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pjs1965 03-28-2010 05:01 PM

Modding for Beginners - Bolt On Performance Mods
 
Introduction
So you've finally bought your Jeep SRT8 and driven it home. You're amazed at the power it has and how well it handles too. There's a big ole grin on your face every time you start it up and you swear it's the greatest thing since sliced bread.

Then you log onto a forum or two and start reading about 'going faster/better' with just some simple modifications. You think to yourself, it's great the way it is until one day you realize, it's not all that expensive to make it just a little better.

You read about cold air intakes (CAIs) and thermostats and 'tunes' but you're not sure which one to buy or when/how/what.... well, not to worry, this thread is an introduction to Bolt On Performance Modifications for your Jeep SRT8.

Comments and Suggestions are more than welcomed!! This thread is meant to inform NOT to sway anyone towards any specific product. Of course it's may not be possible to cover every possible product out there so if you see something that brings value, please post up!
  • Cold Air Intakes
  • Tires
  • Exhaust Systems
  • DiabloSport Tuning & Tunes
  • Misc

pjs1965 03-28-2010 05:01 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Cold Air Intakes
[Wikipedia Reference]
There are several popular makes and models of CAIs made for the Jeep Grand Cherokee SRT8. To date, there's been no formal testing showing how each make/model performs against one another. Having said that, it is important to know that Jeeps with CAI perform better than Jeeps without them. This is especially true on 'tuned' Jeeps.

These are the most popular CAIs
  • AFe Stage II CAI
  • Arrington CAI
  • Bwoody Performance 4" CAI
  • Mopar CAI
  • Volant CAI

Honorable Mention
  • LMI CAI (legmaker)
  • K&N CAI
  • AirRaid CAI

Another option is a drop in filter replacement. While the stock setup is very close to a CAI itself, the bottleneck is the filter. Upgrading the filter to a better flowing one, will increase air volume into the engine and allow for better performance possibility.

Drop In Air Filters
  • K&N Filter
  • S&B Filter

pjs1965 03-28-2010 05:02 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Tires
The Jeep SRT8 comes with Goodyear RS-A EMT run-flat tires. The SRT Engineers chose this tire because of the added sidewall rigidity which improved the handling characteristics of the vehicle. They are a very capable all-season tire yet because of the rigid sidewall of the run-flat, they can be harsh. The wheels and tires are 'staggered' meaning they are different sizes.

Stock Wheels
The OEM Stock wheels are Alcoa Forged 20" wheels or Alcoa Forged 20" wheels with Dura-Brite finish. These wheels have an offset of 34.75mm (front) and 50mm (rear) with a 5x127mm bolt pattern.

Optional Tire Sizes on Stock Wheels
STOCK
Front = 255/45R20 101W
Rear = 285/40R20 104W

WIDE OPTION
Front = 255/45R20
Rear = 295/40R20

WIDER OPTION
Front = 275/40R20
Rear = 315/35R20

Popular Tire Options
  • Nitto 420s
  • Nitto INVO
  • Toyo Proxes ST II
  • Vredestein Ultrac Sessenta
  • Yokohama Parada Spec-X

Other Tire Options
Bridgestone HP Dueler

pjs1965 03-28-2010 05:21 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Exhaust Systems
The SRT8 has a great factory exhaust setup. As per the SRT Engineers, the headers are nearly 'shorty performance headers' mated to a 2.75" low-restriction exhaust system that utilizes a 'suitcase' muffler and 2 resonators to maintain civil sound levels. Standard 3" center exit polished tips finish off the stock system.

Because of the excellent design of the entire exhaust system, there's little if any increase in performance from a cat-back exhaust system. Based on price to performance measurements, it's hard to justify them as performance add-ons yet one can justify the expense for the improved sound quality!

Popular Cat-Back Exhaust Systems
  • Corsa Cat-back
  • Mopar Cat-back (Corsa Built)
  • Magnaflow Cat-Back
  • Borla S Cat-back
  • Borla T Cat-back

Non Cat-back Exhaust Options
There are other options to improving the sound quality of your exhaust without spending alot of money on a cat-back system. Some Jeep owners have used either one of these options or both with great success.

Resonator Delete involves removing the 2 resonators and replacing them with 304 stainless piping.
Muffler Swap involves swapping the stock suitcase muffler with a perfmance muffler.
  • Dynomax 17554
  • MagnaFlow 12599
  • Borla XR-1
  • Borla S Muffler

Long Tube Headers + Midpipes
  • Kooks
  • American Racing Headers
  • Stainless Works
[NOTE: Currently long tube headers will not pass OBDII emissions tests]

pjs1965 03-28-2010 05:24 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
DiabloSport Tuning & Tunes
For HEMI powered vehicles, the only tried and tested tuning option is from DiabloSport. They offer 2 devices for the Jeep SRT8, the Predator and Trinity. Another device coming in May 2010 is the 'inTune' and will be similar to the Trinity (almost iPod Touch appearing) and offer additional features not currently offered in either the Predator or Trinity.

