Gump switch to 5w30 Full Synthetic you'll notice a huge difference. Guaranteed. I did. Only after 3k miles too.

 

When I bought my first MOPAR turbo, a new '84 Dodge 600ES Turbo, I was faced with a new need... a "fleet use" (Taxi cabs, etc.) 30W CD/SF rated oil. I chose Penzoil 30W HD - now SL rated (No 'C', or diesel service, rating.). I used it exclusively and changed oil every 3k miles. I owned four previous new MOPAR turbo's, the '84 600ES, an '88 Sundance turbo (5sp), an '89 Voyager, and, my best car up 'til now, a '90 Shadow ES Turbo (5sp) hopped up with the MOPAR race computer, wires, +40% matched injectors, and K&N filter. They all had well over 100k miles when passed on, with no engine or turbo problems. They each got new radiators ~100k miles, the OEM's plastic tanks leaking, of course. The turbo's ranged from a huge AiResearch in the '84 to a small Mitsubishi in the '90. The key is allowing the turbo to cool after a run prior to shut-down - and regular changes.

I know multi-viscosity oils did break-down more quickly under high temps - like in a turbo. Straight viscosity oils are better 'under stress'. I also know that 30W is like chunky peanutbutter in your crankcase at sub-freezing temps. Of course,at operating temps, it is fine. Here in C.A. (Central Alabama), it has worked well all of these years... with only my '93 Dakota (3.9L V6 -used the same 30W oil!) needing a starter motor...at 138k miles! The owner's manual states 'dyno' is okay for my wife's new '05 SRT-4... may have to call re 30W use. At 400 miles thus far, it will be a few days...

Stainz05

 

I hate to say it, but your increase was probably due to mileage and not the oil. Both 5W30 and 10W30 are the same when it is at operating temperatures, the first numbers are it's cold weight and the last is it's hot weight, so at operating temperatures there is no difference between the two. That is why you want a lower weight oil in the colder winter regions, to aid in oil pump up. The higher weight oils take longer and are harder to pump up which will increase the risk of engine damage and wear. The only time you could have had a performance gain from using 5W30 instead of 10W30 is if you were running it hard when it was cold and not at operating temperature.

 

I'm in RI so that might've been the reason. But it seems to like the 5w30 better. Kinda like it likes Sunoco Ultra 93, and Mobil 93 only...it gets pissy on anything else. Cars can be weird.

 

[sm=icon_rtfm.gif] u cant go wrong...

 

This does not have to be complicated. 5W-30 full synthetic is what DCX recomends. Forget the Castrol ****, or Amsoil, etc. The BEST full synthetic on the market is Mobil. It has the best heat resistance and additive package out there. Mobil is one of the only oil's that use Boron in its additive package. Its really expensive. A few years back, Castrol found a base stock for their synthetic that was half the price of what they were currently using. They never passed the savings to the consumer. My Cycle World mag had a complete test on all synthetics, both cycle and automotive, Mobil one came out on top, naturally. The real issue with the SRT is the heat. If you don't have oil that can take the heat, your screwed. Full synthetic is the only way to go for peace of mind......by the way, who ever said on this thread that 5-30, and 10-30 are the same viscosity hot is correct. BUT, I swear my turbo spools up quicker with 5W-30. Maby it's in my head???? Probably.

 

By the way, if anyone is interested in seeing the test, it was either Cycle World or Motorcyclist magazine, on of the summer 2003 issues. You could probably read it online.

 

Mine did too after you did the change for me. My car definitely performed better with the Mobil1 Full Syn5w-30 than the 10w30. You noticed it on my car too which is why you changed yours. Is it in both of our heads??? [sm=smiley18.gif]