280whp+ Borg Warner turbo set up
 

I’m looking to build my 04 Mazdaspeed Miata to its true form. I want run a Borg Warner 6258 .80 Twin Scroll and 9.5:1 on pump gas 91-93 is the best octane I’m able to get as of my current location. I want to know if this is remotely possible or is this me chasing a dream?

It will work fine but you are going to be knock limited around 280-290 whp.

Dann

Im running a standard T25 6258, and make about 300whp at 17-18 psi. on 93 pump gas.
rods only motor build with pistons out of a 94 miata. these supposedly have lower compression 8.8:1 or so.

280-300hp should be doable for you with proper dyno tuning.

lower compression pistons. 8.6:1 is ideal for high boost pump gas motors. pistons are pricey though ~$500 plus you need to bore out block.

I, too, choose to sacrifice performance from 2200rpm-7500rpm in order for a small bit of extra pickup between 1200rpm and 1800rpm

then your max hp ceiling will be knock limited. how much limited? no one knows. but you will find out when dyno tuning and listening for knock.
another way to reduce knock is methanol/water injection. i've never done it, so dont have much info about this.

im pretty sure you should be able to hit around 300hp with 9.5:1 pistons. on pump gas.

8.6:1. I also build engines and sell the best Borg Warner turbo systems on the market for these cars, FYI, so I have a bit of experience doing exactly what you want to do.

10-15psi will get you 220-280ish whp.
you can do that on stock pistons. Just install stronger rods.

or get forged pistons if money is no issue. With 8.6:1 CR.

9.5:1 pistons is for e85

You will never notice, and you would be hard-pressed to measure the difference.

Raceland or begi

Check out my website or call me for specific recommendations. We also do complete longblocks custom-built to your intended usage.

You won't be able to use 83mm pistons unless you have a perfect block to build into. Any used block will need a slight overbore to correct for wear, and that puts you to 83.5mm in most cases. Few, if any, manufacturers will offer an off-the-shelf forged piston in stock bore size.

If you keep asking the same basic question over again and keep not liking the answer, asking it a few more times will certainly change the answer. That's usually how it works.

BP engines are more detonation prone than some other engines. Compression ratio is one of the biggest factors in whether or not you can run more timing or more boost in our engines. Every point of static compression ratio will hurt your ability to make Power.

Your block will need to be removed from the car for the rod installation and you will have to have the Pistons pressed onto the rods. Your cylinder bores will need to be honed at a minimum to accept different piston rings and have them seat properly. The difference between honing and boring and honing is probably $20 a hole.

I assume from your repeated questioning that you never read any turbocharged engine theory so I will pass on some information to you because I'm feeling benevolent. Power is created by the pounds of air you are able to put into the cylinder to combust. Generally speaking, more are means more power. We are detonation limited by the type of fuel we use. We cannot add as much air to a high-compression motor as we can a low compression motor and still avoid detonation.

You keep asking about compression ratio making a difference in the drivability of the car. I can tell you from years of dynomanometer software modeling that on a 7.6 l V8 the difference between 8.5:1 and 9.5:1 is 12ft lbs at PEAK torque. Divide that 12 down by roughly 4 times for the smaller engine and you get about 3ft lbs. at PEAK torque. That's the equivalent force of one 12 week old kitten being placed on a 12in long wrench. So each one full point of compression ratio drop is about one kitten power loss. the good news is you get to add much more air without detonating. You will make dozens more kitten power in return.


TL;DR: Putting higher than ideal compression ratio brittle stock Pistons up against a fast spooling Borg Warner on pump gas with your limited knowledge and apparent lack of appropriate funds sounds like a fantastic idea. You should totally do that. But I prefer to add kittens instead.

Technically speaking, a BP is over 1.8L anyways. So... nothing of value is lost.

Many people on here done what you wish.
Some even set up shop doing it for other people.
Some were absolutely mental enough to build these monsters 10+ years and berate them on track with 400+whp and solve basically all the issues any person is likely to have.
One of those nutcases is Savington.

If you have a question and he answers it.
It will be quicker and cheaper for you to just take his advice.

Increasing displacement (by only that) shouldn't affect anything insurance wise and the added volume will mean more combustion volume meaning any decrease in CR already has a helping hand.
In all seriousness a change that minor you'd be hard pushed to measure accurately and it will mean your motor won't die. Those are both good things.

Show me one other EFR TWIN SCROLL build on here

At your intended power level, the twin-scroll setup would be a detriment for several reasons, including reliability and response.

are you getting the efr turbo kit from trackspeed?

What manifold are you planning on mounting the EFR too? Stock MSM?

He says he's getting an Artech manifold

Consider a cast manifold instead. Artech makes nice stuff, but no tubular manifold will be as reliable as our 347SS investment cast manifold.

So you are getting the turbo manifold, downpipe and 3" exhaust from artech?

Did you talk to Abe at Artech? i've heard he is kinda retired and no longer does turbo setups. so make sure you talk to him.
If that doesnt work out, i recommend you get the trackspeed EFR kit, its excellent quality, and then have a local exhaust place just fab up a 3" exhaust for you.

You have quite an extensive list of parts. gonna be one hell of a build. make a build thread about it and post lots of pictures.

