The Polar Bear - NP241 Upgrade

[Jeeptech01]

Well first the magnum motors may have had technology slapped and bolted all over them but the same shitty cast heads, heavy rotating asssy and poor cooling/oiling systems remained unchanged. I suppose I should have specified. I realize the technology on the ls is amazing but the technology within it is just as impressive.

Second all the tchnology within the motor vs a typical sbc even without the injection is more than worth the upgrade. Plus both motors we got came without electronics so it was cheaper/easier to get up and running. I was after the 270cfm stock alum heads, hyd roller cam, lightweight rotating assy, 6 bolt mains, priority oiling, steam venting cooling sys, etc.. LOL

[downtowncb]

Well first the magnum motors may have had technology slapped and bolted all over them but the same shitty cast heads, heavy rotating asssy and poor cooling/oiling systems remained unchanged. I suppose I should have specified. I realize the technology on the ls is amazing but the technology within it is just as impressive.

Second all the tchnology within the motor vs a typical sbc even without the injection is more than worth the upgrade. Plus both motors we got came without electronics so it was cheaper/easier to get up and running. I was after the 270cfm stock alum heads, hyd roller cam, lightweight rotating assy, 6 bolt mains, priority oiling, steam venting cooling sys, etc.. LOL

I understand there are just as many technological improvements within the LS motors, that's why I said half . I guess if they didn't come with electronics, that might make sense. I guess for me it comes down to a desire to use the technology I grew up around, i.e. fuel injection. I personally feel more comfortable with fuel injection than a carburetor. The only carbs I have ever tinkered with are those on my Honda 599.

Btw, what is priority oiling?

[Jeeptech01]

Ha after rereading my post I came off like an ass a bit LOL. I get a bit defensive when I see that question since it always seems to spark a massive drawn out debate about carb vs fi. Honestly both have there place. My hotrods/race cars have always had carbs and my dd's and offroad toys are always injected. Alot of people tend to get caught up in the amazing injection and computer system of the ls and dont notice the mechanical marvel that the actual motor is.

The priority oiling basically means that the rods and mains get oil first instead of the camshaft/lifters getting it first and sending it down to the rods and crank.

[downtowncb]

I wasn't worried about you being an ass, that's the problem with the internet, you can't tell the people's connotation. I was just asking out of curiosity more than anything.

[Jeeptech01]

Ha yea I guess everyone should be used to it by now anyway. If I get a 5.3 swapped into the xj it will def be injected and use the computer controlled auto. As much as I really want to do it I also really love having the bulletproof 4.0 aw4 combo. Im really torn at this point and people keep offering 4.0 parts to me lately LOL.

[downtowncb]

My new Jeepin buddy! 10 week old female corgi. Now I'm taking her out for her first camping trip.

[Jeeptech01]

I had a question about what you did for the evaporative emissions stuff are you just letting the jeep pcm run it with the jeep purge solenoid hooked up to vacuum from the chebby intake?

Also what was the reasoning behind the aux fuel pump. The factory one should support the higher pressure easily.

There will be lots more questions I assure you!!

ed: Heres one now. It appears people say it is nearly impossible to run stock gauges in a 97 up XJ which has the same ccd bus as your ZJ. Did you have issues like this (see thread below) with anything other than the tach?

http://www.naxja.org/forum/showthread.php?t=1027402

[downtowncb]

I had a question about what you did for the evaporative emissions stuff are you just letting the jeep pcm run it with the jeep purge solenoid hooked up to vacuum from the chebby intake?

Yeah that's how I hooked it up.

Also what was the reasoning behind the aux fuel pump. The factory one should support the higher pressure easily.

In retrospect, once the fuel pressure regulator was removed I could have probably used just the ZJ pump. When I started this project I had never built a Jeep to this extent before, so some of what I did was simply because it was how I had seen it done, in this case using a Walbro 255 pump and corvette fuel pressure regulator. Right now the pump is wired to always come on when the key is in the on position weather the engine is running or not, in the future I may rewire it so the PCM controls it.

ed: Heres one now. It appears people say it is nearly impossible to run stock gauges in a 97 up XJ which has the same ccd bus as your ZJ. Did you have issues like this (see thread below) with anything other than the tach?

http://www.naxja.org/forum/showthread.php?t=1027402

That is very odd, from the first time I fired mine up all the gauges with the exception of the tach have worked. Not sure what the differences between the XJ and the ZJ are that are yielding these problems.

