jeffreycastgsx

That would be crazy, you could have it all, decent power down low and ridiculous power up top. Except to rev that high you would need a cam to feed it, and that cam would need have the VVT detuned (at the least), or like on 3V's, lock it in a set position so as to not have pistons knocking out valves, which completely defeats the purpose of having VVT.

Irunelevens

I think with the DOHC setup, they can take the "aggressive" setup further than they could with the SOHC setup.

jeffreycastgsx

Maybe we'll see, in my opinion, most 5.0's will mostly see boltons or boost, i dont see many in the grey area.

Irunelevens

Well 430-440rwhp with bolt-ons, and 550-600rwhp on boost will be enough for most people, I'm sure.

The Manalishi

iTrader: (3)

Dohc engines aren't liked by the hardcore drag racers which limits where the knowledgable head porters will take that head. If there isn't a market for it a lot of them won't mess with them. There will be a few guys testing the limits NA but they will have deep pockets and likely won't be sharing that stuff. I agree they will be relegated to bolt ons or boost. Just seems to be the trend with the overhead cam stuff.

s346k

iTrader: (4)

well, now we know what the ford guys felt like in 98 when their modded GTs ran our stock ls1 cars...

the thing you guys are missing is how bad the 4th gen fbod platform sucks. the ls motors in swap cars weighing 3k lbs are damn near untouchable.

The Manalishi

iTrader: (3)

It must not suck too bad there are more than a few in the single digits. There have also been some really successful road race 4th gens so suck probably isn't the word I would choose.

assasinator

your argument ends at 5252. let that same big inch long stroke motor try to rev to 8200 with EXACTLY the same heads.

lets talk about LSX. not mix modular and ls.

if you use a 225cc head on a 5.5liter motor you can rev it well past 7k and make power there. take the exact same head on a 400inch LS and it will make as much horsepower but at a lower rpm. its harder to rev a 4" stroke motor to the moon with a 225cc head.

the 400inch motor will MURDER the 5.5 in torque. so how can the little motor compete? gearing. you gear the 5.5 aggressively to pull 7500k rpms at specific MPH. where a 400inch motor will rev 6200 and pull say 50mph in 2nd, gear the 5.5 for 7500 at the same mph.


forget about 4 valve, or 2 valve, this is about a fixed head on each different displacement , with EACH combo optimized.

same power at vastly different rpms. but, the little motor wins every time. it has a gearing advantage the larger more torquey engine cant match.

assasinator

he coyote is free revving. no PTV issues.

assasinator

the argument was never to scale flow and port dynamics. the argument was wih a fixed flow a 500 inch motor will do very little. to use another extreme example, use the 500 inch motor withe heads that flow 250 cfm and have 180cc ports. its an average number , but at what rpm with the heads "choke" on the 500 inch motor. sonic choke is the limit here. on a 350.....

The HP for your Cylinder Head Flow of 250 is 514.01 at a RPM of 5,259.01 for your engine size of 500 CID - i submit that a 180cc port on a 500 inch motor would choke long before 5200.


The HP for your Cylinder Head Flow of 250 is 514.01 at a RPM of 7,512.87 for your engine size of 350 CID


those are ideal numbers. and are simply head flow numbers converted to lb/minute and the pumping an average 500 and 350 will do.



even with FI port volume is DIRECTLY proportional to pressure ratio across that port. if a port flows 5 lb/minute at 0bar and you force 1 bar across it, the port will flow nearly double the original volume. 10 lb/minute.

5 lb/minute on a v8 per port is just less than 400hp.
10 lb/minute on a v8 per port is 80 lb/minute or just less than 800hp.

The Manalishi

iTrader: (3)

Assasinator you are correct with what you you just posted a small engine with the right gear can beat up on larger engines, on the track. On the street cubes are where its at, since a larger engine would be more tame and streetable. Hell I had a friend that had a 302 chevy in the 9's but it spun to 10k. I wouldn't of drove that damn thing across the street if any kind of traffic was involved. Small engines can make great power but at the expense of drivability and torque.

assasinator

i agree with that.

i imagine an f1 engine which IDLES at 9000 rpms is unmanagable with 7:1 rear end gearing.

Irunelevens

That's where Ti-VCT comes in

LT/LS Guy

I agree. I like the idea of making 600rwhp N/A at only 6,150rpms like this 427 LS3. And it sits in a sub 3k pound FD. Who needs 10,000 rpms on the street.

https://ls1tech.com/forums/dynamomet...s3-427-na.html

or this 440 LS from LME making over 600rw N/A as well. Now that's BIG power.
http://www.camaro5.com/forums/showthread.php?t=36934

interlscubes

Decent death,Now put some more mods and take another swing at it.

Arc00TA

iTrader: (17)

Sorry, I missed the part where you said using the same head, I was assuming you meant two equally optimized engines. Using a fixed flow head doesn't prove rpm=displacement, it just proves the smaller motor will use up the available flow at a higher RPM, giving it a wider powerband. I'm not sure how you think this is a valid argument since nobody sets out to build a handicapped engine. If you let the big engine breathe to 7500rpm just like you let the small one, it will make more power, and also more torque which would give it the advantage assuming traction is set aside. A well built 632ci BBC can make 1200hp at 7500rpm, so whats the point of trying to spin a smaller motor to the moon to make the same power?

I'm not saying your point that the small motor can win using the proper gearing is invalid, just the way you're presenting it doesn't make much sense. You're specifically handicapping the bigger motor to prove your point.

It'llrun

He did that for a specific reason. He wasn't saying larger engines aren't as good or anything like that, just that smaller engines revving much higher can make the same power as a larger engine which can't physically hold together at the high rpm. He was using a set flow just to make the point. Part of the point was that smaller engines are capable of more rpm, which is why they'll equal the power if the head capability matches.

Ke^in

If you are referring to speed, it's about the same as the difference between the new 5.0 and a LS1 stock for stock.
I wasn't referring to the new Camaro. But even it's slower than the new 5.0
AGAIN I was referring to those comparing the LS1 to the 5.0.
Not so sure about that.

Ke^in

Actually there is when you are speaking about different motor designs. If there is no replacement, why isn't the newest Camaro faster than the 5.0? How come the new SRT-8s aren't faster than all 3? There are A LOT of factors that are in the mix. Displacement a lone isn't the only one.
No, what I said was when I was on the Mustang boards when the LS1s came out, those that were insecure about them and had sour grapes were belittling it. Saying it was overhyped, and with few mods they could take one. They were wrong. While I know there have been slightly modded 2v take LS1 fbodies in races, it's not the norm. And if it happens, it's because the LS1 driver sucks. I was comparing that with how some LS1 fbody owners in here are acting towards the 5.0. And it's a legit comparison. Don't like it? Too bad.

Bingo. I didn't think what I said was that hard to comprehend.

WSsick

iTrader: (13)

FWIW (adding fuel to the fire), there have been a pretty good amount of bolt-on f-bodies taking out 5.0s, even on this board alone. I'd say an LS1 has a better chance of beating a 5.0 than a 2v beating an LS1.

Just sayin...