I'm an idiot help me?!
06-23-2012, 05:53 AM
#101
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and check it on the road.
There is gonna be a difference in how much extra timing you can throw in at lower gears.
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06-23-2012, 09:30 AM
#102
Sure there will, but you will be in higher load cells in the higher gears so you can tune for it in the higher gears too. The effect you're talking about it what makes tuning with alpha-n difficult (assuming not a boosted car, I've tuned alpha-n and boost, ---- THAT ----).
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06-23-2012, 12:44 PM
#103
You fundamentally don't understand how tuning a car works. It is not possible to have different tunes for different gears. The most you can do is change the boost setting based on what gear you are in. The fuel and timing map remain the same whether you are in 4th or 2nd. It's based on load and RPM with a few scale factor thrown in for temperature and a couple other things. If you have someone that knows what they are doing on a loading dyno (like a mustang) you can tune the entire fuel and timing map sitting right there on the dyno. You seriously need to change your goals. 200 ft*lbs of torque below 2000 rpm is totally useless. Show us a datalog of you driving and how much time you actually spend in that rpm band when you are trying to do anything other than DD.
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06-23-2012, 03:25 PM
#105
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http://forum.miata.net/vb/showthread.php?t=216061
Justin, your build thread inspired me to turbo charge my car more than the "do it this way or you will die" threads
The TD04-13t has good low end grunt and might be worth considering?
Justin, your build thread inspired me to turbo charge my car more than the "do it this way or you will die" threads
The TD04-13t has good low end grunt and might be worth considering?
Mazda's B series cylinder heads flow like DOG ----...
Just because engines share displacement doesn't really mean diddly ----. Would you like a perfect example of that? Modern day smallblock chevy engines make more power per cubic inch than 400+ Cubic inch Big blocks of the 60s.
1969 COPO 9561/L72 427 cu in (7.0 L) V8 425 hp (317 kW) @ 5600 rpm, 460 lb·ft (624 N·m) @ 4000 rpm
Chevrolet Performance 383ci/425HP ZZ383 Crate Engine 6.2L V8 425 @ 5400 rpm, 449 lbft @ 4500 rpm
Chevrolet Performance LS3 376ci/515HP Engine 6.1L V8 515hp, 575lbft.
See the differences? Old production engine, more modern production engine, most modern production engine. Displacement goes down, power goes up.
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06-24-2012, 07:18 PM
#108
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You fundamentally don't understand how tuning a car works. It is not possible to have different tunes for different gears. The most you can do is change the boost setting based on what gear you are in. The fuel and timing map remain the same whether you are in 4th or 2nd. It's based on load and RPM with a few scale factor thrown in for temperature and a couple other things. If you have someone that knows what they are doing on a loading dyno (like a mustang) you can tune the entire fuel and timing map sitting right there on the dyno. You seriously need to change your goals. 200 ft*lbs of torque below 2000 rpm is totally useless. Show us a datalog of you driving and how much time you actually spend in that rpm band when you are trying to do anything other than DD.
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06-25-2012, 11:40 AM
#109
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Sure there will, but you will be in higher load cells in the higher gears so you can tune for it in the higher gears too. The effect you're talking about it what makes tuning with alpha-n difficult (assuming not a boosted car, I've tuned alpha-n and boost, ---- THAT ----).
5000 rpms, 180kpa for instance though all gears
but have more timing in the same area but at lower gears.
This is why I like maf based systems.
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06-25-2012, 11:54 AM
#111
I wouldn't even consider using the stock maf in a turbo application. I would be straight onto a GM 75mm truck maf with or without the screen depending on placement. I too like maf based systems, though they are less responsive to transients than speed density. Spark knock is related to airflow (assuming head design, temperatures, ect stay constant) and not manifold pressure, it does make sense to control spark based on airflow rather than map.
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06-26-2012, 01:53 PM
#117
It wont always make less power, it will if you have the wrong sized or poorly designed maf. On a car with a good maf, with a maf based tuning solution the only real reasons to switch to speed density is if you flow enough air to max out a 3" maf with no screen, you have a packaging constraint that prevents you from properly placing the maf. We don't have a good maf, and switching to one would take too much work.
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06-26-2012, 07:12 PM
#119
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It wont always make less power, it will if you have the wrong sized or poorly designed maf. On a car with a good maf, with a maf based tuning solution the only real reasons to switch to speed density is if you flow enough air to max out a 3" maf with no screen, you have a packaging constraint that prevents you from properly placing the maf. We don't have a good maf, and switching to one would take too much work.
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