Boosting my NB
 

Hey everyone,

I am doing a full DIY turbo system, that consists of the following:

-KKK K26/6 Turbo (for now)
-Custom log style manifold (temporary, weld els and tees on their way)
-27"x5.5"x2.5" front mount intercooler (on it's way)
-Eagle H-Beam forged rods (also on the way, ARP 2000 bolts)
-Pistons? I was thinking J&E or maybe Ross. Suggestions welcome.
-TiAL 38mm wastegate
-Using a recirc valve instead of blowoff, in hopes of helping with spool
-The rest is all generic stuff. Oil lines, IC piping, etc.

So, tell me what you think. Any suggestions you may have as far as head work, or concerns about what I have so far? Criticism can be one of the best ways to learn, so fire away! :)

Tell us more about your car. What fuel management? What year? What injectors will you run? What exhaust? We need more details, maybe post a few photos.

Interesting turbo, what are you doing for engine management?

That's one of the things I need help with. I know FM has their VooDoo systems, but I don't know too much else about what's out there. And from the research I've done on injectors, it seems like Supra injectors seem popular? I'm planning (hoping) on getting about 300-350 rwhp. Car will have a 2.5" custom down pipe that goes into a 3". No cat, as I don't have to pass any emissions, with a Magnaflow straight through 15" long muffler. Wastegate dumping to atmosphere.

Just share with me the knowledge you have on engine management. I'm not very educated on the Miata engine management systems out there. I'm still stuck in my Porsche turbo world (hence the K26/6). Therefore I'm used to making a turbo car faster. Not converting from N/A to turbo, then making it fast. And I plan on doing everything very meticulously. I know how turbo systems work, and understand A/F ratios, how to tune them, what stoich is, so I'm not completely clueless. I just need guidance as to where I should start.

So please, feel free to give me any knowledge you have. I'm starting over as a noob.

Forgot to mention the car is a 1999.

Ban this racist. Megasquirt is the most common ecu. I would look into getting the newer ms3x

Holy shit. You want over 300 whp, but you've only heard of things like a voo-doo system? Put on your flame suit right now, it's time for your hazing.

Agreed with the above post.

Supra injectors + Voodoo Turd =/= Lots of power.

The next thing you need to do right now is go read ALL the sticky threads and How-To threads.

In for the popped engine running 15psi at 15afr.

Read the BASICS to turboing a miata. Admins have made plenty of good threads stickied.

The Voodoo box will not work for you. Do not consider it.
Popular ECU's here are Megasquirt, Adpatronic, and Hydra. There are others of course, but I think about 90% of standalone guys on this forum use one of those 3.

You're going to need 750cc injectors to run that much power. I would not go with used anything OEM. Deutchworks is a sponsor here, buy from them.

Stock cooling system cannot keep up. Need radiator and coolant re-route at a minimum.

2.5" dump is pretty restrictive for that much power.

Stock 5spd tranny will shit itself quick at 350whp. Open dif will eat tires at 350whp. Stock suspension will not be pleasant at that much power. Serious rubber needed as well... I'd go with minimum 8" wide and 245's, or something really sticky if narrower.

Stock ignition will not handle 350whp reliably. Need aftermarket coil-pack or COP setup... can build your own for cheap'ish.

'99 head flows very well for BP series engines. If going to rebuild, don't go crazy for only 350whp. 3-angle valve job and some DIY port/polish will do the job.

What I'm getting at is for 350whp, there is very little about the stock Miata that will work well or for long. At 200whp, an otherwise completely stock Miata is still mostly fine. At 250whp, the stock engine is still good, but other parts are becoming suspect. At 300whp, the stock engine is on borrowed time, the stock 5spd is a missed shift away from a paperweight, and the other aux systems simply can't keep up.

A reliable 350whp is a $10k proposition if you know exactly what you're doing and maximize function over form.

Roll bar and seat?

Thank you, this is what I was looking for. It's not going to be going straight from 120 rwhp to 350 rwhp. It will be a slow process. Corky Bell told me I could run 8 psi and be safe on stock injectors, so that what I'm doing at first. The motor is getting old, so I'm going to just go ahead and forge everything just so it's ready when I want more boost. If (and I know I will) want more power, then I will rebuild the tranny. The car has a torsen rear diff already (please let me know if these need any upgrading). Also, it has a Ron Davis radiator already, so that should be sufficient cooling. I knew I needed the coolant re-route.

I should have explained this was going to be a slow, gradual process at first, so I didn't sound like an over-ambitious kid....:facepalm:

At what psi of fuel? When I was running stock 240s (stock 99 injectors) at 7psi I was at 100% at 5500-6k rpm.

I'm at like 96% duty cycle on my stocker's in my '99, and that's with a tiny assed sr20 turbo on 7 psi.
To the OP: turbo sizing plays a huge role in boost / fuel calculations. What I mean is, you might get away with around 7 psi on a small turbo (gt2554 or similar), but those same injectors would never supply enough fuel for 7 psi boost on a largerer turbo (gt2871, gt3071, etc.).
Keep the injector sizing related to rwhp. Figure that stock injectors should max out right around 200whp.

Even if it's a slow build, do everything right the first time. This is a hard lesson I learned, I replaced pretty much everything on my turbo system twice over to get it where it was. I spent more in the end than I would have if I had done it right the first time.

The 2.5" DP, even with open WG dump, will be horribly restrictive at those power levels. Do a 3" from the get-go. Contact Abe at ARtech, he made me a beautiful 3" SSDP for a very reasonable price. Much better than anything Begi or FM.

Same thing with everything else, it will be a much better experience if you do it right the first time. Spending the extra penny to do it the right the first time will definitely save you money, time and frustration in the future.

BTW, stock injectors blow dick. They are fine for very low power levels, but I wouldn't push them past 175rwhp. You technically can, but I wouldn't.

Good luck.

Correct every time it's said.
First things first... ECU and injectors.
No reason not to do both now even with no other go-fast parts. You'll learn to tune and won't have to upgrade.

Then supporting mods... cooling and ignition.

Then supspension/rubber... make sure you can put that power to the ground safety.

Then safety... rollbar/harness and a sticky seat... plus a general brake upgrade, pads/rotors/lines/fluid. Stock calipers on the street are more than adequate.

Then if you're still interested, engine and turbo stuff.

Also, you don't have to rebuild the tranny, just get an OEM Miata 6-spd... internals are stronger than 5-spds, but 6th gear is actually a shorter ratio than the 5th in the 5spd. You'll also want a minimum of a 4.1 dif, but preferable 3.9. The 7" ring and pinion is plenty strong... but if you're going to swap for a different ration, I'd shot-peen or cryotreat while it was out... especially for your power. For 350whp, some will recommend the 3.6d but have no experience at that level or with that dif. Some love it, some say it's too long.

Very good advice here. But I have a problem....last night I think I spun a rod bearing in my car. If I did, that means more machine work. More machine work=more $$$ than you originally planned. I have a set of eagle rods on the way, but I have a friend down in Houston with a fully built 1.8L that he wants to sell me. It was built by a friend at the track (Mark Perry, very educated on miatas, very good work. Forgot company name), so I know it's good. He's asking $4,000 for the long block....what do you guys think?

Salty. That's what I think.

Correction. It was built by Gas Head Motorwerks in Houston. Balanced and everything

Post very clear details about the engine and we will tell you if it's worth 4 grand or not.

I will as soon as he contacts me back. He's at the race track so it'll be tonight or tomorrow.