2004 WJ 'Good Stroker Candidate?'

[GP Jeeper]

All-
Great site, lots of valuable information, but for my application not finding anything specific.
The jeep I own is a 2004 Grand Cherokee Freedom Edition.

So, is it fair to assume that all of the tech info for building a reliable stroker applies to the '04 motor?
Currently, the Jeep has 185K well maintained miles on it. I am working in Afghanistan and my son is driving the Jeep so I'm planning for an engine re-dux when I return. Like a lot of guy's posting here, I want a good reliable daily driver but the benefit of the improvements to the 4 liter via the stroker mods. The Jeep is currently stock except for larger tires, Goodyear Silent Armour tires.
Questions:
I've read that there were intake changes after 2003. Is the 2004 head anywhere close to the '95 HO head in flow, if not, can it be massaged to better perform?
Do all the standard intake mods I've read about also apply to this year engine, ex. 62 mm TB and spacer?
Will the 2004 computer 'Learn' the new displacement and data, or will it require re-flashing and tuning?
Have the ATK, Golen, Mopar, replacement engines come down in price enough to just buy a completed replacement?
I saw the ATK on Summit for around $3200. For a better than Poor-Man's build I'll spend that much, right?
Also, the web is wrought with bad press on ATK up to 2005. Have they recovered and are they worth taking a chance with?

Either way, if I go Stroker, or standard engine replacement, there could be problems. If I'm going this far into it I want the best performance I can get.
Future plans for the Jeep are:
short lift less than 4"
tires up to 33"
Diff gears probably 4:11's
Larger wheel wells and BushWacker flares
Otherwise Stock

I live in Michigan so not a lot of natural rock crawling, it will see mostly trail/mud/climbing/towing use, as well as daily driver use.

Sorry if this is another boring request but the information seems to go a lot if different directions. Just trying to bring it in and plan for a successful build.

Regards.

[akadeutsch]

Yes, your 04 motor will love being stroked. Sticking with the same year head will ensure that all of your accessories bolt on. And you should have the improved casting 0331 TUPY head. I believe this is a good head, it may be the best that Jeep ever made for the 4.0 IMO.
Intake mods should be the same. My advise here is to port match your intake runners to your head (remove the step). Then just polish the exhaust runners. Leaving a step between your head and exhaust manifold is supposed to help stop reversion.
Your bolt on mods like a larger TB and spacer will all work fine.
Most likely your computer will take the new displacement fine. I have a close friend who's "poor man's Stroker" runs fine with the stock computer. However it will run much better with a custom tune. Most important seem to be injectors and plugs.
Replacement engines continue to rise in price, as do the kits, as do the craigslist adds. I will spend about 2000 on my build. My rotating assembly was purchased off of craigslist and summit racing. complete 1988 258 for 100 bucks...craigslist, H802SP pistons 101 bucks...summit, rotating assembly = 201 bucks. Can't beat that!!! but it did take 6 months to find the parts.

[Cheromaniac]

Questions:
I've read that there were intake changes after 2003. Is the 2004 head anywhere close to the '95 HO head in flow, if not, can it be massaged to better perform? I'd recommend that you pocket port your existing head.
Do all the standard intake mods I've read about also apply to this year engine, ex. 62 mm TB and spacer? Yes, though I suggest you don't bother with the spacer. Just get a CAI & 62mm TB.
Will the 2004 computer 'Learn' the new displacement and data, or will it require re-flashing and tuning? Unless you build a "poor man's" stroker or the modified version, you'll need FlyinRyan to reprogram your ECU.
Have the ATK, Golen, Mopar, replacement engines come down in price enough to just buy a completed replacement? Prices have gone up, not down. A Golen long block will set you back a cool $4149, while its ATK Baja Stroker equivalent costs slightly less at $3999.
I saw the ATK on Summit for around $3200. For a better than Poor-Man's build I'll spend that much, right? That'll get you the 205hp/280lbft base stroker. You could do better than that with a poor man's if you port the head yourself.
Also, the web is wrought with bad press on ATK up to 2005. Have they recovered and are they worth taking a chance with? Dunno but I could build an equivalent stroker to theirs for a lot less than $4000.

[GP Jeeper]

OK, but you lost me on a couple things:
- can you explain pocket porting vs. port matching?
- what is a CAI?
- would you recommend an aftermarket header, or will stock be fine? Seems I read a build article comparing stock with a Borla.
- lets talk cams...If I use the the existing head with the port work should I stay with the factory cam or move up to more lift and duration? Don't want to go overboard here, but I don't want to have to go in again later to upgrade the cam...
-last, I get the increase in injectors sizing, but what plugs are recommended for this type of upgrade?

