Yep, but doesn't balancing require the entire rotating assembly? May as well say fuck it and do pistons too!

truth, exactly why F1 cars have like no trq but all hp up top its about the cornering and use of the power rather than the trq. you dont want wheel spin you just want rotation increase

Here's what Toyota did with 100 octane race fuel and just a few mods:

http://www.ft86club.com/forums/showt...ota+grand+prix

Add 10hp? My car did that just from aging sucka!

They're typically all strokers, so the displacement is a little moot :p

And yes, I do agree, that the FA20 is rather impressive that it makes 200hp at *just* 7000 RPM.

I'd gladly sacrifice some driveability for more top end hp. AUC for the powerband I use on track is what I care about.

I think 190-200whp is doable on this engine with a budget, around 15k at the most if you do the work yourself. I think the limit to this engine would be 280hp.

But then again this engine in particular has a bit of mystery to it, I don't know any other 2.0 4 cylinder n/a than can scavenge peak TQ at low RPM...which leads me to believe that intake acoustic tuning makes much more drastic changes to the efficiency of the output.

I also don't know any 2.0 4 cylinders n/a that make 200hp or more without aggressive cam profiling like vtek or some serious blueprinting.

if you compare all the engines together in the same class. including the R500 duratec engine, and the K20Z ariel atom mugen. The FA20 with only 200hp is pretty impressive for being an average production engine

Exhaust acoustics as well. No one seems to be paying attention to what I've been saying for some time. You can see it in pretty much every single catless header dyno. The dip 'shifts' in the rpm range and the header makes a bit more ~4800, and up top. The 4800 and top end come from flow gains, but it's the acoustics that move the dip around.

If people want to make mid range or high end power with a header it will be by paying attention to which returns occur at what rpm.

For maximum effect, the same should be done with the intake system and resonators.

This.

You might also want an oil cooler if you plan on tracking your car. Also, lightweight underdrive pulleys would be something to consider as well if you want to maximize power for racing. Getting rid of unsprung weight would be beneficial.

All good points, especially about the F20C. That's part of the reason I have looked at racing a Supercharged S2k as opposed to a N/A one because of how it makes power. The F20C makes its peak power right at the moment you need to SHIFT! It really needs to rev to 10k. Which is possible but then the calculation for cubic dollars spent changes.

But to what end? The CR is already 12.5:1... How much more can this engine go and would that CR increase negate the ability to use pump gas?

Consider a ruleset like that of Improved Touring. I'm thinking the Twins get classified into IT-R when they are eligible to be so (must be in production for 5 years). In Improved Touring you're allowed to balance/blueprint/mill and increase piston size by .040" but you are not allowed to increase compression by more than .5 point. So buying fancy forged/high compression pistons would be unnecessary/disallowed. Also, since IT doesn't allow for head porting or cams then pursuing a higher red line would be an exercise in futility if the stock head/cams won't facilitate it. The problem I see with IT-R is the weight penalty the Twins might receive. Currently the S2000 has a minimum weight of 3005lbs. Awful. I bet if the FRS was classed in IT-R it would have a weight penalty putting it at something like 2800lbs or higher.. ugh.

Other classes are Like SPU, ST (Conference ST not SCCA), or NASA Performance Touring (PTE, PTC..etc). The FRS could be a really fun PT car.

I was hoping some guys like Visconti would chime in and say something like: "yeah, we can do 215whp on 92octane with bolt-ons!" However, I think may have set myself up for disappoint. :(

Lightweight pistons, to reduce rotating mass?

@rice_classic

What does IT say about valves and how do they define porting? If you are allowed valve replacement and seat modifications, you could pick up some low lift flow by going to bigger valves and seating them properly, maybe 5 angle job.

PT it's allowed but I believe you take a "point hit" on that. Would need to verify. However, many racers like having their car be legal for multiple classes. Right now my car is legal for ITA, PTE and H4. If I did the "lightweight" pistons it would disqualify me for ITA and H4. Kind of a bummer but a challenge folks face on deciding to build their cars to the "limits" of the rules or build it to be competitive in multiple classes so a racer can race with more than 1 organization.

IT it's not allowed. Piston must be of factory dimensions including weight with the exception of being .020 or .040" over bore.

IT is very production based. No porting allowed (besides port matching), valve seating can be cleaned up but not changed from factory spec (like over sized valves, 5 way valve job etc). You are allowed to "port-match" your manifolds to the head but only 1" into the head/manifold.

You are not allowed to change the valvetrain beyond OEM parts and spec. The ONLY thing you can change in the valve train is the valve guide material which is "unrestricted". The rule book doesn't say anything about oversized valves and valve jobs. That's how you know it's not allowed.

IT Rules work like this: "If it does not say you can then you cannot."

That simple statement go a long way at simplifying things. Every once in a while I'll hear a conversation at the track that starts out like this: "So show me where in the rule it says you can do that..." Uh oh! :paddle:

LOL,

Just saw this thread:

http://www.ft86club.com/forums/showthread.php?t=24283

300bhp with full-race valvetrain. Like Orbital said that thread: E85 or RaceGas most likely.

Still though... That's quite nice for guys looking to play with their race cars in classes that allow this type of modifcation but don't allow FI. Super cool.