Let me start off by saying I love the S1's, the way they felt, the way my car idled, how smooth the power curve was.... but wow, is all i can say. I recently swapped out the S1's for the Cosi 272's for my IX. Just off of my butt dyno, it seemed as though the cams pulled a little bit more up top than my S1's, and looking at my dyno today, my butt is pretty accurate. Spool up seemed a little bit better with the cosi's but boy my butt was wrong on that one. I will definitely say just cruising around feels tons better than the S1's as well. The car seems to be a lot more controlled and smoother. The idle is definitely a lot better with the S1's, i will give them that.... but all i can say is, look below. You can see the boost, and the tune was not adjusted from the S1's to the Cosi's.... My S1's were about a week of tuning, and the cosi's were just tossed on and ran... so obviously the difference could be more

Solid - cosi's
Dotted - S1's



If you guys have any questions, feel free to ask. Maybe the S1's are better for the stock turbo, but with the mods in my sig, id have to give them a big

they look like they do a lot better than the s1 cams

Looks like the cosi were making more power all the way through.

i dont think so.... the solid is the cosi's ... just looking at the spool do you realize im hitting full boost at about 3300 rpm as opposed to 42 or 43 ? .... that is ridiculous. If you look at the first part of the curve the cosi's gave me about 130 more tq than the s1's..... my 20G9-5 spools like stock instead of like a 50 trim

i figured this thread would have had a lot of people chiming in by now

weird...i hit full boost in my S1's at around 3400rpm...
and my car keeps pulling harder and harder..
i cant comment on the cossies since i havent had first hand experience with them...

but i truely love the way the S1's perform in my car in every aspect.

im on a 20G

but i agree as far as the s1's go, they kept pulling hard once i spooled.

ooh...i am running a stock turbo at around 23psi...btw

this is a 20G at 23 psi, well, 21 creeping to 23, and i went from spooking like **** to stock again

I would expect the cosi to outperform the s1 since they have way more effective duration @1mm on the intake side than the s1. I also have cosi's and made the switch from gsc.

im doin the cosi's next sat so ill def post a b4 and after chart

That's true and that what i have been saying all along...

the specs speak for themselves... Only the S2s could compare with the cossies...

So glad i got the cossies from the first time...

i've seen great results with both, i think my 20G is why the S1's didnt do so well.... but either way, as cam reviews go, this is as close as i could make it to even as i could.

anyhow...maybe cossies make better friends with bigger than stock turbos...

the s1's were intended for the stock turbo in the first place

i agree that maybe that is the reason why... ive seen the cosi's on stock turbos though as well, and they work there as well..... but im definitely not disputing that the S1's dont make power on stock turbos, seen enough posts which is why i bought them in the first place, just didnt think they'd fall on their face with the 20G being a smaller turbo