F37, Same Torque, Same Performance?

logiclee · **Posted:** Wed Jan 30, 2008 3:21 pm

Raised this issue in another thread but it's worth looking at on its own I think.

We know all the opinions on how different the F37 feels after it's performed and later cars were supposed to have it done at the factory.

The KJ CRD Auto is still on sale in the UK and Jeep still quote the exact same figures now as they did back in 2005.

From http://www.jeep.co.uk

Cubic Capacity 2776 cc
Configuration 4 cylinders in-line DOHC
Bore x Stroke 94.0 x 100.0 mm
Compression Ratio 17.5:1
Fuel Delivery Common rail, direct electronic fuel injection
Maximum torque 295 lb ft @ 1800-2400 rpm
Maximum power 161 bhp @ 3800 rpm
Gearbox 5 speed automatic
Fuel Type Diesel

So if Jeep UK are saying that power and torque are not reduced by F37 how does that sit with Jeep US saying it's a detune?
After F37 it certainly feels as though it has less torque but is this just because the map is smoother and torque reduced at critical times only?

Any thoughts?

Cheers
Lee

gmctd · **Posted:** Wed Jan 30, 2008 5:05 pm

Doesn't reduce the overall 'tune' - just detunes it during shifting, to protect the plastic t\c and transmission - TCM has always requested detune moments with the Torque Managment Request line - F31\37 just enhances those moments.................

ATXKJ · **Posted:** Wed Jan 30, 2008 5:41 pm

The Engine only had a minor detune at the moment of shifting -

but what kills the perfomance is that the torque converter no longer locks up at the torque peak - it revs past the torque peak and locks up after the torque has dropped off.

Therefore - the same engine will feel slower because the torque's not going toward forward motion - it's going to heat transmission oil.

widowmaker · **Posted:** Wed Jan 30, 2008 6:16 pm

gmctd wrote:

- TCM has always requested detune moments with the Torque Managment Request line - F31\37 just enhances those moments.................

I could have used those detune moments when I was younger. Maybe I should call suncoast

yakers · **Posted:** Wed Jan 30, 2008 6:41 pm

Very unscientific but my friend has an 05 CRD without the F-37 and I have an 06 with the F-37 and it feels the same on both vehicles.

ATXKJ · **Posted:** Wed Jan 30, 2008 9:10 pm

There was a significant before/after change in mine -
and I have a specific hill on the drive to work
bottom is a traffic light - top is 65mph
before F37 I had to slow down to keep it below 65
after F37 I couldn't hit 65

after Suncoast I can hit 65 - but still not as good as before F37

Reflex · **Joined:** Mon Jan 29, 2007 8:48 pm **Posts:** 567

yakers wrote:

Very unscientific but my friend has an 05 CRD without the F-37 and I have an 06 with the F-37 and it feels the same on both vehicles.

Same experience with me. I'm still unclear whether it was done to mine or not, but I tried out a friends(they are common out here) who was driving an 05 and has had no warranty work done(he's heavily modified it) and I couldn't tell any diff no matter what I did. Maybe his mods put the kibosh on it(extra weight or something) but if there is a difference, its pretty darn subtle.

Groo2 · **Posted:** Wed Jan 30, 2008 10:29 pm

F37 was it good or bad? I would like to say that if it promotes vehicle longevity it is good. Problem is I never had a problem with my CRD until F37 was preformed, now my Jeep is in the shop again for TC number 4, but this was a fix :?:

Sorry to gripe, just wondering if anyone here has suggestions other than killing my warranty and installing a suncoast TC. I have tried bleeding air out of the fuel lines...etc.

Thanks for the ear.

gmctd · **Posted:** Wed Jan 30, 2008 10:40 pm

Can you 'splain the exact nature of failure for each of those t\c replacements - our KJ gotta new one at F37 at ~46kmi

Groo2 · **Posted:** Wed Jan 30, 2008 11:05 pm

With each TC my jeep runs fine for 90 to 120 days, then the wild shimmy starts to poke its head here and there, then by the 180 day mark it will consistently shimmy under the same conditions, which are High torque and low RMPs (approx 1750 - 1900 RPM in over drive) when the thing is supposed to be locked up. It seems to me that the clutch material will hold for a while, then slowly degrade until it finally is ready to crap out.

