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I just put a few miles on the Gen V 6.2 JKU. Very impressive, it drives different than the Gen IV's. The engine feels more aggressive. With the Gen IV engine the programming kept the rpm's as low as possible, then when you needed to accelerate the transmission would downshift. This annoyed some guys who were use to the older 4 speed automatics.
Can any programming be done to counter the lower rpm affect? I know with some of the hand held tuners you can adjust the shift points based on speed and pedal percentage applied for both up and down shifts. I do prefer a more aggressive shift schedule. I would definitely be in the category of guys who would like to move the entire shift schedule up 500-1k rpm especially in the lower range of pedal percentage applied and it can fade back to stock levels around 50-60% of pedal pushed.
 

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Discussion Starter #142
Can any programming be done to counter the lower rpm affect? I know with some of the hand held tuners you can adjust the shift points based on speed and pedal percentage applied for both up and down shifts. I do prefer a more aggressive shift schedule. I would definitely be in the category of guys who would like to move the entire shift schedule up 500-1k rpm especially in the lower range of pedal percentage applied and it can fade back to stock levels around 50-60% of pedal pushed.
Transmission shifting is fully programmable by an experienced tuner. We work with an LS tuner if you have the need for custom tuning.
 

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Discussion Starter #144
What have you done to upgrade the fuel system?

I know a Bosch 044 wont fit inside the stock fuel housing...
There are several options. You can run an in tank Walbro or Aeromotive fuel pump with gph rating determined by your need. Then run a Corvette fuel filter with the internal regulator. This set up works great and we use it on build where there is not a regulator in the tank. Run the filter/regulator as close to the tank as you can. One of the reasons the single line fuel supply was adopted is if you run fuel to the rail and back it gets heated by the engine and when returned to the tank creates higher EVAP emissions due tot he higher temperatures. Keeping the filter/regulator close to the tank helps keep it cool.

For more serious HP you can run a low pressure feeder pump in the tank to an external high pressure pump with a billet fuel pressure regulator. Do not use the JK pump as a feeder it does not flow enough.

The Gen IV and V LS engines run a variable speed fuel pump to control rail pressure, Jeep runs a regulator in the tank. In either case it is a single line fuel supply system unlike the Gen III engines which have a fuel pump regulator on the rail and a return line.
 

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Two more questions that may be relevant here:

- Did the Gen 5 truck motors come with cylinder deactivation? My understanding is that this is leading to oil loss. Can this be deactivated in programming?
- Gearing? 4.56 and 35s work for with the big Gen V for a daily driver? Want to be able to crawl and cruise at 80.
 

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Discussion Starter #146
Two more questions that may be relevant here:

- Did the Gen 5 truck motors come with cylinder deactivation? My understanding is that this is leading to oil loss. Can this be deactivated in programming?
- Gearing? 4.56 and 35s work for with the big Gen V for a daily driver? Want to be able to crawl and cruise at 80.
Yes the Gen V engines use enhanced AFM. I just drove the Gen V 6.2 LS JK and was in 4 cylinder mode about half the time, even at idle. The reason they can do this is the Gen V engine on 4 cylinders actually can produce enough torque due to the high compression and CVVT which allows higher cylinder pressures. With the Gen IV it was near impossible to accelerate a heavy JK in 4 cylinder mode before it would kick into 8 cylinders; however, I found myself driving around the block as a 3.1 liter engine with the Gen V engine. Hopefully this will translate into better mpg. AFM can be disabled. As far as oil loss I do not know I do not have enough experience yet, but I ususlly find GM good at addressing problems quickly since they make so many engines. The Gen IV engines had AFM issues at first regarding oil pressure but it was quickly resolved.

I like 4:10's and 35's. This Gen V engine has so much torque you would rip the tires off with 4:56's, but it would crawl great. Remember you have a 4:1 first gear in the 6l80 so launching a heavy JK is not an issue, with a .67 OD you will cruise at about 2,000 [email protected]
 

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What about the emissions stuff I spoke of earlier? I know you mentioned programming out the 2 downstream 02 sensors and that is something I want to do for sure. What about the evap mods and parts that have to be added? Can I eliminate doing that without issues?
 

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Discussion Starter #148
What about the emissions stuff I spoke of earlier? I know you mentioned programming out the 2 downstream 02 sensors and that is something I want to do for sure. What about the evap mods and parts that have to be added? Can I eliminate doing that without issues?
You can eliminate any emissions you want but I do not recommend it. If you disable the EVAP system you may smell fuel on the trail or in your garage. I like to run the rear O2's for various reasons, remember the rear O2's can be used for fuel control as well as Cat monitoring. These emission systems really do not affect performance so I would leave them active and remain compliant. On the 480 HP engine it can be difficult to find Cats that will hold together, you need to get some good quality high flow Cats like off a Corvette.
 

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You can eliminate any emissions you want but I do not recommend it. If you disable the EVAP system you may smell fuel on the trail or in your garage. I like to run the rear O2's for various reasons, remember the rear O2's can be used for fuel control as well as Cat monitoring. These emission systems really do not affect performance so I would leave them active and remain compliant. On the 480 HP engine it can be difficult to find Cats that will hold together, you need to get some good quality high flow Cats like off a Corvette.
I will not be running cats, is that going to be a problem?
 

