Red07SSNA

There's been some misinformation about the LE5 and LSJ DP/Cat sizes lately. I'm in the middle of trying to install an LSJ DP/Cat in my 2.4L auto. First, the overall length of LSJ DP is shorter than the LE5 auto DP by about 1 1/4". Second, the cat/conv on the LSJ DP is about 60% larger so the flow increase should be about the same.

Pipe diameter:
LSJ: 2 3/4" BUT it is crimped down to 2 1/8" ID at the ends.
LE5 Auto: 2" OD and it is slightly enlarged at the ends to fit the connectors

My DPs are at Mad Hatter Muffler right now -- getting 1 1/4" pipe added between the Manifold mount and the Cat to try and get it to fit in my SS/NA.

https://www.cobaltss.net/gallery/fil..._vs_le5_dp.jpg



https://www.cobaltss.net/gallery/fil...s_le5_dp_2.jpg



I don't know what the DP size is on the LE5 manual. It appears that the 2.0SC LSJ engine is positioned about 1" back OR the LE5 is positioned about 1" forward -- possibly to align the tranny axles and this is the reason the LSJ DP is shorter. Appears the LSJ DP fits the LE5 manual equipped engine -- BUT I haven't confirmed that yet. Anybody that has please post pics of install because the LSJ does not fit the LE5 auto. (CED has measured another new LSJ DP and came up with the same measurements).

As is the LSJ is too short and this causes the Cat to rest on the sway bar:
https://www.cobaltss.net/gallery/fil...1/lsj_dp_4.jpg




Here's a clearer shot of how short the LSJ DP is than the LE5 auto DP -- also notice that the first bend on the LSJ DP is near the manifold connector while the first bend is near the Cat on the LE5 DP:
https://www.cobaltss.net/gallery/fil...s_le5_dp_3.jpg



And again, because the LSJ DP is shorter it is causing the cat-back exhaust to be pulled forward and is up against the car body:
https://www.cobaltss.net/gallery/fil...1/lsj_dp_3.jpg




More to come as I get deeper into Sh....this.

LS6Rally

iTrader: (14)

nice thread. wish i could help with the Manual part of it. maybe someday.....

HunterKiller89

iTrader: (1)

in all of the automatic tranny cobalts (be them 2.2 or 2.4), the transmission forces the engine to be rotated forward slightly. This gives less clearance between the IM and the front of the car, and extra clearance between the exhaust side and the firewall. The exhausts will still bolt up, as the catback can be pulled slightly closer to the engine because of the way its hanging. This is why all exhaust components on the same engine have the same part number, regardless of whether or not it has a 5sp or 4sp.

Unfortunately, this issue means i dont have enough clearance to run any pulley larger than a 3", and an aftermarket LSJ intake wont fit on my car, because none of the LSJ parts were made to fit on an automatic equipped ecotec.

pat_07ss

i have it installed on my standard 2.4 and had no problem with it

and my exhaust isn't touching anywhere neither.... weird

the only thing I might want to check is the contact point with the sway bar, I'll check that in the spring

Red07SSNA

I've gotten that from other manual owners as well. Appears the auto is a different animal...

I picked up the DP after Mad Hatter added 1 2/5" to the pipe between the manifold connection and the Cat/conv. The Cat-back exhaust now bolts up but the converter is still too close to the sway bar -- within an 1/8". I'm going to have to let the Mad Hatter exhaust Guru cut the pipe out and insert a better bend to lift the converter away from the sway bar.

I did take her out for a drive around midnight last night -- the best part is no CEL. Performance wise it is a worthwhile add. Passing power is greatly increased and part throttle acceleration is VERY nice for an NA 4 banger!

Companies that make DPs should take note of the auto differences -- I have read some threads about people buying DPs and they didn't fit -- probably the reason for the problem, not a manufacturer defect.

All the Cobalt exhaust components do not have the same part numbers...I've found from experience now that the manifolds are interchangable and of course, the cat-backs exhausts are interchangeable, but the DPs have different PN's between the Cobalt models and transmissions options.

Downpipe/cat assy:

07 LSJ PN 15873413
07 LE5 PN 22695582 (manual trans)
07 LE5 PN 22703215 (auto trans)

08 LNF PN 25816005
08 LE5 PN 15889903 (manual trans)
08 LE5 PN 15889904 (auto trans)

pat_07ss

**** that's quite good to know, nice thread

I took mine out for a drive just after installing the DP and it changed the sound too at WOT

Brandon97Z

iTrader: (1)

Yup i have an LSJ dp on my 2.4 manual.

rockstar014

hmm interesting

HunterKiller89

iTrader: (1)

hmm.... thats really odd. i understand different years having diff numbers, and different engines of course, but it was my understanding that a 08 LE5 manual exhaust was the same part # as a 08 LE5 auto exhaust... guess i was wrong. Regardless, all the aftermarket ones are interchangeable, so the differences are negligible. Like i said, the auto trans just rotates the engine forward a little, but the exhaust hangers allow enough movement to make everything fit.

