Where 'oh where has the OHV gone..

[SLCraig]

Originally Posted By: mpvue
Originally Posted By: TheBig2003
...I am running a 5.7 HEMI with 423whp/479wtq on only 7.3lbs of boost (which is extremely low...which we all know is low). I will not mention my Quarter times.


why? are you embarrassed by them?
1/4 calculator is showing 12.7 for you, am I close?

seriously, 423HP at the wheels on a BOOSTED hemi? isn't advertised stock 425hp?
seems pretty low, considering over 500hp in a N/A LS engine is pretty common...


Depends on the year, the 5.7 was rated between 340 and 370HP, the first generation 6.1 was rated at 425. 423 WHP on a 5.7 is good. No idea what a stock one would run, for a 340HP version, maybe 300 WHP stock?

 

[SteveSRT8]

^^^Note he is running an older 5.7 that was rated at around 345 HP when stock. At his boost with a proper tune the RWHP is about right but is a dyno number that can vary considerably from many factors.

It is also an AWD model, which means his transfer case will explode one day if he runs it hard off the line.

Make sure when you run the drag calculator that you factor in the increased weight of the AWD system.

 

[OVERKILL]

Originally Posted By: TheBig2003
Really guys, I have no offense to anybody here, but OHV design has and so far will always be the configuration for developing absolute power. I am running a 5.7 HEMI with 423whp/479wtq on only 7.3lbs of boost (which is extremely low...which we all know is low). I will not mention my Quarter times.

I also have under my belt an '06 Grand Prix GT S/C running a 3.8 Series III with an underdrive SC pulley and a total of 9.45lbs of boost and running an 11.44 1/4 mile and yet still pushing 33.8mpg on the highway.

All-in-all, I would say OHV engines are better in ever way. If would like to prove me otherwise, we can always run the 416 or 417 and see who could make Prescott or Cornwall fastest without a fill.

The 5.0L Coyote engine makes more power than your HEMI, and it doesn't have a blower

It also is giving up .7L of displacement.

434RWHP.

Perhaps you can offer up a better example?

 

[TFB1]

On the average, a RWD driveline with automatic soaks approx 18% of the engines HP(stick shifts have less loss)...

Sooo using that figure and a 350Hp engine, only 287Hp is at the wheels...

My Marauder is at approx 525 crank Hp and that of course doesn't include the loss of spinning the supercharger, probably another 30-40Hp...

 

[mechtech2]

OHC designs are great for variable cam timing systems.
They are great for spreading power up or down as needed.
Modern turbo engines can have 10/1 compression or more with variable cam timing. This was unheard of a few years ago.

 

[Mitch Alsup]

Originally Posted By: 92saturnsl2
... oh where oh where can it be? With its torque down low and its midrange pull, oh where oh where can it be?

Referring to pushrod engines obviously, as OHC can also be considered OHV. Anyone wonder why they have all but disappeared?


I'm going to take a differnt tackt, here.

A) the reason that DOHC engines have taken over is that people are more concerned with HP than with TQ. That is most people are stupid or at best under edumacated with respect to what does what in cars and trucks.

B) in block cam engines have NOT disapeared. You just have to buy a GM/Chey truck, Camaro, or Vette to get one.

C) the main differenc in a DOHC versus a IBC motor of equal displacement is that at the point where the IBC motor TQ curve starts dropping, the DOHC motor stays flat for another 1500 RPMs. It is this flattenss of the TQ way up the RPM band that gives them the power. Conversely it is the flatness of the TQ curve that gives them the undeserved monicer of gutless.

 

[ls1mike]

Originally Posted By: SteveSRT8
Originally Posted By: supton
Originally Posted By: ls1mike
You have not been around too many LS1s, they will bend a pushrod with a mis-shift without the piston hitting the valve. Mechanical over rev will do it those. Swap out the Pushrod and BAM back on the street. I have done it, and I am not proud, twice while at the track. Tons of threads about it on line. Some guys, like me, will leave the stock ones in in case we miss a shift that way you bend a 60 dollar set of pushrods, swap them out and move one.


Really? Sounds like the valve train is too heavy and/or pushrods are too weak. But I'll buy that.


It's a deliberate design strategy. The general knows valvetrain tech!

Exactly, easy replacement and nothing else breaks.

 

[Shannow]

Originally Posted By: TFB1
My Marauder is at approx 525 crank Hp and that of course doesn't include the loss of spinning the supercharger, probably another 30-40Hp...


LOL, sorry, but to talk about the "loss" in spinning the supercharger...we may as well calculate theoretical power from fuel input per second...my engines would all have way more power without using energy on the compression stroke.

