3400 LNJ w/ 3800 SC.

[beigmatt]

I have the potential to grab a 3800SC from a junkyard that is in good condition...

I am slightly aware of all the bolt-on and upper intake modifications that are needed to really get a supercharger under the hood of an '05 equinox.

Why are these engines so weak? (185hp/210tq) Would I need to upgrade any internals to be running boost? I would love the chance to run a couple lbs of boost with a simple tune.

Can anybody help point me in the right direction before I Weld on a SC and hope for the best?
What kind of ECU do I need to run and how can I get a proper tune?

Thanks.

[beigmatt]

In addition I am trying to accomplish ~200-215hp with just the supercharger running 2-5 lbs. I heard these engines can handle up to 6lbs boost stock.

After that I was looking into possibly doing headers, I already have a custom CAT and resonator delete along with a CAI.

What really worries me is my tranny. (http://en.wikipedia.org/wiki/Aisin_AF33_transmission) Why is there such a low torque limit on the tranny, especially with such a high first gear ratio? What if I remove the driveshaft and disable AWD? What are compatably trannies with my setup if I can't use my current one?

So much on my mind.... I hope this community can help.

[caffeine]

The cam and valve springs are probably the biggest limiters with the stock engine. If your goal is only 200-215 you can accomplish that without boost.

The LNJ is made in China AFAIK so I'm not sure if it's made to the same quality as other engines in the family. IIRC another guy on this forum with an LNJ had bottom end failure not long after installing a cam.

[beigmatt]

The cam and valve springs are probably the biggest limiters with the stock engine. If your goal is only 200-215 you can accomplish that without boost.

The LNJ is made in China AFAIK so I'm not sure if it's made to the same quality as other engines in the family. IIRC another guy on this forum with an LNJ had bottom end failure not long after installing a cam.

Is there any chance the bottom end failure was due to the person keeping stock valve springs and modifying the cam? Is that even possible?

Anyways, My hope was to get the engine setup with the supercharger w/ minimal horsepower gain running with a good tune.
Then I can turn up the boost and start changing restrictive parts (headers, porting, Maybe new upper intakes??, etc...). I had a previous 3400 with alot of head gasket issues.

Unfortunately, I really have no clue what I am doing as far as the ECU goes. Is a downgrade to OBD1 needed? Can I piggyback?


As far as reaching 200+Hp without a supercharger... Everyone mentions 'tuning' so frequently after adding parts (head, etc...) but every time I look into it I see how hard it is with OBDII. Is this mission impossible or am I just really confused?

[robertisaar]

Why are these engines so weak? (185hp/210tq)

185/3.349 = 55.2HP/L.

the 3500s and 3900s fared a little better.

non-VVT 3500 tops at 201HP for 57.5HP/L
top VVT 3500 was 224HP for 63.8HP/L
3900 topped out at 242HP for 61.9HP/L

if you want impressive HP/L numbers, DOHC tends to do better than an OHV engine.

[caffeine]

The stock LNJ PCM is supposed to be supported by HPTuners but I have no idea how well it's supported. Ideally you could just buy HPTuners and start playing with the tune without even modifying the engine at first.

[beigmatt]

The stock LNJ PCM is supposed to be supported by HPTuners but I have no idea how well it's supported. Ideally you could just buy HPTuners and start playing with the tune without even modifying the engine at first.

From what I researched, they only support Chevy Equinox '07 and up. I don't think they all have a 3.4 LNJ?

I'm really hoping to get some forced induction out of this Nox. Why a 3800? Why not a 3100?
No clue where to start as far as looking for compatibility.

[caffeine]

If your vehicle isn't supported then you have the option of installing an older PCM or going standalone like Megasquirt. Unfortunately I don't see either way being easy.

[Kaiju Senso]

I will be interested in seeing any information people can come up with for this engine specifically. Hopefully my LNJ will hit the 200+ Wheel HP mark when it's tune is finalized for the upgrades I have. My engine though was transplanted into a Fiero using the Fiero manual trans and a bunch of LA1 3400 parts and ECU so I'm not sure how helpful any of my information would be for you.

For example I used the ECU out of a 98 Venture to run OBDII but I doubt it would work correctly with the Equinox BCM, perhaps you could run it piggyback? This way you would have a tune-able OBDII computer.

The weak point of my engine when I installed the WOT-Tech "Strip" camshaft with stiffer Comp springs was the keyway on the crankshaft. The key sheared at the timing sprocket which equated to the camshaft not rotating and all of the valves getting too cozy with the pistons... This issue though could have been my mistake during assembly and missing the torque value of the crank pulley.

Now I have reassembled it with 3500 valves and WOT-Tech stage 2 porting to the heads and intake manifolds (I'm using the LA1 upper manifold to clear the decklid of the Fiero.) A turbo will most likely be in my far future but I don't plan on stripping down the engine again unless I have to.

[beigmatt]

Thanks for the reply. How exactly can I piggyback my existing ECU? and avoid conflicts with BCM?

Ineresting story... What exactly do you mean by too cozy with the pistons? They were getting too close?

ECU for turbo/SC applications sounds like a real pain. Are turbo and SC setups equally complicated as far as the ECU goes?

[caffeine]

If the keyway sheared then the cam would no longer spin with the crank. The pistons would then inevitably hit the valves since this is an interference engine.

[Kaiju Senso]

Thanks for the reply. How exactly can I piggyback my existing ECU? and avoid conflicts with BCM?

Ineresting story... What exactly do you mean by too cozy with the pistons? They were getting too close?

ECU for turbo/SC applications sounds like a real pain. Are turbo and SC setups equally complicated as far as the ECU goes?

Sorry I was vague, caffeine explained it already though. Because I bent most of my valves from piston contact, I decided to go ahead and upgrade to the better flowing 3500 valves.

About piggybacking the ECU, I'm not technically sure how to do it. I was hoping if I bought the idea up someone with more knowledge could chime in. The idea though as I understand it is to hook up a separate ECU to all of the necessary engine sensors and it would run the engine properly. Then if you leave the original ECU hooked up to just the minimal amount of wires, it can still talk to the BCM and hopefully make the rest of the car work properly (ABS, Alarm, shifting the transmission, ect.)

The problem is cars these days have everything talking to each other so it is probably way too much work trying to figure out what can be deleted and what would need to be spliced between all of the different computers....Again I just brought the idea up and really have no idea what exactly it would take to work properly.

A turbo/SC ECU shouldn't be a problem if it is possible to use an ECU from a 3800SC car.

Perhaps a company like Sinister Performance (http://www.gmtuners.com/) can help you out.

[beigmatt]

Sounds like a catastrophic failure. Or is it just bottom end failures that classify as a catastrophic failure? In a situation like that, does the engine still have enough compression to run or will it not combust at all? I ask this because the engine is obviously still salvageable. I had a 3400 previously that blew because of a tick that got worse and worse and next thing I knew a valve fell into the combustion chamber. I have learned a few things since then and would hope I could fix the tick myself if it ever came around again in this new 3400 engine.

@Kaiju
Your saying a 3800SC ECU can be tuned to work with a 3400 ECU?

Also, How compatible are all 3400 engines? What is the ECU differences? I am highly confused with what makes an ECU compatible with an engine. Are all 3400's compatible ECU's? Does it depend on sensors as long as displacement is the same? Age of the car? OBD1 vs 2? Ugh...