Will this Ex. Manifold work for me?
 

I have a 2010 LT 2.2 LAP and I was wondering if anyone knew if an exhaust manifold from a 2006 HHR 2.4 LE5 would bolt on to my car. I've been reading that it is the same as the LSJ manifold, but I'm just unsure as it's from an HHR in '06. Also, would the downpipe be the same? I have a leak and figure it's time to upgrade. I want to go with an LSJ/LE5 header and downpipe and then a 2.5'' ZZP catback after that. Thoughts?

Thanks,

the 2.4/lsj manifold will bolt up without issues as long as your car doesnt have secondary air injection (some 2.2l did, not sure if the lap ever had it though)

that being said, you really wont gain much swapping one exhaust manifold for the next, i doubt it would even be detectable. a mid length or better yet, a long tube header will give you a better increase in power.

iirc there is a different in the auto and manual. I could be wrong but I could of sworn there was a difference

I want to swap for the 2.4 mani and the downpipe and then go with a ZZP catback. I have read that the 2.4 mani and downpipe allow for more airflow than the stock 2.2. Am I wrong in this assumption?

Source? So that I don't buy something I don't need. Thank you

no you are correct, the 2.4l/lsj manifold does flow a little better than the 2.2l manifold, however its not going to give a measurable difference in power

Indeed, but if I left my stock 2.2 mani and downpipe on, while installing the 2.5'' ZZP catback, wouldn't they serve as a bottleneck, whereas the 2.4 wouldn't? I know a simple swap wouldn't net gains, but the mani, downpipe and catback surely would. No? You clearly know what you're talkin about, so I'm interested in what you have to say. Thanks again

The difference between manual and auto is the downpipe. The exhaust manifolds are interchangable.

​​​​​​​source: installed an LSJ exhaust manifold on a 2.2 cobalt sedan auto. Fits like stock. Downpipe has a different bend and will not fit without modifying it and not really worth it.

If you're still naturally aspirated I don't think the 2.2 exhaust mani is really restrictive at all. The cat-back will help a little as our stock exhaust is pretty small but again nothing you can really feel.

I'm guessing your leak is in your flex section of your downpipe? I would just leave the stock ex. manifold on and install a bigger downpipe. With how pricey a good cat-back system is I would only get that if that is what you want it for sound as it's hp/cost ratio is not very good.