Specs HP and torque..

 

About oil weight

My vette 5w30
My kymco scooter 15w50

Difference beetween two vehicle

Vette max rpm 5000, 8 cyl
Kymco max rmp 8000, 1 cyl

I don't believe oil weight is related to car wear, or increased clearences, it it instead related to the max engine rpm and temp

The higher engine rpms, the higher oil weight

 

O.K. Soooo you're being pretty cryptic now, but I'm guessing you posted that to "make a point" that 300 hp isn't "375" hp? Notice that I put the 375 in quotes. That's because...

Did you happen to see the GM produced Graph that I posted? Or the dyno shoot out results?

 

Someone made a comment about thinner oils only being good for fuel economy or getting a few more HP. Your right but your wrong. New cars are running thinner oil for two basic reasons, fuel economy, and the bearing tolerances are VERY tight. Not the old .003" like an old SBC. .001 or less can be spec. You NEED thinner oil or your oil pressure would be stupid high. Newer engines are LESS tolerant to NOT changing the oil on a regular basis than older engines because of the tolerances.

 

OK Tom, I didn't get your implication (about manufacturing techniques). Sometimes you gotta say what you mean...which is why I tend to err on the side of saying too much.

I have to say I don't understand ddahlgren's position in any of this. Sure I get that he doesn't think motor build quality is good. Nor do I (or we?) have stats on longevity. Personally, I expect mid 1990's engines to last 200k or more -- which is a significant improvement over the 120k-150k back in the 60's-70's.

OTOH, I remember be advised to AVOID sports cars with 100k or more. That's because engines driven hard typically don't last as long. I'd have to see stats to be convinced new motors (C4's) don't last "on average" quite a bit better than the 60's-70's era SBCs.

Ddalhgren, I think the onus of proof to back up heavier oil needs more from you. Mostly because I think most of us know how much longer newer motors last. And....that HP ratings HAVE changed! You SEEM on the wrong side of all of this!

Oddly, though, I'm still having trouble believing some of the higher claims for LT1 ratings that Tom posted. Geez, they sound even higher than the LT4. Next thing you'll be saying is the stock LT4 outruns the 1st generation C5....even w/o the hotcam!

 

Yes, that's ONE of the reasons we'd have to quote for newer engines lasting longer than C3's.

I'll be interesting to see if ddalgren thinks the chicken came after the egg....You know, that tolerances were lowered to meet the needs of the
"requirement" of oil for emission's purposes.

I'm joking of course...

 

Indeed, the numbers are ego boosting. But note that they're measured in a "gross" manner; LT headers, no meaningful exhaust, no accessories (except that the LT1 is still burdened by it's water pump). Hence the brag worthy numbers. I think the intent was to level the field between the two engines; one originally gross rated as you know, the other, net. By stripping them both and adding headers, the LT-1 should have produced ~375hp (it didn't) and then the comparison would be fair for the LT1.

So yeah...those were great numbers, but neither engine will produce them as installed in their respective cars.

The other way to do it would be take two box-stock cars; an LT-1 and an LT1 and throw them on a chassis dyno...based on the data we've seen, they'd probably both put down ~270RWHP.

Oh, and with both your posts above.

 

A late 60's car may or may not have AC. All they had for accessories was a alternator and power steering pump, PS and Alternator only consume power if charging the battery or turning the steering wheel. On or off maybe 2 HP free wheeling. There have been a few correction factors and methods over the years even worse from on dyno builder to another the software can fudge things the strain gages all over the place in quality. Personally I get more skeptical over magazine tests as generally they start with desired results and work backwards to the beginning to get them.

 

At least we are all getting to know each other's skepticisms!


But wait!... You posted a magazine test on page 2 of this thread...as your link of resolution!

I have another fun link....
http://mb-soft.com/public2/engine.html

which includes fun facts like:
A gasoline explosion exerts 6300 lbs of force on the top of a piston and that most of that force is transferred to the bearings (i.e., attempting to drive the crank downward -- out of the engine)!

Tangential/Radial force applied THROUGH the crank is 1100 lbs at 1500 rpms. Then there's some massive losses due to cooling system and unused energy traveling out the exhaust.

Bottom line is ICEs are only about 20% efficient so that 1100 lbs ends up around 160 ft lbs of torque at 1500 rpms.



So...what does that determine about the required weight of oil necessary? Uhhhh...IDK. I just thought the link is interesting...and not a magazine article.

Hey...if I was really energetic, I'd probably post something about the resistance of compression of liquids...and hydraulics or whatever. You know....to show why 5w oil might be able to resist 1100 lbs of compression when distributed evenly.

Or...we could all count 1, 2, 3 and yell "Whatever!" to each other.

Personally, I like "Talk to the hand!"

 

The magazine link I posted was to show the GM HP rating of 300 HP and no more.. Talk to the hand as well LOL

 

I actually don't care about which is better. This is about oil weight/requirements. Do you really consider the EXACT power of the LT-1 vs LT1 relevant to this discussion? Really?

If so, the Vette magazine direct comparison is more noteworthy than the general's advertisement.

This sounds like the left hand trying to distract the right hand.

 

I totally Wow. I thought we were all pretty well versed on gross hp ratings vs. net hp ratings by now. ESPECIALLY those of us who throw out credentials such as "IMSA racing team member" and Callaway engine build manager...or whatever. Yikes.


Like many of your claims....that just ain't true. LT-1's also came standard (at no extra cost!), with a water pump. And a smog pump. Let's not forget about the clutch fan, BTW, which CarCraft magazine tested as consuming 8-20hp (depending on the fan) at 5400 RPM; READ HERE. Also, stock manifolds, a full exhaust system, stock jetting, air filter, filter housing, stock "hot air intake", etc.

Here is a '70 LT-1 in a 'Vette. Note the smog pump, water pump and clutch fan...

and another;


So...yeah. A little more then "a alternator and power steering pump"


What you don't "get" is where the "375 hp" came from. They did every trick they could to maximize the power of the engine, on the dyno...then that was their "hp rating". It would be: no air filter, no accessories, Long tube headers, open exhaust, quite likely high octane 100+ fuel, optimized jetting and timing for that dyno session...it's not the same power that you'd get "as installed" in the car. It's not. People who go around thinking that a '70 375hp LT-1 is 375 of today's hp are up in the night. Same goes for the guys who think the big blocks are "bad assed"...they're not.

The multiple links that I posted, prove it. The LT-1 has the same amount of hp coming out of it's crank shaft as an LT1. The dyno graphs have been posted, from GM and independent. Why are you still arguing?? It's just like the monoleaf spring thread.





I know that you're adverse to facts and you have proven that you are happy to dismiss what GM engineers (the people who built these cars) say. If you won't believe dyno charts, have a look at drag track results...pay special attention to the trap speeds which are a very accurate indicator of HP; it's right on par w/any '90's LT1.

MT TEST; 1/4 mile in 14.36 @ 101.69 -I have personally trapped that fast in my stock LT1 -at 4500' elevation! So please tell us; how does a car with "75 more hp" trap about the same as a similar weight car with "75 less hp"?? The answer is that in reality, they both produce about the same power.

And 5w-30 will work better than good enough in either engine.

.