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Small Block Chevy Swap worth it?


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#41 OFFLINE   NWT87PATHY

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Posted 15 August 2014 - 08:49 AM

What are you using for computers?
Retro fit stock stuff or stand alone?



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#42 OFFLINE   V8path

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Posted 15 August 2014 - 01:46 PM

What are you using for computers?
Retro fit stock stuff or stand alone?



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Not sure what you mean by retro fit stock or stand alone?

 

The PCM and engine wire harness are from an 94 LT1.  I had to make a few PCM programming changes and re-worked the engine harness and removed the wires from the harness that were for the GM gauges and instruments.  The rest of it was to determine which Nissan gauge sensors to retain for the Nissan gauges, and which other senders to change for aftermarket gauges and to run the LT1 PCM.  

 

When doing a swap between 2 completely different vehicles, by the time the modifications are made to the harness and PCM, the result is a standalone unit anyways.  Once the wire harness was modified, it was simply power and ground hook ups for the PCM, and the rest was things like brake signal from the Nissan for TCC lockup, and powering the NIssan fuel pump replay (however if necessary or desired, could have used a standalone relay for the fuel pump and do away with the Nissan relay altogether). Delete all the A/C signals, as the PCM will register the extra load when the A/C is on and adjust accordingly.  There will be low/high and temp switches inline in the AC system to trigger fans and shut offs as required. 

 

I am planning to convert the LT1 Opti Spark based ignition with a conversion kit to upgrade (get rid of the Opti Spark) to the 8 coil pack from the LS based engine.  That will require a LS based wire harness with a somewhat major re-work to re-tro fit a later harness with an older engine, and will be running the LS based PCM which allows for way more and better tuning capabilities - such as spark timing, precise injector flow rates, etc. etc., and a much stronger spark given the individual coils for each cylinder.
 

This is my 3rd swap, so its not as scary as it would be for someone who's never done a swap like this before.

 

Am going to build a custom dual rate sway bar (front and rear) to replace the existing custom front and rear  - one heavy rate for on-road, and one relatively light rate to maintain stability but allow for good flex for off road.  By the time I'm done, expect to be pushing 350 to 370 HP and slightly more torque, so want to have this handle on the road, and off road. 

 

Took it out the other day for a test drive, and 0 - 60 was, let's just say, it was non OEM Nissan...



#43 OFFLINE   NWT87PATHY

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Posted 15 August 2014 - 03:59 PM

Ahh nice u retro'd the stock computer's from the chevy.

Should try something like mega squirt+mega shift to really unleash the beast!

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Edited by NWT87PATHY, 15 August 2014 - 04:02 PM.


#44 OFFLINE   V8path

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Posted 15 August 2014 - 10:01 PM

Ahh nice u retro'd the stock computer's from the chevy.

Should try something like mega squirt+mega shift to really unleash the beast!

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The reason for getting rid of the Opti Spark is primarily reliability, and going to individual coil pack is going to help with throttle response and drive-ability.  The LT1 PCM is fairly limited with tuning by going to the LS based PCM, I think it'll be pretty good for fine tuning the injectors.  Going to upgrade to 36 lb injectors.

 

The conversion I'm looking to do will pretty much give me the same tune-ability, and uses off the self parts (outside of the cam reluctor ring), so for the $ I'm likely going to stick to the original plan.

 

I'm guessing I'm at mid 300 HP, and with 4.88 gears, it already pulls unbelievable off the line.  Don't think the need for more HP is really a goal any longer.



#45 OFFLINE   V8path

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Posted 26 June 2015 - 03:25 PM

Been a while since I looked at this posting and notice there's been no comments for almost a year, but more than 2,000 views since my last posting.  

 

Lots of interest/curiosity, but no comments?    



#46 OFFLINE   MrSkaw

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Posted 27 June 2015 - 08:01 AM

I want to do this when time to replace engine. First plan was to get it started with wheeling equipment. What kind of mileage do you get? I use mine as commuter and play.

