Normally Im not one to make threads regarding the horse power gains of intakes, because 9 times out of 10 on a 4 cylinder motor, the gains are minimal at best. However I was kinda surprised by the claims that K&N was boasting with their intakes when I first started looking at performance mods a while back. Now typically K&N is usually pretty accurate with their estimates, and ive never really seen any "over the top" assertions with any of their ads. However some of these numbers puzzled me, and I was curious if anyone has ever had the pleasure of dynoing the difference between stock, and an intake, any intake for that matter.

2005 CHEVROLET Cobalt 2.0L SUPERCHARGED - 8.12 HP @ 5829 RPM
2005 CHEVROLET Cobalt 2.2L NA - 6.6 HP @ 4800 RPM
2006 CHEVROLET Cobalt 2.4L NA - 15.94 HP @ 5900 RPM
2010 CHEVROLET Cobalt 2.0L TURBO - 12.22 HP @ 4600 RPM

Now here's what gets me. Out of all of these figures you would think the LNF would be the one to gain the most with just an intake. You figure, turbo setup, stands to reason that allowing the turbo to breath better, shows the most gains on any car. Especially over a NA car. But the 2.4 NA with VVT showed the highest gain of almost 16hp, which is needless to say, crazy. However throughout all my research (through HPtuners forums and other various forums) unusually large gains from mods like tuning, header, and intake seem to be pretty common.

Does it stand to reason to say that the 2.4 was perhaps dumbed down a significant amount to bridge the gap between the 2.2 base and the 2.0 supercharged models given the fact that all 3 were available as options during the model years they were produced? Logic dictates that the 2.4 is a better platform then the 2.0 or 2.2 merely from the fact that the bore and stroke and variable valve timing are capable of producing more power in the same package when looking at it from a performance stand point. I was just kinda surprised by the figures, and it left me wondering if anyone has ever had some real facts to back it up.

 

the gains are based (if accurately tested) on how restrictive the car was from the factory, not what its got in it so much. NA cars were not designed to be marketed as fast street cars for a competetive edge, they were the lesser performance of the available models.

That basically means the manufacturer already put in a more efficient intake to begin with, so anything aftermarket will have a more minmal impact on performance.

You can polish a turd to look like a diamond, or you can polish a diamond to look like a diamond, which will have a bigger gap in aesthetic gain? lol

 

^very nice anecdote!

i dont think ive seen any actual dyno's but i've heard of ss/scs gaining about 10-12 hp from just an intake... as always, many variables involved, sch as conditions during the before and after dyno, and how much tuning was involved...

 

There's a YouTube on video of a 2.4 being dynod with just an exhaust and k&n intake and it dynod 171whp 166tq

 

Yes, there have been just intake dynos done.

Back in the day, that was everyones first mod before the stage kits came out.

Average gains on the LSJ are between 7-10 whp.

I can't speak for the NA cars though....

 

my 05 ss with a zzp 3" intake and a 3" uncatted dp made 236whp. it's a factory freak. no tune or nothing