Compression ratio 12.5:1. Bye-bye Super charger & Turbo build?

[GotBoost?]

Granted I have never swapped cams out in a 4cyl (only done it on an LS1) but depending on how aggressive you go on an LS1 you can see 20-60HP gains easily. So you will have to excuse me if I don't understand how you can only expect a 15hp gain from cam's and an exhaust.

Also a quick google search tells me that in a 2.5RS with an aggressive cam you can see an increase of around 50whp in a bolt on car. Throw in some heads with that and your looking at around 80whp.

Your also not even considering tuning the motor.

[coyote]

Originally Posted by Kostamojen

Won't happen.

Correct

[serialk11r]

Originally Posted by GotBoost?

Granted I have never swapped cams out in a 4cyl (only done it on an LS1) but depending on how aggressive you go on an LS1 you can see 20-60HP gains easily. So you will have to excuse me if I don't understand how you can only expect a 15hp gain from cam's and an exhaust.

Also a quick google search tells me that in a 2.5RS with an aggressive cam you can see an increase of around 50whp in a bolt on car. Throw in some heads with that and your looking at around 80whp.

Your also not even considering tuning the motor.

LS1 has 3 times the displacement, divide 60 by 3 and you are in the ballpark I mentioned. I don't think you add it up that way, in the 2.5RS example ( I may be wrong...). To be able to use the aggressive cams you need to be able to flow enough air anyways. Very aggressive cams can also hurt fuel economy, low speed performance, idle, etc. pretty bad.

[Allch Chcar]

Originally Posted by GotBoost?

Granted I have never swapped cams out in a 4cyl (only done it on an LS1) but depending on how aggressive you go on an LS1 you can see 20-60HP gains easily. So you will have to excuse me if I don't understand how you can only expect a 15hp gain from cam's and an exhaust.

Also a quick google search tells me that in a 2.5RS with an aggressive cam you can see an increase of around 50whp in a bolt on car. Throw in some heads with that and your looking at around 80whp.

Your also not even considering tuning the motor.

A 4 banger with room to rev stock has more potential. VVT makes a bigger difference since they are already low on torque and gearing makes a big difference in actual performance.

I would go with what the pros are saying on N/A vs FI, anything past boltons and FI makes far more sense per dollar.

[Jordo!]

Originally Posted by Ryephile

12.5:1 static CR with good DI is not a real problem if you want light boost. A quick calculation tells me that with 93 octane, 10PSIg boost would be plausible for a tuned-to-the-edge-but-still-reliable setup, assuming IAT's are kept rational and the knock control as as good as anything from the past 10 model years.

That said, just because the combustion chamber might be able to handle the BMEP, doesn't meant the piston lands, wrist pins, con-rods, crank, bearings, block, head gasket, or cylinder head can handle the increase in BMEP. There is always a fuse, a weak-link, and it'll take testing, measurement, and trial-and-error to determine what's the weak links are to reliably achieve the power level you're interested in.

Since most tuners have minimal real experience with DI tuning, there will either be an influx of amateur engineering experiments flooding the market, or there will be a slow ramp-up by competent tuners that take the time to do things right [which is rare, especially with an affordable car]. By all means, buyer beware!

Well said, and spot on.

And exactly why I am hoping TRD offers a plug and play option sooner than later.

Instead we get three sets of wheel options.

Sigh.

[GotBoost?]

Originally Posted by Allch Chcar

A 4 banger with room to rev stock has more potential. VVT makes a bigger difference since they are already low on torque and gearing makes a big difference in actual performance.

I would go with what the pros are saying on N/A vs FI, anything past boltons and FI makes far more sense per dollar.

The only real question is what can the engine handle.

[Kostamojen]

Originally Posted by GotBoost?

Granted it depends on the block and internals, but it is entirely possible. Throw a really aggressive heads/cam set up on it, plus your headers,intake manifold, throttle body, and other basic bolt on's. I fail to see why you think that its not possible to milk another 60-80 hp out of it.

I'm pretty confident that its a very conservatively tuned motor like most factory production cars.

I've also seen far more aggressive power gains from NA motors, for instance a 99 Formula with a heads/cam/intake/headers pushing 440 whp (305 is stock at crank).

