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[jamiemirror]

banpei Wrote:So, actually people are tuning the 4AC actively
You must understand that 98 percent of the hachis in Europe are equipped with a 4AGE, so we have little knowledge of what those engines are capabele of. Most of us are biased ofcourse.

Which hachi are you talking about? The one you used to own, or the new one?

Once in Club4AG I read about one tuned 4AC SR5 hachi - with up to 170hp@crank. Maybe owner use some 4AGE internals, 11+CR, cam + carbies - I won't really know, he wrote aomethink about hi-CR and Paradise Racing power kit for 4AC. He wrote that he turned 18.5 sec car to 15.8 sec one :-)

[banpei]

Impressive

[jamiemirror]

But banpei, if your goal is 170hp from 1.6 displacement - you can achieve it with SOHC 8V also - the DOHC 16V is not requirement. You can obtain very hight VE values even for such SOHC head with extensive P&P job, big valves, good cam etc. Stock 4AC is weak over 4500 RPM due to poor head/intake/exhaust header design but all these can be improved. I don't know exactly are 4AC internals good for continuos 6000+RPM or not (mine was "tested" over 7000RPM and survived, 100% stock engine).
4AC suffer also from low CR (~9).
PS: This is not easy modification and definitely is more expensive than 4AGE engine swap (at least in Bulgaria).

[banpei]

jamiemirror Wrote:But banpei, if your goal is 170hp from 1.6 displacement - you can achieve it with SOHC 8V also - the DOHC 16V is not requirement. You can obtain very hight VE values even for such SOHC head with extensive P&P job, big valves, good cam etc. Stock 4AC is weak over 4500 RPM due to poor head/intake/exhaust header design but all these can be improved. I don't know exactly are 4AC internals good for continuos 6000+RPM or not (mine was "tested" over 7000RPM and survived, 100% stock engine).
4AC suffer also from low CR (~9).
PS: This is not easy modification and definitely is more expensive than 4AGE engine swap (at least in Bulgaria).

I already knew you could achieve it with a 4AC, but with a 16v head it's easier.

[jamiemirror]

Oh no, I personaly never tried to achieve 170 hp from 4A engine
It's too early for me, I'm focused on mild modifications.

[Wraith]

Yes the 4AC is just a sohc extremly restrictive 4AGE. The 4AGE is the free flowing head while the 4AC is a block of little holes. With a larger carb alone I've seen dyno gains of 12-16 (16 after fuel/air mix was down) whp. This is on a average size aftermarket progressive webber carb. I'm still trying to learn more about Megasquirt and other standalone systems to run a engine. I think it would be cool to have a ITB 4AC done right. I'll post some pics of the coupe.