How does the CRD compare to the 3.7?

Black_Dog · **Posted:** Fri Jun 16, 2006 4:24 pm

This thread has wandered into the inane discussion about street racing their porky high-center-of-gravity SUV’s. Give me a break! Liberty04 wanted to know how they compared relative to possibly purchasing a new vehicle. I bought mine for on and off-road traction and to occasionally pull and haul stuff around. To that end both are adequate: the CRD gets better gas mileage but its drive train unfortunately seems to be plagued by more mechanical problems. As racers they are both piss poor. If Liberty 04 wants a racer there are dozens of cars for the same money that would blow the doors off any Liberty. 10.1 seconds to 60 mph? Give me a break (again)!

DarbyWalters · **Posted:** Fri Jun 16, 2006 4:40 pm

Black_Dog wrote:

This thread has wandered into the inane discussion about street racing their porky high-center-of-gravity SUV’s. Give me a break! Liberty04 wanted to know how they compared relative to possibly purchasing a new vehicle. I bought mine for on and off-road traction and to occasionally pull and haul stuff around. To that end both are adequate: the CRD gets better gas mileage but its drive train unfortunately seems to be plagued by more mechanical problems. As racers they are both piss poor. If Liberty 04 wants a racer there are dozens of cars for the same money that would blow the doors off any Liberty. 10.1 seconds to 60 mph? Give me a break (again)!

Almost any thread here wanders off from the original topic at or about the 3rd page...and usually the original author has quit reading the thread by the 2nd page...but there is always someone that has to be the principal by the third page.

trac95ker · **Joined:** Tue May 23, 2006 3:02 pm **Posts:** 116

I love my 06 CRD limited. It is a pleasure to drive but...it spends more time at the dealer than in my hands. You should think real hard about buying one. The EGR problem does not have a solution and the tranny problems aren't resolved either. Sorry to rain on your parade but I thought I should tell you.

Endurance · **Posted:** Fri Jun 16, 2006 5:20 pm

Black_Dog wrote:

This thread has wandered into the inane discussion about street racing their porky high-center-of-gravity SUV’s. Give me a break! Liberty04 wanted to know how they compared relative to possibly purchasing a new vehicle. I bought mine for on and off-road traction and to occasionally pull and haul stuff around. To that end both are adequate: the CRD gets better gas mileage but its drive train unfortunately seems to be plagued by more mechanical problems. As racers they are both piss poor. If Liberty 04 wants a racer there are dozens of cars for the same money that would blow the doors off any Liberty. 10.1 seconds to 60 mph? Give me a break (again)!

Probably not with the programmer on a CRD. I dont think every car will blow the doors off a SUV with 250hp and 450 torque. I just remember when I had my Grand Cherokee with he 4.7 V8 235hp and 295torque, I blew the doors off of almost any vehicle at the light, including Dodge 1500 HEMI trucks and GT's.

oldnavy · **Posted:** Fri Jun 16, 2006 5:33 pm

trac95ker wrote:

I love my 06 CRD limited. It is a pleasure to drive but...it spends more time at the dealer than in my hands. You should think real hard about buying one. The EGR problem does not have a solution and the tranny problems aren't resolved either. Sorry to rain on your parade but I thought I should tell you.

You really are one of the few who have had problems, most haven't from what I read here on the forum. My some total has been a MAF sensor that was a 10 minute fix, EGR Flow Control Valve, and a filter and fluid replacement about 10,000 mile ago when CRD had about 1500 mile on the clock.

Now if the Jeep was to be for me it would be a cold day in you know where before I would buy one, I am not into off roading and don't like the rough ride and small quarters. Now a Magnum Sport Wagon with a diesel is my kind of vehicle, but a Magnum SRT 8 would be more fun.

Black_Dog · **Posted:** Fri Jun 16, 2006 5:37 pm

Quote:

I don't know what you been driving, but our CRD easly smokes the neighbors 3.7L automatic Liberty and has 3 times now, one of those was on level devided 4 lane. I just walked off and left her when we rolled on at 66 mph. I have also beat a couple of kids in 3.7L Limited at the stop light and they were never able to catch up. I run it up to about 90 before they just gave up, they were about 3 or 4 car links behind me when they quit. Our CRD has seen 113 mph on the speedo. I suppect you haven't learned to drive a modern diesel with the heavy throttle delay built in thanks to the EPA, but there is a way around that problem. The VW TDI automatic was same way, the 5 spd had the same problem but not as bad.

