Apex1.0

So lets say I wanted to build a reliable motor that will spin, and make power up to 11k rpms? Obviously it will need valve train work and cams to move the power up. But what about the bottom end? Is it balanced to 11k rpms? What about the head, ports, intake, etc??? Will and F20c flow enough air to support power up to 11k?

Why?? Well so many people ask about NA builds here and the typical response is that FI will yield much better power per dollar. This is true, but what if your 1st concern is not more power, or a lot more power. What if it was just to double down on what makes an F20C awesome to begin with? Radical high rpm power that never seems to stop pulling.

We all know the air pump theory, and to move more air through an engine (NA), you have three options. Increase the efficiency, increase the displacement or increase the operating rpm. Lets keep the bottom end stock for the sake of simplicity, the F20C is already extremely efficient, maybe it could be better? But increasing the operating rpm and shifting the power up, should net more peak power and make an exotic motor more exotic.

Would this simple recipe work?

Light weight valves, keepers, retainers, springs, etc...
Cams to shift peak power up
Maybe port work and increased compression
Try to leave bottom end stock
Tune, fuel etc...

Maybe a realistic goal of 220rwhp at 10-10.5k, redline at 11k

s2000Junky

I think your power aspirations are pretty low for the rpms you’re working towards. You can easily put down 220whp at stock rpm. It’s easier for an engine to produce hp at a high rpm vs a low rpm, where you have more inertia working for you. You can turn and produce power at 11k rpms with this engine, but its street life will drastically be reduced on the bottom end.

cleenyc99

i don't think the stock bottom end would hold 11k rpm. the amount of energy it would take to change the direction of the piston (up and down). will likely starch the rod and hit the head/valves. but im no engine builder and haven't seen it so its just a thought. the idea of 11k rpm is bad ass and I would like to see you do it. I also think it would make more then 220 hp. go 4 it

jst2878

Your 11k redline race motor will not last too long. Just buy the spoon block and beef up your head. That should work

Apex1.0

So what is the limiting factor for high rpm operation on a f20c? Obviously stabilizing, strengthening and lightening the valve train would be the first issue. Then I got to believe there is not enough air flow to keep building power above 9k. What's the bottom end good for, 10k?

afzan

What's your budget?

s2000Junky

The f20/f22 consumes as much cfm as a typical v8. Flow capability isn't really an issue. Cam timing is probably the largest factor first in shifting the power band in that rpm range you want, and then its just a matter of retuning the fuel delivery in that new range, and making sure you have the proper exhaust system to hone in the efficiency there. You will probably end up with a 4 into 1 header and a decent 70-75mm single cat back I imagine. Then you need to spend some big bucks on light weight valve train and light weight connecting rods and a light weight balanced crank and super light flywheel 8lb or less. Anything can be done, just depends on how much money you have and how long you expect the engine to last.

There has been one guy that comes to mind in particular in the FI/drag racing game (realstreet) Who ran a large turbo on a factory F22 with just upgraded valtrain, to the exact rpm range in question here. If i recall he said he ran that motor for multiple seasons trying to blow it up with no avail, until blowing a HG or something and taking that opportunity to revise the motor. But point being, the stock bottom end took it for limited 1/4 runs (and quite a few) but that's very different then actual long duration street mileage. If you don't throw a rod after some time, eventually you will ovalize the piston walls due to the lateral forces at play, and that will ultimately be the demise of the engines career.

Everyone is into building larger displacement/stroked engines right now, and so thats where the focus seems to be, and they deliver the lack of trq that people seem to crave most, however im sure there are some engine builders here that have been down the high rpm peaky road with this engine, and I agree its a tasty venture. In my experience though, the F22 really hits the sweet spot for trq, high rpm and longevity balance. Given the right supporting mods, its a hard engine to beat out of the box. I started out with an F20 in MY01 but since its demise have always had an F22 in her and would never go back. The effective power band of the f22 is simply better and its a more reliable built engine from the factory.

Suprdave

Uhm, prob call Jeremy Allen @ InlinePro with yer Black Card on Deck...

SlowTeg

This thread..

Apex1.0

Great info, I see why people move to the F22 when its an option. You will just have more power potential with the larger displacement. Also you will have better average power.

I understand about going for torque, and average power. It benefits the street and track. I have also owned 500rwhp + supercharged V8s and LS C6 Corvettes so I know about torque. That being said, for what the S2k is I don't think it lacks driving torque. First it has fairly aggressive gearing which offer torque multiplication, plus the motor runs strong on the primary cam. It will pull every gear almost all the time. Also the motor is incredibly response to throttle inputs. If you actually want to go fast and have a passenger and gear in the trunk, plan on redlining every gear.

For me the high rpm power is where the fun is. I have had FI and there are drawbacks regarding response and latency. See this from the McLaren F1 Wiki:

Engine[edit]

History[edit]


The McLaren F1's engine compartment contains the mid-mounted BMW S70/2 engine and uses gold foil as a heat shield in the exhaust compartment.
Gordon Murray insisted that the engine for this car be naturally aspirated to increase reliability and driver control. Turbochargers and superchargers increase power but they increase complexity and can decrease reliability as well as introducing an additional aspect of latency and loss of feedback. The ability of the driver to maintain maximum control of the engine is thus compromised. Murray initially approached Honda for a powerplant with 550 bhp (410 kW; 558 PS), 600 mm (23.6 in) block length and a total weight of 250 kg (551 lb), it should be derived from the Formula One powerplant in the then-dominating McLaren/Honda cars. When Honda refused, Isuzu, then planning an entry into Formula One, had a 3.5-litre V12 engine being tested in a Lotus chassis. The company was very interested in having the engine fitted into the F1. However, the designers wanted an engine with a proven design and a racing pedigree.[6]


I know times have changed but there is still something about all motor. So back to the build. My thought is to keep it simple, build the head/cams to add rpm and power that the lower assembly can handle. It does not have to redline at 11k, what ever can be achieved reliably. Or is the rotating assembly done at 9k?