Are you planning to run any ProAuto events this year?

We'll be at AMP in two weeks, and are planning on doing INDE in May.

 

I'd like to try and get to the August Inde event and also Mondo since NASA doesn't run either of those. The May Inde event is probably a little too soon, not sure the car will be done by then.

 

This pleases me.

Any plans to run a combo without the front splitter?

 

The way I'm planning on building the engine I don't think I would be able to make quite enough power to run without one, but I wouldn't want to anyway. My handling balance would likely get even worse. I have the wing trimmed almost all the way out and rear sway is full stiff in order to get the thing to rotate nicely already.

So according to that rough CFD comparison of front ends, deleting the splitter adds 2HP worth of drag at 100MPH. So gains are not quite as much as you initially think. I'd be able to run 163WHP at 2450lbs instead of 158WHP. And if I lowered weight I would lose 0.1 mod factor from moving to the next weight bracket and the difference would be even smaller.

That's my thought process anyways.

 

Hrmm, solid thought process for sure.

Where is the CFD comparison you speak of? This one?
https://hanchagroup.wordpress.com/20...esign-is-best/

 

Yep. I figure it's good enough for getting a rough idea of what's going on.

 

Are you planning to attend Nationals?

 

I'm trying to get the car done within about 3 or 4 months. Between then and Nationals there aren't enough events I can run locally in order to be eligible to race at Nationals anyways. But even if I was eligible I don't know if I would travel that far and pay that much if the lower ST classes are going to bomb again and only have 5 or 6 people.

 

Alright, planning the engine build. Just spit balling here, so any input is appreciated.

So right now my untouched original NA8 with exhintake cam mod made 124WHP on my tuner's Dynapack, and 133WHP on the local dynojet. Usually cars are closer together between these two dynos but maybe my 5.5" clutch setup makes it weird between the two. Only thing about my car that is unique compared to a bunch of other local Miatas. Goal is to make between 152 to 154 average WHP. So desired peak, maybe 158 dynojet? I guess shooting for 148 to 150 on my tuner's dynapack?

Also keep in mind trying to make it future proof for boost. Will be running mainly on pump e54, pump e80, and possibly e85 race gas with boost. Flex fuel to safely deal with fluctuations in ethanol content, but for tuning and classing dynos, I'll be "all in" on the highest content pump e85 I can find to be safe when I inevitably get compliance checked.

BP6D
Stock cams and preferably no port work? Or maybe DIY just clean up the casting?
Supertech Heavy Doubles
SUBs?
Manley +1 Valves
Felpro Valve Stem Seals
.020 head shave?
Cometic .030 Head Gasket
83.5mm Wiseco 9.94:1 pistons (Or maybe do the 10.3cr?)
Manley Rods
ARP Main Studs
ARP SuperMiata HB Head Studs
ACL Bearings
ATI Damper
Dry Sump Stuff

Other supporting stuff, bold are not on current setup:
Skunk 2 TB
Skunk or Flat Top Intake Manifold
Homebrew Cold Air Intake
Racing Beat Header/Test Pipe/Catback
ID 1050x
Walbro 190HP
Reroute etc.
Also thinking of going to a Link ECU for CAN support and future expandability. Adaptronic has been awesome but now that they've been taken over by Haltech I feel like their pace of software development has slowed significantly.

 

Just an opinion, but I would go with a square top. I don't trust the weight of the S2 hanging that far off the motor (that already isn't the smoothest) to not crack. Especially with the two position mounting holes being so close to one another.

 

Yeah still haven't decided. Probably square top since the prices have come down quite a bit.

 

Curious about the compression with boost in the plans? That has always been a hanging point for me building an engine for "boost later"...

Are you thinking turbo or Rotrex?

 

Definitely turbo. With e85 and solid tuning a 10:1 CR isn't anything to worry about. That's what a stock VVT is.

 

Plus he can always put a thick head gasket on it to drop the compression ratio if need be.

 

Alright figured out some stuff. Going to try to do something a little different. After talking to my engine builder this thing is going to get some custom pistons and custom rods, and will end up being a 1.9l Long Rod setup. Pretty excited to see how it turns out. Also going to go with 11:1 cr pistons, and if I throw a turbo on it later it shouldn't be a problem on e85.

Getting this thing stripped down, cleaned up and ready to get put on a stand so I can bring it over to the shop.

 

Are you guys going with the standard 140mm rod length?

 

Standard rod length in a BP is 133mm. We'll decide on what length to do after taking some measurements but it'll likely end up around 140mm is what I'm guessing. I'm not using those Mil.Spec brand rods if that's what you're eyeing lol.

 

I wouldn't spend 1k for Rods from a company I've never heard of!

We are looking at building a long rod engine too and we were planning to work with Carrillo for a rod and piston combo.

 

I'm likely going with Saenz and JE.

 

Well, the new K24Z3 swap kit makes building a naturally aspirated BP seem pretty pointless.

I haven't dropped off the VVT motor yet so I'm likely going to sell it and the NA8 motor in the car, and just K swap it. It can be detuned to run TT5/ST5 but it could also easily run TT4/ST4. I'll do whichever has more participation in my region when the car is done.

For now it's time to start taking the car apart and wait for more news on when the pre-orders open up for the swap kit.