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miatauser884 09-28-2010 12:48 PM

2 Attachment(s)
The dyno is 3 hrs from my house. I already paid $450. The cruise cells are good, the intake cam is good, and my timing is good. Are you suggesting I do a few pulls on the street datalogging and adjust myself, or go to a local dyno and pay for a few pulls on it.

The 9-25 datalog is from the last pull on the dyno, and the 9-28 log is from driving to work this morning.

If the tune can be improved, it's hard to blame the dyno guy for my lack of understanding of the settings in MS. I don't have another 450 to spend right now.

I don't mind if people think my tune is shit. That's fine, and feel free to voice it. Just leave some constructive criticism about the best way for me to rectify the situation.

18psi 09-28-2010 01:12 PM

You could tune it yourself. You have a good baseline. Adding wi should allow you at least a couple degrees worth of spark and maybe a bit leaner mixtures. Which will result in finally reaching that 300whp goal of yours (if that's your goal).

Braineack 09-28-2010 01:18 PM

what sorta o2 sensor your running, cause your logs always show you're crazy rich in boost.


running 10.8:1 in boost =/= power.

miatauser884 09-28-2010 01:32 PM

AEM. We tuned off my wideband not his. He said the location of mine was superior to his in the tailpipe anyway.

I guess I need to do a few sustained road pulls and review my logs.

WI is too much hassle for me. I'm going to get what I can out of this turbo and be done. I will however add a Map Daddy unless people think I can push the standard MS mapsensor to 25psi

What is a safe AFR at 20-25 psi

18psi 09-28-2010 01:34 PM

More to it than just "safe for xxx psi". But mid 11's is never dangerous. Low 11's if you wanna be super duper safe.

miatauser884 09-28-2010 02:29 PM


Originally Posted by 18psi (Post 635504)
More to it than just "safe for xxx psi". But mid 11's is never dangerous. Low 11's if you wanna be super duper safe.

I guess I'm trying to determine if AFR needs to drop linearly with boost, or does it look more like a decaying exponetial. i.e 3psi 12.8, 6psi 12.4, 12 psi 11.8, 15psi 11.5, 18psi 11.3, 20psi 11.3, 25 psi 11.3

Braineack 09-28-2010 02:35 PM

don't go richer than 11.5. otherwise that looks good.

I let mine stay fairly lean below 4psi since I do retard timing at the same time. Since my turbo is smaller, I find myself in boost quite often.

http://www.boostedmiata.com/gallery2...gets_msIII.png

miatauser884 09-28-2010 02:40 PM


Originally Posted by Braineack (Post 635576)
don't go richer than 11.5. otherwise that looks good.

I let mine stay fairly lean below 4psi since I do retard timing at the same time. Since my turbo is smaller, I find myself in boost quite often.

http://www.boostedmiata.com/gallery2...gets_msIII.png

I have a similar afr table. I'm a little leaner at idle and richer in boost. You also have a nicer transition between just off idle and cruise.

Just to clarify before I blow my shit up. When I am boosting to 25psi, I don't need to go lower than 11.5 afr???

Braineack 09-28-2010 02:44 PM


Originally Posted by djp0623 (Post 635586)
Just to clarify before I blow my shit up. When I am boosting to 25psi, I don't need to go lower than 11.5 afr???

I acutally idle at 14.7-15.0:1, that's an old map.

yeah, it's just wasting fuel after that. there's no more oxygen to burn.

PatrickB 09-28-2010 03:09 PM

I think your confused about pressure and afr, when you are in positive pressure your afrs targets dont change from 10psi to 25psi.

fmowry 09-28-2010 03:15 PM

Did I miss it, what gas are you running? All 93 octane is not created equal. What CR pistons? 8.5:1, 9:1?

Not sure why that drop couldn't be some detonation either. Was the clean run the first or 2nd run?

miatauser884 09-28-2010 03:17 PM

I'm aware that AFR at 12 psi and 25psi would require different amounts of fuel to reach the same AFR. I was concerned that the increase in pressure would increase the heat enough to increase the likelihood of detonation. Which could be quelled by dumping more fuel at the expense of power. Hence going richer than 11.5.

It seems clear that this is misguided, and that I could probably squeeze a bit more power out of my current tune by leaning it out a bit since it dips into the high tens at 20psi

miatauser884 09-28-2010 03:19 PM


Originally Posted by fmowry (Post 635620)
Did I miss it, what gas are you running? All 93 octane is not created equal. What CR pistons? 8.5:1, 9:1?

Not sure why that drop couldn't be some detonation either. Was the clean run the first or 2nd run?

9:1 pistons, exxon 93., I have enough confidence i he tuner to believe it is not detonation, especially when looking at the enrichment activity going on on my log at the same time.

Thanks for all the help everyone. Keep it coming.

PatrickB 09-28-2010 03:21 PM


Originally Posted by djp0623 (Post 635622)
I'm aware that AFR at 12 psi and 25psi would require different amounts of fuel to reach the same AFR. I was concerned that the increase in pressure would increase the heat enough to increase the likelihood of detonation. Which could be quelled by dumping more fuel at the expense of power. Hence going richer than 11.5.

It seems clear that this is misguided, and that I could probably squeeze a bit more power out of my current tune by leaning it out a bit since it dips into the high tens at 20psi

yeah looks to me like you can for sure get more hp out of the current tune. good luck man.

Braineack 09-28-2010 03:34 PM


Originally Posted by djp0623 (Post 635622)
Which could be quelled by dumping more fuel at the expense of power. Hence going richer than 11.5.

the addition of extra fuel can only cool the charge so much, slow the burn so much, and lower peak pressure so much. after that it's just going to end up coming out raw out of your exhaust and washing down your cylinders.

miatauser884 09-28-2010 03:46 PM

Alright, I know I'm being a big titty baby here......

In a perfect world the afr would go to 11.5 and stay. How much leeway is there if there were a lean spike with afr?

18psi 09-28-2010 03:48 PM

it depends on how long it would lean spike and what your timing for that particular cell is at.

anything over 12 in boost on pump gas is asking for trouble

magnamx-5 09-29-2010 12:20 AM

dude i run 12.5 at 17 psi and do alright most of the people on here that make apreciable power run mid 11's atlaest man up and give it a shot. Your fuel system is duel feed with a walboro 190 right? the pump is fairly new? the injectors are clean and fairlynew as well? What the hell else is gonna fail on you?

If you did blow a fuel line etc, then not only would your motor fuel cut before it self destructed but you would have to worry about an impending fireball as well.


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