Went to the strip! Kind of... ok not really. WJ vs XJ!

[msrorysddad]

you guys rock. Fluid dynamics is what is is, ignorance cannot change that simple fact. As for the cat, yes it is a crime, however, the I like to breathe members, please stop all people on harleys and ask them to put a cat on their pipes. To point out the facts it is a crime, it has very little effect on performance, to use your logic on someone whom obviously does not wish to learn from others is a waste of time, yet still fun to read. As I've posted before, it's like wrestling with a pig, you both get dirty, but one of you enjoys it. I love it flame on:flame:

 

[gradon]

So the 4.7ho wj is rated 265hp and 330lb-ft and weighs 4041 or 4147#(4wd http://www.wkjeeps.com/wk_specs.htm#CAPACITIES). The 4.0ho xj is rated 190hp, 225lb-ft, and weighs 2900-3300#(2dr, 2wd, 4-banger to the 4dr, 4wd, 4.0). So we'll say yours is 215hp/245lb-ft @ 3200# and his is 275hp/340lb-ft@4100 with his cai. Your power-weight ratio is 14.88#/hp and his is 14.9#/hp so they are very close. I found this over on NAGCA:
Jeep Grand Cherokee Overland
Performance:
0-30 mph, (sec.) 3.22
0-60 mph, (sec.) 8.77
Quarter-mile (sec. @ mph) 16.81 @ 83.01
Four Wheeler-February 1998:
Jeep Grand Cherokee 5.9 Limited
Performance:
0-30 mph, (sec.) 2.65
0-60 mph, (sec.) 7.90
[FONT=Verdana, Arial]Quarter-mile (sec. @ mph) 16.14 @ 86.3 [/FONT]

 

[BBeach]

Yeah but he said it's non-HO...so it'd be 235hp. I'm not sure which 4wd/awd system he had but it's bound to have more drivetrain losses than the XJ (at least i'd think). I can't say it's the most impressive thing to beat....especially with the 5 speed in the modded xj.

As far as those 0-60 numbers. I've seen much better from motor trend and car/driver, etc.

0-60 for the non-ho was usually low 7's and quarter around 15 sec. For the 5.9 a little bit faster.

 

[PurpleCherokee]

Look, the bottom line is, the reason I posted this was to HELP the street XJ's out there to give them a little bit of info/guidance on what mods have worked very well for me. Especially since there hasn't been much experimenting w/dual exhaust on XJ's. If you think my exhaust is "poorly designed" then I'm sorry, but you need to go study. Yes, I choose to go catless. Am I saying that's the only way to go? NO. That's the way I choose to go for many reasons which I've already mentioned. My XJ, with basically intake and exhaust kept up nicely with a WJ with intake. Don't even bother telling me I'm wrong, or that the WJ was running bad or whatever your excuse is cause I really don't care if you don't believe me. This thread is for those of us that can actually take advice instead of just getting stubborn and telling me that I'm wrong.

But you guys that just sit here and bash me, bash my exhaust, throw childish insults around, you need to get a life. For real. If you don't like my exhaust, then A: shut your mouth, or B: tell me why you don't like it, and back it up with actual science. Don't just start ridiculing someone on a personal level that you don't even know.

And you guys who keep HARPING on, and on, and ON , AND ON about going catless please just shut up. You've made your point. I'm killing everyone slowly, I know. But seriously, I drive 2.5 miles to school everyday and that's about all I drive. Yet, the person with a 30 minute commute to work or school pollutes MUCH more than I do so should they be attacked like I am for not having cats? It's ridiculous and you've been duped by Al Gore.

 

[jeepinwi]

Please close this thread. It's obviously getting nowhere except bashing each other.

 

[wolfpackjeeper]

Please close this thread. It's obviously getting nowhere except bashing each other.

f* that noise, I love this thread. It is almost getting as good as the last one. needs a dedicated shit talking forum, the problem is that it needs to be in a location where everyone can use it. It just would not be as fun in the den. Then when threads deteriorate, move them over there.

If you cant bare to hear another opinion other than your own, dont stick your head out into the shitstorm.

Personally, I think the duals are more of a wast of money than anything else. I think the arguments against having cats almost always come up short of reality, I have run both my stroker and my old fbody with and without cats, with little difference in either case. The stroker actually seemed to run a little better with one, but that is my opinion.

whatever, turn the shitstorm back on, there is nothing on TV

 

[Archdukeferdinand]

Look, the bottom line is, the reason I posted this was to HELP the street XJ's out there

I didn't realize the special olympics had sanctioned drag racing these days...

