Looks fantastic.

Can't wait to see what it/you can do at Hallett this event.

Ooooh I like that. Makes the 18" wheels look a lot better too.

Agreed.. Could use some side skirt or tupperware action, too. Looks a little weird from a straight-on side shot.

Yeah spats for the rear tires would help with drag there. Car is looking great, looking forward to hearing about it going great as well!

Just got back from Harris Hill Raceway. The car as it stands is now in the same ballpark lap time as my One Lap CRX with the same motor, though they make time in different ways. The Miata is faster in corners due to larger rubber, better balance and more effective aero. The CRX is faster is a straight line because the wheels/tires are tons lighter and the shorter tires give better gearing on this track. Miata also currently suffering in the braking department...typical RF lockup. ABS goes on this winter, as well as ditching the non-ABS prop valve.

Other winter projects include:

• BW EFR 7163 on KMiata manifold tuned to make 450 at 8000 on E85
• Flex Fuel setup
• BMW 5-spd
• Getrag 3.23 rear diff
• bump steer corrrection (the big meats tramline horribly exacerbating the bump steer effect)
• a/c

Should keep me busy...

That's quite a winter list!

In regards to the lock-up, you have front-right lock-up issues?? Is this with a prop-valve on the rear lines? I've only had rear lock-up issues on track with my TTE miata, prop-valve on the rear lines has helped eliminate that.

I used to have the same issue with my CSP autocross Miata. The solution was to swap out the OE prop valve for a pair of unions...which is essentially the same thing as using the ABS "prop valve". The latter is merely a dummy with nothing inside...acts like a pair of unions.

ABS itself is going on to deal with inclement weather and surface irregularities, I already have all the parts.

Harris Hill is especially bad, since the track is typically run CW, and several heavy braking zones are while the car is still loaded up from a right-hand turn (T7 and T10). Have to brake earlier and easier to avoid the lockup.

Which system are you putting on? OEM?

--Ian

Yes. NB2.

FWIW, I'm pondering replacing the NB2 ABS in my car with an E46-based standalone, due to the NB2 one being too intrusive on a dry track.

--Ian

Put a switch on it to turn it off for dry (Emilio tip).

No seat heaters or coolers...I don't think Ann's going to like it as much as the McLaren or even the GT-R

A/c is the only thing she's really adamant about. And decent ride quality.

:drool: subscribing to thread

You shouldn't need the 7163 to make that power. Our EFR6258 on a stock head BP4W will make 370, Andrew is making 450whp on a stock BP5D head with the EFR6758 and that was running out of fuel. Probably closer to 470whp with enough injector. Our goal for the billet crank, CNC +2, cammed BP6D with the 6758 is 500whp. 7163 is overkill for your target IMO.

wouldn't the smaller turbine choke the exhaust from a high flow 2.4l, and wouldn't the 2.4l need more air volume to make positive manifold pressure. Im no turbo expert, just thinking out loud. I think the 7163 would be awesome for that car. Full Race matches the 7064 and up to their K series turbo kits.

I'm not sure it would hold that amount of flow on a proper flowing honda head and 8k of rpm. It will nose over
7163 would likely hold it all the way up

One of my One Lap buds is an engineer at Borg Warner and did the turbo match work. If you want to follow along...click here: BorgWarner MatchBot

This will be a bone stock TSX motor (K24A2), albeit with forged rods/pistons for durability. Stock cams, stock 10.5 compression, stock lower-flowing RBB head.

I am personally on a massive learning curve with turbo knowledge, so I'm relying on others.

:likecat:

i.e. Turbo sizing on crappy Mazda four cylinders is not the same as on Honda four cylinders...especially k-series.

.

.

Succcess!

$6 worth of M10x1.0 brake unions and half a liter of fluid to bleed...and off to Harris Hill to check my work.

Result => huge improvement in braking. RF lockup now almost all gone. Can carry more speed and longer through T6 (see pic) and T9.

Combine that with a little less rear wing and more damper compression, and turned my best-ever single lap there on 200tw tires. 1:22.7

https://scontent-atl3-1.xx.fbcdn.net...f5&oe=5AC74C49

https://scontent-atl3-1.xx.fbcdn.net...f6&oe=5A93529B

I think the 7163 is a good match. It will spool fast on a k24a2 and since the bottom end will be forged, it also gives more room to grow if it's ever needed. 500-550whp should be a retune away.

forgive my ignorance... but what did you change?

