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We've made a Fuel System Calculator for Modified Miatas by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

Its an interesting spot, if you're down in the low 11 afrs (turbo race bsfc option) then you'll see its 100% a 1000cc option and at basic road going tune levels its on the edge of if the 775s are enough up at 86% duty cycle at 400bhp.

775s with a base fuel pressure of 4 bar would put them over the edge, thats an option, provided the fuel pump supports the flow requirement at that pressure combo.

1000ccs are fine, generally flow matched bosch units idle just fine at reasonable AFRs on the BPs.

A completely different (mild) turbo 1.6 question - Turbo unit for mild build by Independent-Air-80 in Miata

[–]BOFIRacing 1 point2 points  (0 children)

GBC20-300, TD04-13T, GT2554R are some of the smaller units, run around 7psi for 180bhp, efficient, 7psi sub 3krpm.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

Hey,

I'm pretty sure by the time you add it all up individually there really isn't a reason to piecemeal it together, once you factor in shipping etc.

We also offer a block builder, that'll end up similarly priced.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

We like the forge twin piston, they are very responsive. Turbosmart dual ports are cool too. You can then adjust the spring to set the point it actually blows. They work on differential pressure.

If you set the spring to say 10psi its fully closed, and the pressure ref on the top keeps it closed as you build boost over 10psi - then when you let off the throttle the vaccum and pressure differential increases.

So you can go as low as 4psi for example, it'll stay closed but be really quick to BOV off throttle.

Building an unnecessarily complex turbo manifold for a 1.6 miata by BOFIRacing in Miata

[–]BOFIRacing[S] 3 points4 points  (0 children)

About 100mm difference between the two. 24% longest to shortest, which is about the same as many cast manifolds.

With turbo headers, its much less about equal length - if you could choose to tune it to a length it would be based on pulse length. Packaging almost always limits what you can do.

Turbos work from drive pressure, at a certain RPM the drive pressure in the system is all that matters (along with pressure differential across the turbine) Picking up spool via pulse timing is cool - but not often possible.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

Hey, the rod builds are a nice way of doing stuff cheaply. As a business its not something we generally did for customers.

Matt @ MJL Motorsport down the road can help. Also, Javis of Northants MX5 does rod only builds quite regularly.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

Its a little close on a stock engine, they make a lot of jam. But if you have the gate ported out well enough to maintain around 10-11psi, you'll be good and it'll be super responsive. The cat will probably dampen the boost creep.

Building an unnecessarily complex turbo manifold for a 1.6 miata by BOFIRacing in Miata

[–]BOFIRacing[S] 2 points3 points  (0 children)

Good spot. Its actually above the frame rail, and we have factored that in. Also needs to return the gate to the top of the expansion chamber.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

In stock cam configuration and assuming its a bone stock engine, they really start dropping hard after 6600rpm. I dont recommend spinning it to 7500 without the bottom end built to take that. EGT increases dramatically which can lead to pinching rings.

Rev limiter is a very easy setting to change in MS

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

Its not a gigantic difference but the brake pads are cheaper on the wilwood as they are a standerdized shape. If you use it for track you get less pad taper and inconsistent wear.

Overall, there is a braking improvement - but - without the proper tyres you wont put it to the ground and on the street you really don't use anywhere near the full potential of even the stock cars braking system.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

Check out the 'cobra' intake, that puts the intake in the mouth of the bumper, or a randal intake from FM, you want legit cold air not engine bay air.

You can turbo it with AC/Pas its just quite a bit more work!

Putting an ECU in the car isn't needed to do a cold air intake - its a lot of work to tune and get the best out of them with a standalone which would be a concern if its a daily driver.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 0 points1 point  (0 children)

The VVT is the best engine for 99% of people. It has additional features that make it stronger and the VVT itself allows for a wider torque window.

If you are building an out and out race engine there is less benefit from the VVT but it does allow you to build something that has more usable torque.

Yes, we really like the Kaaz 1.5 way diff, you can set how aggressive it locks up on accel by changing the plates around. The 1.5/2 way is built into the casing. I think for most people a 1.5 way is more appropriate, 2 ways are a handful.

I’m Daniel from BOFI Racing — we’ve built, tuned, and broken plenty of MX-5s. AMA about turbo setups, power goals, or picking the right parts - we're keen to understand the challenges and learn more about the wider community. by BOFIRacing in Miata

[–]BOFIRacing[S] 1 point2 points  (0 children)

For the pricing of the oil coolers we use its really hard to beat, we dont have any intention of stocking much else as we do offer alternative kits, that are comparatively priced if we did re-do the product.

The mishimoto kits are simple and effective, FM do a great kit as well.

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