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-   -   How to get HP at the tires? (http://www.jeepgarage.org/f108/how-to-get-hp-at-the-tires-44774.html)

JeremyJamesDec15 07-16-2012 12:21 AM

How to get HP at the tires?
 
I have a 2012 WK2 overland summit with the 5.7, I have added a Mopar Cold Air Intake, A Corsa Cat Back Exhaust, I am rumming Royal Purple oil in it. No matter what I do it seems like I am not gaining or cant feel any extra HP. I previously had a 08 WK with the 5.7 which had ALOT! more balls then my 2012. I know they dropped the gearing down to get better gas milage, but my 5.7Hemi feels like a v6 on a good day.

Any comments or help here?

77rednecktruck 07-16-2012 06:04 AM

Re: How to get HP at the tires?
 
just need to wait for a tuner. Intake and exhaust is probably only a few HP anyway, probably won't feel it.

JeremyJamesDec15 07-16-2012 08:36 AM

Re: How to get HP at the tires?
 
But would a tuner even do much since it's geared so low. A tuner can change the axle gearing.

montgb 07-16-2012 09:35 AM

Re: How to get HP at the tires?
 
Apparently B&G Performance is stating that they can tune the 5.7L WK2 in addition to the SRT8. Check the WK2 SRT8 forum for more details.

Edit: Here you go - http://www.jeepgarage.org/f169/2012-jeep-srt8-flashed-ecu-wow-44040.html

77rednecktruck 07-16-2012 01:53 PM

Re: How to get HP at the tires?
 
Quote:

Originally Posted by JeremyJamesDec15 (Post 657198)
But would a tuner even do much since it's geared so low. A tuner can change the axle gearing.


The Hemi leaves a lot on the table with the piss poor programming. A tuner cannot change rear end ratios but will make a big enough power increase to have you feel it right away. Plus, changing shift points and other settings will greatly alter the way the vehicle runs and feels. They also allow for other mods such as cams and forced induction, you cannot do that now without the tuner.

ColdCase 07-16-2012 04:54 PM

Re: How to get HP at the tires?
 
The tranny shift points are the biggest culprit with regards to how good the V8 feels, and a tuner can alter the shift points and make them stiffer.

Unfortunately, and its pretty well known, throwing a CAI or exhaust on the new JGCs does nothing for performance, they are simply noise makers. Although there may be a difference felt initially, the computer will adjust it back to pretty much stock after a few ignitions cycles.

Personally, mine jumps off the line with authority, certainly not a V6. It is the slow cruising throttle response that's annoying to me, along with the delayed down shifts. Running in sport mode 5th or in tow/haul mode does wonders to feel and driving satisfaction with a corresponding significant hit in mpg. My Hemi did not loosen up to around 10,000 miles, however.

Oh, always use mid or high octane for max performance, and switch to synthetic oil.

Tim H Calgary 07-16-2012 05:22 PM

Re: How to get HP at the tires?
 
Catback does nothing performance wise. CAI isn't much of a gain either depending on how restrictive the intake is. My original round of mods (headers, exhaust, cam and a CAI only gave me about 40whp with a CMR tune from Johan. If I could do it over again I would just go straight to the SC. Just my 2 cents.

montgb 07-16-2012 07:51 PM

Re: How to get HP at the tires?
 
Quote:

Originally Posted by Tim H Calgary (Post 657411)
Catback does nothing performance wise. CAI isn't much of a gain either depending on how restrictive the intake is. My original round of mods (headers, exhaust, cam and a CAI only gave me about 40whp with a CMR tune from Johan. If I could do it over again I would just go straight to the SC. Just my 2 cents.

I assume you're just talking about the effects of a cat-back on the WK2, which would provide a bump of about 7-12whp. In other cases, I've seen a cat-back unleash 25+whp, especially when secondary cats and/or resonators are eliminated.

JeremyJamesDec15 07-16-2012 08:46 PM

Re: How to get HP at the tires?
 
Quote:

Originally Posted by ColdCase (Post 657401)
The tranny shift points are the biggest culprit with regards to how good the V8 feels, and a tuner can alter the shift points and make them stiffer.

Unfortunately, and its pretty well known, throwing a CAI or exhaust on the new JGCs does nothing for performance, they are simply noise makers. Although there may be a difference felt initially, the computer will adjust it back to pretty much stock after a few ignitions cycles.

Personally, mine jumps off the line with authority, certainly not a V6. It is the slow cruising throttle response that's annoying to me, along with the delayed down shifts. Running in sport mode 5th or in tow/haul mode does wonders to feel and driving satisfaction with a corresponding significant hit in mpg. My Hemi did not loosen up to around 10,000 miles, however.

Oh, always use mid or high octane for max performance, and switch to synthetic oil.

I only have 2500 miles on mine but I am running Royal Purple full synthetic oil in it. According to the owners Manual it states in RED BOLD print to not use premium fuel in it, it states to use 89 or 87 which I use 89. Will premium fuel harm the jeep and or what are the positives and negitives to using premium fuel?

ColdCase 07-16-2012 09:00 PM

Re: How to get HP at the tires?
 
Quote:

Originally Posted by montgb (Post 657496)
I assume you're just talking about the effects of a cat-back on the WK2, which would provide a bump of about 7-12whp. In other cases, I've seen a cat-back unleash 25+whp, especially when secondary cats and/or resonators are eliminated.

I've seen my share of interpreted/manipulated dyno charts.. like statistics, you can present the same results in a number of ways to prove about anything... :)

Is that gain peak or across the board, immediately after install, a ECU reset or after at least 10 engine hours, 10 ignition cycles. Same temp/humidity, different days? What about torque?

I've read that anything +/- 10% is within margins of error and therefor pretty meaningless. The same engine/setup will run 10hp different from day to day for this type of engine. The data collected for the dyno charts I've seen was collected using flawed procedures, most conveniently leave out important fine print and are probably not worth the paper they are printed on.... except for perhaps marketing.

JeremyJamesDec15 07-16-2012 09:06 PM

Re: How to get HP at the tires?
 
Quote:

Originally Posted by ColdCase (Post 657531)
I've seen my share of interpreted/manipulated dyno charts.. like statistics, you can present the same results in a number of ways to prove about anything... :)

Is that gain peak or across the board, immediately after install, a ECU reset or after at least 10 engine hours, 10 ignition cycles. Same temp/humidity, different days? What about torque?

I've read that anything +/- 10% is within margins of error and therefor pretty meaningless. The same engine/setup will run 10hp different from day to day for this type of engine. The data collected for the dyno charts I've seen was collected using flawed procedures, most conveniently leave out important fine print and are probably not worth the paper they are printed on.... except for perhaps marketing.

All I know is for the 1500 bucks I spent on a CAI and a Cat back I was hoping to notice something. But most my Tech's at the dealership say the axle is just geared so low for fuel economy that there is not alot I can do to "feel' the additional HP. All I know is my 08 5.7 WK had twice the balls so it felt like it.

JeremyJamesDec15 07-16-2012 09:17 PM

Re: How to get HP at the tires?
 
I really cant wait till a tuner comes out. I dont like the idea if sending my computer out to get flashed or what not. Yea it may work but for once I am down without my jeep, two I personally dont know the guy messing with the computer on my $50K jeep and three it's not like with a tuner where if I can go back to stock by simply pulling out my tuner and reflashing it on my own. No offence to you if your one of the guys doing this work.


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