Rexican

Hi All,

I've been lurking/reading up on here for well over a year now and my turbo plans are coming close to fruition. Big thanks to Shuiend/Lars for his turbo basic guide and everyone else on here. The car will be used on the street 98% of the time with hopefully and a occasional track day or autox event for fun.

I got the car (2002 SE 6spd) in 2019 with 100K miles on it. I first went through and tackled maintenance doing the timing belt, water pump, radiator and all radiator hoses. I couldn't narrow down a funky smell that I thought was either gear oil or something burning. I ended up calling the car toasty since it smelt like this for the first 2-3 months I had her. I replaced the shifter boots and did a shifter rebuild but that didn't help. I ended up finding a racing beat muffler on craiglist for 100 bucks to add some fun noise. When installing it I noticed the old one had a rattling sound and out comes a mouse carcass and bunch of dog food. I purchased the car from an old retired man and apparently it had been sitting in storage for a while after he suffered a stroke. The new muffler took care of the smell Just some fun history of the car. Onward and upwards.

Current Mods.
CSF Radiator
949 racing organic clutch
Meister zeta CRDs
6ULs 15x8
Ford unicorn oil in the transmission

Phase 1 mods - Goal 230whp
Kraken- EFR full 3" exhaust kit
Kraken - intercooler kit
Kraken - lines
MS3 pro
AEM x Series AFR gauge and wide band
Flow Force 960cc injectors with WB200 full pump (I could go smaller but figured buy it once for the anticipation of phase 2)
EFR 6258 or 6758. I'm not sure which to get to get here.

Phase 2 -Goal 350-400whp (A year or two down the road)
Pull engine and replace rods with Ebay/Eagle units
ATI -super damper
Coolant reroute

So I have 4 questions.

1. Is there any reason for me to pick the 6258 over the 6758? Prices seem identical. Spool is very similar with the 67 being 2-300 rpm slower. Is 230-240whp too low for the 6758?

2. I have no idea what I'm doing with tuning. I'm trying to follow along with PEdxing youtube videos but don't think that will cut it. I initially got really excited when researching tuners as everyone recommended York and I'm located directly in Mount Airy MD, only to find out they no longer tune. Suggestions for eTuners here or semi local people in the DMV area?

3. I think I already know the answer but is there any downside for going with the larger injectors 960cc vs a 640cc injector? I would rather get the larger ones if they idles the same and can handle the power of the 2nd goal.

4. Does it look like I’m missing anything for goal 1?

Thanks again for all the knowledge and info on here. I will post more updates as I start to install everything.

yossi126

iTrader: (6)

First of all, welcome and good luck with your project. Your goals are pretty spot on although I would suggest grabbing the fluidampr instead of the ati.

Regarding turbo, always get the smallest turbo for your power goal, albeit the 6258 will require higher boost levels to reach 400+ whp, and would not be in its efficient range.

technicalninja

I would add the coolant reroute and the damper to the Phase 1 list.

Start with the biggest injector that you can use. If you chose to go E85 the bigger injectors with give you more "head room".

IMO the 6258 is the better choice for street car. Some have seen 400+ from it. It's a bit smaller. If you have the Kraken low mount the 67 is a much tighter fit.

It is seriously difficult to put big power in a lightweight car down using street tires and it's possible a well sorted 325 hp Miata will be "faster" (more controllable) than a 425hp one.
Put those cars on a race track or drag strip with the appropriate tires and the higher hp car WILL be faster but...
If you're 98% street stay with the smaller EFR IMO.

deezums

iTrader: (3)

Do you have plans to replace the transmission and diff, plus axles? If not I'd go with the smallest one that will easily break everything, and that's 6258.

Rexican

Thanks for the responses everyone. I didn’t plan on this. I thought the stock 6 speed was good for around 350whp so I was hoping to stick to that limitation. If it breaks than I will look into maybe the factory gear set? But they will be in phase 2 for sure.

Is there a consistent vendor for efr pricing? I feel like it’s all over the place from 1600-2200.

technicalninja

Stock 6 speed can have reliability issues above 300lb/ft of torque.
Some will go a bit higher but...
Too many come apart above 300lbs/ft for me to intentionally run one above that load.
The MANNER in which they fail is the killer here...
They either rip the teeth off the gear or push the syncro engagement ring off the gear in 4th.
This happens during torque application. Long after the gear has been engaged.
There is no fixing this...

