LS1 JAY

All I know is that I have always had good results with Amsoil 10W 30 so I plan on sticking with it. I'll leave the 5W 30 stuff for the guys who don't live here in Florida! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Palm Beach Z

A couple years ago, I changed from Castrol 5-30W to Valveoline 10-30 SynPower, full synthetic.
Living in South Florida, 10-30W is the only way to go in my opinion. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

MelloYellow

Going up to 40W or 50W should lose HP, but not staying within 30W.

OBSSSD

No measureable loss from 5W-30 to 10W-30

Y2K2LS1

So what synthetic oils are group 4&5??

<img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

LS1 JAY

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by MelloYellow:
<strong>Going up to 40W or 50W should lose HP, but not staying within 30W.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I agree.

Patman

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Y2K2LS1:
<strong>So what synthetic oils are group 4&5??

<img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Redline, Amsoil, Mobil 1, and possibly Valvoline (although I'm not 100% sure on that one)

StevieZ

iTrader: (3)

Patman hit it right on the nose. Anti-shear, anti-oxidant,and all the rest of an oil's specs come from the additive package. Incidently, Royal Purple "street oils" are not 100% synthetic but the race oils such as # 21 or #41 (my personal choice) ARE 100% synthetic

Patman

The RP race oils are 100% synthetic, that is true, however they also contain a low amount of detergents in them, so that makes them a bit dicey for street use. Problem is, if you use an oil with a low amount of detergents for a long time, you'll end up with more sludge in the engine. With a race engine that obviously doesn't matter since it's not going to go much more than 20-25k without being torn down. But for the average street driven car, we don't have this luxury.

Another thing, race engines are a different breed, they don't have to go in stop and go traffic, they aren't going to be started and shut off 200 times with the same oil in there, and therefore the additive packages that go into a street oil are different than that of the race oils. I'm sure that a RP tech will tell you the race oils are safe to use, however they also want to sell you the oil. There are vastly different additive packages in a race oil versus a street oil, I wouldn't chance it.

The reason they don't put as much detergents in the race oils is because it actually lessens the chance of detonation, and gives the oil a bit better lubricity as well, for slightly more power.

Ls1 382ci SS

I run mobil 5w-30 synthetic. Someone told me that for my 200-250 shot a synthetic 10w-30 would be better cause it's thicker and better since i'll be spraying a larger shot. is this true??

LS1LT1

iTrader: (16)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1JAY:
<strong>Anyone care to say what they are running? 10W-30 or 5W30 ???</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Mobil 1 0W-30, same specs as the 5W-30 but even better cold start up numbers and hopefully more hp too. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

StevieZ

iTrader: (3)

Actually RP #41 has a VERY high detergent package. It is made for endurance racing and has a detergent package that almost compares to a diesel oil . I used in in my 1998 Viper from the very beginning from 250KMS right up until I sold it with 33,000KMS, changing oil every 5000KMS. At 28,000KMS the car dynoed 443 RWHP with just a cat back , air filters ,a pulley ,an aluminum flywheel and a reflashed ECU.(that is about 510 at the crank) I would not worry about using it.