I am relatively new to this however I've been building and modifying my NA Miata for couple of years now.

I am currently running 1.6 with NB drivetrain, Giken dif. It's a fully stripped track car with a cage

​​Engin:

​​​​​Button was built before I bought the car with Supertech pistons, do not know the make of forged rods and ARP studies.
I just rebuild the head with Supertech valves and springs.

The turbo set up started as flying Miata kit. I upgraded fuel pump, 970cc injectors, LS coils and megasquirt with custom Dyno tune E85.

The car has rerouted coolant with SuperMiata radiator and oil cooler.

I know everyone would recommend going to 1.8 motor, however I already have 1.6 fully built and I would just prefer not spending 10k on a new motor

Now for the fun part. I would like to upgrade from Flying Miata manifold and turbo. Probably Kraken Manifold with a more modern turbo. My goal is to be able to produce more boost and faster spool.

Currently car makes 250ft/lb @4500 rpm and 280WHP @ 6700rpm with 20lb of boost. The boost is tuned to progressively increase from 16lb @ 4500 to 20psi at redline.

Would love to hear different opinions.

 

This is kind of a broad question. Tell us more about your current setup and goals other than "I want more better" lol. I'm assuming it is a GT2560R or GT2860R. If that's the case, I've heard from others on here that the GTX 2860R Gen2 can flow enough for 350whp+ while still spooling up similarly to a GT2560 on the same manifold. If you're looking for more power than that I'd jump to a G25-550 which can make mid 400s on E85. Both of these set ups will risk breaking the 6 speed transmission though, so I'd say make that your first step.

My take:
Transmission swap
G25-550 w/ Kraken Low Mount* (if applicable to 1.6L, if not top mount will still be fine. Low mount will help with spool and power though.)

A similar thread where similar stuff was just discussed

Edit, I'm not sure why I didn't consider the EFR turbos. But the EFR 6258 sounds like a great match for what you're looking for. It should spool faster than the 2560R and make mid-300s easily. The 6758 will bump up the power to mid/high 400s but will take longer to spool than the 6258. The 6758 is still likely to be quicker to spool than the G25-550 though. The PSR 4849G (G25-550 clone) is going to be the best bang for your buck. If you're wanting a genuine turbo I'd go straight for the 6758 and bite the bullet due to its price.

 

You called it right. 2560R set up with flying Miata original manifold (1st and 4th cylinders blowing into each other). That manifold did not make sense to me since I bought the car.

I am shooting for mid 350who but as always want to have some room to grow in case i will want more in the future.

G25-550 verses EFR turbo is a big question.

Should I do low mount or top mount manifold?

Copy your concern on the transmission, I just replaced one with a newer 6speed and next time I am definitely going with zf 6speed upgrade. A bit concerned about vibration that some people had an issue with.

Would love to hear more of your opinion.

 

I just realized I've been replying to both of your threads without noticing its the same person I've been talking to. Oops.

Anyways, If money isn't an issue the EFR route is 100% the way to go. Which EFR turbo? I'd probably jump straight to the 6758. You can read a little about it here. Basically, the spool between the two is almost identical but the 6758 can make 150whp more according to his numbers, which I personally think are slightly higher than what other people report, but still... it gives you an idea of what to expect (just maybe 25-50whp less).

If money is an issue I'd do the PSR 4849G. It is a Pulsar clone turbo that is practically identical except the turbine wheel does not use Garrett's Mar-M alloy. Expect 95% of the performance in terms of spool and power. In terms of reliability, I've not heard anything bad about PSR, but I've also not been looking for bad reviews. Many forum members here have had great success with their turbos, myself included. I think shuiend is even an authorized dealer for them and might be able to get you a discount. I just bought mine through Kraken though.

 

"Should I do low mount or top mount manifold?"

IMO, top mount is preferable because:
1. it's easier to install
2. it's easier to spot any issues
3. the longer oil-drain hose is beneficial; EFRs connected to a drain sump-hole that's too small tend to build up oil sludge that can accumulate high enough in the drain hose to enter the turbo, reducing its lubricating efficiency. Even with a larger sump hole, the sludge may accumulate - a longer hose ensures that the sludge issue should never be a problem.

Lower COG and more efficient exhaust flow are beneficial on the low-mount solution, but for me, the above 3x points trump these benefits which I'll never notice.