It could be fixed if you wanted to spend enough. New gears, stiffened case, etc...
Far more economically viable to install a BMW transmission (or something else) as many have done on high HP Miatas.
"Don't run Mazda 6 speeds above 300lbs/ft" is the rule in my book.
A Miata with 300lbs/ft of torque is a VERY quick car already...

technicalninja

Here's a data point that is OFTEN overlooked.
The Mazda (Jatco) automatic can be modified to deliver FAR more than 300lbs/ft.
Both Patmx5 and Newza have successfully put UBER torque through the auto.
Newza is still running his...

Look to their threads for ideas.
Both are drag race cars first but run on the street as well.
Pat abused manuals before changing to the auto.
Pat is prone to do "full" destructive testing on his stuff.

Both guys threads should be "required reading" when highly modifying these cars...

Dr.Sep

This is such a good point that it so often missed -- even 300whp is a quick little car (which would put wheel torque in the 260-290 range). We all (me included 100%) sometimes get wrapped up in power goal numbers, but I feel many have not even been in a miata with verified 300+, it really is something. The HP wars are in full swing with manufactures, hearing 300+ all over the place (my wifes cx30 turbo even is rated at 320ft/lb.........) and it kind of dilutes what 300hp really means in our world, but factoring in miatas low weight it really becomes QUICK. Local guy who "only" put down 300 at the wheels on a land and sea dyno is out there running with 600cc sport bikes up to 110mph or so. Think about that.

c3hutson

iTrader: (2)

I don’t see an oil pump on this list, but I didn’t look super closely. I’m in the transition to phase 2 (my phase 2 is only like 300-325) and from my reading though oil pump is basically mandatory and aftermarket damper isn’t really a replacement for it (again just from my interpretation of the experts here).

borka

iTrader: (1)

Stick with the 6258, that is what I'm running on kraken hardware and the spool is amazing. And I've run it all. T25 sr20, 2560r, 2860 and now the 6258..

The 6258 has the best spool and instant response from all the above turbos and can still make 400hp.

Greg from the car passion channel put down like 450whp on his 6258 on e85 and killed TWO 6 speeds in a matter of weeks. So I don't recommend over 350hp power levels if you want to keep the car in one piece..

My setup has 2 settings, mild and wild.
mild is waste gate only, gets about 10psi and 250hp. Tons of controllable fun. Will light up 1st and spin top of 2nd gears on a power roll,, with 225 rs4 tirea.

Wild is 17psi and 309hp and its pretty wild hp for a miata, can get you in trouble real quick. 1st is useless, 2nd lights up, and might spin 3rd on a cold ish FL morning.

Can't image the need for 400+hp in a miata.
Foe 400+hp you need a BMW transmission and stronger diff/axles. Big $$$

Great parts list. Gonna Be a beautiful build.

Edit. Lookup the phone number from Industrial injection out of salt lake city, that's where I scored my 6258 for $1265 delivered.
Ask for the miata turbo special price. might be a higher now since it's been a few years, but should still be a good deal from them. They also price match, so find the cheapest price online and they will match it.

emilio700

iTrader: (3)

Whats the lowest octane fuel you will run (91 or E85?)

6758 not needed to meet your power goals. 6258 will make 400whp on E85 with a stock NB head.
Walter Motorsports offers a customized Miata 5spd that will hold 300whp.Otherwise, a Kpower BMW trans swap.

Assuming our BP organic clutch, your power goals are beyond it's rated capacity. Might hold, might now. You'll probably want to swap to the ceramic puck disc to be safe at 400whp.

Rexican

Great info! thanks everyone. Looks like I’m going to be getting the 6258 as the 67 is overkill.

I will be using 93 pump. Not enough e85 gas stations by me.

Yes that’s right. Currently have the organic clutch. Will stick with that during the phase 1 and move to the ceramic when taking the engine out for the rods I. Phase 2.

any suggestions for eTunes?

c3hutson

iTrader: (2)

just going to ask again since nobody commented on my post, but are you planning on a boundary oil pump?

Rexican

Not for phase 1 but can definitely add this for phase 2. Waiting for phase two as I’m pretty sure you need the engine out to drop the oil pan and change the pump.

allofit

I've just finished exactly your build here in Greatest Britain.

2002 UKDM NB2 acquired in June 2020. 100k miles. Held together by copious amounts of weight saving rust and road salt.

EFR 6258 with low boost actuator can.
Full Kraken 3" low mount system including intercooler kit, plus oil/water lines & fittings.
FlowForce 640cc injectors (No E85 in my impoverished country. Best we have available is approx equivalent to your 93 octane.)
DW200 fuel pump
The much hated ME221 ECU. Boooooo
AEM X series UEGO wideband
36-2 trigger wheel
BOFI Racing dual friction clutch and lightened flywheel
Meister Zeta CRD's
Koyo 50mm aluminimum rad
E301-13-890A PCV Valve
Plus some other stuff I can't remember right now.