Looks like he removed the factory proportioning valve

See post 367

missed that. thanks.

Horsepower and airflow correlate in lockstep. If you move 50lbs/min of airflow through the compressor, you will make about 450whp. Whether that 450whp happens at 1800rpm or 9000rpm is of pretty minimal consequence.

Not that simple, and we both know there's a whole lot more variables to it than just the compressor map, but I would certainly not mind being proven wrong with actual results vs speculation.
In a perfect world though, I would absolutely agree.

It's not speculation, it's an understanding of the physics behind engines and turbochargers. Head flow and RPM have virtually nothing to do with it.

e: To clarify, if the engine can't support 450whp worth of airflow, then you won't make the power, but there's absolutely no logical reason why a larger engine with a better-flowing head and a higher rev limit would need a larger turbo to make the same power as a different engine with less head flow and a lower rev limit. It would likely benefit from different compressor aero, since the larger engine will make that power at a lower pressure ratio, but making the turbo larger is just going to harm response needlessly.

Andy has to be competitive in autox as well as road course. That means running the smallest compressor that will meet his power goals. That's the 6758, with a little room to spare. The 7163 has headroom he'll never use and the heavier, slower spooling turbine to go with that.

When we built Deviate with a C30-74 Rotrex, we also made more than anyone expected. Gotta take what's published as mfr recommendations with a grain of salt and pay attention to what tuners are actually achieving with them. I'm just taking real world examples and applying it to Andy's stated goals. Bigger turbo is sexier but guaranteed to be worse in an autox environment.

His K series head probably flows around 330CFM, compared to 240CFM for Deviate (Rotrex) and only about 210CFM for Bullet (6258/355whp) and Rover (6758/450whp). Meaning he'll hit his power target at a lower pressure ration (less boost). That means he'll be a bit further down the peak efficiency island than Rover. With the 7163, at lower RPM, he'd be completely off that island for most of the powerband.

Rather than ramble on with a technical explanation of how turbos work, I'm going to reply to your criticism with your own post from earlier today, because I'm flattered when you think I'm wrong on anything, really.

Because science beats uninformed speculation every time there is a clock to answer to. Wanna race?

.

He had a BORG ENGINEER pick the turbo for him. Maybe, MAYBE the dude might know a thing or two about EFR selection.
But hey let's keep arguing, and swinging e-peens.

:likecat:

We can have all the beers you want, dude, but I'm never going to stop calling you out when you post inaccurate or misleading things here. It's not personal., but I don't tolerate fools, and your posts demonstrate a consistent lack of technical competence in the topics you choose to discuss. The short version of the diatribe I don't have time to type out is that your consistently inaccurate postings make my job as a vendor harder. For the good of this forum, be better. You don't have to agree with me on everything, but you can't be blatantly inaccurate, and you are consistenly the latter.

It's classic engineering myopia, IMO. It's not that the Borg engineer doesn't know how to size the turbo, it's just that they are focused on the numbers instead of how it actually works in the real world. I'm sure a 7163 would be the more efficient option given the parameters of the application, there's no argument there. The difference between the BW engineer at his desk with a sizing calculator and me is that I have actual real-world experience with the 6758 at 450whp, and it works. It makes the power, it doesn't complain, it doesn't overspeed the turbo. Is it right at the bleeding edge of the compressor map? Yes. Does it make 450whp? Yes. Will it respond better in an autocross application than a 7163? Yes. Is it, in my educated, experienced opinion, the better turbo for the job? Absolutely yes.

I love me a 6758 at the bleeding edge. But even more I love the ability to crank it up, and have the headroom to do it :D
Anyways, back on topic (Andy if you want any of this rambling removed/deleted just let me know)

I recall engineers at Hoosier telling me their then new 275/35/15 would be best on a 9" wheel but ok on a 10".

In the real world that tire is best on an 11" wheel. Fact, supported by data. Not conjecture. Engineers are wrong every day.

Every single tire manufacturer's website recommends rim widths too narrow for their tires optimal performance. Whether that's written by a lawyer or sanctioned by an engineer is irrelevant. It's wrong.

Figured it was time for me to weigh back in...

