The Polar Bear - NP241 Upgrade

[AgitatedPancake]

Joe I took an engineering class this semester at Sac State, it was badass. One of the most basic classes, but it had HUGE emphasis on solidworks. It was bad ACE!

[Joe Lynch]

I'm still at ARC for a year then finishing at Humboldt. Finally starting my engineering classes.

[Jeeptech01]

Shit you said that already didnt you? Fail on me.

[downtowncb]

Finally cashed in that 50% off coupon for a Power Tank that I won at GSW. I'm going to mount it in the rear on the passenger side at a 45* angle using some aluminum sheet.



Maybe one of these days I'll start working on the bumpers. Need to stash some money before I start spending more.

[downtowncb]

Oooooh, got my new LS6 intake! I won't be able to put it on for a little while because I'm pretty much working seven days a week but god I can't wait for a free weekend. I'm also looking for an LS6 cam to do at the same time.

[it usually runs fine]

Look at you go Mr. Campbell. Thats gonna be Schweet

[ATL ZJ]

what pushrods you going to go with?

[Jeeptech01]

Cool man! Are you gonna get the car rails and tb too? Or frankenstien the truck stuff on? IIRC my tb on my car intake is a 6.0 truck one and you can hardly tell the difference. Not sure if the dbw is different though.

Also remember if you run the 02 up ls6 cam you need .025 shorter pushrods since the base circle is smaller oh and better valve springs. That is probably why cam asked that. I'll shut up now.

[downtowncb]

Cool man! Are you gonna get the car rails and tb too? Or frankenstien the truck stuff on? IIRC my tb on my car intake is a 6.0 truck one and you can hardly tell the difference. Not sure if the dbw is different though.

Also remember if you run the 02 up ls6 cam you need .025 shorter pushrods since the base circle is smaller oh and better valve springs. That is probably why cam asked that. I'll shut up now.

For now I'm going to use the truck 5.3 throttle body and the car manifolds and injectors are on the way as we speak. I'm going to use an f-body water pump and I'm going to maching some .75" aluminum spacers to move it out so the belts line up correctly. This way I don't have to dick with pulling pullys off.

As far as the pushrods go I don't know yet, any suggestions? JT, you're fine, I still have a lot to learn about these LS motors and I wasn't aware of that, so good to know. So if there is a difference between years, which is better, and which valve springs should I go with?

[Jeeptech01]

If you use the 02 up cam you can use the matched ls6 yellow springs. They are relatively cheap. Then either get some 7.425 moly pushrods or 7.4 moly pushrods and mill the heads .025 for more compression. I used to get most of that stuff from scoggin dickey www.sdparts.com They have good prices but cust svc is so-so. Id also reccomend a better timing set too. The higher spring pressures and lift heights warrant the chain and pushrod upgrade.

Oh and they sell those spacers all over the place but you may be able to do em cheaper. IDK

[ATL ZJ]

A friend of mine who has been running LS/LQ motors for almost 10 years told me that he thought pushrods are the weakpoint of these stock motors. jeeptech, would you agree?

[blackbeer]

What are the expected hsp/tq numbers? Obviously everything yer getting now is to better those numbers jus curious what u are looking at after the cam and intake are installed

[downtowncb]

I actually couldn't tell you for sure. From the factory it was 290hp 330tq I believe. I've got a 3" full back exhaust, free flowing intake and performance tune already. Add the intake and cam and maybe 340-350 hp, 380tq? I'm just guessing. Also once I get everything installed I'm going to have it custom tuned so I can get the most out of what I have. Maybe JT can chime in with a more accurate figure.

[ATL ZJ]

your numbers sound about right esp with a decent tune... Man that d30 is gonna be pissed!

[downtowncb]

It's not a D30

And don't worry, after I get the engine dialed in how I want I'm going to start working on axles. In the mean time I have chromos front and rear to tide me over... hopefully.

[Jeeptech01]

Yea the pushrods will pretzel themselves the minute you start adding perfomance valvetrain components. They just arent designed for the higher seat pressures and quicker ramp rates.

Downtown I think your numbers are pretty close but you have them backwards. Once you start adding the car type parts the torque will almost always take a back seat to hp.

Oh and its not a d30.. its a d30 with a 44 r&p

So.. you gonna mill the heads?

[downtowncb]

So.. you gonna mill the heads?

Haven't decided... convince me.

What are the gains? What are the costs? I assume running premium?

[Jeeptech01]

Well this is where the can of worms known as camshaft theory begins to open. I could write pages on the subject and Im not even scratching the surface compared to what some know.

Basically the longer duration bleeds off compression (dynamic not static) in the lower rpm range which will hinder the low speed torque production. So adding in some static comp will raise the dcr back up some. Also for every 1 point of comp hp and tq will usually raise 7%. .025 should yield approx .5 raising you from 9.5 to 10.0:1 fuel type will depend on your tune but prepare for 89 octane at minimum. Plus I can say from experience that these motors love compression. My 6.0 was 11.1:1 on 93 oct with 45* advance but it was carbed so iat was a bit lower hindering detonation.

I have a book at home called how to build and mod.. ls engines. IIRC it is by will handzel. It ias an excellent book and I have read it cover to cover several times. It had tq spec hp numbers buildups etc. I def reccomend it. I'll look tonight bc there was a test with a 5.3 and ls6 cam exhaust etc that listed hp and tq. I'll try to remember to post it up when I have a min.

[Jeeptech01]

Ok I checked that buildup last night. Here are the specs:

stock 5.3
free flowing exhaust (stock mani's)
free flowing air filter (not cai)
ls6 cam
truck intake
added 4 deg advance (your tune is prolly better)
no alt or ps on motor

348 hp at 5700rpm
352 ft lb around 3600 or so

interestingly 295 ft lb at 2500 rpm on up (nice!!)

So the swap to the car intake will probably add some hp higher up and kill a bit of low end torque.

[downtowncb]

350 ish horsepower sounds like fun to me! I just ordered the replacement fuel injector pigtails. As far as the waterpump spacers go, I already have the aluminum left over from a previous project. Once I go buy a set of water pump gaskets it will take me two seconds to whip up a model to CNC out. So in my case it's cheaper to make them myself; plus I can send them out in a batch to be hard annodized at work for free.

[Jeeptech01]

Hell make a couple. They go for good money on ebay.

The low end torque will be really nice esp that early on. The wide lobe separation will make for a broad curve too so it wont peak out on you.

[downtowncb]

Stopped by the parts store at lunch and picked up a set of gaskets to model the spacer after. Gotta go talk to the machinist and see who locally will do a small non company job for cheap.

[Jeeptech01]

THAT is cool. I may have to try learning to use one of those drafting/design programs at some point.

[downtowncb]

Solidworks is awesome! Unfortunately it is also very expensive. Luckily I got it for free at college and now through work. You don't need the latest version, there are couple year old versions out there that have been cracked and work just fine.

If you think that's cool, wait till I post up shot of the new front and rear bumper designs and new rear coil over setup.

[JDirt]

If you think that's cool, wait till I post up shot of the new front and rear bumper designs and new rear coil over setup.

NO, we don't want to wait! Do it NOW!

I hate you because I swapped a 360 into my ZJ and now I want a Vortec!

Keep the posts coming, a lot of us are addicted to this thread I think.