I have no experience with the 6758 but I can say the 6258 is awesome. Instant spool. Get the 6258 unless you're a lunatic and want 450hp+

Helpful bits of advice I can offer. Things I wish I'd known or done differently before embarking;

1. Don't bother with the Kraken lines. They're decent enough and cheap but I really wish I'd gone with AN fittings for everything instead.
2. If you get the low mount manifold you'll need to chop and weld your water pump inlet to fit. It's a very tight fit, but it does fit, and you can keep your heater core system if that matters to you.
3. Also If you get the low mount manifold, have Kraken weld on some studs so you can use the OEM heat shield.
4. If you change out your EFR boost can, make sure to get the rod lined up really well with the actuator arm to avoid binding & boost creep later. Trackspeed made a helpful video on YouTube years ago.
5. You'll need to either remove or adapt your power steering cooler pipe to fit the intercooler up. I opted to remove it since it's usually always cold and miserable here. If it becomes a problem later I'll just remove the P/S.
6. Your plastic engine under tray (and the front bumper tray) will no longer fit. You'll have to either cut and adapt the existing or buy/fabricate something. I'm trying to figure this out right now.
7. Find a good tuner before you finish the build. VladiTuned is universally recommended around here from what I can tell.

I'm running a stock VVT engine (with the EUDM flat top of course) and slowly getting my tune dialled in. Running approx 50kpa / 7 PSI by 2600 RPM. Ramping up to around 90kpa / 13 PSI by redline. Conservative timing. The map is a work in progress but I've attached a scatterplot from MegaLogViewer to give you some idea. You can also see how well the integrated EBC is working. No boost creep. Just need to refine the map and feed in some more top end.

Like your good self, I'm also planning a Phase 2 forged engine in anticipation of the inevitable rod bending extravaganza.

95RedM

I’ll be excited to see your progress on this as I’m doing a similar build on my VVT engine. In my experience more is never enough. 250whp miata is fast until you get used to it. It took me about 2 weeks to get used to it and want more. I do agree that 400+ is a little scary to drive on the street, if you watch Greg punch it in his 420whp miata on YouTube the car gets extremely squirrelly as he fights to keep it straight with 245/40R15 slicks on it in 3rd gear. 325-350 I think is the sweet spot for miatas and the 6258 will scream in that range.

my buddy just picked up a 6258 from turbokits.com for $1550 shipped. You used to be able to get it from TCS for $1300 but they closed down a few months ago

Rexican

Got the Turbo ordered with Gavin over at Industrial injection for (1400). Per everyone's comments I've decided on the 6258. AllofIT suggested the low boast actuator. Does that sound right for my phase 1 goal of around 230Whp? I'm also thinking of upgrading the recirc valve to the kompact Turbosmart unit as a lot of users seem to have issues here.

I'm pretty sure I'm going with the flow force 900cc injectors and will upgrade the fuel pump when going for the phase 2 goal. Will the stock pump be able to handle the 900cc injectors for the Phase 1 goal? Thanks again for the comments everyone.

Dyladjent

Yeah to keep the boost down to a manageable level you will need the low boost actuator as you will never be able to go lower than what that is set at. I believe the medium is somewhere between 12-14psi and that is well into breaking things on a 6258. The low boost actuator is set for 7 I think. That should be perfect for your goals. My setup is a bit different but I'm on the stock pump and 650cc injectors and have 0 fuel issues at the hp level you want. I think the stock pump will be fine in the meantime.

der_vierte

In short form:

Stock pump okay, if healthy (these are CHEAP compared to the rest of the build).
Low boost actuator should be pretty much on point

allofit

Good choice on the 6258!

Theoretically the OEM fuel pump is just about sufficient to flow enough fuel for 230whp, but after 20 years of wear and tear, there's no guarantees. Personally I opted to install the DW200 at the same time as FF640s to avoid potential issues.

With the low boost can (p/n 179282) you'll be able to run a safe 7-8psi and you also have the option of using EBC (and you really should!) to feed more boost in if you're feeling brave. I'm running 8psi at 3,000 rpm. Building to 10-11psi through the midrange and peaking at 13psi by redline. Haven't blown my stock VVT motor yet.

Get the Turbosmart Kompact CRV. The stock EFR CRV has an annoying whistle at times and it kinda spoils the otherwise awesome EFR experience.