GT2560, 12psi dyno - Page 3 - Miata Turbo Forum

elesjuan · 05-03-2009, 02:59 PM

Quote:

Originally Posted by pdexta

It was a different dyno this time, dyno dynamics. One of my friends pulled on both dynos and lost a couple hp this time around, FWIW.

Yes, this run was on a new clutch, about a month old.

The guy that pulled before me was an old Smokey and The Bandit looking Firebird. The guy said he was making around 400. He seemed pretty heartbroken when it put down 257, then he disappeared real quick after I made 262.

That might've made 400@ the crank in 1980 backed with a TH400 Torque Eater..

Nice numbers man! Good to hear you got it figured out!

hustler · 05-03-2009, 04:14 PM

Quote:

Originally Posted by pdexta

It was a different dyno this time, dyno dynamics. One of my friends pulled on both dynos and lost a couple hp this time around, FWIW.

Yes, this run was on a new clutch, about a month old.

The guy that pulled before me was an old Smokey and The Bandit looking Firebird. The guy said he was making around 400. He seemed pretty heartbroken when it put down 257, then he disappeared real quick after I made 262.

ok, lets see the log, spark table, and static compression ratio. You're making more power on a smaller turbo than me and I don't appreciate it.

edit: what are the atmospheric conditions and what correction factor?

260whp is pretty fun, huh?

pdexta · 05-03-2009, 05:13 PM

Quote:

Originally Posted by hustler

ok, lets see the log, spark table, and static compression ratio. You're making more power on a smaller turbo than me and I don't appreciate it.

edit: what are the atmospheric conditions and what correction factor?

260whp is pretty fun, huh?

Haha, sorry... you've got more torque! It was 91 degrees when I dyno'd and 52% humidity. I have no idea on the correction factor, I'll see if I can talk to the guy though.

The dyno is known to read high. I dyno'd my old SC'd S2000 on it and was realistically expecting ~280 and it made 301. The guy said he'd adjusted it since the last dyno day and yesterday people seemed to be putting down more realistic numbers. A 2009 C63 AMG put down 377hp, they're rated 457 which comes to 18% drivetrain loss which seems pretty reasonable. A LS1 Camaro w/ just a lid that dyno'd 310 the first dyno day I went to put down 307 yesterday. Another friend w/ a full bolton GSR teg made 157 yesterday after making 170 when he was tuned.

My motor is completely stock from a '95 miata. My spark tables ended up closely resembling Paul's '99, certainly more conservative than what you're running. How much boost were you running to make your numbers? It's about time to bump that up a bit isn't it? haha. Yes, 260whp is awesome. It's amazing that a 50hp bump can take you from no traction problems at all, to spinning into 3rd gear.

hustler · 05-03-2009, 06:07 PM

Quote:

Originally Posted by pdexta

Haha, sorry... you've got more torque! It was 91 degrees when I dyno'd and 52% humidity. I have no idea on the correction factor, I'll see if I can talk to the guy though.

The dyno is known to read high. I dyno'd my old SC'd S2000 on it and was realistically expecting ~280 and it made 301. The guy said he'd adjusted it since the last dyno day and yesterday people seemed to be putting down more realistic numbers. A 2009 C63 AMG put down 377hp, they're rated 457 which comes to 18% drivetrain loss which seems pretty reasonable. A LS1 Camaro w/ just a lid that dyno'd 310 the first dyno day I went to put down 307 yesterday. Another friend w/ a full bolton GSR teg made 157 yesterday after making 170 when he was tuned.

My motor is completely stock from a '95 miata. My spark tables ended up closely resembling Paul's '99, certainly more conservative than what you're running. How much boost were you running to make your numbers? It's about time to bump that up a bit isn't it? haha. Yes, 260whp is awesome. It's amazing that a 50hp bump can take you from no traction problems at all, to spinning into 3rd gear.

I expect that to be a little high. I have a bigger turbine housing, less restrictive turbine, bigger compressor, more displacement, more advance, superior head, and 15 psi. I'm pointing to the dyno.

As for cranking up the boost, I'm at 15psi currently and probably flowing around 27cf/m

Things go south quickly in terms of efficiency if we assume 10bhp per cf/m. But I'm kind of in a funny place because the jump from 13 to 15psi is like the turbo wakes up (230whp to 261whp from 2 psi)...so maybe I'm actually to the left of prime-efficiency, and its just starting to come alive. That's a 15% shift in pressure creating a 13% shift in output...which indicates prime-efficiency to me.

The motor definitely wants more boost because I can run 91-octane with not detonation at 4000rpm/15psi/252wtq/25*advance. If we consider a conservative 12* spark angle to respect EGT melt-down, I could easily put 20psi through this motor before I need water, if the turbo stays efficient, which it won't. Also, I went 5* advance to establish that i had MBT, lol. so essentially I've had 30* advance at 4000rpm/15psi with no detonation, confirmed by det cans...low compression is the shit.

Yeah, spark changes things quickly. On 225 RS2s I can lay stripes in 3rd on concrete with a little effort (no more tire rolling in 4th, thanks to the new suspension).

I need to fix a few things on the dyno with my shitty fueling out of boost, and now that I have COPs which made the car noticeably faster. That spark table I always post is 2* retard from MBT.

