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3.1L to 3.4L swap (non dohc), or 3.1L (96-99) to 3.1/3.4 (2000+)


anryu451

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I have a 1997 Chevrolet Lumina circle track car, bump to pass. This last weekend, inexplicably, the bottom end suddenly let go, spun a bearing or two, material deposited throughout top and bottom end.

 

Long story short, it needs a new motor. Since I have to take it out, is it possible to swap in a 3.4L? Not the DOHC, but the standard 3.4? Any differences that need to be addressed? Likewise, if I find a 3.1, 3.4 2000 or newer motor, can I use my existing injection (I know the 2000+ intakes and TBs are desirable) system, and harness and ECU? A bit lost here.

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Go with the 3800 supercharged motor. I am having a guy do my swap. You can probably find one with tranny for about 800. Why not put a supercharged motor in?

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Your 97 computer is programmable for a 3400 if you desire it, regardless of injectors/fuel rail. Or you can do the l67, its been done a billion times so everyone on this site can help with that.

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You might need a EGR adapter if you are running any sort of smog equipment, or it can be blocked off and tuned out, with some minor exceptions its bolt in and go (save for a PCM tune)

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You might need a EGR adapter if you are running any sort of smog equipment, or it can be blocked off and tuned out, with some minor exceptions its bolt in and go (save for a PCM tune)

 

No, no smog equipment. So the PCM, even in an OBD II environment will need a tune to run a 3.4L OHV (not DOHC)? It isn't plug and play?

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Go with the 3800 supercharged motor. I am having a guy do my swap. You can probably find one with tranny for about 800. Why not put a supercharged motor in?

 

Forced Induction is not allowed in this class, all cars must be naturally asperated. I'd be happy to run a 3800, but I need something that will work with my existing harness/pcm, or with the pcm out of the car the motor came from.

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Programmable? YOu mean it will compensate automatically for the extra displacement? That being said, can I put a 2000+ 3.1 or 3.4 into a 96-99 vehicle?

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You can drop in an OHV 3400, and run it on a 3100 tune, but it'll be running hella lean...although Lean=Power, alsoLean=Detonation=BOOM.

 

The PCM will not compensate for the difference in displacement...a simple retune/reflash is all that's needed.

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well, the strongest drop-in engine/trans/PCM that's N/A is the LQ1...

 

you can run a 3400 on a 3100 tune, especially if you let it learn fuel trims before beating on it, but it won't be 100%.

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You can drop in an OHV 3400, and run it on a 3100 tune, but it'll be running hella lean...although Lean=Power, alsoLean=Detonation=BOOM.

 

The PCM will not compensate for the difference in displacement...a simple retune/reflash is all that's needed.

 

The problem is this is dirt cheap racing. I.E I have no way to reflash the PCM, no flasher, no dyno. That being said, can you run the 3100 tune with 3400 injectors and regulator?

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The problem is this is dirt cheap racing. I.E I have no way to reflash the PCM, no flasher, no dyno. That being said, can you run the 3100 tune with 3400 injectors and regulator?

 

As everyone has said, it will run decent, but it won't be right or as good as it should be. It would be better to use the newer injectors and regulator to help get the engine the fuel more of the fuel it needs. The injector harness for the new injectors will not plug into the engine harness. You will need to splice about a dozen or so wires.

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I ran my 3400 on 3100 injectors and a 55psi FPR for a couple yrs. no issues other running a littl lean up top. Once tuning started, those injectors were way too small.

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X2...particularly for racing, I'd be inclined to go with the LQ1. Makes most of it's power in the upper part of the RPM band, and a 7,000 RPM redline would be very useful.

 

well, the strongest drop-in engine/trans/PCM that's N/A is the LQ1...

 

you can run a 3400 on a 3100 tune, especially if you let it learn fuel trims before beating on it, but it won't be 100%.

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Forced Induction is not allowed in this class, all cars must be naturally asperated. I'd be happy to run a 3800, but I need something that will work with my existing harness/pcm, or with the pcm out of the car the motor came from.

 

My bad. I just realized that it is your circle track car. I thought it was your daily driver.

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I charge 75 to reflash a PCM, and have done a 3400 swap tune in a 96 achieva before. I would run a 2000+ 3400 with the EGR blocked off and disabled.

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