Yeah, guys,...all cool, but this is not a numbers build. I'll be happy with "some" more poke. The amount is not important, and ultimately, the goal is a "stock +" Miata with as few as possible consequences and drawbacks (yes, I understand the can of worms that opens), but there is the intent: Low hanging fruit- what can I grab?
For injectors, especially as you should consider E85, get some CNG panther platform injectors off EBay to modify.
https://www.miataturbo.net/engine-performance-56/howto-mod-crown-vic-1680cc-injectors-bp-52059/
Pete. (l33t FS) said:I had a car make 200whp on one dyno and 150whp on another dyno. Injector duty cycle suggested 270 at the crank. Then the telephone game begins where 270hp turns into 270whp turns into 350hp, etc.
And THANK YOU for the comment on altitude correction. There was a guy who had some sort of turbo Audi who claimed to make 469whp, because his car made 370-something and he did it in Colorado so he applied the correction factor. Altitude correction does not work that way!
Were they both dynojets? Inertial dynos are not the best for tuning, but when operated correctly they're pretty good about being consistent between different dynos of the same model. There's nothing fancy to calibrate -- it's just a drum of known mass being accelerated by the tires, all you need is a cheap, simple, reliable RPM pickup and you can read power right out of the rate of change of the rotation.
All the other types of dynos have much more delicate/complicated/etc sensors that need regular calibration.
Altitude correction was designed for naturally aspirated cars and does OK at that. Turbos compensate for the altitude (a very useful feature in piston-powered airplanes!), so you can just toss the formula out the window.
Captdownshift (Forum Supporter) said:For injectors, especially as you should consider E85, get some CNG panther platform injectors off EBay to modify.
I would not call E85 "low hanging fruit", personally. There's a lot of complexity involved in doing it right/reliably.
wheelsmithy (Joe-with-an-L) said:Yeah, guys,...all cool, but this is not a numbers build.
The big reason for talking numbers, IMHO, is that once you define a hp target it tells you what you need to upgrade to get there.
In reply to codrus (Forum Supporter) :
Neither were Dynojets. Most places I have seen do not use those because you can't do steady-state tuning or all wheel drive.
To add confusion to the mix, the low number was a hub dyno, which should have eliminated various losses.
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I would not use gigantic huge injectors no matter how cheap they are. It sounds nice on paper, until you find yourself chasing your tail trying to tune it because you have the injector characteristics 10% off and all of the error factors become huge because the injector duty cycle is about the same as the opening time under low load. Or that the latency changes when things get hot, and this may not make a large difference when you have 6ms pulsewidths but it makes a huge difference when you have 2ms pulsewidths.
In reply to Pete. (l33t FS) :
that is fair re: injectors. The problem is that stock Miata injectors can support very little power. IIRC the ones from the later cars were the best (purple tops I think?) and they could only support something like 180whp. The vast majority of RX8 injectors out there are low quality Chinese fakes. It's why I suggested EV14's. Turbo Miatae with EV14's are also pretty common, and it should be easy to track down a base map and dwell settings that would be in the ballpark. Idle tuning is the hardest part of any tune and definitely harder with big injectors using small pulsewidths, but it can be done. May not matter as much for a Challenge car.
In reply to ShinnyGroove (Forum Supporter) :
Thanks for that, Sir. Being an internet discussion, support for any opinions really helps me in the decision making process, and is, in fact why I asked here. I do have a 2002 variable valve timing engine on hand. It likely has a bad head gasket, but the injectors should be fine. That may be the best route to the challenge, and EV14s later, as the budget goes out the window. Again, your input is greatly appreciated.
I see from your profile, you have real world experience with turbocharging and megasquirting a Miata, so I'm all ears when it comes to advice.
The MSPNP2 does not need a wideband gauge, but it does need a wideband controller. In many cases, the gauge and controller are integrated into a single package, like with the AEM gauges and the Innovate MTX. But sometimes they're separate, like the Innovate LC-2 or the AEM "inline" unit.
In reply to MadScientistMatt :
Nice>I've got a Spartan2 that I got with the turbo. That should save some scratch.
In reply to ShinnyGroove (Forum Supporter) :
Will the transmission acceptably handle more power than the stock injectors can support?
I do not know how related the Miata trans is to the old 3N71/4N71 transmission, which was pretty stout.
180whp is a fun amount of scoot in a Miata, too, and if the PNP can do boost control, you can still get a big fat midrange without running out of fuel. And automatics do love midrange.
To anyone it may help:
This very forum linked to a Sloppy Mechanic reference that is very handy.
@ the FLAPs, Bosch # 17212 is the 4.9D O2 sensor I'll need for this, and many of you will need for...stuff.
Pete. (l33t FS) said:In reply to ShinnyGroove (Forum Supporter) :
Will the transmission acceptably handle more power than the stock injectors can support?
I do not know how related the Miata trans is to the old 3N71/4N71 transmission, which was pretty stout.
180whp is a fun amount of scoot in a Miata, too, and if the PNP can do boost control, you can still get a big fat midrange without running out of fuel. And automatics do love midrange.
Accepted wisdom is that stock Miata drivetrain components can reliably hold up to 225whp. Running injectors near the top of their capacity is a recipe for disaster as the lean conditions are the ones that blow up motors. I would also not bother with electronic boost control on an MS2. So then the challenge is finding a small enough turbo to not exceed the injector capacity.
My setup is old school - but has worked for 20 years now.
1.6 Miata
Td04h small turbo
fuel pressure regulator by Aeromotive
walbro 255 fuel pump
1.8 injectors
Bipes ACU
begi intercooler
FM turbo exhaust
5 - 8 psi all it's life
And it works. Makes all the cool sounds and is quicker than stock.
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