Stg1 clutch, the hard dog sport bar, and mostly removed interior. That should give you an idea of where my mind resides.

[Brian]

So I have those Moto-East stg 1.5 cams and not a fan in the daily driver. As a regrind they need to spin fast and they make a lot of noise as a result and they take away that joy of the off the line torque the 2.5 has because they shift that torque so much higher. So, I regret doing that part of it and would only do those on a race car. If Mike now has those as virgin grind that would change just half of my objection.

[ArmandH180]

I've been exchanging emails with Mike over at MotoEast about some of these parts. If I understand correctly they aren't doing regrinds. Currently the description on their page reads:

"We NO LONGER take cores. All of our current production cams are fresh blanks from Mazda! Includes lash caps necessary for most applications."

It intrigues me that they state their "stage 4" custom cam is intended for high CR, aftermarket intake, and large headers; all of which I'm saying "yes" to. Hmmmmmmm I'd really like to see comparative dyno runs on these. Sure would take away the guesswork but what fun would engine building be?

[Brian]

For me it comes back to what this car is for you, is it a daily driver or not? If a daily driver, why are you so intent on shifting the power up to where it is not as available off the line? The reality of the daily drive is LOTS of stops and goes with every stop sign and every stop light and every bit of traffic. For me the joy of the 2.5 with stock 2.5 cams is MEATY TORQUE from go...you can pull your way out of every stop like you have a V6 under the hood. For me I see no point to shift that to the upper rpms unless you are building a race car. Cams essentially just shift the power, they really don't make power, why shift your peak torque up and away from where 'normal' driving is done? As Miata owners we get trained for years to keep the cars on boil above 4000 rpms for real passing power but try to imagine a Miata that you can drive hard out of the hole from 2000 rpms, that's what the 2.5 can be if you do not cam it. For a race car that lives in the upper RPMS the cams makes sense, for the street driver I don't see the point and I think you are just avoiding the best part of what 2.5 can give you in these cars.

[ArmandH180]

I'm following you now, Brian. Cams aside, how's the rest of the build list look?

[Brian]

Build list looks great though I would run it past your tuner of choice too. So, assuming Mike is your Tuner talk the details with him as well.