Would you like to see some parts for your CRD?

geordi · **Posted:** Wed Jun 17, 2009 8:03 pm

nursecosmo wrote:

I would sure like to have an old fashioned wastegated turbo availible as a drop-in option for when the OE unit goes south. Of course it would require the appropriate alteration to the ECM, etcetra, etcetra. I guess I'm just a little old school about having the fewest possible electronics on the vehicle.

I'm with geordi about a better OD on this little beast also. Most of my driving is unloaded and most of the air/fuel being pumped through the engine is wasted heat. I would like to see an RPM around 1300-1500 at 70MPH, with the ability do easily down shift for steep hills.

My target is 1300-1500 rpm at 80, since that is realistically where most of the highway driving takes place. I would accept 1500, if 1300 was at 70... Which should be totally achievable. Does anyone know which gear (if any) are 1:1, or how to run the math to calculate what that OD ratio would need to be to reduce the engine to 1500 @ 80mph?

IIRC, (since its been 4 months) the CRD is turning about 2300 or so at 80. I've never been that impressed with the ratio that Gear Vendors chose for their boxes, only a .78 OD. IIRC, our second OD is deeper than that. In higher gears, the engine can put up with a MUCH larger step between the gearing, I don't think it would be that much of a problem. Especially when it needs to downshift, it doesn't go to 4, it goes DIRECTLY to 3, which is a HUGE jump in RPM.

Thankfully, it doesn't need to do that often, and if it did, you should have taken your foot off and done it manually with the button first.

kdlewis1975 · **Posted:** Wed Jun 17, 2009 11:00 pm

geordi wrote:

nursecosmo wrote:

I would sure like to have an old fashioned wastegated turbo availible as a drop-in option for when the OE unit goes south. Of course it would require the appropriate alteration to the ECM, etcetra, etcetra. I guess I'm just a little old school about having the fewest possible electronics on the vehicle.

I'm with geordi about a better OD on this little beast also. Most of my driving is unloaded and most of the air/fuel being pumped through the engine is wasted heat. I would like to see an RPM around 1300-1500 at 70MPH, with the ability do easily down shift for steep hills.

My target is 1300-1500 rpm at 80, since that is realistically where most of the highway driving takes place. I would accept 1500, if 1300 was at 70... Which should be totally achievable. Does anyone know which gear (if any) are 1:1, or how to run the math to calculate what that OD ratio would need to be to reduce the engine to 1500 @ 80mph?

IIRC, (since its been 4 months) the CRD is turning about 2300 or so at 80. I've never been that impressed with the ratio that Gear Vendors chose for their boxes, only a .78 OD. IIRC, our second OD is deeper than that. In higher gears, the engine can put up with a MUCH larger step between the gearing, I don't think it would be that much of a problem. Especially when it needs to downshift, it doesn't go to 4, it goes DIRECTLY to 3, which is a HUGE jump in RPM.

Thankfully, it doesn't need to do that often, and if it did, you should have taken your foot off and done it manually with the button first.

O.D. ratio = (engine RPM) * [(tire diam. in ft.)/(MPH/60*5280)] / (axle ratio)

For 225/75R-16 tires, at 1500 RPM, an axle ratio of 3.73, the O.D. ratio would have to be 0.438.
Same assumptions with the 3.55 gears, O.D. would have to be 0.460.
If the RPM was allowed to be 1800, then O.D. of 0.525 and 0.552 would be need for 3.73 and 3.55 gears respectively.

Keeping what we got for an O.D. switching from 3.73 gears to 3.55 would reduce RPM from 2296 to 2185 for 80 MPH.

(axle ratio) = (engine RPM) * [(tire diam. in ft.)/(MPH/60*5280)] / (O.D. ratio)

Assuming stock tire size, O.D. of 0.67, and 1800 RPM at 80 mph, axle ratio would need to be 2.92.
Same assumptions, but at 1500 RPM, axle ratio would need to be 2.44.

Conclusion...we're pretty much stuck with what we've got.

onthehunt · **Posted:** Wed Jun 17, 2009 11:53 pm

Third gear is 1:1. We have a double overdrive already. Three would be great.

geordi · **Posted:** Wed Jun 17, 2009 11:54 pm

Maybe, maybe not... Going down into the 2's for axle ratios probably wouldn't be the best thing for people who tow a lot (like me) but is there a gearset that is in the low 3's? Like in the 3.25 or so?

I'll admit, gear ratios and the physical job of changing them out is something of a mystery to me right now. If I had gotten a truck instead, it still would have been a diesel, and I would be looking to swap to 3.2x gears to up the mileage at the expense of some towing capacity.

That is part of the reason I was interested in the GearVendors... It further reduces the existing RPM, and can be either engaged... Or 1:1 when off. I'm going to ask the shop that my CRD is at what the owner knows about gearing options. Hes pretty familiar with the 545, maybe something could be done.

