Hemi 5.7 or 6.1?
08-02-2009, 07:43 PM
#21
JK Enthusiast
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when do u plan on doing this... and are u going to do the install?
08-03-2009, 07:05 AM
#22
JK Super Freak
Incoming wall of text.
I have about 1000 miles on my 6.1 conversion in a 2 door 07 Rubicon. It was done using the premium AEV kit with the 5.7 manifolds. The Jeep has the stock 32’s and 4:10 gears.
Initially I was having a slightly used 5.7 put into it, but the shop doing the work came across a 6.1 from a wrecked SRT8 300 with 1000 miles on it. For the price difference I could not resist the 6.1.
I notice some bog if I just basically idle off from a dead stop. The tranny shifts to 2nd gear in a short distance and tends to bog the engine. Give it too much gas at that point and it will downshift back to first which you do not want in close traffic. I usually just come off the brake, ease on the pedal till it shifts to 2nd, then give it enough pedal to accelerate in 2nd but not enough to shift back down. Traffic will not leave you behind doing that. After 1000 miles I guess I am used to it now and do not notice it much. So, yes, the 6.1 has some “sluggishness” issues just idling around, at least with the AEV setup. But it has some “redeeming” qualities also!
The 5.7 may not have any issues like the above, but I find it hard to believe it is more fun when you mash the pedal. I leave the ESP button on to avoid burning up my BFG’s. The one time I turned it off and nailed it I lit up the tires on pavement and spun it around in a circle of smoke (scared the crap out of the guy with me, he had only time to say “what’s that button you pushed do?”). Not doing that again, not ready to buy new tires (or axles) yet. If you leave the ESP on and floor it from a dead stop the Jeep gets pretty light on the front suspension and the torque actually leans her over pretty good. There is certainly no sluggishness then, and that 6.1 pulls way hard. It would surprise me if the 5.7 has the same YEEEEHAAAAA factor the 6.1 does once it spins up. I think I read the rev limiter shuts it down at 6400 RPM? Personally I have not noticed (I can see the tach in my peripheral vision slamming back and forth between shifts and the speedo passing 60 before 3rd gear) but if I keep on it in 3rd I better be looking way down the road, where the Jeep is going to be in a few seconds. Then again, maybe the 5.7 is the same...I do not know.
Gas mileage. The computer is telling me I am getting 14-15 just cruising around the country roads. Around our small city it still says 14 or so. That is with me only doing semi-spirited 0-60’s every 20 miles or so (hard to resist). I do not drive aggressively most of the time. At 60 with the cruise set I have seen the computer tell me 17. Setting the trip odometer between fillups and then just glancing at it, the computer mpg is probably not wildly off.
Even if the computer is off a mpg or two, I fail to see how people are getting the 8-10 mpg I see quoted various places unless they are pinning themselves to the seat every stoplight. I could track the actual gas mileage I suppose, but I see no point in doing that. I fill it with premium, say ouch, and then start grinning when I turn the key and it fires up and I forget all about the price of fuel and mpg. I laugh when people talk about spending thousands to stuff 400+ HP in a heavy brick and then they worry about mileage. Get the 5.7 if you want to use cheaper gas and get better mileage for sure. I have an LT1 Firebird that gets 26 higway for that.
For me, it is about the fun factor while still having something that is transportation. Always has been. I am like you in that I keep vehicles around. I have had my Formula Firebird 11 years and my 84 Ranger (stuffed a Mustang HO 302 in) for 12 years. I will have this Jeep for a long time and now that gerbil powered 3.8 is gone it is my favorite vehicle.
I have done little off road yet, the few mild things I’ve climbed she went up in 4 hi with little effort. I need skid pans under engine/tranny yet before anything challenging. Using 4 lo in a Rubicon, I can not believe there would be a crippling difference in low end torque between Hemi’s. The original 3.8 had plenty of power in 4 lo!
I paid a little over 16k for the complete install and the shop did all the parts hunting also. I just dropped it off and picked it up. That was about $2500 more than the 5.7 install would have been, and included them hunting down parts and replacing all the accessories on the car engine. I may add headers down the road, but not at $900 a set. I will lift, regear, and go to 35” eventually.
Anyway, no regrets on the 6.1 here. When I lift the hood and see that beautiful motor, life does not get much better. Your mileage may vary! Good luck.