Street XJs? Could you be a dear and post up some ideas for how to get my foxbody mustang modded for some rock crawling? I mean it crawls okay now, but I crawled against this stock camaro and totally schooled its ass.

Oh, I would have dyno numbers but blah blah I don't because its a cop out.

Or do you mean "street XJs" Like the XJs are hard core, because they know about that rough thug life, y'know... On the streets?

 

[wolfpackjeeper]

I didn't realize the special olympics had sanctioned drag racing these days...

Street XJs? Could you be a dear and post up some ideas for how to get my foxbody mustang modded for some rock crawling? I mean it crawls okay now, but I crawled against this stock camaro and totally schooled its ass.

Oh, I would have dyno numbers but blah blah I don't because its a cop out.

Or do you mean "street XJs" Like the XJs are hard core, because they know about that rough thug life, y'know... On the streets?

magnificent, grand use of sarcasm and ridicule sir

 

[Darky]

I didn't realize the special olympics had sanctioned drag racing these days...

Street XJs? Could you be a dear and post up some ideas for how to get my foxbody mustang modded for some rock crawling? I mean it crawls okay now, but I crawled against this stock camaro and totally schooled its ass.

Oh, I would have dyno numbers but blah blah I don't because its a cop out.

Or do you mean "street XJs" Like the XJs are hard core, because they know about that rough thug life, y'know... On the streets?

Funny, but wrong. XJs do pretty decent on the street. Not every XJ is destined for rock-crawling

.
But Purple, really, you say that people need to have evidence to back up they're claims that your exhaust is poorly done, but when people like Shelby tell you they've actually run a vehicle on the drag strip is a controlled environment both with and without cat and saw no difference, you tell them to screw off. People tell you about fluid dynamics, you call them idiots. Just admit you have decided you are correct and will not hear any correction. There's an old proverb, "The fool hates reproach, but the wise man loves correction."

 

[PurpleCherokee]

I didn't realize the special olympics had sanctioned drag racing these days...

Street XJs? Could you be a dear and post up some ideas for how to get my foxbody mustang modded for some rock crawling? I mean it crawls okay now, but I crawled against this stock camaro and totally schooled its ass.

Oh, I would have dyno numbers but blah blah I don't because its a cop out.

Or do you mean "street XJs" Like the XJs are hard core, because they know about that rough thug life, y'know... On the streets?

This forum has been created for people to discuss modification and tuning issues related to street XJ's.

This may include lowering XJ's, or just performance tuning a stock suspension XJ and more.

IF you do not care for this type of modification, that is fine. Bashing or rude comments towards posters will not be tolerated.

As always, the "Report This Post" feature is the best way to deal with a post that is out of line.

Enjoy the forum!

If you don't like "street XJ's" then get the fuck out of this thread.

Funny, but wrong. XJs do pretty decent on the street. Not every XJ is destined for rock-crawling

.
But Purple, really, you say that people need to have evidence to back up they're claims that your exhaust is poorly done, but when people like Shelby tell you they've actually run a vehicle on the drag strip is a controlled environment both with and without cat and saw no difference, you tell them to screw off. People tell you about fluid dynamics, you call them idiots. Just admit you have decided you are correct and will not hear any correction. There's an old proverb, "The fool hates reproach, but the wise man loves correction."

The cat thing is more of a cost/sound issue to me. I'm not sayin it'll even knock a tenth off your 1/4 mile time, but to me, if it sounds better, is cheaper, and performs better then it's a done deal. I don't think I'm killing anyone by toolin around w/out cats.

Haha, and I'll admit to loosing my cool occasionally but some of these idiots are just ridiculous and take things way too far. And when I'm right, I'm right. Sorry if that sounds egotistical but it's true. Like calling someone an idiot when they tell me that having a 90 degree bend in your exhaust is like me taking a 90 degree turn in my jeep while doing 100mph. And that exhaust is a fluid... wtf?? Exhaust is a GAS. Yes it responds SIMILARLY to the principles of fluid dynamics, but also very differently, the big difference being the huge difference in mass between the two. Trust me, I'm not above being corrected, but some of these arguments being thrown at me are absurd.

But I can tell you are an intelligent dude because of what you said and how you said it. If everyone acted like you when they disagree with someone this would be a LOT nicer forum to throw ideas around in. Instead of just ridiculing, and name calling. That's my $.02.

