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wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
10/30/23 7:01 p.m.

I am not abandoning my primary challenge hope, but I'm branching out, perhaps into $2k in an envelope territory. 

It is fair to say I have lost some motivation in recent years, and I hope to gain some momentum by doing something I kind of don't give a E36 M3 about. Enter Buck.

To be brief, This is an Auto '94 Miata without title. It is rusty, but complete, and runs.  This car is to be a donor to an NB that has a lot more potential, a title, and was also cheap. The only thing is I want the NB to be nice, so I'm giving up on its potential challenge life, and using Buck as a test bed for what is to come.

Buck (hopefully) will go to the challenge, but I'm forgoing niceties like a manual transmission, the swanky 3.9 torsen diff I bought, and, in fact, any plans beyond the event. This POS is to compete, and donate parts.

So, I've amassed some parts, and I don't really know how to best utilize them. 

First up, one of Whiskey Business' turbos. I figure I'll make a log manifold, and hope for the best.

Then came a lucky find.

-a PnP megasquirt for the year car I have. 

The Questions:

- What about RX 8 injectors? I've heard this is the hot/cheap setup

-Fuel pressure regulator?

- What type of laptop should I get to interface with this thing? Also, what connecting cables?

-Does anyone know the pin outs of manual vs. auto '94 and '95 Miatas?

-What fuel pump should I run?

I think I can figure stuff like intercooler mounting/plumbing on my own, but am open to suggestions on cheap ways to do that sort of thing. 

I'm sure there are many more questions to come, but those were some of the bigger things on my mind. Thank You all in advance, and be well.

 

bmw88rider
bmw88rider GRM+ Memberand UberDork
10/30/23 10:31 p.m.

Shoot, I should have thought about that. I have the perfect injectors that I'm going to sell anyway. 550CC ones they sold with the early FM kits. But really the RX8 ones are perfect for a low boost 200ish HP build. 

You'll need a serial to US cable like https://www.diyautotune.com/product/usb-to-serial-adapter-works-with-tunerstudio/ Then it will just plug into any modern laptop. I use a 6 year old Dell for my tuner laptop. 

It's loaded with the base map right now if I remember right. 

 

calteg
calteg SuperDork
10/31/23 5:26 a.m.

https://www.miataturbo.net/  is going to be one of your best resources

bottom end will live a short, unhappy life north of 220hp. Stock injectors should be fine up to that point, provided the spray pattern is decent.

Last time I checked, the DW200 was the fuel pump of choice, but there might be a cheaper option by now: 

https://www.amazon.com/9-201-0848-DW200-255lph-tank-install/dp/B007SNR532/ref=sr_1_2?crid=C0ONYS876NNJ&keywords=dw200+fuel+pump&qid=1698744321&sprefix=dw200+%2Caps%2C101&sr=8-2&ufe=app_do%3Aamzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0

bmw88rider
bmw88rider GRM+ Memberand UberDork
10/31/23 9:08 a.m.

Oh, I forgot too: https://trubokitty.com is a great source too. It does a few common sense walkthroughs on getting it installed. 

maschinenbau
maschinenbau GRM+ Memberand UberDork
10/31/23 9:31 a.m.

This is the fuel pressure regulator all the sloppy mechanics folks are running lately...basically an Aeromotive knockoff. I just installed this smaller one by the same brand recently and it works fine.

You should weld the diff. Do it...

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
10/31/23 10:53 a.m.
calteg said:

https://www.miataturbo.net/  is going to be one of your best resources

bottom end will live a short, unhappy life north of 220hp. Stock injectors should be fine up to that point, provided the spray pattern is decent.

IME, the stock bottom end will do 250 rwhp just fine as long as you feed it good fuel.  OTOH, I haven't seen much more than 200 out of the stock injectors -- maybe they'll stretch that far if you run a whole bunch of fuel pressure.

The Miata automatic is reported to not be very strong, don't be surprised if it blows up with moderate amounts of boost.

Any Windows laptop less than 10 years old will be plenty powerful for tuning it.  The biggest challenge with an old/cheap one is that the battery will probably be worn out, which limits how long you can go tune it for.

 

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
10/31/23 5:59 p.m.

Good points, all, and thanks.