1) I know a lot about tires, suspension, NA motors, etc...but my turbo knowledge is still on the steep part of the learning curve. So I am having to rely on others.
2) I have a short timeframe for development, since the car needs to have all of this working by early Spring.
3) While the car will indeed see some autocross action, it's primary purpose in life is the track. The car already has more than enough power to autocross in 2nd gear on street tires.
4) 450 hp is an arbitrary target. It came from doing some simple math. My McLaren is 600 @ 3000 lbs, and to accelerate the same, a 2000 lb Miata needs 450. If I end up with the capability for more than that, I'm not gonna complain. In fact, having some headroom is a desirable for future development.
5) Where it gets tricky is that the gearing as currently contemplated requires the turbo to spool as early as 3300 rpm to minimize use of 2nd gear. The models show this to be the case, but reality may be different. Worst case, I have to use 2nd gear more than I would otherwise. Just trying to avoid some shifting.
6) In other venues from other people I respect, I am getting the opposite input...go bigger...3076. This includes at least one person with direct turbo K24 experience. Hard to know who is right...if there is such a thing as "right".
7) The good news is that the 6758 and 7163 share the same housings/dimensions. So they can be easily swapped. The bad news is that I need to buy a turbo ASAP, since we are starting manifold fab right away.

Anyway, happy to get good, well-informed input...especially if it is educational (I can certainly use the education at this point). I really appreciate those that are taking the time to do so (especially my guy at BW, who has been holding my hand from the start).

Truth.

Bad example.

Those recommended widths have little to do with optimal performance, and everything to do with fitment and safety margins. They don't even come from the tiremaker. They are specified by the Tire and Rim Association, of which every tiremaker is a member. Lawyers have as much to do with those recs as do engineers, and they are same across all tire models/brands for any given marked size. Even when the actual size of the tire varies. This is especially bad when you have folks like Hoosier that make their tires over-wide versus typical, yet they still have to use the same rim recs per the marked size.

No, great example. The engineer at Hoosier told Emilio that, not the tire and rim Association. In the same vein, your friend at Borg told you the 7163 would fit based on the numbers without any real-world experience with that turbo, most likely. The phrase "fitment and safety" is pretty accurate to describe his recommendation, actually. The 7163 will be more efficient and safer, but the 6758 will work better in the real world. i see vendors and engineers alike consistently recommending "the larger turbo" when the best response and power band is always going to come from the smallest turbo that is able to make the peak horsepower goal. If you want to make 450 wheel horsepower with the best response and have the car spool the earliest and respond the best, that is the 6758. Period. If you want headroom to grow, then use the 7163, but you are absolutely giving up response and spool to do so.

Here is some musings from someone that actually knows a crap ton about turbo k-series (Geoff @ FullRace) in regards to a 6758 on a K20.

"This (EFR 6758) is the turbo we spec as the high power R18 (crappy SOHC 1.8L from '06+ Civics) setups, it is the 2nd smallest turbo in the EFR family so a little small for most K20's but the spoolup and lowend torque will feel like a crazy supercharger!"


Add 400ccs and a little small changes to small.


I should say, I'm not arguing that a 6758 couldn't work well on andy's K24 but it will take a lot of work in the manifold and it will take a giant wastegate to prevent the turbo from choking the flow and causing a bunch of additional heat and back pressure.

In my experience, a 7163 would be a better fit for this application and will likely spool and behave like a 6258 on a Mazda BP engine.

Hey guys, can we keep this civil? I'm all for education/discussion/disagreement/debate, but no need for "tone".

So I asked my guy (Matt) at BW for more specifics as to why he rec'd the 716 over the 6758. He said it was ok to post his reply here:The match link for the 7163 is here: BorgWarner MatchBot , if anybody wants to look at the #'s.

The altitude factor is one I had not previously considered...and we are headed to High Plains Raceway outside of Denver this year for One Lap.

Andrew, sounds like you may be getting a phone call.

I don't disagree with anything he said there. On track, the 7163 will be happier, albeit less responsive. If you are going to ramp the boost in slowly, I would use a 7163 too. My personal mantra is to reduce response lag by using the smallest turbo that will do the job, in spite of the efficiency loss. You can cope with that in other ways (bigger IC, good cold-air intake). My experience with E85 and similar power levels on a much, much shittier engine (BP) indicates that detonation will be a complete non-issue on either turbo. I have not played with the mixed-flow turbine on the 7163, the inertia comment is interesting and very cool.