I like what you say about the cost/value of buying a complete motor. I am not averse to doing the work myelf. I've tinkered with mechanics all my life, restored show-quality antique outboard motors, but electronics give me the shakes and a rash so I'll be contacting FlyinRyan when the time comes...

Thanks for the input.

[Cheromaniac]

OK, but you lost me on a couple things:
- can you explain pocket porting vs. port matching? This article explains all:

http://www.popularhotrodding.com/engine ... ewall.html


- what is a CAI? Cold air intake.
- would you recommend an aftermarket header, or will stock be fine? Seems I read a build article comparing stock with a Borla. Your stock header would be fine.
- lets talk cams...If I use the the existing head with the port work should I stay with the factory cam or move up to more lift and duration? Don't want to go overboard here, but I don't want to have to go in again later to upgrade the cam...Keep the stock cam & valve springs. With all the reliability issues associated with aftermarket flat tappet cams, you're better off keeping the stock unit. It's pretty good anyway.
-last, I get the increase in injectors sizing, but what plugs are recommended for this type of upgrade? Stock.

[wjtom]

OK, but you lost me on a couple things:
- can you explain pocket porting vs. port matching? This article explains all:

http://www.popularhotrodding.com/engine ... ewall.html


- what is a CAI? Cold air intake.
- would you recommend an aftermarket header, or will stock be fine? Seems I read a build article comparing stock with a Borla. Your stock header would be fine.
- lets talk cams...If I use the the existing head with the port work should I stay with the factory cam or move up to more lift and duration? Don't want to go overboard here, but I don't want to have to go in again later to upgrade the cam...Keep the stock cam & valve springs. With all the reliability issues associated with aftermarket flat tappet cams, you're better off keeping the stock unit. It's pretty good anyway.
-last, I get the increase in injectors sizing, but what plugs are recommended for this type of upgrade? Stock.

Im sure im going to get opinions on this but....
The stock header is to small and restrictive.id like to see an 1 5/8 one but nobody makes one.
Dont be afraid of an aftermarket cam just pay to have it double nitrided.well worth the little expense.From what i see most pick way too small of a cam for these strokers.30000 miles and no cam problems.525 lift 218 228 duration at .050 on 110 and its a daily driver.
Why when alot of guys are using the ls1 valves nobody uses beehive springs is beyond me...just have to machine the spring pocket.
62mm throttle body is too small.
plugs will depend on what you run for compression and cam but im at 10.3 to 1 on premium with 3 heat ranges colder and no problems.alot of the pinging problems guys have are caused by running the extended reach stock plug.

[SilverXJ]

Im sure im going to get opinions on this but....
The stock header is to small and restrictive.

This. The stock cast exhaust manifold Is a bit on the small side.

id like to see an 1 5/8 one but nobody makes one.

If youw ant to do extra work Doug Thorley's 99 and down header is 1 5/8".

[wjtom]

Be careful with the doug thorley i know the 2001 header is listed as 1 5/8 but is actually 1 1/2 its listed wrong.Plus in new york we have crappy ca. emissions standards for yearly inspections just not as strict.Maybe in other states.

[GP Jeeper]

wjtom,

Thanks for the input. I like your ideas. The spark detonation, to my understanding, is more related to CR and octane, not plug length, as the pre-detonation occurs prior to actual spark ignition. Also, mine will be a daily driver too so the economy has to be there too, so I'm not interested in in building a Premium fuel only engine. In Michigan we are already gouged enough on fuel costs, especially when there is a mystery hic-up within the supply. It's not uncommon to see major overnight spikes because the Saudi Prince farted sideways...I digress...

Currently, there is no emission testing in Michigan. We tried that a number of years ago and it turned out to be too corrupt so it was dropped.

I like the cam idea and I will look into that further, as I said I do not want to have to go back in later when I should have made the upgrade the first time.
Why do you suggest a 62mm TB will not be enough? Suggestions? Thanks for the input.

Mark.

[wjtom]

wjtom,

Thanks for the input. I like your ideas. The spark detonation, to my understanding, is more related to CR and octane, not plug length, as the pre-detonation occurs prior to actual spark ignition. Also, mine will be a daily driver too so the economy has to be there too, so I'm not interested in in building a Premium fuel only engine. In Michigan we are already gouged enough on fuel costs, especially when there is a mystery hic-up within the supply. It's not uncommon to see major overnight spikes because the Saudi Prince farted sideways...I digress...

Currently, there is no emission testing in Michigan. We tried that a number of years ago and it turned out to be too corrupt so it was dropped.

I like the cam idea and I will look into that further, as I said I do not want to have to go back in later when I should have made the upgrade the first time.
Why do you suggest a 62mm TB will not be enough? Suggestions? Thanks for the input.

Mark.