Isn't this casing also configured for a 6-speed? I wonder if that extra ring can be installed... Hmm.

kdlewis1975 · **Posted:** Thu Jun 18, 2009 8:19 am

I'd like to be geared a little higher as well...maybe not in the 2', but I'd settle for low 3's. From what Danoid and some others have said...we already have a "six speed" transmission and it would require a change in the software code to unlock that sixth gear. This doesn't necessarily mean that it would be a taller overdrive though.

If we wanted other rings/pinions for the axle, this is doable. There's all kinds available for the rear. The front axle is the problem. It's based on the Dana 30, but it denoted as a Dana 30A. The pinion shaft is apparently longer, so components for a Dana 30 won't work. Chrysler is the only vendor for the rings and pinions for the Dana 30A and only offer 3.55, 3.73, and 4.10 gears.

geordi · **Posted:** Thu Jun 18, 2009 8:32 am

Not that I'm planning that, but are there any options for swapping the front differential to something a bit more flexible than a special version?

tjkj2002 · **Posted:** Thu Jun 18, 2009 11:01 am

geordi wrote:

Not that I'm planning that, but are there any options for swapping the front differential to something a bit more flexible than a special version?

SFA swap

geordi · **Posted:** Thu Jun 18, 2009 11:34 am

Uhm... more flexible for the options, and PLEASE not less flexible for the suspension! I like the comfortable ride, and I'm not going to take a $18,000 car over rocks that are better known as boulders.

Off road? Yes, I have. Rappelling / climbing? Sure, but wearing a harness, not a KJ. :lol:

tjkj2002 · **Posted:** Thu Jun 18, 2009 9:32 pm

geordi wrote:

Uhm... more flexible for the options, and PLEASE not less flexible for the suspension! I like the comfortable ride, and I'm not going to take a $18,000 car over rocks that are better known as boulders.

Off road? Yes, I have. Rappelling / climbing? Sure, but wearing a harness, not a KJ. :lol:

Solid axles flex better then independent suspensions,it's a proven fact,independent suspension just rides better some of the time .I take mine over boulders all the time and my KJ will ride better when I get the SFA swap done with long arm suspension.

On a side not you will almost spend as much for a SFA swap as you would trying to put another front diff(IFS) to have a better selection of gear ratios since there are very few front IFS diffs that have a good selection of gear ratio's.Your looking at about $10,000 min to get a better selection of gear ratio's.

flash7210 · **Posted:** Fri Jun 19, 2009 7:52 am

ptperformance wrote:

What I am looking at is some go fast goodies for your CRD.

Upgraded stock turbo (new compressor wheel with clipped turbine side to balance the pressure ratio)
Intake to turbo inlet
Exhaust
????

What would you like to see? Admin let me know if this is OK to run or if I need to be a vendor on the site in order to make a post like this. Thanks.

Transmission upgrades would be the best benefit to the CRD.
More power is lots of fun, but if the tranny cant handle it then you will only
be breaking more parts.
A TCU upgrade would be great and so would better gear ratios.
Make that 2' (prime) gear actually usable.

But for exhaust, I would like to see a better downpipe.
Even better would be a "off-road" pipe that deleted the cat.

jinstall · **Posted:** Fri Jun 19, 2009 9:17 am

i would like to see an exhaust option that could come in 2.5 or 3" that has a no muffler but allows you to install whatever muffler you like. Kind of like with a test pipe you could take out and replace with you favorite brand muffler. Stainless would be a plus. it seems very simple but I have not seen anyone do this yet. If I had the equipment I would have done this by now.

05infernoCRDL · **Posted:** Fri Jun 19, 2009 12:53 pm

flash7210 wrote:

Transmission upgrades would be the best benefit to the CRD.
More power is lots of fun, but if the tranny cant handle it then you will only
be breaking more parts.
A TCU upgrade would be great and so would better gear ratios.
Make that 2' (prime) gear actually usable.

there are updated and heavy duty kits available for our transmission... suncoast provides them... i'll let ya know how my trans holds up to the inmotion SII... even if you go get the trans rebuilt sans suncoast there are updated parts (like the wimpy accumulator cover is beefier)

our trans is a very common trans in several dodge PU's

Sir Sam · **Posted:** Fri Jun 19, 2009 2:12 pm

SFA will articulate better and provide better traction than any IFS.

JDaPP · **Posted:** Fri Jun 19, 2009 3:28 pm

I think it was posted earlier, but I would like to be able to shift up or down a gear with my automatic. kind of like the clutchless manual / automatic systems (chrysler 300, BMW, etc). If I could control the shift up to 5th/OD I would be happy and is all I really need.

kdlewis1975 · **Posted:** Fri Jun 19, 2009 4:44 pm

JDaPP wrote:

I think it was posted earlier, but I would like to be able to shift up or down a gear with my automatic. kind of like the clutchless manual / automatic systems (chrysler 300, BMW, etc). If I could control the shift up to 5th/OD I would be happy and is all I really need.

In terms of how the transmission shifts and controlling, the problem is changing or adjusting the programming of the TCM. This has been discussed at length. No one is able to do it yet.

The CRD is unique in that it is the only one that has this type of TCM.

Would you like to see some parts for your CRD?

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