weight of minimalist miata

In reply to alfadriver:

I also recommend the Good-Win Racing RoadsterSport 3 exhaust. It is just barely louder at idle, has a nice growl (almost Subaru-esque) below 3500rpm but from the on up it screams like a super bike. When I added the Racing Beat header, it mostly made it louder at idle and up to 3500rpm and then the volume level stays the same above that.

In reply to alfadriver:

Instead of a cheesy hot air intake:

https://www.flyinmiata.com/na-randall-cowl-intake-duct.html

That would change the appearance of the engine bay a bit, perhaps a bit too modern?

I know some folks swap the valve cover for a Ford one to give it a quasi Cosworth look, the only drawback is that the timing belt cover no longer works, so it looks a bit weird.

I suspect relocating, covering or changing much of the wiring and hoses so they have a more uniform and clean look will help quite a bit.

A polished ceramic coated header will brighten then engine bay a bit.

I would think either individual throttle bodies or dual side draft carbs (with injectors) would be more fitting of this design theory. Strip the engine bay of non-essentials or maybe a light wire tuck.

Stefan (Not Bruce) wrote: I know some folks swap the valve cover for a Ford one to give it a quasi Cosworth look, the only drawback is that the timing belt cover no longer works, so it looks a bit weird.

Posting a great idea like this with no picture? Not cool.

RossD wrote: I would think either individual throttle bodies or dual side draft carbs (with injectors) would be more fitting of this design theory. Strip the engine bay of non-essentials or maybe a light wire tuck.

Esthetically, I agree.

But there is a sound part- anyone have an audio track of itb's?

alfadriver wrote:

RossD wrote: I would think either individual throttle bodies or dual side draft carbs (with injectors) would be more fitting of this design theory. Strip the engine bay of non-essentials or maybe a light wire tuck.

Esthetically, I agree. But there is a sound part- anyone have an audio track of itb's?

From what I understand from reading about them, here on the board I believe, was that they can be LOUD as in louder than what was allowed at Sears Point db-wise.

A good airbox would probably be a good idea for many reasons.

I wonder if an Alfa side draft airbox could be adapted? That would help with the period look.

In reply to Stefan (Not Bruce):

That would end up looking a lot like the stock manifold, seems like.

Maybe the airbox for spica Alfas. And i have one of those.

Irtbs are not subtle on the street. Especially on a high compression engine, they make a hammering noise under load. And yes, I've blown sound at Laguna Seca (95db, I think) from the intake noise even with a plenum. Add the difficulty in tuning and they're more for show than go on a street car.

Says a guy who has owned three irtb cars at the same time.

Yes, the doors do get floppy when you remove the inner structure. Btdt.

There's some decent aftermarket side draft boxes available now. Along with DCOE style throttle bodies that bolt up to DCOE Manifolds so you can use EFI and get the benefit of Webers without their drawback (aside from lack of vacuum signal)

You could also have an airbox fabricated by a local fabricator/metal worker for that period look without being cookie cutter or having to settle for a less than suitable solution (I.e. It reduces performance, etc)

Heck find a local DIY shop that has a foundry and you could cast your own manifold from scrap aluminum after creating the design and mold yourself.

In reply to Keith Tanner:

Yep, there's a reason I pulled the TWM DCOE throttle bodies off my 924 and went back to a single TB.

The car was much easier to tune, drivability was better and fuel economy wasn't measured in feet per gallon.

I don't even miss the noise.

I might look at going back to them down the road because I think I can do a better job at it, but for now I just want to drive the damned car.

So, a good question would be "how retro?"

Can have all the drive ability of old cars, too. Or translate to same difficulty tuning it.

Stefan (Not Bruce) wrote:

alfadriver wrote:

RossD wrote: I would think either individual throttle bodies or dual side draft carbs (with injectors) would be more fitting of this design theory. Strip the engine bay of non-essentials or maybe a light wire tuck.

Esthetically, I agree. But there is a sound part- anyone have an audio track of itb's?

From what I understand from reading about them, here on the board I believe, was that they can be LOUD as in louder than what was allowed at Sears Point db-wise. A good airbox would probably be a good idea for many reasons. I wonder if an Alfa side draft airbox could be adapted? That would help with the period look.

It dawned on me last night that a MAF based system would work perfectly with ITBs. So this kind of intake leading to an air cleaner would do the job pretty well.

In reply to alfadriver:

You can adapt a MAF to MS, there's documentation on how to do it. It's not widely done, I believe, but it's certainly possible.

In reply to Stefan (Not Bruce):

When I get home, I'll research the options.

Then figure if there is a itb set up for the idea. I still have a SPICA st of throttles.

So the easy button for MS and MAF is actually Microsquirt.

