I see a lot going on here and people like to grab too often to parts or technologies that are far too extreme for their goals, sacrificing driveability and reliability.
And they bring not always the gains that are expected....
IMO 99.5 % of us don’t need these parts below …I have them all seen here on vortex
14 mm lift cams
+ 300 degrees Cams
Dry sump systems.
Too big ITBs
Once the engine is run above 7500 rpm, it goes at the cost of Torque
and its not needed unless more than say 125 hp /L are expected
Bores bigger than 83,5 mm
Except if you want to build a + 190 Fw hp 8V or + 250 fw hp 16V/20V 2.0 L engine…
.and even then its not always needed.
Many off these parts are used to get the last 5-7 % out
Races are won on TQ , not ultimate HP
( the ability to climb the revs / were the most time is spend )
you DON’T need 8000 rpm to make decent power
The best N.A / 2.0 engines make very serious powerlevels @ 7000 rpm !
( 260 / 270nm @7000 rpm )
N.A tuning is doing the basics right and do many small things that ad up
You can find maybe 20 to 30hp just by making work on the small things that are too often overlooked.
So here a list with things you can work on
The higher the revs the more frictional losses.
build the perfect NEW ``WORN`` engine
( a few 0.01mm on crank /rod bearings and Bore)
Flywheel /crankshaft and Piston /rod weight reduction
Balancing crankshaft, pulleys, flywheel, clutch, pistons, rods, etc
Valve train component weight reduction
Valve Spring pressure
Belt (s) tension /tooth shape
Coated bearings / piston skirts
Surface finish (roughness)
make all water and oil flowing well
big gains can be made here , but go not in extremes
This is the most important part to make power.
I think there is enough info on that available, just a few things,
Don’t make the valve guides too short, this compromises valve sealing.
( even if it cost some flow )
Its not the size of the valve that matters, it’s the throat under the valve that matters.
Symmetry on ports and valve height
sand paper port walls to avoid wall wetting ( less flow )
But the best head and cams will not work if they are not proper timed and inlet an exhaust system are not in Tune
Run your engine cool
this helps to reduce inlet air and under bonnet temperatures
above 70 C there is power loss
electric water pump
Sump with oil control baffles
Crank oil scrapers
good air ventilation bloc and head
Keep fuel cool
Higher fuel pressure 4 -8 bar
High flow injectors with good atomisation
Put the injector 15 to 25 cm from the valves so that the fuel/air has time to mix
Use good /race fuel and do the ECU mapping on this fuel
1600 / 4 cil 42 mm
2000 / 4 cil 45 mm ( 48 mm on a FULL spec engine )
Keep heat away from inlet manifold / ITB
Airhorn length and shape
Use airhorns with different lengths in one setup
don’t use an airbox as it will bring more hp
in theory there is a gain because off pulses in tune with an airbox / plenum
but in praxis its VERY hard to achieve by try and error
and who has acces to CFD software as WAVE / VECTIS ?
A long 4-2-1 or 4-1 header / diameter 41 to 45 mm
63.5 mm system
Wrap or coat headers
i know its far from complete and but in the end......
its not all magic , but a lot common sense....
Modified by HPR at 5:41 AM 9-25-2009