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Discussion Starter #150
I will not be running cats, is that going to be a problem?
It's not really a "problem". On Gen IV and V engines the rear O2's can be used to fine tune fuel trims, determin Cat temps and for diagnostic information. For example the rear O2 is considered protected from the engine by the Cat. For this reason the ECM may use the rear O2 to check the performance of the upstream O2 to diagnose a fault. Removing the downstream O2 removes this monitoring so it not so much a problem as it is less functionality.
 

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You can eliminate any emissions you want but I do not recommend it. If you disable the EVAP system you may smell fuel on the trail or in your garage. I like to run the rear O2's for various reasons, remember the rear O2's can be used for fuel control as well as Cat monitoring. These emission systems really do not affect performance so I would leave them active and remain compliant. On the 480 HP engine it can be difficult to find Cats that will hold together, you need to get some good quality high flow Cats like off a Corvette.
Robbie,
What cats would you recommend for running the LS3/525? I just ordered the engine yesterday and have begun buying all the rest of the needed parts.
 

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Discussion Starter #152
Robbie,
What cats would you recommend for running the LS3/525? I just ordered the engine yesterday and have begun buying all the rest of the needed parts.
That's a tough one. Ordinary cats will blow out within a year on the 480 and 525HP engines due to the high rpm and cylinder pressures. You will have to spend some money for Corvette or high performance cats. John at Overland may make a recommendation since he has a lot of experience with them. We run high performance spun 7" bullet converters

Since the 525 engine is not compliant you may consider not running the cats as an option.
 

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Its something that can be added later for sure though if the need or want arises. I think I will go without for the time being.
 

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Robbie,
What cats would you recommend for running the LS3/525? I just ordered the engine yesterday and have begun buying all the rest of the needed parts.
I blew out my cats behind the LS3 and had a local hot rod shop put together a complete stainless system from manifolds back and used the Vibrant GESi 7525 cats. You can find them on amazon at a decent price.

 

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That's a tough one. Ordinary cats will blow out within a year on the 480 and 525HP engines due to the high rpm and cylinder pressures. You will have to spend some money for Corvette or high performance cats. John at Overland may make a recommendation since he has a lot of experience with them. We run high performance spun 7" bullet converters

Since the 525 engine is not compliant you may consider not running the cats as an option.
Thanks Robbie,
I spoke to John today, we didn't discuss cat options though. He's got his feelers out for a 0 mile 6l90 for me.

Random question. I'm going to be ordering a Hero 3spd transfer case in the next couple days. They have a option of a VSS tail
housing. Is there any reason I would want to have this added?
Could this be used instead of the one needed wheel speed sensor to make the speedo work? I have no idea.
 

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Discussion Starter #156
Thanks Robbie,
I spoke to John today, we didn't discuss cat options though. He's got his feelers out for a 0 mile 6l90 for me.

Random question. I'm going to be ordering a Hero 3spd transfer case in the next couple days. They have a option of a VSS tail
housing. Is there any reason I would want to have this added?
Could this be used instead of the one needed wheel speed sensor to make the speedo work? I have no idea.
The 6l80 and 90 have a transmission output shaft sensor -TOS which is used for GM VSS in high and low range. The JK gets it's VSS signal from the 4 wheel speed sensors which is sent to the ABS module then the network. No need for a VSS on the TC have them plug it. Some Gen IV OS's use an additional VSS on the rear of the TC and a 4WD signal into the ECM to tell it it's in 4 low. I was one of the first guys back in 2007 to get this signal functional with help from EFI Live and OS patches. After running both ways, off the TOS and replicated signal with 4WD indication I found little difference. You can also program a 4 low pattern into your transmission and get a different shift pattern than normal but I find the normal pattern sufficient.
 

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The 6l80 and 90 have a transmission output shaft sensor -TOS which is used for GM VSS in high and low range. The JK gets it's VSS signal from the 4 wheel speed sensors which is sent to the ABS module then the network. No need for a VSS on the TC have them plug it. Some Gen IV OS's use an additional VSS on the rear of the TC and a 4WD signal into the ECM to tell it it's in 4 low. I was one of the first guys back in 2007 to get this signal functional with help from EFI Live and OS patches. After running both ways, off the TOS and replicated signal with 4WD indication I found little difference. You can also program a 4 low pattern into your transmission and get a different shift pattern than normal but I find the normal pattern sufficient.
Thank you Sir.
 

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While I am leaning to the 480hp ls3, I watched a few videos of the 525hp version and lawd that idle sound. Briefly what all else would be needed to support the 525hp version?

I am guessing at the least an upgraded fuel pump and looser convertor. What else am I missing?
 

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Discussion Starter #160
While I am leaning to the 480hp ls3, I watched a few videos of the 525hp version and lawd that idle sound. Briefly what all else would be needed to support the 525hp version?

I am guessing at the least an upgraded fuel pump and looser convertor. What else am I missing?
We have a good tune for the 480 HP engine and the automatic transmission. The 480 and 525 HP engines are GM Performance engines, not production engines so we do not have OE calibrations for them.

The 525 HP LS3 builds we have done ran manual transmissions. We loosen up the converter on the 480 HP builds and run the stock pump. I would run an upgraded in tank pump with the 525 HP engine and a high performance converter. We work with Edge Converters in California and they did a good job, the 6l80 converter is different than the old converters so you have to know what you are doing.

You may contact John at Overland for a 525 HP automatic tune to see what he offers. Running the 525 engine with an automatic transmission can have issues if you do not have a good tune. John has spent over a year on the 480 HP automatic tune and the drivability is near stock, even the idle.
 
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