That is true until you start changing everything about this motor quench,compression,cam,etc.If the the plug is too hot it cant cool off fast enough and will cause the same issues.Trust me on this one i went through it after putting it together every heat range cooler was a huge improvement with this problem.I know ryan usually recommends 1-2 heat ranges colder on most of the stuff he tunes which are usually much milder than what i did.It only costs a few dollars more per tank to use premium so why limit what you can do when building for performance? We have the same issues here with gas prices in wny.My mileage is still about stock with 4.88s so im happy with that.With no emissions testing that makes things alot easier for you.Mine is a 70mm and it was a big improvement over the 62mm.Ive actually used a 68mm on a bone stock one and it worked great.I know ryan has proven many times while tuning the 68-70mm throttle bodies work better on these.

[FlyinRyan]

I use 2 range colder plugs in almost every stroker I tune, with very few exceptions. The notion that stock range plugs and stock camshaft is somehow a good idea or ideal is setting future stroker builds up for disappointment. The stock heat range is too hot for a STOCK motor!

The amount of emails I get alluding to "why does my stroker run like crap" is alarming. Much of it has to do with improper plug selection, improper fuel sync setting (the toothpick method doesn't cut it), and attempting to bandaid a stock cal with big injectors.

[SilverXJ]

Be careful with the doug thorley i know the 2001 header is listed as 1 5/8 but is actually 1 1/2 its listed wrong.Plus in new york we have crappy ca. emissions standards for yearly inspections just not as strict.Maybe in other states.

Not sure where you got the info for the 00+ Thorley header, but I have not seen it advertised as 1 5/8". It is 1.5" In my previous post I was also referring to the 99 down(excluding the WJ) header. For the 00+ header the only option is 1.5". However, I don't have data on AFE or OBX's header but I doubt its anything different.

The spark detonation, to my understanding, is more related to CR and octane, not plug length, as the pre-detonation occurs prior to actual spark ignition.

Detonation can also be related to plug heat range as well as plug length. A hotter plug will stay hotter longer and can be a "hot spot". Extended reach plugs can cause the same problem.

Trust me on this one i went through it after putting it together every heat range cooler was a huge improvement with this problem.

What plugs did you end up going with?

Mine is a 70mm and it was a big improvement over the 62mm.Ive actually used a 68mm on a bone stock one and it worked great.

I'm a little hesitant to put the 70mm on my stroker because the throttle response is already a bit touchy. I will when I get the MP90 installed though as I don't think I have a choice as the 63mm I am running will definitely be a bottle neck.

[Cheromaniac]

It's not uncommon to see major overnight spikes because the Saudi Prince farted sideways

[wjtom]

Be careful with the doug thorley i know the 2001 header is listed as 1 5/8 but is actually 1 1/2 its listed wrong.Plus in new york we have crappy ca. emissions standards for yearly inspections just not as strict.Maybe in other states.

Not sure where you got the info for the 00+ Thorley header, but I have not seen it advertised as 1 5/8". It is 1.5" In my previous post I was also referring to the 99 down(excluding the WJ) header. For the 00+ header the only option is 1.5". However, I don't have data on AFE or OBX's header but I doubt its anything different.

When i ordered the wj header last year from summit it was listed on thorleys and summits website as 1 5/8.I f you read the note on summits site it say as of sept 2013 1 1/2.It was supposed to be 1 5/8 when origanally designed but somewhere along the line got changed.The tech guy at thorley had to check the jig because he didnt believe it was different than what was listed size wise.Oh well.

The spark detonation, to my understanding, is more related to CR and octane, not plug length, as the pre-detonation occurs prior to actual spark ignition.

Detonation can also be related to plug heat range as well as plug length. A hotter plug will stay hotter longer and can be a "hot spot". Extended reach plugs can cause the same problem.

Trust me on this one i went through it after putting it together every heat range cooler was a huge improvement with this problem.

What plugs did you end up going with?

If i remember correctly champion rc59yc but dont quote me until i check for sure.They have been in there for a while at this point with no fouling or problems at all even with the sub zero temps last winter.So i know they work fine.

Mine is a 70mm and it was a big improvement over the 62mm.Ive actually used a 68mm on a bone stock one and it worked great.

I'm a little hesitant to put the 70mm on my stroker because the throttle response is already a bit touchy. I will when I get the MP90 installed though as I don't think I have a choice as the 63mm I am running will definitely be a bottle neck.

The 70mm will probably be too small for the mp90 but its a step in the right direction.i know the throttle body becomes the restriction on those. I think they make a 76mm for that.I have no problems with the throttle being touchy even with the 4.88s and being slightly over geared for the tires on it right now.Ice and snow all last winter and no problems.It is responsive but by no means is it hard to drive.Im pretty sure some of that can be adjusted for with tuning if you think its too responsive but thats a question for Ryan.