Hi guys,
I see a lot of talk on the topic of dyno gains and what part makes the most hp and torque (< that alone is contradictory)
Over at the Maserati forum we where discussing modification on the 4.2 and 4.7L Ferrari/Maserati engine, there where some posts there I think might be interesting for prime.
I see a lot of talk on the topic of dyno gains and what part makes the most hp and torque (< that alone is contradictory)
Over at the Maserati forum we where discussing modification on the 4.2 and 4.7L Ferrari/Maserati engine, there where some posts there I think might be interesting for prime.
A.S. Motorsport said:Very tricky subject this..
We've head a lot of in dept discussions concerning this on other forums.
here is my take on the subject,
Condensed, you can't predict exact gain or stack gains up, nether do dyno sheets offer any guarantee what so ever...
Detailed explanation why i make that statement, (sorry for the length)
First of all, generally performance is measured on a dyno with performance mod's nearly everyone does a wheel dyno
Only way to get a reasonably accurate comparison is full back to back comparison, same dyno,car, variables & day.
Basic Variables on a wheel dyno that influence the end result
- Dyno make and model (every make and model does a different read out e.g. shows up different figures)
- Dyno calibration (critical, it forms the basis of the whole experiment)
- Atmospheric & Barometric (temperature, altitude have a HUGE influence on a engine
- Heat soak (how hot is the engine, how long has it be on the dyno, this really effects the run)
- Car condition and modifications, (this goes as far as millage and how dirt accumulation & cats and manifolds)
- Fuel octane rating (Regional differences come in to play!) and oil viscosity (factor in drive train loss)
Additional
Also keep in mind don't view mods as individual components!
It's a package that makes the engine preform all play to gather to make it perform.
Changing one variable can effect the whole setup and performance result.
When it comes to forced induction and cold & ram intakes.
Air speed is generally not factored on a dyno,
the car is standing static on a dyno with only a blower to give some airflow to the radiator.
A car driving at speed will benefit greatly from ram effects (if designed for!) on both it's air filter induction (NA cars) or inter cooler efficiency. (FI cars)
The OE's run tests on a engine bench dyno out of the car, this give a clean rating and is much more accurate even so there are output variations in a batch of cars (Nissan GTR is a good example)
Like already mentioned giving a firm power increase to a customer before hand isn't a smart idea it doesn't that simple.
The number of actual factors is very large.
Then think of supporting mod's that make a system as a whole preform better (for example thermal spacers) it's hard to pin point what they do on there own but they effect the parts around them.
Calculations
That being said I often calculate ratio factors.
By quantifying each component in a numeric variables you can start to add those up and give a increase prognoses on paper with a margin for error.
For example:
Part A, increase flow 20% and cools 5% @ given RPM add that cooling factor to your mixture, density, etc,etc gives you a idea what the modification does in a system.
Reverse calculating for example:
Combustion chamber > Camshaft spec > Valve specs > Runner & Plenum > RPM > Throttle body
Over on the NSX forum there are in-dept discussions disusing these formula's and methods, going further on the subject of valves, runners and throttle setups.
A.S. Motorsport said:
