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  #73  
Old 10-12-2011, 04:02 AM
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Re: Accelleration in the v8 vs v6

I keep my hemi in 3rd all day (ie limiting to max of third gear). This way I feel it drives like it should. Not for highway use of course, but around town.

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  #74  
Old 10-21-2011, 10:23 AM
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Re: Accelleration in the v8 vs v6

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Originally Posted by brandont View Post
The V8 offers gobs of torque which is what you feel when you drive the car. As the saying goes people drive torque but buy HP. The feeling of great power when you tip in the throttle is torque - that's what people like. HP is actually a measure of efficiency not outright power.
That torque people "feel" means there is a lot of horsepower available when they stab the throttle because horsepower is torque applied at a given rpm. So, the more torque you have at a specified rpm, then the more horsepower you have available at that rpm; they are are not independent. The Hemi has more than the Pentastar all over. You can have 500 ft-lbs of torque applied to something (static) but if it isn't moving, then you have no horsepower and feel nada.

Also, comparing peak torque ratings is not the whole story; more importantly is the size of the area under the torque curve. Torque peak is where the engine maximizes volumetric efficiency (maximizing the air-fuel volume intake charge) and occurs at an rpm that is determined by the engine's cam valve timing and intake/exhaust system design...turbo engines can generate peak torque across several thousand rpm (huge torque curve area) while N/A engines cannot but come close with variable valve timing.

Variable valve timing enhances the peak range torque so that it is fatter and flatter (i.e. the Pentastar and Hemi can have 80%-90% of peak torque thousands of rpm lower than their rated peak torque rpm)...broadening the torque curve. The key here is the more toque at a given rpm that you have, then the more horsepower that you have and that is why the Hemi is quicker. Horsepower is the measure of work available...a measure of work being done. The broader the torque curve is, then the more horsepower (available work) you can do across the rpm range.

IMHO, the Hemi WK2 is one heck of a lot quicker than the C&D test and several drag strip observations of stock Hemi WK2s confirm that.
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  #75  
Old 10-21-2011, 10:43 AM
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Re: Accelleration in the v8 vs v6

Quote:
Originally Posted by Bmwister View Post
That torque people "feel" means there is a lot of horsepower available when they stab the throttle because horsepower is torque applied at a given rpm. So, the more torque you have at a specified rpm, then the more horsepower you have available at that rpm; they are are not independent. The Hemi has more than the Pentastar all over. You can have 500 ft-lbs of torque applied to something (static) but if it isn't moving, then you have no horsepower and feel nada.

Also, comparing peak torque ratings is not the whole story; more importantly is the size of the area under the torque curve. Torque peak is where the engine maximizes volumetric efficiency (maximizing the air-fuel volume intake charge) and occurs at an rpm that is determined by the engine's cam valve timing and intake/exhaust system design...turbo engines can generate peak torque across several thousand rpm (huge torque curve area) while N/A engines cannot but come close with variable valve timing.

Variable valve timing enhances the peak range torque so that it is fatter and flatter (i.e. the Pentastar and Hemi can have 80%-90% of peak torque thousands of rpm lower than their rated peak torque rpm)...broadening the torque curve. The key here is the more toque at a given rpm that you have, then the more horsepower that you have and that is why the Hemi is quicker. Horsepower is the measure of work available...a measure of work being done. The broader the torque curve is, then the more horsepower (available work) you can do across the rpm range.

IMHO, the Hemi WK2 is one heck of a lot quicker than the C&D test and several drag strip observations of stock Hemi WK2s confirm that.
I have raced a pretty wide array of vehicles with my wk2 and it is definately quicker than what the magazines say. I did get completely killed by a new mustang gt though, but damn did that gt sound good pulling away. The closest race I had was my brother in law's nissan altima with the 3.5. He won, but not by a lot, that was a good race.
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  #76  
Old 10-27-2011, 01:35 AM
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Re: Accelleration in the v8 vs v6

IMHO You buy the V6 because its nice and you buy the Hemi because you can.
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  #77  
Old 10-27-2011, 04:55 PM
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Re: Accelleration in the v8 vs v6

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Originally Posted by Slowgan View Post
so is there a clear cut answer as to which accelerates faster? and by how much?
Consumer Reports: 2011 JGC Laredo V6 4x4 vs. 2011 JGC Limited V8 4x4. Remember that they do not brake torque on the launch, and therefore, the times are very conservative compared to Car & Driver. But, they match how we drive 99% of the time.

Curb Weight: 4930 vs. 5260 lbs
0-30: 3.7 vs. 3.0
0-60: 9.1 vs. 7.9
45-65: 6.2 vs. 5.1
1/4 Mile: 17.0 @ 86 vs. 16.0 @ 89
0-60 with 5000 lb Trailer: 19.2 vs. 15.7
CR overall MPG: 18 vs. 14
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  #78  
Old 10-30-2011, 10:32 AM
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Re: Accelleration in the v8 vs v6

The official Jeep brochure says:
V6
286 HP at 6 350 RPM
0-62: 9.1 sec

V8
352 HP at 5 200 RPM
0-62: 8.7 sec

Which is slightly different from what you are quoting...

And, here in Poland, we have another solution - italian 3.0 CRD version
241 HP at 4 000 RPM
0-62: 8.2 sec

Quite fast, uses less fuel but... hmmmm... is made by VM...

Price is set between V6 and V8.
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  #79  
Old 10-30-2011, 11:19 AM
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Re: Accelleration in the v8 vs v6

try driving the jeep in the sport mode it might be a little quicker
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  #80  
Old 10-31-2011, 02:29 PM
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Re: Accelleration in the v8 vs v6

My question is...

When compiling these acceleration numbers, did they engage Tow/Haul mode along with Sport mode for the maximum possible performance?



Is there any way to find out the specific setting used in various acceleration tests?
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  #81  
Old 10-31-2011, 03:00 PM
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Re: Accelleration in the v8 vs v6

Quote:
Originally Posted by bilex View Post
The official Jeep brochure says:
V6
286 HP at 6 350 RPM
0-62: 9.1 sec

V8
352 HP at 5 200 RPM
0-62: 8.7 sec

Which is slightly different from what you are quoting...

And, here in Poland, we have another solution - italian 3.0 CRD version
241 HP at 4 000 RPM
0-62: 8.2 sec

Quite fast, uses less fuel but... hmmmm... is made by VM...

Price is set between V6 and V8.
The V8 has proven way faster than 8.7 seconds 0-60. The original V8 testers had major ECM calibration issues with the throttle opening that caused them to be very sluggish off the line. My V8 4x4 overland at 5400lbs test weight has gone 0-60 in the mid 6 second range bone stock as tested with my HP Tuners scanner.
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  #82  
Old 10-31-2011, 05:43 PM
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Re: Accelleration in the v8 vs v6

Quote:
Originally Posted by Trevorj View Post
IMHO You buy the V6 because its nice and you buy the Hemi because you can.
Not really. Here in Korea, Hemi is not available. On top of that, Overland costs almost $70grand.
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  #83  
Old 10-31-2011, 06:41 PM
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Re: Accelleration in the v8 vs v6

Quote:
Originally Posted by Terminator2 View Post
The V8 has proven way faster than 8.7 seconds 0-60. The original V8 testers had major ECM calibration issues with the throttle opening that caused them to be very sluggish off the line. My V8 4x4 overland at 5400lbs test weight has gone 0-60 in the mid 6 second range bone stock as tested with my HP Tuners scanner.
I have raced and beat a few different cars with 0-60 times a lot faster that 8.7 seconds. I have a bone stock Laredo X with the Hemi.

I have a Ford Fusion and previously had a 2005 Crown Vic. The vic was rated around 8 flat to 60 and would beat my fusion by ~2 cars to 60mph. The new Jeep is rated at 8.7 to 60 but yet it beats the fusion to 60 by about 6 cars. It is definately faster than 8.7 to 60mph.

I can believe the mid 6 second range. When I do my 0-60 runs counting in my head (one one-thousand, two one-thousand, three one-thousand, etc...)I always come up with 6.63 seconds.
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  #84  
Old 10-31-2011, 06:51 PM
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Re: Accelleration in the v8 vs v6

Ok, and what about V6? Maybe that one is a little bit faster too?

And bigpanda - in Poland Overland V6 costs around 75 000$
Overland V8 - 87 000$

I want to live in US!
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