bigger engine??

[NoHachi]

Thats just nitpicking.... ;-)
But seriously..GZE is the best option if you want serious power...
Beams 3S-GE is 4 times as expensive and makes the same power approximately...nice engine though..would rather have an all aluminium lump..

Which brings me to the following..the solution to all your problems:

A rover V8..all aluminium...just a little heavier then a 4 age..and some american engines performance goodies fit right in (cheap cheap!)..

I have seen engines come by for around 200E..Drop around a grand on second hand performance parts like carbs and cams and you'll be laughing your ass of....now go and build it! quickly!

[Max_Misawa]

Hondata and IPS have been working together they are making some killer NA power figures

it is a proven fact that you can gain almost 30hp with a great ex manifold on the K20

http://www.prototyperacing.com/dynok20b.htm

IPS cams are said to make about another 42hp

i am doing .5mm over bore also
hasslegren will be doing the engine work and assyembly

I was also planning on useing the honda CPU for more power

the finally i was going to make a custom ITB manifold using AE101 or AE111 itb's that should be good for another 15 hp

so with my math
220 base + 30 for a custom ex manifold + 40 for cams + 15hp for itbs +5~20 for CPU tuning that takes me at or about 300 hp NA roughly

There was a big spread in one of the rags a few months back
it was all about a 320hp to the wheels RSX (NA)

so yea i think its definatly possible for me with the help of my buddy over at hasslegren

Max

[NoHachi]

I'm sorry...but that dyno is just to much for me to believe...
Just slap on a new filter and exhaust and pick up around 70 hp!? 250hp@ the wheels versus 200hp@ the crank stock and a better toque curve everywhere..I'd really like to believe that, but i'm not convinced yet..

I also don't really believe in the additive nature of all the additions.. You need cams and rpms to make real power...Where exactly is the great innovation of the K-series? Even Hasselgrens F-Atlantic engines "only" make about around 240hp@the crank..Thats a puny 150hp/l..nothing compared to the ~175hp/l RSX you mention...those are WTCC and DTM values!

Most Dynographs@ hondata seem to be more plausible..

[Max_Misawa]

The 4AG head was designed in the late 70's
The K20 Head was designed in the late 90's

to me that makes all the diffrence in the world

K20A is 220hp at the crank to start with
making an addtional 80hp should not be that hard to do

That would be pretty much the same as going from a stock 112hp 4ag to a 153hp 4AG
its only a 36% gain

i am sure with cams, ecu, hand made ex manifold, and itb's just about anyone could make an honest 153 hp at the crank in a 4ag

Max

[NoHachi]

Thats the whole point..the whole simple upgrade path shouldn't be so simple..The engine is already near the limit of an ordinary engine..Also technology hasn't really sprinted ahead the last few years..A bit better metalurgy->lighter parts->more safe revs and slightly better combustion chamber design..

When I look at the dynosheets you referenced at hondata, those seem reasonable. Around 240crank hp with headwork, exhaust and cams+tune..

The other link is just crazy...would love for it to be true though...
more power then a subaru impreza STi (european spec), out of the same displacement, but without a turbo...
Thats lightyears ahead of the competition....

[Max_Misawa]

I dont think Fuji is as good as building heads as honda
Cyclinder head design is pretty much where all the power comes from

According to hondata's website they did almost 210 to the wheels with a K20A2 with ITR cams, injen intake, and a cat back exhaust

thats what maybe 220~230 at the crank?

which to me makes 220hp at the crank from a K20A seem just about right, considering the K20A has a higher CR

Max

[NoHachi]

Which dynoplot are you referring to? I can find only plots showing flywheel hp. The toda cammed engine does around 240fwhp (a lot) and the stock 05-RSX with intake manages 200fwhp.

Cylinder head design is nice and all, but anyone who has ever toyed with simulation packages knows that building hp comes mainly from 2 sources..cams and rpm..Head-design helps, but even with ideal heads (0-flow resistance) the gains aren't dramatic. Same goes for the intake and runners, good for 10% extra power when optimal..but not much more..