I have had my transmission line pressure checked and all is good, the fluid level is good, the TC is not good. I thought maybe the tranny pump was part of this equation, but with a period of normal operation, and the line pressure is good it doesn't make sense. According to the service manager there was a bad batch of replacement TC's for the CRD, but how I am the lucky guy to get three of them (hopefully not a fourth) eludes me. My wife thinks I should have lemoned it, but I like too much, and I am too stubborn. There has to be a solution, just don't want to kill the extended warranty that I bought (though at this point in time I may have to).

gmctd · **Posted:** Wed Jan 30, 2008 11:24 pm

I notice you have the ARB rear locker - what activities are you involved in between those 120day intervals, that require a locker? Reason I ask is lockers are required for low-speed hi-torque activities, where the plastic stator would of necessity be under a whole beaucoup of stress - any relevancy, there?

Groo2 · **Posted:** Wed Jan 30, 2008 11:34 pm

Mostly going out the farm and tooling around the pasture. Maybe a hunting trip. Sounds like if I want to use my Jeep as an SUV I am going to have to invest in a new TC. Though I do have to say, for some of those periods of time my wife was driving it while I was deployed, and it only saw pavement (she drives a tractor around the farm), and is afraid to use the locker. I would expect that the TC should hold up to the limited four wheeling I get to do... then again I am assuming and we all know what that does :wink:

gmctd · **Posted:** Wed Jan 30, 2008 11:53 pm

There's a nut that holds the steering wheel in our KJ that is totally vehicle illiterate - knowing how large a part the stator plays in transfering and multiplying torque to get the vehicle moving from a dead stop, and being awed by the torque output of that little 4cyl turboDiesel, I immediately opted to bite the bullet and make things somewhat more impervious to an expected series of unfortunate events, totally beyond my control and the expectancies of DCJ engineering, if you can ascertain my meaning.

Needles to say, I sleep a lot easier, now - particularly after seeing the results of the job the local monkeys did during the dealership R&R - sure wouldn't want our KJ in that bay any more than that one time, and that was one time too many.

So, yeah - I'm thinking your best step would be to do the deed, B4 they ruin something resulting from the repeated R&R's.

Sir Sam · **Posted:** Thu Jan 31, 2008 2:42 am

gmctd wrote:

There's a nut that holds the steering wheel in our KJ that is totally vehicle illiterate - knowing how large a part the stator plays in transfering and multiplying torque to get the vehicle moving from a dead stop, and being awed by the torque output of that little 4cyl turboDiesel, I immediately opted to bite the bullet and make things somewhat more impervious to an expected series of unfortunate events, totally beyond my control and the expectancies of DCJ engineering, if you can ascertain my meaning.

Needles to say, I sleep a lot easier, now - particularly after seeing the results of the job the local monkeys did during the dealership R&R - sure wouldn't want our KJ in that bay any more than that one time, and that was one time too many.

So, yeah - I'm thinking your best step would be to do the deed, B4 they ruin something resulting from the repeated R&R's.

FYI its a 13 mm bolt, not a nut.

ATXKJ · **Posted:** Thu Jan 31, 2008 10:57 am

I believe he was referring to the nut holding the outside edge of the wheel - not the inside retainer........

sbohner · **Posted:** Fri Feb 01, 2008 10:21 am

I may be naive, but there appears to be clear evidence of the detune and its consequential impacts. The timed nuetering to protect the failing torque converter (TC) betrays DCJs ignorance of diesel production vehicles by their use of a TC designed for petrol engines. They have played with moving the shift points and reduced the performance of the engine at strategic shift points, as bandaids to a design flaw in the production vehicle (a Uniform Commercial Code offense?). They have offered a satisfaction recall to nurse the failing units past the warranty period as it will shift the reoccuring problem into the hands of the consumer.

