back in a fiero after an almost 10 year departure. LZ9 vs 3800 s/c? (Page 1/1)
m0sh_man APR 04, 01:50 PM
10 years ago the 3800 series II supercharged engine was the most common swap here on PFF, In fact i have an ECM already programmed for a 5 speed getrag 3800 s/c motor.

my problem is that they are all getting older and high miles, I'm curious if the LZ9 is a viable "newer" swap option for us? its 240HP and 240FT/lbs with 90% of it's torque available from 1500-5000 RPM, so a very broad torque curve. *IF* its a much harder swap to put into an 88 formula 5 speed then i'll probably just go with the ole trusty 3800 series II s/c motor that we've all come to know and love.

are there pre-built ECM tunes out there for a 5 speed or F40 6 speed LZ9? would a Cobalt SS turbo or supercharged motor be a better option with the F23? I'm weighing in all my options here on the eventual swap, i've done quad4's, i've had two 3800 s/c fiero's and had been tempted by a 3.4L DOHC, and i'd still love to do that swap, but it seems like it's not very cost effective for the power output.

any advice would be very appreciative. My new ride is a 1988 formula, 5 speed, bright red hard top, tan interior with power windows, locks, cruise, tilt, and rear defrost. it's severely sunfaded and had been sitting for 2 years but with a fuel pump change and some exhaust work (doing now) it does run.

matthew.
OntarioKev APR 06, 09:11 PM
If you want much more power then the LZ9 makes then go with the 3800SC. Far cheaper/easier to mod it for some significant improvements in power/tq. The NA LZ9 would need a more serious investment to see any serious gains.
Raydar APR 06, 10:18 PM
I was going to do an LZ9, until I stumbled across a deal on a 3.4 DOHC that I couldn't pass up.
Unlike the earlier 3400 and 3500 engines, there's nearly no aftermarket support for the LZ9 (or LZ4, for that matter.)

I think the PCM wouldn't be so bad. The LZ9 was even available with a manual trans, in the G6, so you wouldn't have to reinvent the wheel, to get it running.

If you decide to do this, check out the LGD. It's a Flex Fuel version of the LZ9. It came in about a bazillion Impalas and FWD minivans. It also has the simpler upper intake plenum, instead of the two stage piece that the LZ9 has (unless that's a thing, for you.) The horsepower and torque ratings of the two are identical.

ALL 3.9s have variable cam timing. Also, unless you want the complexity of DOD, stay away from the LZ8.

[This message has been edited by Raydar (edited 04-06-2019).]

anaverin APR 07, 01:46 PM
http://www.fiero.nl/forum/Forum1/HTML/098706.html

The 2.0 supercharged LSJ from the cobalt SS/ ion redline requires some work to get in, but is totally viable for anyone who has done a few swaps. I am doing mine slowly in this thread. Not sure if i will need a BCM or not, but if i do, I will hide it somewhere. The engine harness is already seperate from the body harness and therefore is the correct length so that is an advantage. If your curious, I have included a link to my progress above. The engine can support 450 HP on the stock block, 600 with some stronger rods and pistons.
m0sh_man APR 09, 08:15 AM
I'm real interested in the LSJ swaps as well. I like that they are 90lbs lighter fully dressed than a 3800 s/c is. at this point it's going to come down to which motor i can get for a more reasonable price, mileage has never bothered me, it's more about how the motor appears to be cared for. I'm pretty confident that i'll probably come across a 3800 series II long before i find a cobalt or ion LSJ. I do watch www.copart.com and IAAI.com pretty frequently though.

*IF* my 88 formula was an automatic i'd be swapping an LS4 with no questions asked. but seeing as i'm a getrag i'm going to keep the getrag. I also like the idea of a 3.4L DOHC, but when it comes down to it, the 3800 s/c is by far the easier/cheaper option with much more power to be made.