[Jeeptech01]

Thanks for the answers. I have been going over your thread for the last few days taking notes. What year was yours again? Im thinking maybe those guys may have not had as strong of a grasp on the concept as maybe you or I might. Nothing against them but they could have overlooked something. Plus theirs were 97 and 98 which were disastrous wiring years for the xj.

Im gonna try unplugging some stuff and see what happens. Plus I have a cool idea for the fuel pressure that Im working on.

[downtowncb]

Trying to figure out how to make the tach work. I took the cluster apart and the gauge is deceptively simple.

Here's a shot of the back. It looks like somehow the needle position is controlled by two sine waves.



It consists of two separately wound coils with a resistance of about 285 ohms.



I'm not sure exactly how this works, it isn't something I've seen before. If I can't figure out an easy way to make it work, I'll just replace it with a stepper motor or tiny servo.

[it usually runs fine]

wow made in u.s.a. don't see that much anymore.

[IndyZJ]

This might sound retarded as I've had a few cold ones and haven't done much research into this, but what kind of tach signal does the Chevy PCM put out? I know it puts out a signal that will make most factory 4 cyl. tachs work, but IDK what kind of signal it works off of - I would assume just a pulse. If the Jeep tach works off of sine waves, doesn't that just mean that it gets a certain number of pulses per rpm? I wonder if Redline or Dakota Digital would be friendly enough to help you out here...

I wonder what would happen if you wired it this: http://www.lt1swap.com/lsx_tach.htm
But since that's for a 4 cyl. signal, it would probably read at 1/2 speed if it worked at all.

[Jeeptech01]

Cant wait till you figure it out. It will be one more variable crossed off my list!!

[downtowncb]

I've got an email into an old professor to see what he thinks. My best guess is that it uses two ac sine waves to hold the needle position and uses a phase angle between the two to move the needle. If this is the case, I'm not sure how to generate the signal with a microcontroller. We'll have to see... It would be easy to replace with a stepper or servo and control that.

[downtowncb]

Found some info:

http://www.arduino.cc/cgi-bin/yabb2/...m=1202081315/2

Looks like someone makes a chip meant to control these guys. Might order a couple and see if I can make a simple circuit.

[downtowncb]

Finished designing the circuit and ordered enough parts to make 3 prototype tach signal adapters from Digi-Key. They should be here some time this week and if all works according to plan I'll have one for you if you want, Jeeptech, and whoever else wants one. I believe this same style gauge setup is used in the wranglers and cherokees and there are a ton of those out there now getting LS engines so if there is enough of a demand I'll have a small production run done by a company in China I've used before and sell them for a couple bucks.

[Jeeptech01]

Werd!!

[downtowncb]

Made some progress on the tach adapter. Got the prototype working, now I just need to make a circuit board for it and dial in a few components so the scale is accurate to the gauge.

[paulkeith]

that's pretty damn impressive.

[Jeeptech01]

All I can say is wow. How large will the complete assembly end up being?

[downtowncb]

Thanks guys. I was deffinitely stoked when the needle finally moved last night. I've got a tentative board laid out that is 1.4 x 2.0 inches.

[IndyZJ]

Sweet. I would say you're definitely on to something here for all of the later-model Jeep LS swaps, especially if it can be done inexpensively. Maybe you could sell the product/ idea to Novak or Advance Adapters.

[Jeeptech01]

After you sell your mc buddies uber cheap prototypes for testing..

[IndyZJ]

After you sell your mc buddies uber cheap prototypes for testing..

Of course. He has to make sure it works in other Jeeps, too

[downtowncb]

haha well I bought enough parts to make three prototypes but I would need a favor in return. In order to calibrate it to WJ, XJ and TJ gauge scales I would need you to measure how many degrees it is from the needle rest position to the max on the scale as well as the resistance of each of the coils in order to make sure it would function the same as the one I made for my ZJ.