 

[chiks]

Originally Posted By: TheBig2003
Really guys, I have no offense to anybody here, but OHV design has and so far will always be the configuration for developing absolute power. I am running a 5.7 HEMI with 423whp/479wtq on only 7.3lbs of boost (which is extremely low...which we all know is low). I will not mention my Quarter times.

I also have under my belt an '06 Grand Prix GT S/C running a 3.8 Series III with an underdrive SC pulley and a total of 9.45lbs of boost and running an 11.44 1/4 mile and yet still pushing 33.8mpg on the highway.

All-in-all, I would say OHV engines are better in ever way. If would like to prove me otherwise, we can always run the 416 or 417 and see who could make Prescott or Cornwall fastest without a fill.

ummm...ahhhh
good valves make the power.
How you get them to work ie. pushrod or not does not dictate that.

 

[ls1mike]

Originally Posted By: SteveSRT8
Originally Posted By: ls1mike
Originally Posted By: Cujet
The variable twin cam timing systems used today can achieve things not possible with simple, pushrod, cam in block designs.

Things such as virtual Atkinson cycle, where expansion is greater than compression. Things such as multi valve engines with high valve lift and duration numbers achieving wide torque curves and impressive peak HP, all while meeting stringent emission requirements.

Sorry, but technology and development prevail.


True, and I don't care what you drive, but I will remeber that next time I show a Honda tailights.

"At least his car was more technologically advanced" I am sure the Corvette guys are worried about that to. Power is power no matter how it is made.


So very true! I laughed so hard I cried on this one!

Thanks, I try.

 

[Silk]

Originally Posted By: supton

No damage? As in, 200kmiles after a valve-kissing experience, no dropped valves? I mean, I'll accept it if it's been proven to have no impact on longevity, I just find it hard to believe there isn't any latent valve damage in this case.


The pushrods are puny, they don't stand a chance. Even the Mitsubishi 4D56 which breaks rockers on a belt failure never suffers valve damage, same with the Mazda 2.5 diesel. Getting a 4D56 to last 200,000 miles is not going to happen, valve failure or not - I used 4 cyl heads in 330,000km on mine.

 

[Cujet]

Originally Posted By: ls1mike
True, and I don't care what you drive, but I will remeber that next time I show a Honda tailights.

"At least his car was more technologically advanced" I am sure the Corvette guys are worried about that to. Power is power no matter how it is made.


We all know that the Chevy Small Block is a compact, light weight, powerhouse of an engine. To ignore that is foolish. Heck, it's even quite efficient, at a BSFC of 0.55LB/HP/HR.

But, in the ever tightening fuel economy and emissions race, you won't be seeing Chevy Small Block powered hybrids achieving 50MPG. (and, yes, I agree, hybrids are no fun to drive) The Prius engine achieves a BSFC number of 0.4LB/HP/HR or put another way, the Prius engine is 28% more efficient. Sorry, but that technology is winning the day.

I want a V8. Maybe it's time, before it's too late!

 

[Cujet]

LS1 Mike, My turbo Miata ran 12's at 127, with an RPM/gearing limited top speed of 168.

Would the Miata have been better off with a small block? Not likely. As the weight difference would affect it's lap times, and the RPM limits on a street driven V8 would have limited it's top speed with the stock gearing.

 

[Jarlaxle]

Originally Posted By: Ben99GT
Originally Posted By: SteveSRT8
Also, there's packaging. Ever see an ls7 out of the car? It's one of the smallest v8's you ever imagined. Those Fords with the mega heads are HUGE up top and create very real packaging issues. They are also heavier.


From January 2006 issue of Sports Car International on page 25 (regarding the LS7):

"The net result is a fully trimmed engine that weighs 458 pounds, only 10 more than the 6.0-liter LS2.

For comparison, AMG's all-new 6.3 liter V-8 (it is actually a 6.2 liter V-8, but it will be called a 6.3 liter V-8 to pay homage to the 250 hp 1967-1972 300SEL 6.3) weighs 438 pounds vs. 485 pou!)nds (old 5.4 liter supercharged V-8). The new V-8 has 510 hp at 6,800 rpm and 630 Nm at 5200 rpm."

The AMG 6.3 is a DOHC 4V VVT engine.
The 5.0 4V Coyote weighs 425 lbs per Mike Harrison.


Weight does NOT equal packaging! The LS engines are compact, where Ford's OHC engines are very wide. (The DOHC is wider than a Boss 429!) An LS engine will fit in a Miata...try that with a Coyote.

 

[Jarlaxle]

Originally Posted By: SLCraig
Originally Posted By: mpvue
Originally Posted By: TheBig2003
...I am running a 5.7 HEMI with 423whp/479wtq on only 7.3lbs of boost (which is extremely low...which we all know is low). I will not mention my Quarter times.


why? are you embarrassed by them?
1/4 calculator is showing 12.7 for you, am I close?

seriously, 423HP at the wheels on a BOOSTED hemi? isn't advertised stock 425hp?
seems pretty low, considering over 500hp in a N/A LS engine is pretty common...


