4.0 vs. 3.7

[j99xj]

As you probably already know, a 4.0 HO was rated 190 hp, the 3.7 was rated at 210 hp. (flywheels)

According to K&N, the 4.0 was capable of 163 rear wheel horsepower.
Again, according to K&N, the 3.7 was capable of 167 rear wheel horsepower.

The calculated driveline losses are at 14.2% for the 4.0 [1-(163/190)]*100
The calculated driveline losses are at 20.5% for the 3.7 [1-(167/210)]*100

I honestly don't see how the Jeep Liberty can have a 6.3% increase in driveline losses over the Cherokee. Both Jeeps in the test were automatics. So I'm going to throw out the possibility of error in this department.

Here are the dyno sheets:

Assuming driveline losses are the same for both vehicles, either the Jeep 4.0 was underrated by 16 hp, and should have been rated 206, or the Jeep 3.7 was overrated by 16 hp and should have been rated 194.

Am I crazy or is this just another case of DC fudging numbers to sell cars???

 

[Dr. Dyno]

Here's another dyno chart for the 4.0 XJ:

and two more for the 3.7 KJ:

http://www.knfilters.com/search/product.aspx?Prod=77-1540KP
http://www.knfilters.com/search/product.aspx?Prod=63-1103

It seems that some engines are better than others but the bottom line is that the XJ 4.0 is correctly rated at 190hp but the torque should have been rated at 240lbft instead of 225.
The KJ 3.7 is overrated for HP but correctly rated for torque. The true HP output of the 3.7 seems to be anywhere between 195 and 210.

 

[j99xj]

Very interesting Dr. Dyno. I'll take your word that the 4.0 is 190 hp and 240 lb-ft.

Anyway, as I see more and more KJs and other 4wd minivans on the road and attempting trails, I stop and wonder what the heck happened to the Jeep brand. The 4.0 is gone. Solid axles are gone. Attractive body lines are gone, (the Commander is a bloated waste of steel imho). Everything that made the company great has gone to hell in a handbasket. It really ticks me off to see proven and popular (not to mention profitable) products thrown away like they aren't worth beans.

I'd really like to see the Jeep division bought by another manufacturer that can restore its former glory.

 

[87manche]

has anyone considered that perhaps the AW4 was just that much better than the ChryCo clushbox that's likely in the KJ?

 

[Sniggs]

Marketing Propaganda

 

[MogifiedXJ]

Very interesting Dr. Dyno. I'll take your word that the 4.0 is 190 hp and 240 lb-ft.

Anyway, as I see more and more KJs and other 4wd minivans on the road and attempting trails, I stop and wonder what the heck happened to the Jeep brand. The 4.0 is gone. Solid axles are gone. Attractive body lines are gone, (the Commander is a bloated waste of steel imho). Everything that made the company great has gone to hell in a handbasket. It really ticks me off to see proven and popular (not to mention profitable) products thrown away like they aren't worth beans.

I'd really like to see the Jeep division bought by another manufacturer that can restore its former glory.

Agreed...except I still like the new wrangler rubicon and that hemi srt grand cherokee, it proabably sucks off road but it would make a nice mall crawler.

 

[Beej]

Very interesting Dr. Dyno. I'll take your word that the 4.0 is 190 hp and 240 lb-ft.

Anyway, as I see more and more KJs and other 4wd minivans on the road and attempting trails, I stop and wonder what the heck happened to the Jeep brand. The 4.0 is gone. Solid axles are gone. Attractive body lines are gone, (the Commander is a bloated waste of steel imho). Everything that made the company great has gone to hell in a handbasket. It really ticks me off to see proven and popular (not to mention profitable) products thrown away like they aren't worth beans.

I'd really like to see the Jeep division bought by another manufacturer that can restore its former glory.

Seems pretty simple to me. All products are subject to economics and capitalist tenets: supply and demand for one.

Products change towards what the consumer wants. Our preference in vehicles just isn't shared by the vast majority of consumers. People who want a capable offroad vehicle are much rarer than people who want a safe, affordable grocery-getter and kid-transporter. If someone bought the Jeep division and "restored it to its former glory" it would go broke, just like before in its 'glory' days. Just collect and drive the Jeeps you find...

 

[j99xj]

I understand and agree with the economics of the entire thing. DC is in the car business, but ALL business are in the business of making money. lol

One thing that sort of contradicts the notion of manufacturers bending to the soccer mom croud is the Dodge Power Wagon. I wouldn't mind one myself. It comes with front and rear lockers, electronic swaybar disconnects, and 12000 lb warn winch. The only thing it needs is the Cummins diesel.

