LZ4 vs. LX9

[jwevans1024]

Hello, I am new to this forum and I needed some guidance as to what would be my best engine option. I am a 10 year (former) General Motors master technician (no BS I swear) so feel free to get as intricate in your descriptions as possible. I have an idea for a relatively fast and easy to assemble daily driver. My plan was to take an LZ4 3.5 liter V6 and 4T45E automatic transmission and drop it in to an 07-08 Chevy Cobalt automatic. I Chose this because from what I've seen, the mounting points on all 4T45E transaxles are the same and I would not need to change drive shafts. I know I'd need the V6 trans because the bell housings are different. As for the engine fitting, I'll worry about that later. I know the epsilon chassis uses a different front engine mount than the delta car, however the 2008-09 Vue XE AWD has an LZ4 with a torque axis mount that bolts to the vehicle the same way a Cobalt does. The body control system on the Cobalt is pretty much identical to the Epsilon (the BCM and the other body modules have the same part numbers in the GM parts catalog) and if I get a Cobalt 2.4 liter, even the ECM is the same part number, I'd just need the 3.5L programming and engine harness. At any rate, my question is would I be better off performance wise using an LX9 or an LZ4? I know they make headers for the LX9, however I'm using the G6 GT's 4T45 trans with the 3.25 final drive instead of the G6 V6, Aura XE with the 3.09 final. According to everything I've read, a G6 GT with an LX9 is just as fast as an Aura XE with an LZ4 (the G6 has the better final drive and it's just as fast). Just wondering if anyone is using these headers and seeing any significant gains on the LX9? I know it won't just be plug and play and wiring will need to be matched up, but no one has done this and I think it would be cool. I thought about a 3.6, but it's way more fabricating than I'd like (no delta car has ever used a 6 speed auto, and the mounts are VERY different VS the epsilon). Any info would be greatly appreciated, thanks!

[ericjon262]

well, my understanding is that the LZ4 has better heads out of the box, but, if I were to consider an LZ4 swap, I would skip to an LZ9, the added displacement will be worth it, and the swap would be about the same amount of work.

That being said, I am in the middle of a LX9 swap, but mine is in a Fiero, not a cobalt. the LX9 is a much simpler engine, thus easier to swap around.

[jwevans1024]

I considered an LZ9, but the G6 GTP uses a 4T65E tranny. The mounting points are totally different and the drive shafts aren't the same. The only thing that stopped me with the LX9 is there is no application for that engine that uses a torque axis engine mount and nothing for the 3400 and 3100 are even remotely close to what a Cobalt has. At least the LZ4 in the Vue uses a mount that bolts in identically to the Cobalt and the 4T45E that the 3.5 uses has the same mounting holes on the case that the 4 cyl. does. I'm just looking for as little fabrication as possible. That torque axis mount thing didn't occur to me until after I posted the thread.

[ericjon262]

well, I would consider swapping the 65E, they are much stronger than the 45e and have a larger aftermarket. or, you could swap an F23 5 speed...

[jwevans1024]

I considered the F23. I would have to swap the bell housing from a Getrag 282 but it would work well. The only issue is, as a daily driver I want it auto. I know the 45E is weak, it's already maxed out on the LX9. I had an '07 Saturn Aura 3.5 when I worked at Saturn. When I went on GM's service information website, they said the maximum torque the 45 can handle is 200 ft./lbs., the LZ4 has 220 ft./lbs. I was concerned to say the least. At Chevy I saw two LX9 Malibus that had the planet gears in the final drive completely torn up. I'll have to see what's involved in the 65. Hell, if the cradle in an Epsilon has identical mounting points to the delta cars, I'm just swapping in a 3.6 LY7 with a 6T70! They look aweful close, I just have to measure.

[ericjon262]

I considered the F23. I would have to swap the bell housing from a Getrag 282 but it would work well. The only issue is, as a daily driver I want it auto. I know the 45E is weak, it's already maxed out on the LX9. I had an '07 Saturn Aura 3.5 when I worked at Saturn. When I went on GM's service information website, they said the maximum torque the 45 can handle is 200 ft./lbs., the LZ4 has 220 ft./lbs. I was concerned to say the least. At Chevy I saw two LX9 Malibus that had the planet gears in the final drive completely torn up. I'll have to see what's involved in the 65. Hell, if the cradle in an Epsilon has identical mounting points to the delta cars, I'm just swapping in a 3.6 LY7 with a 6T70! They look aweful close, I just have to measure.

WRONG! 01ish J-bodies witht he iron puke use the F23 with the metric bellhousing!

[ericjon262]

F23 bolted to my LX9

[jwevans1024]

Oh DUH! I completely forgot the old 2.2 OHV existed! That's right, for 2000 they dumped the Isuzu tranny for the F23. I like the F23 aside from one thing, I don't like how the gears pressed to the shaft and not splined. I have seen the sleeve slip on the shaft and cause great issues. If only the MU3 didn't only work on an ecotec! Awesome idea though, I've also considered the F40 from the G6 GTP.

I like what you're doing to your car, an LX9 with a stick is pretty sweet! That's what I like about Fiero guys, you do so many different things to your cars and have to fab up different things, I love it! I go on to so many different forums (*cough* *cough* Cobalt forums) that have NO idea about anything other than what is already in the car. Although to their credit, most people don't realize how similar delta and epsilon cars are. But you guys, anyone who can figure out how to shoe horn a Northstar V8 and a 4T80E tranny, a setup that is tight by all accounts in a full size car, in to a tiny 2 seat roadster, has my admiration! Thanks guys!

[ericjon262]

Oh DUH! I completely forgot the old 2.2 OHV existed! That's right, for 2000 they dumped the Isuzu tranny for the F23. I like the F23 aside from one thing, I don't like how the gears pressed to the shaft and not splined. I have seen the sleeve slip on the shaft and cause great issues. If only the MU3 didn't only work on an ecotec! Awesome idea though, I've also considered the F40 from the G6 GTP.

I like what you're doing to your car, an LX9 with a stick is pretty sweet! That's what I like about Fiero guys, you do so many different things to your cars and have to fab up different things, I love it! I go on to so many different forums (*cough* *cough* Cobalt forums) that have NO idea about anything other than what is already in the car. Although to their credit, most people don't realize how similar delta and epsilon cars are. But you guys, anyone who can figure out how to shoe horn a Northstar V8 and a 4T80E tranny, a setup that is tight by all accounts in a full size car, in to a tiny 2 seat roadster, has my admiration! Thanks guys!

anytime! I hope to have my car on the road here early next year, but if you've seen my build thread, you know that's not likely! :P

[hookdonspeed]

my 86 fiero 3.5 LX9 stick shift swap is running and on the road, just no exhaust done yet, i used the 4speed muncie trans from the fiero, plan to upgrade to an F series when i turbo it.
OBD2 ECU

[gar70614]

I had a lx9 nvg282 in my 98 z24 it had plenty of power, 3500 pulled alot harder than the 2.4 thats for sure. I say go all the way and just go with the ls4 since you are considering a auto anyway the trans mounted starter wont be an issue. In retrospect I wish I would have just gone v8. Tho its unnecsary

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[ericjon262]

holy thread revival batman!