DiabloSport Predator
Description from DiabloSport's website
Quote:

The Predator is a state-of-the art, high performance tuning flash programmer in a sleek handheld design. Once connected to the vehicle, the Predators internal computer recognizes the vehicles PCM and automatically picks the proper tuning files designed specifically for that PCM. Inside the Predator's memory are the actual tuning files that optimize the tunes in your vehicle. Unlike other 'tuners', DiabloSport's programming is performed in very small increments throughout the entire RPM range, for a smoother, wider and a more predictable power delivery. DiabloSport engineers spend many hours on the dyno, street and track to ensure the tunes provided with the Predator are the best they can be.
U7135 Stock Vehicle Tunes
  • 93 Octane Performance Tune
  • 91 Octane Performance Tune
  • 93 Octane Performance CAI Tune
  • 91 Octane Performance CAI Tune
  • Modify Factory Tune

DiabloSport Trinty
Description from DiabloSport's website
Quote:

The DiabloSport Trinity is simply put, one of the most advanced tuning devices in the market. With the capability to tune, log and record data, display and customize virtual gauges, read and clear trouble codes. and even compute multiple track times the DiabloSport Trinity is the answer to all of your EFI tuning needs. Trinity supports all vehicle application under a single part number which means you have the option to tune multiple vehicles with only one Trinity (Only 1 vehicle can be tuned at any given time). With a high resolution color touch screen, state of the art graphics/GUI, and the ability to customize gauge layouts the Trinity enhances the interior of any vehicle. The Trinity also has the capabilty to control/communicate extrenal devices such as the DiabloSport Extreme PowerPuck, DiabloSport EGT Module, and other third party devices.
T-1000 Stock Vehicle Tunes
  • 93 Octane Performance Tune
  • 91 Octane Performance Tune
  • 93 Octane Performance CAI Tune
  • 91 Octane Performance CAI Tune
  • Modify Factory Tune

What's a Tune?
????

Types of tunes:
  • Stock/Original Tune - a ECM image from Jeep installed at the factory or by a dealership/
  • Canned Tunes - tunes shipped with a DiabloSport device.
  • CMR Tune - a tune developed specifically for your vehicle by a CMR specialists (tuner) to enhance the performance and driving experience. Generally, CMR tunes can be revised by datalogging specific PIDs and sending the logs to the tuner who makes adjustments as needed.
  • Dyno Tune - a tune enhanced specifically for your vehicle by a CMR specialist (tuner) using a dyno to simulate load on the engine/drivetrain so the tuner can monitor PIDs and make adjustments as needed.

Common Terms:
  • CMR = Chip Masters Revolution, a DiabloSport product.
  • Tuner = a specialist with CMR software who can manipulate parameters within the ECM to improve performance and the overall driving experience. Good tuners have a solid knowledge of the inner-workings of the HEMI engine/drivetrain.
  • PIDs = parameter IDs. These are specific parameters within the ECM and have a value.
  • datalogging - capturing information on PIDs to a log file which you can share with your tuner for analysis. There's 2 ways to datalog, a) on the device itself or b) connecting the device to a laptop and using the DataViewer program to capture logs.
  • DataViewer - a Windows-based application developed by DiabloSport for analysis and review of logs and data captured by a device.
  • DSDownloader - a Windows-based application developed by DiabloSport to update a device as well as copy tune file from your laptop to the device and vice versa.

pjs1965 03-28-2010 05:24 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Additional Items

There are some mods which are IMO stand-alone and/or simple one-liners which I've chosen to list here. This doesn't mean they are less important or less meaningful than the others I've listed previously.

Engine
180* Thermostat
There's at least 2 options here Motorad or Jet.

Suspension
Lowering Springs
Eibach ProSeries
Bwoody Performance Lowering Springs
H&R Lowering Kit (WK)

Swaybars and Swaybar Links
Swaybars = Addco Swaybars
Swaybar links = Bwoody Upgraded Sway Bar Links

Driveline
Paramount Performance Stage II Valvebody
Improved shifting, less slippage may enhance the life of your transmission when adding HP to your Jeep. Better shifting = better performance!
From their website:
Quote:

  • Designed by using a fully operational, test NAG1 that monitored all clutch pressures, torque converter pressures, and torque converter lock up clutch pressures all with accurate analog gauges.
  • The Stage II modified valve body will increase the NAG1 shift pressures.
  • The more aggressively the NAG1 is driven, the firmer the shift.
  • The downshifts are firmer than stock also, but not to the point of being too harsh.
  • Unheard of Full warranty for 1 year!

SUMMARY/CLOSING COMMENT:
This is not intended as a comprehensive list of all modifications rather it's a great introduction to MODS that will provide any Jeep SRT8 owner with additional power and an improved overall driving experience without breaking one's budget. Comments and added insight is greatly appreciated here. I will gladly add more information to each post as warranted.

I will continue this series with a "Intermediate Modding" for the next stage of our passion :)

Scottina06 03-28-2010 05:53 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
excellent Peter! Only thing I can add is that the Bwoody is the ONLY true CAI. the rest are short rams

jeeppro 03-28-2010 05:54 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Quote:

Originally Posted by Scottina06 (Post 177977)
excellent Peter! Only thing I can add is that the Bwoody is the ONLY true CAI. the rest are short rams

when we going to see it for the 4.7s

Megatron 03-28-2010 06:05 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Do I smell sticky?

Scottina06 03-28-2010 06:08 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
try to stay on subject for this fellas.....SRT8 performance! Thanks!

pjs1965 03-28-2010 06:10 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
Quote:

Originally Posted by Scottina06 (Post 177977)
excellent Peter! Only thing I can add is that the Bwoody is the ONLY true CAI. the rest are short rams

I'm working off the definition provided through Wikipedia so as not to sprial this discussion into a 'he said/she said' but rather to keep the discussion technical and practical :)

Rather than this:
Quote:

The Bwoody is a 'fender mounted cold air intake' which "provides even more isolation and still cooler air".
I'd rather see this:
Quote:

A fender mounted cold air intake provides even more isolation and still cooler air than a short ram intake.
And even this:
Quote:

Intakes with heat shields are better than stock yet not completely isolated from the engine bay.
We can discuss the pros and cons of each intake by keeping it generic yes?

See Scott, now I've got some editiing to do to my post :D You bring up an excellent point and food for thought!

Scottina06 03-28-2010 06:15 PM

Re: Modding for Beginners - Bolt On Performance Mods
 
true....very true


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