Depends on the year, the 5.7 was rated between 340 and 370HP, the first generation 6.1 was rated at 425. 423 WHP on a 5.7 is good. No idea what a stock one would run, for a 340HP version, maybe 300 WHP stock?


I saw a stock 2006 Charger R/T on the rollers last year on the Power Tour...IIRC, it put down about 285HP. Note: this was a warm (85-degree) day, which certainly cost power.

 

[Jarlaxle]

Originally Posted By: Cujet
LS1 Mike, My turbo Miata ran 12's at 127, with an RPM/gearing limited top speed of 168.

Would the Miata have been better off with a small block? Not likely. As the weight difference would affect it's lap times, and the RPM limits on a street driven V8 would have limited it's top speed with the stock gearing.


Ooh, time to launch a hanging curveball: on a scale, an LS Miata is usually ~2600lbs, with a 52/48 weight balance. My friend has one (a 1991), his is lighter (no A/C or power steering) and balanced a bit better. (all that weight is off the FRONT). His scaled at a hair under 2300lbs with the soft top, the rollbar added about 100lbs.

He hasn't hit the drags yet...need to finish the cage first. (A 12-second roadster and a 9-second hardtop need essentially the same safety gear.)

Someone on Miata.net actually did a back to back comparison (he V8-swapped his track-prepped Miata).

Right from the owner of Flyin' Miatas: his first report comparing an LS1 Miata with a track-prepped Miata. And his follow-up. Short version: his FIRST run with the LS1 car was faster than his BEST run with the boosted 2.0 car...same suspension setup, same tires, and on a very short track (0.9 mile, 12 turns, average speed <50MPH) where power just is not a major factor.

 

[Mitch Alsup]

Originally Posted By: Jarlaxle
An LS engine will fit in a Miata...try that with a Coyote.


I have seen a SBF 302 in the engine bay of a Miata!

On the other hand one could put a Ferrari 348 motor in the front of a Miata with only a minor buldge in the fron of the bonnet.

 

[Jarlaxle]

No, not a 302, the new 5.0 DOHC. Won't begin to fit a Miata, it's WAY too wide.

And, of course...a Ferarri 348 is a tiny 3.4L with 320HP (at a screaming 7500RPM!), while an LS3 is nearly twice the displacement (6.2L) and makes 430HP at only 5900RPM...and yet, it is a SMALLER engine, dimensionally!

 

[torino351]

Originally Posted By: 92saturnsl2
There was a day when OHV was king, and OHC was relegated to high performance applications like the GM Quad 4.


this line was good for a laugh.


Originally Posted By: 92saturnsl2
Before some takes it personally, or this turns into a OHC vs pushrod war, I agree there are LOTS of great SOHC/DOHC examples out there that are nothing short of a marvel in engineering. Just saying that OHV engines have a lot of great attributes, and it's unfortunate that they're no longer widely available.


as in alot threads too many posters miss the op's original topic. we get it. we don't need to hear about your 10,000 horsepower v8 dusting every base model civic down the street. or about your 2.0 eclipse with 50,000 psi of boost and how you ran a 2second quarter mile last week. it's the same thing as a bunch of gorillas sitting around and beating their chests and grunting at each other.

 

[Ben99GT]

Originally Posted By: Mitch Alsup
I'm going to take a differnt tackt, here.

A) the reason that DOHC engines have taken over is that people are more concerned with HP than with TQ. That is most people are stupid or at best under edumacated with respect to what does what in cars and trucks.

B) in block cam engines have NOT disapeared. You just have to buy a GM/Chey truck, Camaro, or Vette to get one.

C) the main differenc in a DOHC versus a IBC motor of equal displacement is that at the point where the IBC motor TQ curve starts dropping, the DOHC motor stays flat for another 1500 RPMs. It is this flattenss of the TQ way up the RPM band that gives them the power. Conversely it is the flatness of the TQ curve that gives them the undeserved monicer of gutless.


This is complete nonsense, seriously. For example, we have a N/A 286 cid 4V here than made a verified 560 HP on Roush's dyno, I can bring this engine's effective powerband down by 1500 rpm by advancing the intake cam by 8-10 degrees.

Where an engine makes power is determined primarily by intake manifold runner length/cross section, intake port volume/cross section, valve diameter, cam design and installed centerlines (excluding VVT/VCT). You can make a DOHC 4V a low-rpm stump puller just as easily as you can make a pushrod motor a high-rpm screamer with a gutless bottom-end.