Quote:
Originally Posted by Red__Zed
Yes, they're NA. I can't tell you why, I can just echo what I saw.
A lot of the "factory freaks" are either optimistic dyno's, or underrated cars. My WRX dyno'd at about 25x whp on the same dyno that the new STI's are laying 265. Doesn't really account for the difference between 305 and 265, but that's just a function of the WRX being underrated from the factory.
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Yes -- definitely. A lot of cars get underrated from the manufacturer.
I didn't know about the old domestics and the possiblity of getting a different cam -- but to me that must be the truth behind the "factory freak" -- and it certainly would be an unintetnional fluke to put a wildly different cam in a motor just because they ran out of the specified one.
On modern engines, any "freak" would have to be due to either slightly different ECU tunes (as in the early model 2ZZ Celicas) or maybe JDM vs domestic (totally different motors on the 240/Silvias!).
That guy with the Honda - man, I just don't know. If you know him or the people at the shop, it would be interesting to learn more about it.
We need to get Mythbusters on this one
On the Z, I think the major differences will be due to:
1. Even on the same dyno, the ECU needs MORE than 3 pulls to make adjustments that will show gains in power. Plan on 6 runs, not 3 to make sure that bolt on did as advertised.
There is almost no point to making comparisons between runs from different types of dynamometers (e.g., dynopack vs dynojet), but see further here
http://www.turbomagazine.com/tech/03...ash/index.html
2. These motors burn oil! That could mean if you have an oil burning engine, poor ring sealing, and slight loss of compression, meaning a little less power.
3. VVEL is an untunable (currently) and mysterious thing... there is almost definitely a LOT of adjusting the ECU makes to VVEL depending on ambient conditions and engine load.
Moreover, on the Nismo, I think the map is very different, which is why they tend to make more power with the same mods, even as compared to a tuned non nismo Z.
4. Break in -- some people dyno for baseline well before 5K on the motor. I think that's too early (but would like to here from someone more knowledgeable on break in periods), and I bet compression (and power) will be higher after 5K than before. I'd say 3K at the earliest, but ideally, wait unitl 5K.
5. The gear used during the dyno run. My recommendation is for BOTH AT and MT to dyno in 4th gear even though 5th is 1:1. For rationale and further details, see further here
The Effect of Dynoing in Different Gears