Your path to power - Selecting your starting platform and eliminating the weak links
03-24-2011, 03:29 PM
#21
im pretty noob on this site and to the miata and thought this was a great thread, i would recommend adding to the FAQ. Its a lot easier then the infamous "did you try searching" reply you get from more senior people on here.
this may not apply to the miata but if your engine is fully blueprinted and balanced you need to make sure that your flywheel doesnt have any OEM counter balancing same goes for the crank pulley
this may not apply to the miata but if your engine is fully blueprinted and balanced you need to make sure that your flywheel doesnt have any OEM counter balancing same goes for the crank pulley
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03-25-2011, 07:54 AM
#23
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That was my original intention, but I guess I put the cooling system down at the bottom of the list. Moved it, renumbered, and added some HP comments to cooling and PCV. Thanks!
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03-25-2011, 12:05 PM
#29
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the 93 is only 100lbs lighter than the 94.
and the 94 has:
bigger brakes
bigger diff
bigger displacement
bigger clutch
2nd air bag (just sayin')
but only had what like 10 more horses? mazda obviously saw a need for the upgrades.
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06-08-2011, 02:30 PM
#38
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Power:
Stock engine is basically safe to 200whp and ~7500rpm.
Folks start to bend rods in the 250whp range. M-Tuned rods are the fix.
Past 300whp, you'll start to see issues in the cast pistons. Supertech pistons are a no-brainers.
300whp/8000rpm is the generally accepted limit of the stock oil pump gears. Billet gears are available from Boundary Engineering.
350-400whp, OEM main bolts are dubious. Upgrade to ARP main studs and use an MBSP if you intend on pressing past the 350whp mark.
Crank and block limits are unknown, but both are higher than 500-600whp. The next power limit is likely the OEM cast main caps, at somewhere around 500whp. Someone else can find that out
Limit of the stock head studs is unknown, probably because EVERYONE upgrades them. You should probably just upgrade them and avoid becoming the guinea pig on that one.
Revs:
Stock rods will not accept anything past about 7800rpm without stretching. Spec Miatas are documented to stretch rods on single sub-8000rpm overrevs. If you push past 7500 on a regular basis, you need forged rods.
Stock oil pump gears have a generally accepted limit of 8000rpm due to crank harmonics. Push past that (or run at 8k for a long time) and billet gears are strongly recommended.
OEM valvetrain is good up to the ~7800rpm mark. At a certain point, the valves will start to float, which means you either need stiffer springs or lighter retainers.
Making power at 8000rpm is hard. You need a huge centrifugal blower, a lot of port work, big cams, or a combination of at least two of those things. Most people do not spin the motor this hard.
FOOTNOTE: VVT users MUST adhere to a strict 7400rpm limit due to an intake cam harmonic. Change the intake cam and you may press past that limit.
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