Why do you find it unreasonable to put 280 out of a FR-S / BRZ

This is a strung out Subaru motor. The highest power EVER from a normally aspirated 4-cylinder Subaru motor from the factory.

People have tried, and failed, to get to 250+ N/A power with previous N/A Subaru 4-cylinders. The only one I've ever seen was a completely redesigned block on a pure race car in Japan that got 280ps, but probably cost $30,000 just to design and build.

Can you get another 20hp with this motor? Probably pretty easily with bolt ons (intake/exhaust) and a tune. 30hp? Maybe with better fuel. Cams? Probably not more than 5-10hp more. More compression? Maybe another 10-15. Slightly more displacement? Couple more. Custom fancy intake parts that don't exist yet? No idea.

Unless that DI is capable of some serious magic, I don't see any way right now to get 50-60hp MORE out of this motor.

[coyote]

FB25 block is the only way you'll get near 280hp NA.

May as well go with a 400hp unstressed EJ.

[Allch Chcar]

Originally Posted by Kostamojen

This is a strung out Subaru motor. The highest power EVER from a normally aspirated 4-cylinder Subaru motor from the factory.

People have tried, and failed, to get to 250+ N/A power with previous N/A Subaru 4-cylinders. The only one I've ever seen was a completely redesigned block on a pure race car in Japan that got 280ps, but probably cost $30,000 just to design and build.

Can you get another 20hp with this motor? Probably pretty easily with bolt ons (intake/exhaust) and a tune. 30hp? Maybe with better fuel. Cams? Probably not more than 5-10hp more. More compression? Maybe another 10-15. Slightly more displacement? Couple more. Custom fancy intake parts that don't exist yet? No idea.

Unless that DI is capable of some serious magic, I don't see any way right now to get 50-60hp MORE out of this motor.

I'm trying to find the 300HP EJ25 I read about on NASIOC. It had maybe $10k in work, which is par for a N/A build.

[Kostamojen]

Nobody has done 300hp, lots of people have talked about it and nobody has been anywhere close.

Is this the thread you were looking for?

forums.nasioc.com/forums/showthread.php?t=125165

This is the car I mentioned with the nutty build for a racecar in Japan:

[Allch Chcar]

Originally Posted by Kostamojen

Nobody has done 300hp, lots of people have talked about it and nobody has been anywhere close.

Is this the thread you were looking for?

forums.nasioc.com/forums/showthread.php?t=125165

This is the car I mentioned with the nutty build for a racecar in Japan:

290PS, still very respectable for a N/A EJ20. And plenty past what the other guys are talking about. It is possible with the displacement. Honda K20 guys do it, and Mazda MZR 2.0L have done 300HP. And this engine starts at 200PS @ 7000RPM, stock.

Stock engines are usually heavily choked. It doesn't matter that it is the highest N/A output, they have to meet strict emissions and there is always room for improvement. The question remains how much. But I am optimistic that there is room just in a 93 octane tune.

[Buggy51]

I'm just looking at this: http://www.drivingsports.com/site/20...v-first-drive/

and they said Mazda changed the compression ratio for the US? Think that'll happen?

[Kostamojen]

Originally Posted by Allch Chcar

290PS, still very respectable for a N/A EJ20. And plenty past what the other guys are talking about. It is possible with the displacement. Honda K20 guys do it, and Mazda MZR 2.0L have done 300HP. And this engine starts at 200PS @ 7000RPM, stock.

I had a photo of that engine a long time ago, I think it was in a tuner mag from Japan circa '99 or '00...

It doesn't resemble the original motor at all. Custom built from scratch heads, ITB's, extra injectors all over the place, carbon fiber intake ducts, the works...

Its VERY respectable, but replicating that motor is not possible unless you can find the original one, and certainly not possible to replicate those numbers with a stock block or even a modified stock block.

[Kostamojen]

Originally Posted by Buggy51

I'm just looking at this: http://www.drivingsports.com/site/20...v-first-drive/

and they said Mazda changed the compression ratio for the US? Think that'll happen?

12.5 should be fine for the U.S., but remember we have crappy gas quality compared to the rest of the world so they might have to de-tune it slightly for us (although I'm fairly certain they designed this as a "World Car").