Think of the compression as more of safety rather than power, because you really dont get much power from compression. I would rather run 9:1 compression and boost 1 extra pound than 10:1 compression because from that 1 psi of boost you will make more than that 1point of compression will provide. Also the 4g63 motor has low compression for that very same reason so everyone is not blowing their motor left and right, from changing variables. I use to have a turbo honda, and on 9psi 9:1 compression barely more than a stock evo, stock bore I put out 343hp..Now the torque was very crappy because it was a 60-1 on a 1.8liter and of course we know hondas dont produce torque.

 

If you ask any turbo honda guy, they will tell you itr cams do best in a turbo motor. b16 cams are worst of the oem cam profiles. itr/ctr > gsr > b16. I have seen it lots of times on the dyno also.

 

Yes this is true, stock ITR and GSR cams make very very good power on turbo hondas. There are people making over 650whp on them.

 

i'm sure a k seris head will flow more than a f20.
k seris engines are knows to make was more NA power than s2000's. i seen k seris put out 250whp bult all motor on 91 octane
and i seen the 2.4 k seris do 300whp all motor on 91 octane

 

yes, i know that ITR cams are the best stock cams for turbo, i was heading that route before i got the Evo. but FullRace came out with there own turbo cams with custom specs and they mention that it requires at least 100+ lb seat pressure on the valves which probably means that these cams have a very high lift and or aggressive ramp angle. FullRace tested their turbo cams and showed that it can yield up to 100 whp over the ITR cams.

here's the link about FullRace turbo cams - http://honda-tech.com/zerothread?id=1567097

 

I am well aware of k series capabilities, but I have definetly got to see 300hp on 91 octane considering they are running high compression probably 12:5:1 to get that hp and I do not think 91 octance is sufficient enough for that compression, but if you could prove me wrong I would love to see it. But K series are very strong motors, on stock compression I seen one actually put out almost 700 like 690hp on a gt35, completely stock motor never opened also using a xs power intercooler lol. The only downfall is the rod bearing journals which are very small, which could cause problems at high reving.

 

that might be true for oem cams... but aftermarket i'm sure there something better... just like those full-race cams

 

690whp on a stock K series motor, 550whp on a stock Evo motor, 590whp on a stock STi motor. It's all in the tune and how much you're willing to push the motor.

 

I think that the head design of honda is far more superior than mitsu..
ppl also say that aluminum block is no good and cant sustain much boost but again honda k series is an example.
And ppl are also criticizing the block of Evo 10 for being a Aluminum block.
Lets hope for the besT!

 

Honda-tech.com 4 life!

 

Internet Myth...

A given engine can ingest only so much air period. Installing a turbo with more potential flow will not generate more power at the same boost pressure unless... UNLESS... by installing the larger turbo you also reduce back pressure (better flowing turbine side) hence improving its ability to ingest more air, i.e. VE. A larger turbo may also be more efficient at a given PR and provide more power since the charge is cooler but not by much unless you are comparing a GT3076R to a T3-60 or something. A real mismatch. A better comparo would be a GT3071R to a GT35R or similar.

All things equal a larger turbo does NOT make more power at a lower boost level.

Here is why...

Pressure is just resitance to flow. 10 psi out of a 50 gallon tank with 50psi is the same as 10psi out of a 100 gallon tank with 100psi. The larger tank with higher pressure has more potential but if the engine cannot process that potential what is the difference? None.

The ONLY way to get more power at a lower boost pressure is to improve on the engines ability to breathe, or it's Volumetric Efficiency by reducing the resitance to flow. This can be accomplished by improving the flow before the head (intake), at the head (porting, cams, valves) or after the head (manifold, turbine, exhaust).

Honda heads flow more than the Mitsubishi heads is the simple answer to this question. For all those VTEC haters out there... remember MIVEC is Mitsu's version of VTEC. Too bad more Hondas aren't RWD or AWD. All that power and no way to get it to the ground... The Nissan SR20DET head flows well too, not as good as the Honda though and the Suby heads cannot compete with any of them.

 

<- member since 1998.

 

The K motor is interesting because the steel main caps are cast into the aluminum block. Also, the K block is build like a top fuel motor with the bottom half of the block seperating to hold the crank.

 

Think in terms of compressor efficiency. A more efficient compressor will pack more air molecules into a given space. Same reason why the car makes more power on a cold day as cold air is more dense.

 

cry me a river