And I total disagree with you on the 3.7L V6 vs 4L I6, but that is for a different section. :roll:

If your CRD smokes your neighbor’s 3.7L then either your neighbor doesn’t realize that you are racing or his vehicle is not in proper working condition. The 3.7L engine is capable of producing significantly more peak power than does the CRD engine, you just have to rev it up to 5,200 rpms to tap into it. The CRD only ekes out a maximum of 160 hp compared to the 3.7L at 210.

Don’t confuse torque for power. Torque is a component of HP. HP is not a component of Torque. In automotive terms peak power (aka horsepower) = engine speed (aka RPM) times engine torque divided by the conversion factor of 5252. The CRD produces greater torque but the 3.7L is capable of much revving much faster so at its peak it can produce 31% more power than the CRD at its peak.

Because the engine torque of the CRD is greater it produces more power at normal (i.e. low) working RPMs than does the 3.7L. Since it is hard to modulate a vehicle while rock crawling when the engine is revving at 5200 RPMs, the CRD is better suited for most off-road and controlled maneuver situations where large quantities of peak power are not required. The CRD also pulls better around town when the engines are not racing but once the revs are up the contest is over and the gasser will dust the oil burner.

This said, I might still rather own a CRD because of the mileage and low-RPM performance. If it just had a reliable tranny...

Black_Dog · **Posted:** Fri Jun 16, 2006 5:50 pm

Endurance wrote:

Probably not with the programmer on a CRD. I dont think every car will blow the doors off a SUV with 250hp and 450 torque. I just remember when I had my Grand Cherokee with he 4.7 V8 235hp and 295torque, I blew the doors off of almost any vehicle at the light, including Dodge 1500 HEMI trucks and GT's.

You can buy aftermarket chips and other performance mods for cars too if you want to play that game.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

Sorry but my experience does not hold with what is posted above-- the diesel is slower off the line--- but rocks on the highway or while moving at speed. I would say this is because the HP/torque curve on diesel and gas engines is not the same.

I drove a gasser KJ when the CRD was in for transmission studder. The gasser was more responsive off the line. The acceleration was also much better modulated. The gasser will require 1/8 of an inch to accelerate briskly off the line, and its throttle response is consistent and predictable. The CRD, on the other hand, requires half throttle to accelerate at the same speed-- and it can still lag for a split second as that half throttle is used to get the turbo moving (new exhaust system helped this). The opposite happens when accelerating at highway speeds-- the gasser becomes less responsive than the CRD. You have to press the gasser almost to kickdown to get what a 1/8 inch amount of input gets you on the CRD. The gasser will also downshift much more while accelerating. The CRD only downshifts under hard accelerating-- I can easily pass at 75 without downshifting out of overdrive.

As an fyi, some 0-60 times have the CRD slower than the gasser-- but I read a review in motor trend and it has it 1 second faster. I tend to agree with Motor Trend. Realize that not everyone who tests the CRD (consumer reports anyone?) knows how to drive it-- I still learn new things every day and have < 11,000 miles on it. If you simply floor it off the line-- it will not accelerate anywhere near its potential. You must get the turbo going and then feed it fuel. Otherwise, the computer limits the fuel flow and steals your punch. It is like older cars with an out of tune carb that hesitates and sputters when given too much throttle too quickly.

I too have noticed the potential for the transmission to upshift too late-- it does this much more under WOT. You will notice the following when it happens-- the RPMs climb to redline while you are accelerating at a fair clip, then the shift occurs and you start zooming forward way faster as the RPM is falling. I think this transmission is still trying to shift like a gasser-- the diesel has a narrower power band and the tranny needs to shift sooner. Also, WOTing any diesel to accelerate faster is generally a waste of time-- I don't do it on a regular basis. I have never driven a diesel that accelerated much faster under WOT than 3/4 throttle (2 MB diesel's--> 240 and 300SD and this VM one. And yes, you could say the 240 never accelerated fast to begin with.) Think of it this way-- with the diesel smaller throttle inputs govern acceleration and larger ones govern longterm speed. (Gas being opposite).