Also..a cylinder head designed to flow efficiently at 200hp is no good @300,,I think that you need portwork and bigger valves at a minimum.

Only two things will let you get to a 300hp power level..mad cams (300+ minimum) combined with very high (10.000+) rpm. Below 10.000 i think that about 250whp is the absolute limit..But by then you are already into motorcycle territory..dunno what that would mean in terms of reliability.

[Max_Misawa]

The RSX is the K20A2

It is not the same as the K20A (Type R JDM)

150 hp/l dont seem that hard to me
I do have a buddy at hasslegren helping me out
here is a pic of his car



Max

[Speedline]

Let's calculate some 300hp at 9.000rpm on the mentioned Honda engine.

For 300hp at 8.000rpm you need a whopping 265Nm (57Nm or 27% more then standard!) which is almost impossible to reach without extensive tuning of all engine subsystems. At higher rpm the torque figure goes down;

For 300hp or 221kW at 9.000rpm you need 235Nm.

235 x 2 x pi x 150 (rpm in Hz) equals 221.000W or 221kW/ 300hp.

The standard engine delivers 208Nm at 7.500rpm in Euro spec. You need to extract another 27Nm 1.500rpm higher up the power band.

This is not impossible but is difficult and as mentioned is only possible with different camshaft profile (more lift, more overlap), higher compression ratio and perhaps some head and port work including bigger valves. I do not have experience with these kind of Honda engines; I base my opinion on more conventional engines which almost always need the mentioned combination of mods for high specific outputs/ high rpm operation.

These conventional engines which are not equipped with variable valve timing and lift will show a(n enormous) lack of torque down the rev range with the high lift cams due to slow airspeed in the manifolds. Thus with any engine it's probably a better idea to tune the engine in the daily drive powerband. And that's mid range or the rpm band between best torque and best hp.

At 9.000rpm mean piston speed of the 84mm stroke Honda engine is 25.2meters per second which is very very high. With this mean piston speed engine life will be greatly reduced. For endurance racing it's probably a better idea to tune the engine to max out at 8.500rpm for longevity.

I think the 270-280hp at the crank with extensive mods by tuners like Mugen are a more realistic figure. 300hp is not impossible but the cost to build and tune an effective 300hp engine is staggering.

Just my 2 cents.

[Ian.G]

This is becoming a very interesting thread.

I think the crux of the problem is smaller NA engines wont make stupendous power - they are limited by capacity and have to make their power with revs.

For example - look at something like a Suzuki Hayabusa engine - its a 1.3L capacity but it makes nearly 180bhp - and its all done from revving the engine to nearly 12,000rpm.

Lots of revs = lots of cash in order to give the engine the strength it needs to withstand what happens when you push the motor an extra 2000-3000rpm.

From a purely financial point of view building up a 4AGE motor to get to the stock HP output of the Honda K series motor is an expensive job.

This is why I think using a higher capacity engine will get you the power you require without the engine being so wildly tuned.

For the about price of a 220bhp 4AGE engine I can buy a pair of complete Honda F20C engines with transmissions and all.

Right now in the UK the honda K20 series motors actually fetch more money used than the F20 motors because they are extremely popular for use in Lotus elise cars in their std transverse configuration.

Like you say - the power is possible for less expense with the 4AGE engine if you go the forced induction route - dont get me wrong - I really like turbocharged cars - I've had some good fun in them over the years - but I think NA suites the hachi more.

Obviously the issue with using another motor is its never really a straight swap and lots of additional work needs to be done to the rest of the car to support the engine transplant. Hopefully though - if done properly there is no reason why the large capacity engine shouldn't last as long as it would have done in its original car - and I dont see any real reason why you would need to spend more money tuning it as any more will be way beyond the limits of the chassis