And given the minimalist ideas, the limited functions are prefect.

Actually, with so few loads (just the alternator), not having an idle control valve is not unheard of- I can use a controlled leak like was used in Alfas.

Now I have to make some measurements to see if the Alfa throttles would work, or are there some good bike throttles that would work.

I may have a set of TWM throttle bodies sitting in my garage for a 1.8 if you're interested.

I run my ITB'd 1.6 without an idle control valve. It's fine once it's warm, but you kinda need to keep it alive to that point.

Keith Tanner wrote: I may have a set of TWM throttle bodies sitting in my garage for a 1.8 if you're interested. I run my ITB'd 1.6 without an idle control valve. It's fine once it's warm, but you kinda need to keep it alive to that point.

Hopefully yours don't stick when they warm up like mine do. Causes erratic idle issues among other problems.

They were too big anyway, so I've got a set of 40mm units from another vendor that should work better for my use.

Not sure why you'd want to use MAF, but to each their own and I wish you luck.

MS2 Extra code with ITB mode works very well. ITB mode uses a blending of Speed Density and Alpha-N and avoids adding another potential restriction in the intake path.

http://www.77e21.info/mstuning_blendedansd.htm

Stefan (Not Bruce) wrote: Not sure why you'd want to use MAF, but to each their own and I wish you luck. MS2 Extra code with ITB mode works very well. ITB mode uses a blending of Speed Density and Alpha-N and avoids adding another potential restriction in the intake path.

MAF works quite well for OEMs, there's no reason it can't work in the aftermarket. Properly-sized hot wire MAFs are not restrictive at all, we're not talking about flapper doors here.

My E39 M5 has 8 individual throttles being run off two MAFs. So it can definitely work.

Stefan (Not Bruce) wrote:

Keith Tanner wrote: I may have a set of TWM throttle bodies sitting in my garage for a 1.8 if you're interested. I run my ITB'd 1.6 without an idle control valve. It's fine once it's warm, but you kinda need to keep it alive to that point.

Hopefully yours don't stick when they warm up like mine do. Causes erratic idle issues among other problems. They were too big anyway, so I've got a set of 40mm units from another vendor that should work better for my use.

The modified TWMs on the 1.6 are a bit sticky, but the nicely cast 1.8 units are fine. I don't recall what size they are, but relatively small. They were worth 15 hp on my 2.0 engine with no loss anywhere. Other than the noise. I also had an idle speed control on a separate mount, feeding through those red lines. Car behaved like it had fuel injection, just started and idled like a Real Car.

Stefan (Not Bruce) wrote: Not sure why you'd want to use MAF, but to each their own and I wish you luck. MS2 Extra code with ITB mode works very well. ITB mode uses a blending of Speed Density and Alpha-N and avoids adding another potential restriction in the intake path. http://www.77e21.info/mstuning_blendedansd.htm

Besides being what I am used to, it also eliminates the issues with ITB's, and the SD-Alpha-N blending.

edit- what I need to learn is how a MAF system calculates load for the ignition tables... I know how we do it- which is really easy. And it's very related to the calculation used for the live fuel calculation.

It's how BMW runs the valvetronic systems.

For the most part, the only SD work we do anymore is with boost- as the turbo dynamics can really screw up the MAF system, unless you spend good money and get a directional MAF sensor. SD works well enough for that.

Oh, and +1 on the observation that AM sensors don't add big restrictions. The 500hp Mustang is a single AM.

Ok. I'd think it wouldn't fit with your "throw back" styling.

As long as you understand that there is very little info in the MS world about MAF usage compared to using SD or Alpha-N. You're essentially on your own with that.

Luckily you're not exactly a newb :)

On mine, I used the stock Bosch idle bypass solution which just needed power and responded to heat to open/close. Worked fine without it other than needing to warm up the car a bit before you'd be able to drive it without a foot rolled onto the gas pedal at stops.

In reply to Stefan (Not Bruce):

Actually, the Alfa manifold you posted really got me thinking. On that style of cars- which are 1600cc cars- the air cleaner is in a canister on the left side of the car- just like the Miata. So with the right tube, and the right intake, it would still look pretty classic. Where I next had a conundrum- what air box to actually use? We (F) have a few round canisters that have MAF's attached to them. Or one could use the original square box, since it's somewhat subtle. OR, even a cold air intake system would work.

the other idea that came from that was to use a SPICA box- just seal it up. it's plumbing is pretty close to the path the Miata already takes. So it would look OK, too.

One thing I keep seeing pictures of- the runners on the Miata slope up. Whereas the Alfas are level. So all of this may not even work. But the thinking is still not totally out of the question.

Alfa, I hope this turns into a build thread!

The slope is to get the runners above the frame rail, I believe.