Modifying your Jeep SRT8: For Dummies [Archive] - Cherokee SRT8 Forum

: Modifying your Jeep SRT8: For Dummies


Sr Tate
06-27-2007, 10:46 PM
Just for starters Dummies don't buy SRT8 Jeeps....

I've been soaking up this board for 2 days straight. I've pretty much done bolt on upgrades in the past for other cars I've owned. With time/wallet to factor in I've decided to start with a Mopar CAI and Corsa/Mopar exhaust, 180 thermostat for the first round of mods. Kind of a stage 1.

As I was reading GotStroke's dyno list most folks do the CAI/exhaust upgrades and then different directions. I was wondering if the "Performance Modification Key" from GotStroke's list could be organized so a beginner would start here and pick the path to the garden. Criteria could be HP/Cost/ease of installation. This can give newbies like myself a guide to <see title>.

Derwood98
06-27-2007, 10:57 PM
Ha, Volant is still the front runner on CAI's and the Borla type S cat back is also front runner. Personally, I am still not sold on changing the thermostat. IMHO.

GotStroke?
06-27-2007, 11:09 PM
Ha, Volant is still the front runner on CAI's and the Borla type S cat back is also front runner. Personally, I am still not sold on changing the thermostat. IMHO.

BuilderBill among others have verified a .2 gain in back to back testing at the drag strip with a 176* stat. The PCM doesn't pull as much timing with a cooler motor which translates into more power.

CAIs and exhausts are typically the first mods done because they are the easiest to do (catback anyway) and they also change the way the vehicle sounds. Headers make power but they are a PITA to install and depending on brand you may end up with a MIL/CEL.
If I could do it over I'd get Runnin9s/generalconfusions soon to be released CF CAI, a 176-Tstat, the full exhaust I have now, and a B&G or Diablo tune (personally I'm waiting for Diablo). H/C have shown excellent gains as well, though unless you have a friendly dealer you can kiss your powertrain warranty goodbye.
Just remember, you'll never have a truly optimal combo (see the HP it should make) until we can custom tune our Jeeps on the dyno.

HoustonSRT-8
06-28-2007, 11:45 AM
BuilderBill among others have verified a .2 gain in back to back testing at the drag strip with a 176* stat. The PCM doesn't pull as much timing with a cooler motor which translates into more power.

After my overheating experience, I'm thinking of staying with the stock t-stat and not putting the 180 back in. I'm convinced that the extra pressure created by the aftermarket t-stat caused the problem. 2 tenths isn't worth being stranded by the side of the road, IMO.

SOUTHERNHOTROD
06-28-2007, 12:14 PM
Just for starters Dummies don't buy SRT8 Jeeps....

I've been soaking up this board for 2 days straight. I've pretty much done bolt on upgrades in the past for other cars I've owned. With time/wallet to factor in I've decided to start with a Mopar CAI and Corsa/Mopar exhaust, 180 thermostat for the first round of mods. Kind of a stage 1.

As I was reading GotStroke's dyno list most folks do the CAI/exhaust upgrades and then different directions. I was wondering if the "Performance Modification Key" from GotStroke's list could be organized so a beginner would start here and pick the path to the garden. Criteria could be HP/Cost/ease of installation. This can give newbies like myself a guide to <see title>.
I would highly recommend the Volant intake.

Check it out...
Volant Cool-Air Intake: 2006-07 JEEP Grand Cherokee SRT-8 (http://www.southernhotrod.com/store/product.php?productid=16564&cat=0&page=1)
I have them in stock and ready to ship.

I can also get you the Corsa.

Just give me a call if you have any questions.

Thanks!

GotStroke?
06-28-2007, 12:27 PM
After my overheating experience, I'm thinking of staying with the stock t-stat and not putting the 180 back in. I'm convinced that the extra pressure created by the aftermarket t-stat caused the problem. 2 tenths isn't worth being stranded by the side of the road, IMO.

What happened? Do you have a Stant cap too?

GodfatherSRT8
06-28-2007, 01:22 PM
I did the 180 stat mod and changed to the stant cap and still have a leak. Cant figure out where the heck its coming from.

http://i8.tinypic.com/4mv4nxy.jpg

http://i18.tinypic.com/6gt90es.jpg

HoustonSRT-8
06-28-2007, 01:35 PM
What happened? Do you have a Stant cap too?
http://www.cherokeesrt8.com/forums/showthread.php?t=5040

No, I don't have a Stant cap. If you think about it, though, running the Stant cap just pushes the extra pressure somewhere else.