I have about 1000 miles on my 6.1 conversion in a 2 door 07 Rubicon. It was done using the premium AEV kit with the 5.7 manifolds. The Jeep has the stock 32’s and 4:10 gears.
Initially I was having a slightly used 5.7 put into it, but the shop doing the work came across a 6.1 from a wrecked SRT8 300 with 1000 miles on it. For the price difference I could not resist the 6.1.
I notice some bog if I just basically idle off from a dead stop. The tranny shifts to 2nd gear in a short distance and tends to bog the engine. Give it too much gas at that point and it will downshift back to first which you do not want in close traffic. I usually just come off the brake, ease on the pedal till it shifts to 2nd, then give it enough pedal to accelerate in 2nd but not enough to shift back down. Traffic will not leave you behind doing that. After 1000 miles I guess I am used to it now and do not notice it much. So, yes, the 6.1 has some “sluggishness” issues just idling around, at least with the AEV setup. But it has some “redeeming” qualities also!
The 5.7 may not have any issues like the above, but I find it hard to believe it is more fun when you mash the pedal. I leave the ESP button on to avoid burning up my BFG’s. The one time I turned it off and nailed it I lit up the tires on pavement and spun it around in a circle of smoke (scared the crap out of the guy with me, he had only time to say “what’s that button you pushed do?”). Not doing that again, not ready to buy new tires (or axles) yet. If you leave the ESP on and floor it from a dead stop the Jeep gets pretty light on the front suspension and the torque actually leans her over pretty good. There is certainly no sluggishness then, and that 6.1 pulls way hard. It would surprise me if the 5.7 has the same YEEEEHAAAAA factor the 6.1 does once it spins up. I think I read the rev limiter shuts it down at 6400 RPM? Personally I have not noticed (I can see the tach in my peripheral vision slamming back and forth between shifts and the speedo passing 60 before 3rd gear) but if I keep on it in 3rd I better be looking way down the road, where the Jeep is going to be in a few seconds. Then again, maybe the 5.7 is the same...I do not know.
Gas mileage. The computer is telling me I am getting 14-15 just cruising around the country roads. Around our small city it still says 14 or so. That is with me only doing semi-spirited 0-60’s every 20 miles or so (hard to resist). I do not drive aggressively most of the time. At 60 with the cruise set I have seen the computer tell me 17. Setting the trip odometer between fillups and then just glancing at it, the computer mpg is probably not wildly off.
Even if the computer is off a mpg or two, I fail to see how people are getting the 8-10 mpg I see quoted various places unless they are pinning themselves to the seat every stoplight. I could track the actual gas mileage I suppose, but I see no point in doing that. I fill it with premium, say ouch, and then start grinning when I turn the key and it fires up and I forget all about the price of fuel and mpg. I laugh when people talk about spending thousands to stuff 400+ HP in a heavy brick and then they worry about mileage. Get the 5.7 if you want to use cheaper gas and get better mileage for sure. I have an LT1 Firebird that gets 26 higway for that.
For me, it is about the fun factor while still having something that is transportation. Always has been. I am like you in that I keep vehicles around. I have had my Formula Firebird 11 years and my 84 Ranger (stuffed a Mustang HO 302 in) for 12 years. I will have this Jeep for a long time and now that gerbil powered 3.8 is gone it is my favorite vehicle.
I have done little off road yet, the few mild things I’ve climbed she went up in 4 hi with little effort. I need skid pans under engine/tranny yet before anything challenging. Using 4 lo in a Rubicon, I can not believe there would be a crippling difference in low end torque between Hemi’s. The original 3.8 had plenty of power in 4 lo!
I paid a little over 16k for the complete install and the shop did all the parts hunting also. I just dropped it off and picked it up. That was about $2500 more than the 5.7 install would have been, and included them hunting down parts and replacing all the accessories on the car engine. I may add headers down the road, but not at $900 a set. I will lift, regear, and go to 35” eventually.
Anyway, no regrets on the 6.1 here. When I lift the hood and see that beautiful motor, life does not get much better. Your mileage may vary! Good luck.
08-03-2009, 07:44 AM
#23
JK Junkie
The second problem with the 6.1 is that since they are all using the 5.7 programming the standard 6.1 tranny isn't used. The normal tranny for the 6.1 has much tighter ratios and keeps the engine reving a bit higher than the 5.7. The 5.7 tranny just doesn't keep it in the optimal powerband.
