LS1 JAY

First off let me start by saying that I HOPE I am posting this in the right forum? they are having a debate over at LS1.com about 5W-30 -VS- 10W-30. Here is a quote from someone over there: Alas... I don't want to get into an argument and I've not personally run oil tests on samples from my motors. I do know what works and I do know what makes better power. I've seen as much as 8-10 rwhp losses from running 10w30... ain't that amazing! My Z71 would run like a dog on 10w... talked with some 30 yr plus Chevy techs and found out it was a common loss and is why Chevy recommended 5w30 only. I have always run 10W-30 in both of my LS1's and now I am hearing this, I'm not too sure I agree however, if you can pick up 10RWHP by switching though, I'll be getting some tomorrow! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

LS1 JAY

Anyone care to say what they are running? 10W-30 or 5W30 ???

LEO

iTrader: (3)

Those #'s seem a bit high, I believe I read an article where there was a test between Mobil 1 syn. vs conventional 10w 30 - the difference was like 2hp.

Hugger

iTrader: (21)

I have always run 5W-30 mobil 1

ShooterSS

iTrader: (3)

Royal Purple 5W-30 Synthetic here. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

felton316

Why???? Once the oil is at operating temp, won't both be acting like a 30 weight? I thought the 5W or 10W was the cold weather viscosity. It might be true for the 20W-50 (which they call the high performance oil). But it shouldn't matter if both are 30's.

Patman

It's not true. I switch back from 5w30 to 10w30 after every winter and I never notice any power difference. Most 10w30 oils are slightly thicker at 100C than their 5w30 counterparts, but not enough to change the horsepower that much.

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 Patman:
<strong>It's not true. I switch back from 5w30 to 10w30 after every winter and I never notice any power difference. Most 10w30 oils are slightly thicker at 100C than their 5w30 counterparts, but not enough to change the horsepower that much.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I have always ran Amsoil 10W 30 in all of my F-Bodys and have never gave it a second though, I don't see how oil alone could cause such a gain or loss in RWHP, it just doesn't make sense, if this were true I would think more would be talking about the performance benefits of 5 -vs-10.
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

gdr4u19

That is a very broad statement. Let's consider mineral vs. synthetic,how many miles are on the oil? Which brands are we comparing?
I personally think the weather has more to do with making horsepower,than oil.

Nine Ball

iTrader: (38)

Only Castrol GTX 10W-30 has gone into my motors.

Tony

Bad Blu Formula

iTrader: (3)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Nine Ball:
<strong>Only Castrol GTX 10W-30 has gone into my motors.

Tony</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Same here.

Andy West

I dont know about weights, but I have read that with fully synthetic oil, you can gain 10 HP.

Thats what I hear anyways.

Patman

It's an old wive's tale that you can gain 10hp from the switch to synthetic. It's really not that much more slippery. In some cases the antiwear additives in dino oil are just as slippery as in their synthetic counterparts. Where synthetics shine are in the fact that the base oil is better, so it withstands the heat better, maintains it's visosity longer, can flow better at extreme cold temps, and can withstand longer drain intervals. But giving you more MPG and more horsepower, not really, not a measureable amount anyways.

LS1 JAY

But what do you guys think about the You will gain 10 rwhp switching from 10W 30 to 5W 30 is this BS or what? personally, I think I'll stick with 10W 30.

cantdrv65

iTrader: (3)

This should answer all your questions:
http://www.roadkill.com/~davet/moto/oilinfo.html
As you can see, Mobil 1 leaves the field in the dust. I highly doubt you would see any difference on a dyno, the friction difference between a dino and synthetic can't be much.

<small>[ May 18, 2002, 02:34 PM: Message edited by: cantdrv65 ]</small>

Skelton

I use castrol 10w-30 also. I dont think I'm losing any hp.

2QuikTA

Good 'ol Royal Purple here...it prob. doesn't make any difference but it just gives me peace of mind

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 cantdrv65:
<strong>This should answer all your questions:
http://www.roadkill.com/~davet/moto/oilinfo.html
As you can see, Mobil 1 leaves the field in the dust. I highly doubt you would see any difference on a dyno, the friction difference between a dino and synthetic can't be much.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That page is so old it's meaningless now! The oils on that page are of the SG rating, and since then there have been three reformulations, SH, SJ and now the latest SJ. So all the oils on that page are totally different now, you can't compare those numbers anymore.

SS00Blue

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ShooterSS:
<strong>Royal Purple 5W-30 Synthetic here. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">ALWAYS!

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Patman:
<strong>It's an old wive's tale that you can gain 10hp from the switch to synthetic. It's really not that much more slippery. In some cases the antiwear additives in dino oil are just as slippery as in their synthetic counterparts.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I can agree that dino is the same... for the first hour, MAX. After that the dino breaks down like an 'e' curve, where the synthetic just stays reasonably stable. And yes, it's been shown time-after-time, in laboratory-after-laboratory, and dyno-after-dyno that synthetics free horsepower. No matter how the oil cartels try to deny that truth, the truth just keeps marching ahead.

SC

<small>[ May 18, 2002, 07:05 PM: Message edited by: SS00Blue ]</small>

Patman

The problem is, there aren't as many true synthetics out there anymore. Royal Purple is not a full synthetic, neither is Castrol or Quaker State or Pennzoil. Mobil 1, Amsoil and Redline are. A lot of oil companies are using group 3 hydrocracked oil for their base, which isn't a true synthetic, but they are technically allowed to label themselves this way even when using this inferior base oil. The true synthetics use a group 4 or group 5 (or combination of both) base oil, which is a pure synthetic, not a highly refined petroleum like group 3 is.