Which leads to a summary of why the CRD is faster on the highway than the gasser, despite the mighty HP of the gasser. The CRD is in its powerband and the gasser is not. We don't care if the top end is 500 mph, we mainly want to power up a hill or pass a car without having to WOT the engine and rev it to 8000RPM. Either of these motors (3.6 or CRD) is capable of powering the car to way over a safe speed. The gasser has more horsepower, but it has to rev like crazy to get to it. The diesel has its peak horsepower and torque available much lower in the RPM range and it only requires moderate throttle input to tap it all instantly at cruising speed. The gasser has much less HP available while it stuggles up its powerband to get close to redline. On the other hand, when off the line-- the diesel is out of its power band and has very little HP compared to the gasser.

Also note that the diesel is easier to mod. For +-$500 bucks and a voided warranty-- you can add 30+ hp at the flywheel and 60+ ft/pnds with a pulse modulation chip. And your fuel mileage might even go up! More power is available if you open the exhaust/intake and even more if you drop major cash and get bigger injectors/fuel pump. Some chip companies (Digi Chip) say the VM block will put out well over 400 foot pounds of torque chipped with other mods but that the transmission (TC) can't take more than 400. I don't think the gasser has as many options (it is not forced induction friendly).

Note to DC: If you are not going to grace us with a manual tranny that can tow 5000 pounds, at least give us autostick in the future-- we have the same tranny as the GC so why not?

Endurance · **Posted:** Sat Jun 17, 2006 3:45 am

Black_Dog wrote:

Endurance wrote:

Probably not with the programmer on a CRD. I dont think every car will blow the doors off a SUV with 250hp and 450 torque. I just remember when I had my Grand Cherokee with he 4.7 V8 235hp and 295torque, I blew the doors off of almost any vehicle at the light, including Dodge 1500 HEMI trucks and GT's.

You can buy aftermarket chips and other performance mods for cars too if you want to play that game.

Yes, but you will never get anywhere close to the results when chipping a gasser. Diesels just have much more potential.

jinstall · **Posted:** Thu Jun 22, 2006 3:50 am

I think some of you need to go back to driving school. The next time I am at the track for an event I will get the time slips for 4x4 and 2x4. if you stage and spool correctly there is absolutely no lag what so ever. You actually have to worry about toomuch wheel spin. I have driven a 3.7L and there is no way that the 3.7L can take my CRD in the 60' period. At around 40mph yes it does fall back. Above 50mph the 3.7 will pull on the CRD. When stopping at 100mph or more the 3.7L is way more nose happy than the CRD. You want to street race your KJ, please leave your license at the local police station you do not deserve it. Racing is for the track only, less lives are needlessly lost. No one I have seen here in europe races a SUV, well except for me. Oh wait BMW had a X5 witha F1 V10 in it, stupid fast, stupid expensive, stupid fun. Even if you lowered, tubed and put a 502 Merlin motor in it with twin turbos on it, it would be what? SLOW AND FAT for a racing car/truck/SUV. Do what ever you want with it above OEM specs but remember, you are tinkering with what the manufacturer mades as a RELIABLE vehicle. I really do not thinks any of you beat on their KJ as hard as I do. If it lasts more than 30K miles I am happy as hell. I see me getting new tires in a few months at around 8-9000 miles. Almosat daily I can get the ESC to kick in while going around curves. I have had 6500 miles of trouble free service with the KJ CRD. I highly recomend it to anyone, as long as they are stationed in europe. It seems that the only issues so far have been in areas that have HS Diesel. As for the tranny issues I have no idea, I had one hic-up and that was it. Now I wait 1 min before shifting.

If you street race and get caught, you deserve to loose your license. I would recomend 6 moths suspension. I also recommend the German way of getting a license, 6 months of school and around $2500 IF you pass the first time. You would see alot more people driving better.

oldnavy · **Posted:** Thu Jun 22, 2006 10:21 am

jinstall wrote:

If you street race and get caught, you deserve to loose your license. I would recomend 6 moths suspension. I also recommend the German way of getting a license, 6 months of school and around $2500 IF you pass the first time. You would see alot more people driving better.

Amen to that and we should have better roads and unlimited speed on some sections of the interstate sytems. But then that would require the road tax like the Germans have making their fuel twice the cost of our fuel.

We still have the frontier attitude with the right to do what ever, and nothing is a earned privilege as in so much of the rest of the world.

jinstall · **Posted:** Mon Jun 26, 2006 10:03 am

Don't worry the Germans are getting tot he American way of doing things. The great smooth autobahns are now being covered in asphalt, higher gas prices, higher taxes cheaper roads. Theya re not the brightest people sometimes. I am so disappointed in some of the new road construction I hae seen in the past 10 years.

How does the CRD compare to the 3.7?

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