I know that AEV is working on the programming for the 6.1 which would correct both of these issues.
08-03-2009, 06:50 PM
#24
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The problem with the 6.1 at the moment are two things. The programming is the same on the 6.1 and 5.7. Anyone who tells you different is wrong, or doesn't understand unless they have had a custom tune done. You do feel a power difference between the two because the 6.1 is making more power, but it isn't operating as effectively or efficiently as the 5.7. The 5.7 programming is all that Chrysler has released so far, so that is the only one available that acts like it is stock.
The second problem with the 6.1 is that since they are all using the 5.7 programming the standard 6.1 tranny isn't used. The normal tranny for the 6.1 has much tighter ratios and keeps the engine reving a bit higher than the 5.7. The 5.7 tranny just doesn't keep it in the optimal powerband.
I know that AEV is working on the programming for the 6.1 which would correct both of these issues.
The second problem with the 6.1 is that since they are all using the 5.7 programming the standard 6.1 tranny isn't used. The normal tranny for the 6.1 has much tighter ratios and keeps the engine reving a bit higher than the 5.7. The 5.7 tranny just doesn't keep it in the optimal powerband.
I know that AEV is working on the programming for the 6.1 which would correct both of these issues.
08-03-2009, 07:07 PM
#25
JK Newbie
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Incoming wall of text.
I have about 1000 miles on my 6.1 conversion in a 2 door 07 Rubicon. It was done using the premium AEV kit with the 5.7 manifolds. The Jeep has the stock 32’s and 4:10 gears.
Initially I was having a slightly used 5.7 put into it, but the shop doing the work came across a 6.1 from a wrecked SRT8 300 with 1000 miles on it. For the price difference I could not resist the 6.1.
I notice some bog if I just basically idle off from a dead stop. The tranny shifts to 2nd gear in a short distance and tends to bog the engine. Give it too much gas at that point and it will downshift back to first which you do not want in close traffic. I usually just come off the brake, ease on the pedal till it shifts to 2nd, then give it enough pedal to accelerate in 2nd but not enough to shift back down. Traffic will not leave you behind doing that. After 1000 miles I guess I am used to it now and do not notice it much. So, yes, the 6.1 has some “sluggishness” issues just idling around, at least with the AEV setup. But it has some “redeeming” qualities also!
The 5.7 may not have any issues like the above, but I find it hard to believe it is more fun when you mash the pedal. I leave the ESP button on to avoid burning up my BFG’s. The one time I turned it off and nailed it I lit up the tires on pavement and spun it around in a circle of smoke (scared the crap out of the guy with me, he had only time to say “what’s that button you pushed do?”). Not doing that again, not ready to buy new tires (or axles) yet. If you leave the ESP on and floor it from a dead stop the Jeep gets pretty light on the front suspension and the torque actually leans her over pretty good. There is certainly no sluggishness then, and that 6.1 pulls way hard. It would surprise me if the 5.7 has the same YEEEEHAAAAA factor the 6.1 does once it spins up. I think I read the rev limiter shuts it down at 6400 RPM? Personally I have not noticed (I can see the tach in my peripheral vision slamming back and forth between shifts and the speedo passing 60 before 3rd gear) but if I keep on it in 3rd I better be looking way down the road, where the Jeep is going to be in a few seconds. Then again, maybe the 5.7 is the same...I do not know.
Gas mileage. The computer is telling me I am getting 14-15 just cruising around the country roads. Around our small city it still says 14 or so. That is with me only doing semi-spirited 0-60’s every 20 miles or so (hard to resist). I do not drive aggressively most of the time. At 60 with the cruise set I have seen the computer tell me 17. Setting the trip odometer between fillups and then just glancing at it, the computer mpg is probably not wildly off.
Even if the computer is off a mpg or two, I fail to see how people are getting the 8-10 mpg I see quoted various places unless they are pinning themselves to the seat every stoplight. I could track the actual gas mileage I suppose, but I see no point in doing that. I fill it with premium, say ouch, and then start grinning when I turn the key and it fires up and I forget all about the price of fuel and mpg. I laugh when people talk about spending thousands to stuff 400+ HP in a heavy brick and then they worry about mileage. Get the 5.7 if you want to use cheaper gas and get better mileage for sure. I have an LT1 Firebird that gets 26 higway for that.