 

[Big Red]

Very interesting Dr. Dyno. I'll take your word that the 4.0 is 190 hp and 240 lb-ft.

Anyway, as I see more and more KJs and other 4wd minivans on the road and attempting trails, I stop and wonder what the heck happened to the Jeep brand. The 4.0 is gone. Solid axles are gone. Attractive body lines are gone, (the Commander is a bloated waste of steel imho). Everything that made the company great has gone to hell in a handbasket. It really ticks me off to see proven and popular (not to mention profitable) products thrown away like they aren't worth beans.

I'd really like to see the Jeep division bought by another manufacturer that can restore its former glory.

It is a shame, I hear you. You still have the Wrangler with straight axle and coil suspension with the advent of the Rubicon model with dual dana 44s/241 4:1 t-case etc, but besides that Jeep is going to make a car (Compass I think it's called), the Grand Cherokee has IFS as does the KJ that replaced the XJ, the Commander is huge and not catered to offroading.

What I like about XJs and ZJs is that they are vey streetable and are probably the best "Sleeper wheelers" out there. With a few mods, you can have a great offroader, as well as a good dd. It sucks that Jeep isn't staying true to it's brand and heritage, but you can still get a XJ for dirt cheap, ZJs a little more than the XJ, but not much.

You can get a Wrangler or CJ as the true Jeep icon and heritage maker and keeper. The Jeep brand basicly went to Hell in 02' when the XJ run was ended and replaced with the KJ which is positioned to not be a 4 wheeler, but a Kia, Suzuki Sidekick, Honda SUV competitor. There is so much more $ for a manufacturer in selling a soccer mom/grocery getter than building a offroader, from a liability standpoint alone, we did get quite a Jeep vehicle in the Rubicon. Beyond that you have to build it how you want it where the factory left off, but nothing current is off-road worthy, get a cheap XJ and build it how you want.

Troy

 

[j99xj]

What I like about XJs and ZJs is that they are vey streetable and are probably the best "Sleeper wheelers" out there. With a few mods, you can have a great offroader, as well as a good dd. It sucks that Jeep isn't staying true to it's brand and heritage, but you can still get a XJ for dirt cheap, ZJs a little more than the XJ, but not much.

Amen. I have a baby 2 inch lift and 29 inch tall tires and although it isn't a serious rock crawler, it really whips tail with the front swaybar disconnected. I have off roaded on serious trails here in Colorado for nearly 4 years and its only gotten stuck once, (in about 2.5 feet of snow without chains or snow tires.) But every bad experience is a learning experience, and now I have a 9000 pound winch on a nice steel bumper, and a good set of tire chains. No more getting stuck in the snow for me! Unless of course there are no trees/rocks. But thats rare here in Colorado.

 

[Starscream]

Bad day to make a run.

Here's another dyno chart for the 4.0 XJ:

 

[j99xj]

Bad day to make a run.

Yea, bad day and time. 8:45 was when American Airlines flight 11 hit the WTC. I think the entire nation lost horsepower that day. But we hit the nitrous very quickly after that day and really started to kick terrorist ass.

 

[Flip94ta]

Its always nice to see dyno numbers but when they are from an aftermarket company trying to sell product the results can be questionable. Do we know if the rear end and tranny fuilds were warmed up, what was the engine temp? Old racers tell me 1% less hp for every 10* over 160.

Its sad to think that my XJ is only 290 rwhp shy of my trans am.

 

[crabhab]

I second the AW4 better argument. The chrysler 44re in our 1996 ZJ sucked the power out of our 4.0. Our 2000 and current 1999 XJ 4.0 shift alot better with the AW4 than the 44re. I understand that the XJ is alot lighter than the ZJ but, the AW4 lets you feel the power being put down.

 

[Dr. Dyno]

What I like about XJs is that they are very streetable and are probably the best "Sleeper wheelers" out there. With a few mods, you can have a great offroader, as well as a good dd.

Or you could have a very good offroader that's a great dd. In stock form, it's already pretty good offroad. All you need is a pair of quick disconnects for both the front and rear anti-roll bars and you'll gain a lot of suspension articulation for offroading, while you can reconnect the bars to keep body roll to a minimum on the street.

 

[bjoehandley]

I second the AW4 better argument. The chrysler 44re in our 1996 ZJ sucked the power out of our 4.0. Our 2000 and current 1999 XJ 4.0 shift alot better with the AW4 than the 44re. I understand that the XJ is alot lighter than the ZJ but, the AW4 lets you feel the power being put down.

I third it.