Matt emailed me, so I shared my results from Acamas, Soviet's 485whp uncorrected hero pull, fourwhls' restricted 400whp 6758 setup, and Emilio's hi-boost 6258.

I can confirm that the 7163 on a mazda designed 2.5 is totally fine for auto-x. Andy will be fine. Its better for auto-x than a 6758 on a 1.8 vvt.

So...learn me some intercoolers...

I am loathe to add a ton of weight to the car, so I'd like to size this as close to optimal as possible. In/out are opposite of the BP motor, so piping will have to be fabbed. Car will also have a/c compressor in the way on the driver's side, along with a condensor to pass air over.

Also, there is a version of the EFR compressor housing that has a forward-facing outlet, so the over-the-top tube routing is a very real possibility. Example here: https://trackdogracing.com/intercoolerkits.aspx

Alternatively, I could do a more traditional "bottom" routing, with more bends, and the option of changing out the intake manifold for a downward facing center-feed.

Given the weight consideration, and the fact that I only care about what it does on the track for relatively short time trials...am I a fool for even considering tube and fin? I like the efficiency versus weight of the hybrid style that Griffin makes: RRE Intercoolers and Parts

What is working in the real world of 450hp track Miatas?

If you're not afraid of a hole saw there is room behind the headlight and outside the frame rail to route the piping there. Leaves plenty of room for accessories and hood venting and keeps the bends to a minimum.
https://cimg7.ibsrv.net/gimg/www.mia...438e384725.jpg
I'm not making anywhere near the HP you're looking to make so can't help ya on the intercooler selection.

For your power goal I don't think you can go over the top. 2" ic piping pretty much tops out at 350hp on that motor. And bigger doesn't fit over the radiator.

If turbo k motors in civics are OK on the track with half width rads you could copy my garrett setup but it's borderline for 450hp for heat rejection, but being on track should help that.

Otherwise traditional through the holes behind the headlight is you best bet, and I think in your setup anything short of a garrett or bell core with custom end tanks will be a disappointment.

TDR routing drops the radiator a bit by modifying the stock radiator mounts and also you trim the sheet metal in front about 1/2-3/4 inch. Then 2-1/2” easily clears the hood and radiator. Possibly a little bigger with more trimming.

It’s the same setup I ran on my 2000.

Can’t speak to the IC efficiency but the routing was straight forward with minimal bends.


https://cimg1.ibsrv.net/gimg/www.mia...95bd2ff2b.jpeg

https://cimg2.ibsrv.net/gimg/www.mia...e747e1c46.jpeg

https://cimg3.ibsrv.net/gimg/www.mia...701228213.jpeg

https://cimg4.ibsrv.net/gimg/www.mia...1e9898184.jpeg

Pos-cat added for this, I've always wondered why the recommendations don't reflect real-world statistics.

In Australia, some tyre chainstores refuse to fit 205" tyres on 8" rims because they're not recommended by the manufacturer despite the user consensus that they work great on 8" rims.
It's easy enough to find someone who will fit them but I always found it odd that some performance tyres aren't recommended at their optimal width.

Can you confirm the tubing on yours is 2-1/2"?

Gary @ TDR says they do 2" and 2-1/8". I really need 2-1/2"

The pic I took of the cold side is 2-1/2" for sure because I did it. The hot side is the TDR original. If you look at the front edge it touches the crossmember. I actually notched a little more from the front to get a little more clearance.

The back of the pipe had ample clearance you can see.

The hot side could've easily been the same size but the IC package came of my old MP62 setup so I reused as much as I could but needed to fab the cold side to add the BOV and IAT bung. Car is gone now so I have no more pics.

Progress...

https://cimg9.ibsrv.net/gimg/www.mia...e3d0a909c3.jpg


https://cimg2.ibsrv.net/gimg/www.mia...23c0f0037c.jpg

2.5" will fit over the rad on an NB. You just have to lower and tilt back the radiator. I have a picture of how I re-drilled my lower brackets somewhere. If I find it I will post it.

Progress...

https://cimg1.ibsrv.net/gimg/www.mia...23eb052887.jpg



https://cimg3.ibsrv.net/gimg/www.mia...9689597a9b.jpg

Love seeing it actually in the engine bay. Even with the larger EFR it fits quite well.

The short actuator and cheater bracket will gain you a bunch of room at the shock tower. Did you end up with the 67 or 71?

He's got the 7163 on his facebook page

https://www.facebook.com/OneLapMiata