515whp EFR6758 build
 

Just a data point, thought I'd share.

We no longer offer built engines. This one we shipped to a customer back in 2015.
TSE EFR6758
E85
84.0mm 9.0:1 pistons
Moldex billet crank
Tomei cams
Supermiata CNC BP6D head, +1 stainless intake, +2 Inconel exhaust
Carrillo H beams
Billet oil pump gears
Supermiata damper
ACL bearings
Oil pan baffle plate
Supertech heavy double valve springs
Supermiata SUBs

I think this motor still has more on tap with additional tuning. For reference, we made around 440whp with a 6258 and stock cams on a similar build.https://cimg8.ibsrv.net/gimg/www.mia...500eb7d1ba.jpg

Thats a lot of power, thats awesome. But has a Garrett guy I have to wonder why these EFR turbos arent spooling faster. I thought they were the best spooling turbos ever? I must say though thats a nice looking curve inspite of the slower than expected spool.

The graph might look mis leading. That’s 300hp by 4250rpm, stock cams, less boost, and that curve would flatten out nicely I’m sure.

As mentioned in the post, that plot is by no means the maximum that particular hardware combo is capable of. As Josh mentioned, stock cams will spool faster. I just posted because I haven't seen any 6758 plots here. My 420whp 6258 plot with stock cams and a few others around the same on stock NB cams is all.
Based on what we have done in our shop, I think this hardware should be capable of another 100whp from 2500-4000, pull to 8,000 and peak at 560whp or so. We once briefly touched 440whp at around 5500 with stock cams with our 6258 before blowing the spark out. I'm convinced we could have hit 450~460whp with IGN1A coils, but we stopped development there. Thus, I think the 6758 with cams has a more in it.

Yarp. Tomei BP6D cams are asleep until 4500 even N/A. Stock cams will spool faster as you said.

Ahhhh, I missed the fact that it has Tomei cams. That makes a lot of sense now. I mean at 500whp a miata is stupid fast, I can only imagine how this car must feel.

I remember your allofit 6258 plot at 25-26psi you were making really good power on that as well.

Having tuned the new gtx2863 and efr6258 personally just recently I can say they are similar in spoolup. When compared to the old stuff, it's no contest, efr wins.

Cool man thats good to hear. Transients probably still a nod to the efr however with its gamma Ti turbine.

Talking to owner, they had ECU set to cut fuel and spark for rev limiter. They did a routine scoping and notice a tiny bit of det damage to one piston so they're pulling it down to put new pistons in.
I could be wrong but I suspect that fuel cut at rev limit (8400rpm) might be the culprit. Personally I always do hard spark cut on our race engines, leave fuel on. Better to have that latent heat of the fuel mass doing some work cooling bits off on overrun IMO.
Made a few other suggestions on tune WRT to spark, VVT and a few other tables. Curious to see how much more they can get out of it.

Yea, I agree 100% on the spark cut and leave fuel on. Just seems much easier on the engine and also possible fireballs from the exhaust. Let's be honest we all love fireballs.

How much damage on the piston? Probably slightly deformed on the intake side I'm guessing.

Just a tiny dot on one piston. But the owner is playing it safe.

Yah, more fireballs.

what boost level are you running to get that? Can you share a spark map?

I'm finding that I can't get above 400hp at 27psi on my 6758. But I don't have larger valves or cams. Also, I'm at 5200ft.

400whp uncorrected in Colorado out of a BP is a BIG challenge. I haven't been able to get there yet either.

Not mine to share. Its a customers build who wishes to remain anonymous.

If you haven't already, I'd start a new thread on your tuning questions. I'd want to see screen caps of VVT table, VVT settings, Ignition, boost duty, fuel, AFR targets, injection timing, rev limiter settings and pic of intake... in a new thread.

Nice numbers :likecat: I'm trying to get same power leves with EFR7163 and stock BP6D head

What transmission are they using?

Don't recall. Not an AZ6 though. When we built this engine for them we let them know a stock AZ6 would frag at half the power this motor would be capable of. So they did some sort of trans swap from the get go.

If 4th gear was stronger the AZ6 would be probably alright until 400ftlb. Ive already broken one 4th gear, is that typically all that breaks on them? I too would like to see more info on this setup if the owner is willing.