Further evidence of the performance degrade is the changing of the EPA MPG numbers. This is evidence of the detune as with the change in the setup, they were required to update the EPA data. Needless to say, the consumer (us) have been left twisting in the wind.

The preponderance of evidence reported on websites like this one are overwhelming. A few (DCJ shills?) claim no change (and whiter teeth), but over 99% of the folks who have had F37 acknowledge the reduced performance. Most who have had the procedure, would prefer that it had not been done.

On my own CRD, a reflash ECM was forced onto me during a routine maintenance procedure (done without my permission and DCJ refused to let the dealer put it back to the way it was). Note the TCM was not changed. Even with this change, a substantial reduction in torque and performance was quit apparent (I reported this in a post last year). I'm grateful that they were not allowed to do the full castration.

There are a number of people who have had the Suncoast TC replacement and all seem to be happy. I guess this will be in my CRD future to get back some of the performance and reliability promised to me by DCJ.

Reflex · **Joined:** Mon Jan 29, 2007 8:48 pm **Posts:** 567

sbohner wrote:

The timed nuetering to protect the failing torque converter (TC) betrays DCJs ignorance of diesel production vehicles by their use of a TC designed for petrol engines.

DC makes diesel products all over the world and has for years. They have lots of experience in this area, including in the Liberty which has had a CRD version outside the US almost since its inception.

Quote:

Further evidence of the performance degrade is the changing of the EPA MPG numbers. This is evidence of the detune as with the change in the setup, they were required to update the EPA data.

Every manufacturer was required to update their data on all models. This had nothing to do with changes to the models, this had to do with the fact that the EPA changed their methodology. Go to fueleconomy.gov and you can find 06 and earlier estimages as well as most of the older vehicles with the new 07 and later style estimates.

Joe Romas · **Posted:** Fri Feb 01, 2008 1:49 pm

Reflex wrote:

They have lots of experience in this area, including in the Liberty which has had a CRD version outside the US almost since its inception.

The problem with your logic is with the introduction of the 2.8L in model year 2005 the design limit of the 545 transmission was met :roll:

The previous engine was 2.5L :lol:

ATXKJ · **Posted:** Fri Feb 01, 2008 1:54 pm

The fact that a company has the technology doesn't mean they use it even internally.

GM actually owned Detroit Diesel at the same time that they told Oldsmobile to develop their own diesel - made no sense and set back automotive diesels in the US by 20 years.

rubicon03 · **Joined:** Sun Jan 06, 2008 1:52 pm **Posts:** 28

I will have to agree with ATXKJ on power loss.
Definate loss of torque on long steep hills.Have many where I live and the vehicle used to accelerate in high gear up the hill ,now it will only maintains the speed you are at when you start up it. It DOES NOT pull 2500 lbs in a trailer up these hills like it used to either in high gear ;it used to easily maintain travel speed with the cruise set and did not down shift.Now it downshifts with the same exact load,an aluminum trailer with three four wheers.Adding the TDI powerbox more than restored the original power,no more downshift.
I had read post from many people claiming the shift points changed after performing the update. The recall notice said the update "will reduce torque slightly"
Before I had the f37 done I asked the dealer if the shift points would change and the service manager replied that no,nothing changes.So I reluctantly had the de-tune and convertor done. Noticed the loss of power driving out of the lot immediately,what a dog!
The dealer reflash was apparently incorrectly performed on the first f37 done and the vehicle retained the original shift points.That I was fine with.Most of the roads I run are posted 55 and are heavily monitored,62 and they pull you over.The second jeep was done by a different tec and the shiftpoint to 5th was raised to 63mph. I was p---ed at them and asked the dealer if they were going to take care of the speeding tickets to get the jeep into high gear. They did a nationwide dealer part search and found a new on shelf 05 original transmission control module, and they installed it at no charge,returning this jeep to the original shift points as well.
rubicon03

F37, Same Torque, Same Performance?

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