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#47 OFFLINE   V8path

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Posted 27 June 2015 - 01:54 PM

There are so many variables to mileage - tire size, ring and pinion gear ratio, tuning, whether your stomping on the gas, etc. etc.  I've seen identical motor sizes in different vehicles and some have great mileage and some terrible, so what my gas mileage is won't really be the same for someone else.

 

I had a 4.3L in before this swap, and that was about the same as the original 3.0 but the 4.3 had a lot more torque and I had gone to 4.88 gears and 33" tires.  So far, the Lt1 (5.7) is a bit thirstier than the 4.3L but not by a lot if I take it easy.

 

The problem is that with all that HP, especially since its like a new toy when I first had it out, it was almost impossible to resist the urge to stomp on the gas pedal.    

 

I've entered into the next phase of the obsession and started to get into PCM tuning with some of the LT1 software.  We'll see where that leads and I'll get an update when I get around to doing some serious tuning.  Part of the reason I've delayed the tuning is that I'm considering ditching the OptiSpark distributor and going to a full LS based PCM and the 8 individual coils, which allows for major tune-ability over the LT1 PCM  

 

From there I'm looking at a doubler setup with a 241 for reduction, and a NP205 (DSD), and it if makes sense (an doing a lot of homework on it still) going to a 6 speed manual T56  trans, which combined would give me double low gears for off road, and double over drive (the T56 comes with a final overdrive of .62 to .5) for the highway.  

 

 

 

 

 


Edited by V8path, 27 June 2015 - 01:55 PM.


#48 OFFLINE   RF600

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Posted 23 July 2015 - 04:19 PM

I would go with fuel injection, not carbed. Drop a LS engine in there. Should get decent mileage.

#49 OFFLINE   MrSkaw

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Posted 15 September 2015 - 05:29 AM

There are so many variables to mileage - tire size, ring and pinion gear ratio, tuning, whether your stomping on the gas, etc. etc.  I've seen identical motor sizes in different vehicles and some have great mileage and some terrible, so what my gas mileage is won't really be the same for someone else.
 
I had a 4.3L in before this swap, and that was about the same as the original 3.0 but the 4.3 had a lot more torque and I had gone to 4.88 gears and 33" tires.  So far, the Lt1 (5.7) is a bit thirstier than the 4.3L but not by a lot if I take it easy.
 
The problem is that with all that HP, especially since its like a new toy when I first had it out, it was almost impossible to resist the urge to stomp on the gas pedal.    
 
I've entered into the next phase of the obsession and started to get into PCM tuning with some of the LT1 software.  We'll see where that leads and I'll get an update when I get around to doing some serious tuning.  Part of the reason I've delayed the tuning is that I'm considering ditching the OptiSpark distributor and going to a full LS based PCM and the 8 individual coils, which allows for major tune-ability over the LT1 PCM  
 
From there I'm looking at a doubler setup with a 241 for reduction, and a NP205 (DSD), and it if makes sense (an doing a lot of homework on it still) going to a 6 speed manual T56  trans, which combined would give me double low gears for off road, and double over drive (the T56 comes with a final overdrive of .62 to .5) for the highway.  
 
 
 
 
 

Awesome

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#50 OFFLINE   V8path

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Posted 17 September 2015 - 11:49 AM

Awesome

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The T56 plans are still under consideration.  I've been looking at the Tremec TR6060 which is the newer version of the T56, and is stronger and there are better choices of a final OD gear ratio.  The older T56's were mostly .50 or .56 which (on paper) puts me at 1,600 to 1,750 RPM for highway cruising.  That's a bit low for the engine for efficient power and torque., and let's face it, these projects are not built for 100 mile per hour plus runs, but it would be nice to have great highway capabilities as most of us are hours away from good off road locations, and having the engine whining at 3K plus RPM's for hours isn't great for the ears or gas conservation. 

 

This is one of those "once you start the swap", not finishing it becomes a very costly change of heart.

 

I'm going to need a custom trans to t-case adapter, clutch linkage, etc., and new front and rear drive shafts.  Outside the custom adapter, is finding a clutch that will handle the weight and torque of a truck and 35" tires.  The original T-56's were never meant for that, and from the research, the clutch is a major area to address if longevity and reliability is the goal. There's no point doing this unless it performs!