Did you hit MBT in any cells?
Did you back out of MBT 2* like a wise person?
What octane?
I want to see a log on your current tune.

pdexta · 05-03-2009, 07:20 PM

I wasn't trying to turn this into a pissing match by any means. There's no doubt that your car has every advantage in the world over mine and should absolutely bitchslap me. We all know comparing one dyno to another dyno doesn't mean shit anyway.

I haven't dyno tuned the car so I can't answer in regards to MBT. Everything I've done has been done through help from the tables you guys posted, my ears w/ det cans, and reading the spark plugs. Once I was reaching the point that I was hitting close to the numbers of people with a similar set up I stopped messing with it. I'm running 93 octane. I'll try to get a log for you tomorrow and post it up.

Looks like you've got a little more room left, 18psi walks you right out toward the tip of the island right? (I'm still trying to figure out these damn compressor maps)

hustler · 05-04-2009, 02:01 AM

come on man, this is not a pissing match. Its an open discussion on mechanicals and tuning. If anything this thread has made me realize that I shouldn't be so freaked out over reliability because apparently my motor hasn't seen any real stress yet. I was terrified the whole time I tuned it, lol.

pdexta · 05-05-2009, 01:22 AM

Here's the datalog, if anyone has some constructive criticism I'd love to hear it.

pdexta · 05-06-2009, 12:56 AM

gospeed81 · 05-06-2009, 02:06 AM

wow, badass

Isn't that EXACTLY what hustler made?

Spookyfish · 05-06-2009, 05:00 AM

That log is not from the dyno run, is it? And 194kPa = 13.6335473 psi.
Still good numbers! They are all wheel numbers?

Spookyfish · 05-06-2009, 05:06 AM

Plz, post your msq too. Curious...

pdexta · 05-06-2009, 10:51 AM

Quote:

Originally Posted by Spookyfish

That log is not from the dyno run, is it? And 194kPa = 13.6335473 psi.
Still good numbers! They are all wheel numbers?

No that log was not from the dyno, and yes those were wheel numbers. Here's the PSI graph from the dyno run.

It seemed odd to me that it plateaued around 3300rpms and ~11psi, before creeping up to 13.5 and bouncing back down. Is that normal, being that it's internally gated? Or is there a problem somewhere?

Thanks for the comments.

Spookyfish · 05-06-2009, 11:08 AM

Weird psi graph. I assume you are in full target boost (13-14psi) around 3300rpm like me. Where did they measure that?

pdexta · 05-06-2009, 11:36 AM

I'm not sure where they pulled the signal from, that's what I'm always seeing though. I even made a helper spring to try keeping the wastegate closed. Guess I should check for a boost leak again.

cueball1 · 05-06-2009, 12:34 PM

Quote:

Originally Posted by hustler

260whp is pretty fun, huh?

From a driveability standpoint you have to love the 200+ lbs of torque from 3000 to 6900 rpms! Nice wide power band. Good job.

People ask me all the time about how laggy my turbo car must be. F that. Our cars making good torque numbers at 3000rpms is perfect. Makes for a very driveable car. Fun fun fun.

papo · 05-07-2009, 11:49 PM

at least urs makes 200 mine is at~80 lulz

**levnubhin** · 05-08-2009, 10:14 AM

Pdexta, you should come across the alley and check us out on out dyno day. p51hellfire is almost 100% sure he's coming. You two can race across the alley lol.

http://www.miataturbo.net/forum/t34335/

ZX-Tex · 05-08-2009, 11:19 PM

Quote:

Originally Posted by pdexta

I'm not sure where they pulled the signal from, that's what I'm always seeing though. I even made a helper spring to try keeping the wastegate closed. Guess I should check for a boost leak again.

Do you have EBC or MBC? If not that will help your spool tremendously. It worked great for me with my 2560. I could hit 12 psi at 3200 IIRC. In fact, I'm getting to 12 psi sooner than you with my 2871

I'm using open-loop EBC.

pdexta · 05-12-2009, 02:47 PM

Quote:

Originally Posted by Phillatio

Pdexta, you should come across the alley and check us out on out dyno day. p51hellfire is almost 100% sure he's coming. You two can race across the alley lol.

http://www.miataturbo.net/forum/t34335/

I'd love to go, but money is kinda tight right now. Hopefully I can work something out.

Quote:

Originally Posted by ZX-Tex

Do you have EBC or MBC? If not that will help your spool tremendously. It worked great for me with my 2560. I could hit 12 psi at 3200 IIRC. In fact, I'm getting to 12 psi sooner than you with my 2871

I'm using open-loop EBC.

I'm using a cheap ebay ball and spring MBC now. Hopefully I can get it figured out, if not I'm pretty happy with the car as it is. How do you like the 2871 compared to the 2560? When I started building the car the 2560 seemed perfect, now I've started to wonder if I should have gone a little bigger.

ZX-Tex · 05-12-2009, 03:48 PM

The 2871 definitely has some lag compared to the 2560. Not so much in terms of boost versus RPM, but in transitional throttle response. The RPM has to be higher with the 2871 to get the same snappy throttle response I got with the 2560. But I suppose that is to be expected. The 2871 compressor wheel is much larger and thus has more rotating inertia.

Unless you want 300+ RWHP I think the 2560 is a great turbo.

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