GotStroke?
06-28-2007, 01:53 PM
http://www.cherokeesrt8.com/forums/showthread.php?t=5040

No, I don't have a Stant cap. If you think about it, though, running the Stant cap just pushes the extra pressure somewhere else.


I must have missed that thread. So it was a bad fan control module? I personally think the Stant cap is mandatory with an aftermarket T-stat. Though I do occassionally find coolant spray around mine (like Godfather's) after running it hard w/ the cap, it would be much worse without it. Also I couldn't detect any difference between stock/aftermarket T-stats pertaining to the amount of coolant that leaks out. The Stant cap definitely helped get rid of most of the spillage.
As far as I can tell the cap is the weak link in the system, everything else seems to be able to tolerate the added pressure which isn't a whole lot (cap is rated at 18psi).
Did you find any coolant coming from the T-stat/water pump area?

BuilderBill
06-28-2007, 02:05 PM
I must have missed that thread. So it was a bad fan control module? I personally think the Stant cap is mandatory with an aftermarket T-stat. Though I do occassionally find coolant spray around mine (like Godfather's) after running it hard w/ the cap, it would be much worse without it. Also I couldn't detect any difference between stock/aftermarket T-stats pertaining to the amount of coolant that leaks out. The Stant cap definitely helped get rid of most of the spillage.
As far as I can tell the cap is the weak link in the system, everything else seems to be able to tolerate the added pressure which isn't a whole lot (cap is rated at 18psi).
Did you find any coolant coming from the T-stat/water pump area?
Stroker,
I believe that on the way home from picking up the a new JGC from the dealer, the 1st stop should be Pepboys / Autozone to pick up the radiator cap, and possibly 2 thermostats (176* & 180*). Only the 180* if you will never take the beast to the track.

I am trying to keep an open mind about how a lower temperature causes higher coolant pressure. Hmmmmm. Maybe I am misisng something???
Very puzzled Bill

ChrisWK
06-28-2007, 02:31 PM
Moving the intake air temperture sensor is the best and cheap mod to do, I got one of the dashhawk things my tempertures are about 6 to 8 degrees of the outside temps,The tstat did not help all the much. But if stock it is just going to give you poor gas mileage.Moving the IAT my jeep is very respone on these 90 plus days.

Later

cobrakid
06-28-2007, 03:05 PM
....just a personal note, from my experience.

I did not get to track test this.

I moved the IAT....................

Bought another one afterwards, and remounted in stock location.....why?

Because when I sprayed my truck, it slowed down about 1.5-2 tenths and
2-3 mph with the IAT moved to a cooler spot.

My reasoning/explanation was that when the nitrous was subsequently hitting
the IAT, it was doing something "good" to the Jeep. My nozzle is mounted
about an inch behind the factory IAT sensor, and across from it.

These are just my conclusions? any thoughts?

Conditions were the same from 1 week at the track to the next. I just
thought about what was changed and changed back, and times came right back?

GotStroke?
06-28-2007, 03:08 PM
....just a personal note, from my experience.

I did not get to track test this.

I moved the IAT....................

Bought another one afterwards, and remounted in stock location.....why?

Because when I sprayed my truck, it slowed down about 1.5-2 tenths and
2-3 mph with the IAT moved to a cooler spot.

My reasoning/explanation was that when the nitrous was subsequently hitting
the IAT, it was doing something "good" to the Jeep. My nozzle is mounted
about an inch behind the factory IAT sensor, and across from it.

These are just my conclusions? any thoughts?

Conditions were the same from 1 week at the track to the next. I just
thought about what was changed and changed back, and times came right back?

Did you do any N/A testing with the sensor relocated? Also, if so, did you track the difference in DA between test days?

Sr Tate
06-28-2007, 07:58 PM
It seems some have verified the improvement of replacing with a 180*+ termostat. Interesting that everyone is not sold on it. I would assume the coolant temp is lower than when the stock thermo was in. Which would be less pressure on the system. Which equates to more HP as the motor is cooler.