- Realistically, for the end product, 200 hp is fine(yeah, I'd love 225, but stock injectors and not destroying diffs, transmissions, etc. is way cool by me). Should have established that in the first post. I have no hope of winning the challenge. I simply want to attend, and DFL is fine, but I'd like to do better. On that front, Blowing the auto is fine-maybe a badge of honor. I do have a good diff out of budget for the end product. Welding the 4.10 had crossed my mind.

-My chromebook is a POS. This is a great excuse to buy a decent new laptop. My go-to is ACER. Anyone have good recommendations? Where do I get programs to interface with the Megasquirt?

- What about pin outs for Stock 5-speed vs. Stock auto vs. Megasquirt? I really don't want to blow up my shiny new black box.

-I will be perusing those links. Thanks.

OK, so I've got suggestions on fuel pump, FPR, a recommendation to weld the diff, it seems the stock injectors will be okish, and I know what I need to hook a laptop up to the MS.

What am I missing?

The turbo is oil cooled only-should be fine for the Challenge, we'll see after that,

BMW88rider, I may be interested in those injectors-either pre or post Chalenge. 

 

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
10/31/23 6:29 p.m.
wheelsmithy (Joe-with-an-L) said:

-My chromebook is a POS. This is a great excuse to buy a decent new laptop. My go-to is ACER. Anyone have good recommendations? Where do I get programs to interface with the Megasquirt?

- What about pin outs for Stock 5-speed vs. Stock auto vs. Megasquirt? I really don't want to blow up my shiny new black box.

...

The turbo is oil cooled only-should be fine for the Challenge, we'll see after that,

I would email DIYautotune to ask if the pinout is different for automatic vs manual cars in whatever year you're getting the wiring harness from.

I like Lenovo laptops, but realistically anything will do.  You'll use TunerStudio to tune it and MegaLogViewer to look at the logs.  There are free/demo versions, but it's worth paying to get the full version.  You will need a USB to serial adapter, get one with a cable long enough that you can run it from the ECU to a laptop in the passenger's lap.

Are you sure about oil-only?  The photo of the turbo includes a banjo fitting that looks like a turbo coolant line.

Other stuff you'll need:  you will want a free-flowing exhaust, at least 2.5".  Normally I'd say clutch, but, well, auto.  If you're just doing challenge stuff then the OEM radiator might be fine, but anything more sustained and you'll want something that flows better, especially if you're going to put an intercooler in front of it.  Make sure you have ducting in front of the radiator (intercooler often requires enough trimming that the stock one won't work) and behind (stock undertray can usually be trimmed to fit OK).

You'll also need a wideband to tune it, an air intake temp sensor (DIY sells one), and if you're going to run EBC a boost control solenoid. 

 

calteg
calteg SuperDork
10/31/23 6:49 p.m.

The extreme budget option for optimizing flow through the radiator is this a plastic mixing tub from your favorite orange retailer :

(might be this one??) https://www.homedepot.com/p/Medium-Mixing-Tub-A-41/318924439

the miataturbo folks have been cutting them in half and apparently it's a fairly close fit for the mouth of the front bumper/width of the rad

81cpcamaro
81cpcamaro SuperDork
10/31/23 8:51 p.m.

The pinout for automatic vs manual is close. The MSPNP is setup for manual trans models only. Some have been able to get the auto to work as there are only a couple wires between the ecu and transmission. Later cars 96-up are not so lucky.  Also, the years of the harness need to match the ecu, they aren't interchangeable between different years. 

TunerStudio is the software to use for tuning.  The Lite version is free and will let you tune the ecu as much as you need to. Tunerstudio works with windows, mac or linux PCs and laptops.

If you need the installation guide, pnp manual or base maps, they are on our mspnp.com site.

bentwrench
bentwrench UltraDork
10/31/23 9:04 p.m.

Since you are adding boost the injectors will likely need to be bigger. To match power/boost levels. 

Regulator will need to be boost referenced so injectors don't get smaller as boost increases.

AIT in the charge pipe to the TB.

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) Dork
11/1/23 3:33 p.m.

EV14 injectors or nothing.  Stock won't be enough, and don't waste your time with anything else.

