If the LSJ is the same size as a rounded out 2.2L D opening it's a TAD less than 2 inches.

 

The 2.0 manifold and the 2.4 manifold are the same.
I just measured mine and it's slightly less than 1 3/4" at its most restrictive part.
Plus, the o2 sensor protrudes into the airflow at the narrowest point, further blocking the flow!

 

yep yep. The LSJ at the flange is 2.25" and the GMPP one I have is almost 2.50" at the flange. It does neck down, but without getting into venturi principals, fluid speeds and manifold pressures the measured exit area is still larger than 2.0".

Maybe it's negligible all things being equal, but I would not expect it to perform any better than the GMPP extrude Hone manifold.

 

I understand the basics of the venturi theory and the necking down increases gas velocity and moves more gas..

I am really torn, if I install it and test it out there is NO way I can try to return it.

I could probably expand the opening to 2.25 inches, but I would grind off the coating and probably compromise the heat protection.

 

If it were me, I would get one with a larger collector. 2.5" minimum. JMO.

 

I know but I got the thing sitting here!

Thanx for the measurements skykapp!

 

Can't return it? Or sell it in the 2.2 section? You may just end up wishing you never put it on.

 

I think it would be **** for a 2.4 too. If I didn't have my CA header I would offer to buy it off you.

The "Great Pyramid" of the collector looks super for mid-range extraction for us n/a guys - a lot smoother flowing than my CA header for sure. True, I have a 2 1/4" collector and 1.7" primaries, but I'd bet on a real engine (not a flow bench) they would perform very similarly. For a stock SC with a stock downpipe and exhaust, it would probably give great gains throughout the entire rpm range - at least in theory. I'd think you would get a little better gains than from a GMPP manifold. It looks a little small for a modded 2.0 though.

I'd love to see a mag do a header dyno shootout on the SC. It would put an end to the controversy once and for all.

 

yeah i would just be skeptical of the 2 inch collector i know zzp header is 2.89 which is what i was looking for when i got mine , good luck with the header it looks like it has good craftsmanship

 

Well I took my header off and compared the two. I returned the DC header, it's just not designed for the LSJ. It's the same size or smaller.

 

Good call.

So which header are you looking at now?

 

Yes, It's worth it - just not for your car. If they won't take it back, some 2.2 guy will love it.

 

I actually installed the header and I did notice a increase in power and the engine feels stronger. I recommend it!

 

I have bought most of my stuff from P-Tuning.

Mike at P-Tuning told me he didn't have much faith in the DC Sports Header... so I dunno what to say....

I bought my B&M shifter, Magnaflow 2.5inch Cat Back, Progress Technology Springs, and DC Sports Front Tower Strut bar off those guys and they have yet to steer me wrong, so I am going to take his word for it.

I would be interested in seeing the numbers from that header though.

I am kinda in the same boat... trying to pick the best header and downpipe combo to compliment my 2.5in Magnaflow Catback, so if anyone has any ideas, I am open to suggestion. I am at a bit of a standstill though because I don't know if I want to carry on and upgrade the supercharger, or jump into the Twincharged application.

Makes me wanna pull out my hair...

 

Cool. Glad it worked out for you. With such small primaries and collector, I'm sure it has insane low and mid-range torque due to it's abilities to extract air at high velocity, especially with your 2.5" dia. pipe. Most of the time you operate your car is in the low-mid range, so it sounds like a very practical header for a daily driver.

What I was concerned about is it's ability to flow enough air for peak hp on your modded 2.0. Have you had it dyno'd before and after, run it in the 1/4 before and after or have any other measurements as a basis for your seat of the pants opinion?

Sometimes a small power increase, (especially a broad one that comes on low) can seem like a larger one. I thought that my e-rams produced much more power than they do, because they come on all at once and pull throught the rpm range. But after having it dyno'd with and without, I only observed a 6hp increase (5ft/lbs torque) from the e-rams. True, it's all across the rpm range, so I have a lot more area under the curve, but the point is that the seat of the pants feel is deceptive as far as actual hard numbers gained.

I think your header may be coming on like gang busters down low, but is probably tapering off to near stock hp numbers up-top. Still, you probably have a lot more area under the curve, so it's useful, streetable power.

 

Too bad it didn't work out. This was the best looking header i've seen yet, just too small. The collector looked A+.

 

Definately a high-quality looking piece. Too bad it wasn't larger.

 

So overall due to the small primaries and collector I should get rid of it and get something like the ZZP header something larger. I do plan after a new clutch going to a 2.6" pulley and #60 injectors and some other minor things...

 

nice

 

any ideas if this works on the 2006 models?

 

It should, I believe all the ecotec exhaust headers are the same dimensions.