What transmission did you use to handle that much power?

What's holding it back up top? Even if revved to 8000, horsepower has already peaked and started falling off at ~6000. I don't mean that as a slight to the setup at all, just curious.

Excellent question. As mentioned in an earlier post, I asked the owner to send the tune file. Saw several things that would affect the power adversely. Made some suggestions. They'll retune after Keegan Engineering (that built it originally) puts new pistons in it.
Tune is not mine to share. But yeah, on paper, this combo should make a bunch more up top and spool faster as well.

Folks have sheared 2,3,4,5 gears on AZ6's at 300-350 lbs. When shifted fast on track where trans temps are high and the aluminum shift forks start to bind in the steel grooves they sit in, folks get them either stuck in gear or unable to engage. Shifting improves once they cool down but the damage is done by then. Of all the cars produced with AZ6's, only the 99-05 Miate had aluminum shift forks. And no, the steel ones don't fit. Yes a few folks have investigated beefier shift forks and they are not cheap.

Still no relatively cheap PNP alternative with ideal ratios exists. BMW ZF conversion from Kmiata is robust but not cheap and ratios leave something to be desired unless you spring for the pricey 6 spd option (~$5000). Quaife is noisy, ragged on the street, has perfect ratios and costs about $11k to complete.

The reality is that a PNP 400lb tq AZ6 solution with syncros and good ratios is going to cost ~$4k and even that is more than most of the Miataverse is willing to spend. So the ROI to develop all the proprietary internal bits of a AZ6 "Superbox" just isn't there. The half dozen or so guys that would click buy tomorrow, won't be enough. We'd have to sell at least 50/yr with no warranty returns to make it worthwhile and even then its a low margin product for us. We spent about a year working with a few suppliersr and decided the margin just wasn't there for us. Walter Motorsports is currently the best bet for a beefy AZ6.

I miss my big-power '93 but I don't miss all the shenanigans caused by the lack of a strong-enough transmission. I went through two Quaife gearsets (installed in a 5-speed case), both of which died on the track. After investigating and eventually discounting the KMiata conversion option, I installed an MSM 6-speed about a year before I sold the car in preparation for getting my 30AE. After all those years of chasing horsepower, I'm now perfectly happy with less than 200 normally-aspirated horsies. I'm really enjoying a car that you have to cane in order to pass on a twisty back road, rather than roll on a half-inch of throttle to surge by on a tsunami of mid-range torque. If I have to slum it, power-wise, it's not a bad way to go.

If I had 500 or more hp, I personally would seriously consider either a G-Force GSR or GF-5R transmission.

Thanks for the info man great reply. Question, I checked Walters site I only saw the built 5 speed. I guess they also can do an az6?

They list it as under development.

https://walter-motorsports.com/shop/...ission-6-speed

I just noticed that. I was on my phone. On my laptop I see that it's in development. I just emailed them to see what they say about it. I'll send them my broken 6 speed that's sitting in the basement tomorrow. Lol

We sort of initiated tha AZ6 project with him but it stalled for costs. There just isn't room for margin for supermiata to be included. So he's continuing to develop the AZ6 amongst the many other projects that he has going. He has delivered several upgraded AZ6s to customers. But it is an evolution, it is not as if it is a single specification.

Sort of derailing this thread with talk about transmissions but one critical factor that is sort of a deal-breaker for a lot of users, is that any blueprinted transmission must be broken in. If it is not broken properly it simply will not perform the way it's engineered to. We have one of the early prototype AZ6 boxes in one of our cars. Busy with other projects, we have not run high boost through it. I will say this though, it shifts better than any Miata transmission I have ever used.

Yes, sorry to go off topic on the thread. Appreciate your info on the trans stuff. I emailed them and I think that's the route I'm headed.

Update to the original post. After using some of my suggestions on cam tuning, the owner was able to improve the spool mightily. 500 lbs torque at 4000? Yes please.
This particular longblock is safe to about 8500 but you can see the short duration cams doing their work with a 6000rpm power peak and 4200 rpm torque peak.
I don't recall the specs but, turbo BP's used for auto-x or track like short cams and lots of lift.
https://cimg8.ibsrv.net/gimg/www.mia...a701e70237.jpg

That is a monster, nice work.

That is beautiful