I think the auto cars had different cams that were sad, but it may not matter. MS2 is fine.  You'll need an AFR gauge, I had decent luck with AEM.  Stock fuel pump and FPR are fine.  Ebay intercooler is fine.  Tune for 200-220hp with 7k redline on pump 93 and nothing should go wrong.

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
11/1/23 3:43 p.m.
ShinnyGroove (Forum Supporter) said:

I think the auto cars had different cams that were sad, but it may not matter. MS2 is fine.  Stock fuel pump and FPR are fine.  Ebay intercooler is fine.  Tune for 200-220hp with 7k redline on pump 93 and nothing should go wrong.

The different cams was only on the 1.6.

They had less overlap (for more torque, less high end power), some people suggested that was actually better for turbo use.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
11/1/23 5:36 p.m.

So, Great information here-Thanks!

Some responses/further questions, etc:

I'm pretty sure the turbo is oil only. To whit:

Oil drain??????

Oil inlet(!?!)

I think I'll be fine with limited driving, frequent oil changes, and making a habit of letting it idle before shutting it down. Oh, and synthetic oil.

Thoughts? Criticisms? I believe I've got a sizable ACVW oil cooler and thermostat somewhere. Could come in handy.

Can anyone tell me about this Spartan II thing I bought because-I did???

I like the other info, and don't mind spending $ on tuner software, as this is my first time, and I'm delicate.

 

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) Dork
11/1/23 5:54 p.m.

Honestly, the Ebay T3/4 churbos work magnificently for this application and cost under $150.  I have an extra one sitting in my basement brand new that I'll sell you for dirt cheap.  Starting with a weird unknown turbo and backing in from there is probably a path to heartache and misery. 

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
11/1/23 6:08 p.m.

Yeah, if it were a water-cooled turbo there would be water ports on the other two sides of the CHRA.  I can't quite tell from your photos, but it looks like it doesn't have them.

The red circled banjo fitting is what looked like a water line to me.  Maybe it's an oil feed instead?  Is it a sleeve bearing turbo?  I'm mainly used to looking at ball bearing ones, which need a restrictor in the oil feed, so most people just run a -4 AN line to them instead of a big banjo fitting like that.

I'd never heard of the spartan thing before, but googling it looks like it's a wideband sensor controller for a standard Bosch sensor, so yeah, that'll probably work.  Do you have a sensor to go with it?

 

MadScientistMatt
MadScientistMatt UltimaDork
11/1/23 7:05 p.m.

IIRC, the manual and automatic ECU pinouts for '94-'95 cars were the same - with the exception of the wires the automatic cars had running from the ECU to transmission controller. DIYAutoTune never had the chance to try and figure out what the TCU would do without those signals or if there was a good way to spoof the signals; they were not able to line up a suitable test car when I was there.

No need to change the fuel pressure regulator; stock is fine. I would go with more modern injectors instead of used RX7 injectors; high flow drop in injectors are a lot easier to find now than when the RX7 injector swap was worked out.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
11/2/23 6:18 p.m.

Responses:

 The conversation led me to believe that this turbo was reasonably sized for a 1.8. It may well be a path to tears and regret, but we're just talking the challenge here. Afterwards, I can buy a Garrett if it seems appropriate. I hope to have a better understanding of WTF I'm doing by then.

If the auto doesn't work out, I've got a $50 % speed and a flywheel/clutch for I forget how much, but cheap. Might be fun to challenge the auto since I'm not a hot shoe. I'm glad you showed up, MSMatt. Also, I like not changing too much.

 

All input appreciated

 

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
11/4/23 9:33 a.m.

Ok, I had some time to scratch the surface of all this.

That Spartan 2 thingie is a wideband O2 controller. I need a LSU 4.9 O2 sensor, and a gauge.

This gauge jumped out at me from fleabay.

Chinesium $28 gauge It comes with an O2 sensor, but I can't tell if it is the correct one. It claims to be wideband. The Spartan needs a 0-5v gauge, and I'd like an old school dial type, but cheap must prevail. Anyone got ideas?

Ebay also has O2 sensors-Bosch for $28 each. Seems like a fair plan.

I have what I believe to be a Powerstroke intercooler that I found in a ditch that could perhaps be cut down. Need to scrounge @ the PAP.