You don't seem to have an uprated clutch on your list. At 280whp you are very likely to need it. You also don't list uprated suspension, uprated brakes, wider rims, sticky tyres etc either...

I'd suggest calling one of the vendors on here like Savington@Trackspeed or Emilio@Supermiata (other vendors are available) and asking them for a shopping list of what's needed to make a 280whp car start and stop safely, and what's necessary for a reliable setup - then listen carefully to what they say...

Right. What manifold are you planning on using?

1) 15x9s
2) Gross.
3) Don't use slotted rotors
4) FM, ACT, Supermiata clutch

15x8 with 225's is a no no. you need 15x9 6ul for 225 tires. the offset of 15x8 and 225 tires will rub fenders badly. with 15x9 no rubbing on NB miatas and slight roll needed on NA miatas.
ignore above, i i thought the offset of 6ul 15x8 was more agressive, as compared to 15x9.
225 will fit on a 15x8. but 15x9 is more optimal for performance.

If money is no object, seeing as your list of stuff is already $10K+, then get Xida coilovers, they are THE best miata suspension.
I recommend FM level 2 clutch. i had it and its a very good clutch and will hold onto the upper 300's hp. with a decently light pedal and good slipping feel.
no bbk is needed really, unless you are planning on going to the track. stock calipers/rotors are more than adequate for the street. just put good brake pads. such as stoptech or hawks. street/sport pads.

Wut.

1) 225s are best on a 9
2) Not too many people running them should be a clue, and not in the direction you're headed
3) because it's not the 1950s and we don't need to vent pads anymore
4) Any of those three are good. I have ACTs on both of my cars at the moment, but i'm also not in need of holding power like you are, so my experience with them are irrelevant other than that they're quality clutches.

My mistake. i thought 6ul 15x8 offset was same as my advanti storm s1.
with my storms, i had 15x8 (+25) and had to sell them and get the same wheels in 15x9 (+35) to run 225.

1) No, it's because 225s are wider than 8".
2) GL fam.
3) I'm not.

Why every noob that comes here wants to be different, we tell him he is :nuts: then he wants to be "unique" :greddy2: by running parts that no one recommends, and most say to not use?

stock bore, WHY? if building a $3000-4000 engine, what possible reason is there to stick to stock bore size?
Stock compression, at least you agreed is beneficial to go lower.
overpriced trix coilovers that no one runs, cost $1900, same as the BEST miata coilovers the Xida. :dunno:

I'd suggest you don't go on a rant in this thread or a new one if you try those coilovers that nobody recommended at that price point that gets you tried and proven options. You probably won't like the response.

Sounds like someone watches thecarpassionchannel and is trying to replicate many parts of his build without understanding it.

OP, before you go down the massive rabbit hole and spend $15k on all the goodness I suggest taking your time, upgrade in stages and learn a lot.

First, put a megasquirt on your MSM, with a wideband and EBC, maybe do the injectors and fuel pump, get it tuned and live with it for a little while, you should get 200-210whp on it. No exhaust/intake mods at this time so you limit the potential, but that would be a waste of money if you continue with the plan for a different turbo, never the less it will feel night and day better than the stock ECU.

Then get the turbo (just go with Trackspeed, save yourself some headache), get it installed and tuned, you'll be able to hit 250-270whp on your stock motor if you get it tuned well. Live with that for a little while, do the clutch, do suspension, decide if you need brakes, do all the other fun mods. Oh yeah, maybe do a radiator at this point (again, TSE is your friend).

Then when you get bored, or the motor starts showing signs of wear, do the full engine build. You'll decide your original plan of 280whp is boring and you'll want all of it and end up about 320whp.

If you do the whole thing at once with your current understanding of Miatas and turbos, you're gonna have a bad bad time. You'll sell your car and a pile of parts for penny's on the dollar. OR, give the car to a professional along with a big pile of cash and step away for a few months while they build it (this is a serious and viable option if you have the money!).

It's easy to get beat down here if you don't do your due diligence, I'm surprised people have been as nice as they have to you actually. There's been a lot of spoon feeding lately now that I think about it.

I watch Greg's videos too, they're entertaining and I think they contain some useful information. But he's been at it a long time, he researches, he takes chances here or there and is prepared to discover and correct mistakes (IAT on the intake manifold FFS!). He has reasons behind doing what he does and using the parts and it's not always the best way, sometimes it's budget based, sometimes it's sponsor based. He has knowledge and experience to backup his decisions though, so don't just follow what he does without giving it some thought and your own research.

I have an MSM, I'm taking my own advice, it's actually the collective advice of other's experience across nearly 30 years of the Miata's existence. I'm currently running the stock motor and turbo on a Megasquirt with a flex fuel setup for 250whp on E85 (with a bunch of other supporting and unrelated mods). I'm hoping to stay here for another year, then upgrade the turbo setup (TSE is my forerunner). Then do the motor after that. In the meantime, I read everything. I come up with questions that may or may not be relevant to me in the future and I research it. My plans have evolved many many times, yours will too, so my advice to you is: don't rush!

Greg runs the trix coilovers because they were given to him for advertising. Not because they are awesome.

same with his dual plate clutch, which btw destroyed TWO 6 speed transmissions in a matter of weeks.

So dont take his parts selection as gospel