For me, it is about the fun factor while still having something that is transportation. Always has been. I am like you in that I keep vehicles around. I have had my Formula Firebird 11 years and my 84 Ranger (stuffed a Mustang HO 302 in) for 12 years. I will have this Jeep for a long time and now that gerbil powered 3.8 is gone it is my favorite vehicle.
I have done little off road yet, the few mild things I’ve climbed she went up in 4 hi with little effort. I need skid pans under engine/tranny yet before anything challenging. Using 4 lo in a Rubicon, I can not believe there would be a crippling difference in low end torque between Hemi’s. The original 3.8 had plenty of power in 4 lo!
I paid a little over 16k for the complete install and the shop did all the parts hunting also. I just dropped it off and picked it up. That was about $2500 more than the 5.7 install would have been, and included them hunting down parts and replacing all the accessories on the car engine. I may add headers down the road, but not at $900 a set. I will lift, regear, and go to 35” eventually.
Anyway, no regrets on the 6.1 here. When I lift the hood and see that beautiful motor, life does not get much better. Your mileage may vary! Good luck.
I have about 1000 miles on my 6.1 conversion in a 2 door 07 Rubicon. It was done using the premium AEV kit with the 5.7 manifolds. The Jeep has the stock 32’s and 4:10 gears.
Initially I was having a slightly used 5.7 put into it, but the shop doing the work came across a 6.1 from a wrecked SRT8 300 with 1000 miles on it. For the price difference I could not resist the 6.1.
I notice some bog if I just basically idle off from a dead stop. The tranny shifts to 2nd gear in a short distance and tends to bog the engine. Give it too much gas at that point and it will downshift back to first which you do not want in close traffic. I usually just come off the brake, ease on the pedal till it shifts to 2nd, then give it enough pedal to accelerate in 2nd but not enough to shift back down. Traffic will not leave you behind doing that. After 1000 miles I guess I am used to it now and do not notice it much. So, yes, the 6.1 has some “sluggishness” issues just idling around, at least with the AEV setup. But it has some “redeeming” qualities also!
The 5.7 may not have any issues like the above, but I find it hard to believe it is more fun when you mash the pedal. I leave the ESP button on to avoid burning up my BFG’s. The one time I turned it off and nailed it I lit up the tires on pavement and spun it around in a circle of smoke (scared the crap out of the guy with me, he had only time to say “what’s that button you pushed do?”). Not doing that again, not ready to buy new tires (or axles) yet. If you leave the ESP on and floor it from a dead stop the Jeep gets pretty light on the front suspension and the torque actually leans her over pretty good. There is certainly no sluggishness then, and that 6.1 pulls way hard. It would surprise me if the 5.7 has the same YEEEEHAAAAA factor the 6.1 does once it spins up. I think I read the rev limiter shuts it down at 6400 RPM? Personally I have not noticed (I can see the tach in my peripheral vision slamming back and forth between shifts and the speedo passing 60 before 3rd gear) but if I keep on it in 3rd I better be looking way down the road, where the Jeep is going to be in a few seconds. Then again, maybe the 5.7 is the same...I do not know.
Gas mileage. The computer is telling me I am getting 14-15 just cruising around the country roads. Around our small city it still says 14 or so. That is with me only doing semi-spirited 0-60’s every 20 miles or so (hard to resist). I do not drive aggressively most of the time. At 60 with the cruise set I have seen the computer tell me 17. Setting the trip odometer between fillups and then just glancing at it, the computer mpg is probably not wildly off.
Even if the computer is off a mpg or two, I fail to see how people are getting the 8-10 mpg I see quoted various places unless they are pinning themselves to the seat every stoplight. I could track the actual gas mileage I suppose, but I see no point in doing that. I fill it with premium, say ouch, and then start grinning when I turn the key and it fires up and I forget all about the price of fuel and mpg. I laugh when people talk about spending thousands to stuff 400+ HP in a heavy brick and then they worry about mileage. Get the 5.7 if you want to use cheaper gas and get better mileage for sure. I have an LT1 Firebird that gets 26 higway for that.
For me, it is about the fun factor while still having something that is transportation. Always has been. I am like you in that I keep vehicles around. I have had my Formula Firebird 11 years and my 84 Ranger (stuffed a Mustang HO 302 in) for 12 years. I will have this Jeep for a long time and now that gerbil powered 3.8 is gone it is my favorite vehicle.