I'm seeing somewhat conflicting views on injectors. Stock injectors and regulator would likely get me to 200 hp? Anything better readily available @ the junkyard? I see EV 14. Thanks for the input, ShinnyGroove.

Do we all agree that the fuel pump needs replacing? Seems like maybe stock would be OK with the stock regulator? New stock pump to be sure? Just go with the DW 200-Thanks, Calteg.

Please excuse my ignorance, I have not fully researched, and will do so as time goes on, but appreciate all responses.

 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
11/4/23 9:43 a.m.

There seems to be confusion, some people are speaking crank horsepower/BHP and some people are saying wheel horsepower, which can be 20-40% lower depending on the dyno used, so is not a good metric at all.

 

 

MadScientistMatt
MadScientistMatt UltimaDork
11/4/23 11:17 a.m.

That gauge is a narrow band; the seller either doesn't know the difference or is lying, and deciding which is worse is left as an exercise to the reader.

Don't cheap out on a no-name wideband. A good wideband is a lot cheaper than a new set of pistons.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
11/4/23 12:17 p.m.

In reply to MadScientistMatt :

Thanks. and OK.

Question: Does MS interpret air/fuel ratio? i.e. do I really need a gauge, or can I read info through Tuner Studio?

Pete: Good point, but, really, the answer in this instance is "more". The question is how much horsepower. Also, the question is "where do we start hitting the law of diminishing returns"? Where do I have to start spending real money? Is 5 psi enough? Likely. What can an idiot with no real turbo experience do? I think, once again, the answer is "more". Real #'s are not important, but if there is low hanging fruit, I want to grab it. This is a 120XXX mile engine (OK, with lowish compression-'94 Auto), so I DO NOT want to ventilate the block. I've got spares, but want to have at least, a re-buildable core at Challenge's end. I'm also not shooting for podium. We've got to be realistic.

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
11/4/23 4:04 p.m.
Pete. (l33t FS) said:

There seems to be confusion, some people are speaking crank horsepower/BHP and some people are saying wheel horsepower, which can be 20-40% lower depending on the dyno used, so is not a good metric at all.

OTOH, wheel horsepower is something you can actually measure without taking the engine out of the car.  The various formulas for converting wheel hp back to crank hp are pretty worthless, in my experience.  Most turbo Miata rules of thumb are based on dynojet rwhp numbers, which tend to be about the most consistent number you can get (although keep in mind that altitude correction doesn't work).

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
11/4/23 4:06 p.m.
wheelsmithy (Joe-with-an-L) said:

Ok, I had some time to scratch the surface of all this.

That Spartan 2 thingie is a wideband O2 controller. I need a LSU 4.9 O2 sensor, and a gauge.

Wideband gauges are actually not all that useful, because the times when you would care about AFR (usually at wide open throttle with lots of boost) are times that you want to be looking out the windshield, not staring down at a gauge.  It's not a bad idea to have one as a basic tuning tool, but you won't use it much after doing the basics.

Widebands are most useful as inputs to ECUs that support datalogging and autotuning of fuel tables. 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
11/4/23 4:14 p.m.
codrus (Forum Supporter) said:
Pete. (l33t FS) said:

There seems to be confusion, some people are speaking crank horsepower/BHP and some people are saying wheel horsepower, which can be 20-40% lower depending on the dyno used, so is not a good metric at all.

OTOH, wheel horsepower is something you can actually measure without taking the engine out of the car.  The various formulas for converting wheel hp back to crank hp are pretty worthless, in my experience.  Most turbo Miata rules of thumb are based on dynojet rwhp numbers, which tend to be about the most consistent number you can get (although keep in mind that altitude correction doesn't work).

I had a car make 200whp on one dyno and 150whp on another dyno.  Injector duty cycle suggested 270 at the crank.   Then the telephone game begins where 270hp turns into 270whp turns into 350hp, etc.

I feel wheel horsepower is a not very useful metric in and of itself, but is useful for gauging tuning changes when used on the same dyno on the same day with the same operator.

And THANK YOU for the comment on altitude correction.  There was a guy who had some sort of turbo Audi who claimed to make 469whp, because his car made 370-something and he did it in Colorado so he applied the correction factor.  Altitude correction does not work that way!

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