 

[wolfpackjeeper]

And that exhaust is a fluid... wtf?? Exhaust is a GAS. Yes it responds SIMILARLY to the principles of fluid dynamics, but also very differently, the big difference being the huge difference in mass between the two.

actually you are very wrong on this one. gases are fluids, they do not "respond similarly" they follow the exact same laws as any other fluid. The common hangup comes from people assuming that liquid and fluid are interchangeable words. This is why fluid dynamics governs the design of a wing or the design of a submersible. If you look into the manufacture of both you will find that the same groups run the research and building of both aircraft and watercraft. They are subject to the same variables of viscosity, temperature, velocity, ect. Boyle's law and Bernoulli's principle apply to both gases and liquids, as they are laws that govern the behavior of fluids.

if you want to dispute this I can send you a reading list of the books I had to read for classes in Mechanical and aerospace engineering during college. I can also direct you to where you can find copies of the flight training manuals the DOD issues me earlier this year.

 

[-96JeepSpeed-]

seriously, Theres no way in hell a 4.0 could pull on the 4.7 from 55-75MPH. Unless theres somthing wrong it. I can barley get my XJ to 85MPH. I also drive WJ 4.7HO everyday, It ROMPS on the XJ like joke. It could easily pull my XJ up any grade faster then my XJ can own its own power.

 

[BBeach]

And when I'm right, I'm right.......

And that exhaust is a fluid... wtf?? Exhaust is a GAS.

:roll::roll::roll::roll::roll::roll:

 

[PurpleCherokee]

:roll::roll::roll::roll::roll::roll:

Sorry, I meant liquid. The point remains, you can't compare a gas to a JEEP. There's a little bit of difference in mass there...

 

[nick86]

I'm not gonna argue the the fluid dynamics issue. But honestly after the manifold all the scavenging has been done and the 4.0 really doesn't care if you run 2 1/2 exhaust or 1 3/4 exhaust. Other than sound, it just doesn't matter. There are some engines that run better with some back pressure, but the 4.0 is not one of them.
Some dumba$$ with a brand new 2008 chevy p/u wanted to lose his muffler & add dual turbo set-up to give it a nice sound the other day. Problem was at highway speed the engine cuts out to 4 cylinders. You can imagine how that sounds. $500 later we put a stock muffler back on. Dumda$$.

 

[msrorysddad]

I love circular arguments. You IDIOTS, that's what get's me, anyone who doesn't agree is an idiot, no matter what evidence is brought forth. I meant liquid, you idiots. Basically I'm not sure what I mean, but damn it, I'm not wrong! I say the cat makes no difference, if you wanted more flow, and cost savings, I personally would have stepped up tube diameter, not split the tube. Two one and a half inch pipes (just an example) flows like one 3", well, what about the disturbance at the split, there are a lot of variables. I say for the same flow 3" would beat two 1 1/2" pipes, as for cost effectiveness, the bending of two pipes takes longer than that of one, the flanges, ect... If we're now moving on to cost savings and still on the attack wave1: Purple). As for sound, can you hear it with the stereo on, will it wake me up when you drive down my street? My H.D.s used to make me some happy neighbors. You know we're just a toned down Pirate

 

[PurpleCherokee]

We're not going to get into the dual vs single argument, that's another thread. Two 1.5" pipes wouldn't flow anywhere near one 3" pipe. 2.125" has almost exactly the same capacity as one 3". And I don't know what you're talking about about the "disturbance at the split". And I paid $150 for an exhaust shop to bend ALL the pipes and weld in ALL the mufflers. I don't consider that very much. It prolly would've cost anywhere from $50-$100 for to do the same but for one pipe. Not too much price difference there. And as far as sound goes, it's remarkably quiet. I'd like to get a video up with a dB meter in the jeep. As I've said before, it's comparable, if not quieter than an FM 40 or a turbo chambered muffler.

 

[billyjp2]

i bet your jeep is a slug off the line with that lack of back pressure

 

[PurpleCherokee]

Lol :roflmao:... what an ignorant statement...

 

[msrorysddad]

by split, I mean it comes off one header exit, so the single is split somewhere. Unless I'm wrong, which I am at times, the split will create turbulence, turbulence= not a grand flow. I worked for a time on flow control in fluid applications (pipeline), the headers (splits) caused losses we were trying to stop. It was amazing to see flow losses in bends, and such. I think my xj sounds just like an xj, albeit one that sucks.