I have done little off road yet, the few mild things I’ve climbed she went up in 4 hi with little effort. I need skid pans under engine/tranny yet before anything challenging. Using 4 lo in a Rubicon, I can not believe there would be a crippling difference in low end torque between Hemi’s. The original 3.8 had plenty of power in 4 lo!
I paid a little over 16k for the complete install and the shop did all the parts hunting also. I just dropped it off and picked it up. That was about $2500 more than the 5.7 install would have been, and included them hunting down parts and replacing all the accessories on the car engine. I may add headers down the road, but not at $900 a set. I will lift, regear, and go to 35” eventually.
Anyway, no regrets on the 6.1 here. When I lift the hood and see that beautiful motor, life does not get much better. Your mileage may vary! Good luck.
08-04-2009, 03:51 AM
#26
JK Newbie
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Is it possible to have custom tuning done?? I would love to know who/where! The "sluggishness" (sometimes as much as a deadspot at low RPMs) has been a real disappointment for me. I have a feeling, after reading all the comments from the other 6.1L owners, mine is a little worse than most!
08-04-2009, 04:36 AM
#27
JK Super Freak
Great info! The wall is what I was hpoing to get. Your swap was done with an AEV premium kit(the one with the AEV exhaust) or was yours a custom exhaust job? I will agree on the point of when you open the hood. I think the 6.1 looks the best. How is the idle? Smooth? Have you seen, driven the 5.7? I'm looking for a comparison of the smoothness and manners of the two.
I have the AEV exhaust with the 5.7 manifolds. The idle is very smooth for both engines I have heard. I did ride in a 4 door with a 5.7, and it seemed pretty quick also. Without driving it I could not say the performance differences.
I do not know about the programming being the same for both engines, but agree that the A580 is probably a better tranny match. That mismatch and the restricted exhaust manifolds probably cause some of the issues. On the other hand, I have read of more problems with the 580 than the 545 as far as reliability.
I did use the AEV Procal programmer to put my exact tire size in as measured, and it seemed to help some.
Keep in mind also that I was already aware of the sluggishness problem before I had the 6.1 installed. I followed with interest the forums and companies working on the JK/Hemi stuff for a long time (as you are).
The aftermarket for Jeep is amazing. Someone may sort it out and leave me options for the future. I may change things up if and when AEV sorts out the A580/6.1 programming. That is if there is an upgrade path available for the kit I already have. The Jeep will never be done if I have not at the moment Just Emptied Every Pocket. A year or two down the road, who knows?
I feel I got a pretty good deal to have it done for 16k without getting greasy or taking months (a first for me). I do not have a hoist, am no longer young, and am working 2 jobs.
IMHO, based on what I have read, the 5.7 is in probably a better match and more efficient and drivable at low RPM in traffic (at least using the AEV kit). "Efficiency" is decieving though when you are pushing 400+ HP
With a 5.7 you can burn 89 octane and get better mileage. But I live in the country and do very little stop and go city driving, which may be why I do not find low end preformance annoying.I would choose the 5.7 if the price was a bunch lower than the 6.1, until they get the issues sorted out. Personally, for very little difference in cost to have the 6.1 installed, I have no regrets.
08-04-2009, 04:38 AM
#28
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Coming from a Mopar backgroung of almost 20 years in one location. I would say that either choice is great. we offer both with either the AEV set up or our own custom setup. Both motors are good and they are mated to the same trans. The calibration comes down to the 5.7 and 6.1 are close. The 6.1 does run a little fatter wich is good for the motor. I would have to say the 6.1l does have the extra get up and for sure the cool factor. Let us know if we can help you with anything.
Gerry
Gerry
08-04-2009, 05:01 AM
#29
JK Junkie
This came directly from Dave Harrington who owns AEV and is supplying most of the AEV swap conversion kits. The only other company out there doing it is Squire / Hotwire and they only have one tune. They are working on a second tune for the 6.1.
08-04-2009, 05:02 AM
#30
JK Junkie
Is it possible to have custom tuning done?? I would love to know who/where! The "sluggishness" (sometimes as much as a deadspot at low RPMs) has been a real disappointment for me. I have a feeling, after reading all the comments from the other 6.1L owners, mine is a little worse than most!