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-   -   300-350whp goal build (https://www.miataturbo.net/engine-performance-56/300-350whp-goal-build-98381/)

Savington 10-29-2018 01:12 AM


Originally Posted by codrus (Post 1508740)
our charts do not look like normal Miata dynojet charts -- the torque builds more quickly than anyone has seem from that kind of setup before and the torque curve from 3900 to 5500 is much too flat. Miatas with stock cams almost always have a noticable peak in torque around 4800 RPM, that's just what the cams are tuned for.

Half agree. 94-00 motors have a defined torque peak at 4800rpm. VVT motors generally produce peak torque within 5% or so from ~4000rpm to 5500rpm or so. They can extend that plateau further depending on the intake manifold setup. A Squaretop will stretch that to 6000rpm, and a short-runner Honda manifold a bit further than that. Look at the two charts I posted a couple of posts ago - Acamas has a big torque spike at 4100 owing to a bit of boost overshoot, then tapers to a very flat torque plateau at ~400wtq from 4400-5500rpm. Boost is flat through this area. Theseus' old 2871R plots had very stable boost control all through torque peak, and more than 280wtq from 4200-6400 on a 294wtq peak.

codrus 10-29-2018 01:22 AM


Originally Posted by Savington (Post 1508742)
Half agree. 94-00 motors have a defined torque peak at 4800rpm. VVT motors generally produce peak torque within 5% or so from ~4000rpm to 5500rpm or so. They can extend that plateau further depending on the intake manifold setup. A Squaretop will stretch that to 6000rpm, and a short-runner Honda manifold a bit further than that. Look at the two charts I posted a couple of posts ago - Acamas has a big torque spike at 4100 owing to a bit of boost overshoot, then tapers to a very flat torque plateau at ~400wtq from 4400-5500rpm. Boost is flat through this area. Theseus' old 2871R plots had very stable boost control all through torque peak, and more than 280wtq from 4200-6400 on a 294wtq peak.

Yeah, but RTC's virtual dyno plots are FLAT. It shows 290 wtq plus or minus about 2, from 3900 to 5500. 5% would be a 15 wtq swing, which just isn't there.

--Ian


ridethecliche 10-29-2018 07:27 AM

I have logs and the tune on my thread. I'm still tuning vvt, but the torque flatness may be due to some boost being fed in there. VVT is oscillating like mad right now.

I understand that VD is sensitive to variations in the ground which is why I usually do a pull in both directions and look at both together on a graph. Truth lies somewhere in the middle. That said, I do need to get over to a dyno to see what this thing is actually putting down. I'm pretty happy with things regardless, but just curious is all.

Savington 10-29-2018 12:23 PM


Originally Posted by codrus (Post 1508743)
Yeah, but RTC's virtual dyno plots are FLAT. It shows 290 wtq plus or minus about 2, from 3900 to 5500. 5% would be a 15 wtq swing, which just isn't there.

--Ian

No argument that RTC's VD numbers are flawed at best. Just saying that VVT motors produce a different torque curve than a 94-00 motor does ;)

aidandj 10-29-2018 12:27 PM

Dyno operator would be me :D (that is the raw dyno file I plotted in DynoJet viewer) guess I never looked closely at the scaling.

Wiring the wastegate shut on my currently stock bottom end would probably be a bad idea :fawk:

Either way, that dyno day was not supposed to be representation of what my setup could do, it was a tuning tool. I used it to gather data at multiple boost levels so I could set up flat torque curves later on. My motor killing itself stopped that though.

I will say, 6758 at 7psi is still pretty fun :D

Savington 10-29-2018 12:30 PM


Originally Posted by aidandj (Post 1508781)
Wiring the wastegate shut on my currently stock bottom end would probably be a bad idea :fawk:

Bad for you, entertaining for us :party:

aidandj 10-29-2018 12:54 PM

Trade you a built shortblock for the carnage video :party:

ridethecliche 10-29-2018 05:10 PM


Originally Posted by Savington (Post 1508779)
No argument that RTC's VD numbers are flawed at best. Just saying that VVT motors produce a different torque curve than a 94-00 motor does ;)

Numbers are just numbers. It's a tuning tool at the end of the day. All my runs have been done in both directions on the exactly same stretch of road. I'm controlling for the easy stuff but it's obviously far from perfect.

I want to hit the dyno with a new map sensor and a tune for 30psi. Fucking stoked!

aidandj 10-29-2018 06:37 PM

E85?

503 10-29-2018 06:40 PM

No, just lots of this
https://cimg5.ibsrv.net/gimg/www.mia...3743f851f8.jpg

ridethecliche 10-29-2018 08:24 PM


Originally Posted by aidandj (Post 1508868)
E85?

93 pump.

Thoughts and prayers.

Hopes and dreams.

And probably some of that octane booster shit for the lulz.

aidandj 10-29-2018 08:35 PM

:rofl:

I had to start pulling crazy amounts of timing up there to make power without knock. Single digits timing is stupid.

Would not do again.

503 10-29-2018 08:37 PM

Yeah... But you're still pushing 30psi, do you know how cool the BOV will sound with that much boost?

Really cool :naughty:

codrus 10-29-2018 08:49 PM

Welcome to 1700F+ EGTs. Good for melting stuff. :)

--Ian

ridethecliche 10-30-2018 12:22 AM

MIATA FONDUE!

Tran 10-30-2018 07:15 PM


Originally Posted by codrus (Post 1508881)
Welcome to 1700F+ EGTs. Good for melting stuff. :)

--Ian

How far can you go with the boost levels before the EGTs reach stock valve melty levels? (1650F?)

codrus 10-30-2018 10:50 PM


Originally Posted by Tran (Post 1509002)
How far can you go with the boost levels before the EGTs reach stock valve melty levels? (1650F?)

It depends heavily on how much timing you run, and thus on how much octane you have.

--Ian

Savington 10-31-2018 01:13 AM

Anything less than 10deg of timing makes me nervous. In a track car, anything less than 12-13deg. If you need that much power in your track car, you need 100+ octane or E85.

ridethecliche 10-31-2018 11:19 AM

I don't think my map goes down that low anywhere

Nurburgring 11-04-2018 08:35 PM


Originally Posted by Savington (Post 1509033)
Anything less than 10deg of timing makes me nervous. In a track car, anything less than 12-13deg. If you need that much power in your track car, you need 100+ octane or E85.

Interesting. May I ask why? Youīve seen damage with that timing, or just afraid of EGT going off the charts?
Apples to oranges but I ran a stock turbo Evo 8 for years at the track on single digit timing at peak torque, 25psi, 93 oct. It didnīt burst into flames, regretably.
My only turbocharged miata experience involved this cutting edge ECU and a rising rate FMU. Miraculously it didnīt explode either.

http://flyinmiata.com/Store/images/07-97000.jpg


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