 

When this starts, the plan is to do the doubler and trans at the same time.  A Pathy with 350HP, a /doubler/NP205, and 6 speed manual double over drive, would be a great thing.


Edited by V8path, 17 September 2015 - 11:50 AM.


#51 OFFLINE   V8path

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Posted 28 September 2015 - 09:24 PM

Assembling the parts for the doubler

 

IMAG1322_zps5y4qvo5b.jpg

 

 

 

 

 

 

IMAG1324_zps4jdouwkf.jpg



#52 OFFLINE   mjotrainbrain

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Posted 01 October 2016 - 04:37 PM

Holy smokes, this is awesome!  Are there any pictures of the whole truck?  Any updates?  Crazy build, it looks amazing man!



#53 OFFLINE   V8path

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Posted 11 October 2016 - 11:10 PM

Holy smokes, this is awesome!  Are there any pictures of the whole truck?  Any updates?  Crazy build, it looks amazing man!

 

The T56 upgrade will come a bit later as that's a major conversion (which is not very common) so there's more research before moving ahead with that.  Been keeping my eyes out for a good priced T56 or T56 Magnum.

 

I've started on the doubler, and the plan is to get it working with the 4L60E that's currently in the truck.  That requires a few special parts/modifications, as the 4L60E has a custom 30 spline output shaft, and machining on the input shaft and related parts of front reduction of the doubler is needed.  

 

Am going to twin stick the NP205, and have started the tear down and will be looking a replacing any worn parts, gaskets while I'm at it.  

 

Am also almost ready to do the "coil on plug" (no more distributor) conversion on the LT1 in the next couple months.

 

So lots in the works, but finding or making time to work on this has been a challenge.



#54 OFFLINE   V8path

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Posted 24 November 2016 - 10:22 PM

Doubler started

 

IMAG2702_zps2ckycem1.jpg

 

 

IMAG2643_zps5bfrrnjj.jpg

\

 

IMAG2642_zpsv6eny8p2.jpg



#55 OFFLINE   V8path

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Posted 17 January 2017 - 11:39 PM

I want to do this when time to replace engine. First plan was to get it started with wheeling equipment. What kind of mileage do you get? I use mine as commuter and play.

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Found this online re mileage for an 88 Pathfinder with the 3.0

  • fuel consumption and mileage: 14/18 mpg (U.S.)
  • 2389 cm3 / 145.5 cui, advertised power: 145 hp 

I can say that the LT1 (when driven lightly) gets better than 14 mpg in town.

 

With close to same mpg, but an extra (approx) 200 plus HP and about the same amount of ft lbs torque increase, is there any question as to the answer for the title of this thread?

 

Update re doubler - just waiting for the machine work to be done on the input shaft for the NP241.


Edited by V8path, 17 January 2017 - 11:45 PM.


#56 OFFLINE   Charlie_Brown

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Posted 30 January 2017 - 06:08 PM

Damn crazy build! Any pics on her at full flex yet?

#57 OFFLINE   V8path

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Posted 19 March 2017 - 03:41 PM

Damn crazy build! Any pics on her at full flex yet?

 

No pics yet, but during the test stage of the build, had no trouble getting tons of flex from the 14" coilovers.  I know "big flex" is a wow factor for a lot of guys here, but my main goal was an all around road/trail rig, so I didn't take pics, and it was before being a NPORA member.  

 

Have been using her as a daily driver for about a year, and started to get into shock tuning (the coilovers).  This is opening to whole new world to handling and just took her off the road (for a few months) to play with that, and I've started to do the ignition conversion (with the LSM PCM) mentioned a while back in this thread. 

 

The doubler is on hold for a bit while I get the shock tuning and the PCM conversion done (along with a few other torque increasing goodies - plan is to up torque to approx. 450 lbs.)    

 

I try and get more pics up when done.  



#58 OFFLINE   Keeyinn89pathfinder

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Posted 12 June 2018 - 04:36 PM

Would love to see/hear the progresa on this!




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