Red07SSNA

As a side note...any 2.4L auto owners that are interested in the LSJ DP -- buy some 2 3/4" steel pipe when you get the LSJ DP! It is hard to find. I was hoping to get this finished this weekend but Mad Hatter won't be able to get any 2 3/4" pipe in until next week. I called all the exhaust shops and Parts houses in town and no one carries 2 3/4" pipe either!!!

Red07SSNA

Update for those interested in the LSJ DP/Cat in an auto 2.4L Cobalt/G5. I haven't been able to measure the difference in engine positions between the manual and auto equipped 2.4L Cobalts/G5s -- the LSJ DP is not an easy install on the auto equipped cars (appears the manual equipped cars don't have this problem). Mad Hatter had to cut my LSJ DP apart and install new 2 3/4 inch pipe to get it to fit. The LSJ DP is shorter than the auto 2.4L DP so that was part of the problem. It appears the engine may also sit lower because the Cat was resting on the sway bar each time they tried to fix it -- ended up cuting it apart to get the top pipe bend right (the part from the exh mount to the Cat). The neat thing is that they cut off the end of my LSJ DP where it is crimped down to 2 1/8" and made it flush with my RT 2 3/4" cat-back exhaust.

The flow certainly is greater through the LSJ DP/Cat since the cat is about 60% larger then the Auto 2.4L Cat. I haven't had a CEL pop up -- at this point I don't think it will. I will be running a diagnostic on it soon and checking the HO2S-2 readings to see if they are within the factory specs.

Red07SSNA

Just finished viewing the diagnostics on my 07 Cobalt 2.4L:

Factory Data Values for the HO2S-2 sensor are supposed to be 10-1,000mV

My scanner recorded 155-860 (363 avg at idle). This indicates that I should not see any CELs from the LSJ DP/Cat. If you have the capability of tuning the HO2S-2 sensor then you have the ability to go with a freer flowing Cat. If not, then the LSJ DP/Cat is a way of freeing up your exahust on a 2.4L or 2.2L without getting CELs. Just remember that the manual equipped Cobalts appear to be able to just "stick" the LSJ DP in...but the auto equipped Cobalts don't appear to be able to just "stick" the LSJ DP in without reworking the piping to get it to fit.

krenfro88

off topic, where do you live? we have a mad hatter here, but its the only one ive ever heard of.

Dave7417

Excellent thread!

Thank you for your input.

Dave P.

Red07SSNA

Thanks.

I have also discovered that the engine mount is different between the auto cars and the manual cars. While the tranny mounts are different between the transmissions, it is obviously due to the different design/shape of the trannies, however, if the engine was in the same position then it would make sense that the engine mount should be the same -- it is not:

2.2, 2.4, 2.0 manual equipped engine mount: (orange) PN 15256690 (PNs are from 07 GM parts book)

2.2, 2.4 auto equipped engine mount: (blue) PN 15256691

Dragin'Don

So were do you get these down pipes?

scottyguy401

I have the lsj downpipe on my car, and it fits. The only thing is the cat is really close to the sway bar, almost resting on it

Red07SSNA

Yours a stick or auto...and did you have a custom exhaust put on it?

scottyguy401

I have an 07 auto. Completely stock exhaust, other than the dp being switched out

Red07SSNA

...things that make you go Hmmmmm.......

https://www.cobaltss.net/forums/2-2l-l61-performance-tech-45/slight-difference-dp-168968/

395 plus

iTrader: (1)

If I had know you had this too but I wasnt looking in the 2.4L section. So is our only choice to hack the LSJ DP or does anyone make a DP to fit? besides a header/DP combo.

Red07SSNA

I have read 2.2 post where they bought an aftermarket DP for their auto equipped Cobalt and had to take it to get "adjusted".

Best to get it altered at an exhaust shop if you already have it...if you resell make sure you address this

395 plus

iTrader: (1)

Yes wish I had this info a few weeks back???? I am going to talk to Dan at Clearimage and see if they can make a DP for it?

scottyguy401

Thinking back on the install i remember now that there was a gap between the end of the downpipe and the rest of the exhaust. But I just pulled them together and bolted it in and it was fine. Idk about you guys but I was able to pull the back part of the exhuast forward that extra 1 1/4 in

Red07SSNA

When I pulled my cat-back forward to bolt to the LSJ DP it caused the pipe to rest against the body. I wanted everything to fit like "factory" so I had my DP lengthened and welded in a way that it is away from the sway bar and it does not hang low enough to hit a speed bump.