โFeb-10-2019 08:52 AM
โFeb-22-2019 08:25 PM
โFeb-22-2019 01:50 AM
otrfun wrote:
Used to own a CBR600f4i. Words can't describe how awesome it sounded pushing DOHC's at 12,000++ rpm's!
โFeb-21-2019 07:17 PM
TomG2 wrote:I believe you're allowing your emotions to cloud your reading comprehension, TomG2.otrfun wrote:Some folks have to have the last word. You got it. LOL!
It's how people "lighten up". You may want to give it try yourself.
Have a good one--lol!
Bringing up your experience with 12,000 rpm engines was meant to impress and it sure did. LOL Not.
โFeb-21-2019 05:44 PM
otrfun wrote:
It's how people "lighten up". You may want to give it try yourself.
Have a good one--lol!
โFeb-21-2019 05:40 PM
TomG2 wrote:Lighten up?! LOL!! Seriously?!otrfun wrote:Some people get sarcasm, and some don't. When you started talking 12,000 rpm engines, I made a joke. Sorry that you didn't get it. NOBODY seriously promoted 12,000 rpm RV generators. Lighten up.
TomG2, I simply responded in-kind to your glowing comment about a 12,000 rpm OHC generator! Don't be a party-pooper and drop your RPM's back down to 3,600-5,000--lol!.
โFeb-21-2019 05:20 PM
otrfun wrote:
TomG2, I simply responded in-kind to your glowing comment about a 12,000 rpm OHC generator! Don't be a party-pooper and drop your RPM's back down to 3,600-5,000--lol!.
โFeb-21-2019 05:10 PM
marcsbigfoot20b27 wrote:Yup, the valvetrain on a DOHC engine takes up a lot of space with the cams sitting up-high, above the valves. An OHV, pushrod engine has the cam situated down in the block reducing the size of the heads and valve assembly significantly.
1990 to 1995 corvette ZR1 had the LT5 DOHC engine. It is literally stuffed into the corvette engine bay. Pushrod engines are more narrow and not as tall in general.
โFeb-21-2019 04:58 PM
otrfun wrote:twodownzero wrote:I was waiting for someone to find a loophole or two--lol! Congratulations! Granted, GM may feel there are no advantages to using OHC in the Corvette. However, common sense says the other 98% of cars (to include exotics) on the road that do have an OHC configuration, were not the result of manufacturers and their engineers being hoodwinked into using it for "hypothetical benefits"--lol! If you're saying they were hoodwinked, it would make for one helluva conspiracy theory---would love to hear about it.otrfun wrote:You mean like America's flagship sports car, the Corvette, the best bargain in its performance class anywhere on Earth, which has been OHV for almost all of its existence, including what are unquestionably the best performing Corvettes ever made (those in the last ~20-25 years?
No, there's nothing wrong per se with an OHV engine. OHV is fine for lower RPM applications like the lower revving, high torque truck applications you speak of. However, you'll rarely see OHV in high-rpm applications. An OHC design has a lot less moving mass in the valve train assembly (vs. an OHV design) which allows for more efficient, accurate control of the valves at higher rpm's. This is the reason why the vast majority of cars on the road on the road today use an OHC configuration. If OHV was a better design I assure you car manufacturers would use it---but, the fact is they don't.
There might be hypothetical benefits to OHC, but they sure don't seem to show themselves in real life.
โFeb-21-2019 04:51 PM
TomG2 wrote:TomG2, I simply responded in-kind to your glowing comment about a 12,000 rpm OHC generator! Don't be a party-pooper and drop your RPM's back down to 3,600-5,000--lol!.otrfun wrote:We are impressed, but hardly germane to a discussion about RV generators which generally max out at about 5,000 rpm and many at 3,600 rpm.TomG2 wrote:Good idea! Used to own a CBR600f4i. Words can't describe how awesome it sounded pushing DOHC's at 12,000++ rpm's! If you really like rpm's, try a turbine generator. They absolutely and literally scream!
Now we know how a 2,000 watt generator can run these big air conditioners. Crank them up to 12,000 rpm. OHC models only.
โFeb-21-2019 04:45 PM
otrfun wrote:TomG2 wrote:Good idea! Used to own a CBR600f4i. Words can't describe how awesome it sounded pushing DOHC's at 12,000++ rpm's! If you really like rpm's, try a turbine generator. They absolutely and literally scream!
Now we know how a 2,000 watt generator can run these big air conditioners. Crank them up to 12,000 rpm. OHC models only.
โFeb-21-2019 04:35 PM
drsteve wrote:When they engineered this engine, no doubt they knew going in they were constrained to lower RPM's due to the OHV design and designed it accordingly. Based just on the even up HP/torque numbers (650/650) it's obviously a relatively low revving engine. When the torque numbers get significantly higher than the HP, then the max rpm's drop accordingly (i.e., diesel). When the HP numbers become a multiple of the torque rating (F1), then you're talking massive rpm's and a mandatory DOHC configuration.
But at the same time, Chevy engineers get 650 HP and 650 lb-ft of torque out of a pushrod activated small block V8 that passes emissions specs and will run for many thousands of miles, even if the owner has a lead foot.
โFeb-21-2019 04:25 PM
TomG2 wrote:Good idea! Used to own a CBR600f4i. Words can't describe how awesome it sounded pushing DOHC's at 12,000++ rpm's! If you really like rpm's, try a turbine generator. They absolutely and literally scream!
Now we know how a 2,000 watt generator can run these big air conditioners. Crank them up to 12,000 rpm. OHC models only.
โFeb-21-2019 04:25 PM
otrfun wrote:drsteve wrote:Agree. The pushrods on an OHV motor would turn into a pretzel at 12,000 rpms--lol!otrfun wrote:High RPM power, of course. Modern F1 uses 1.6 liter V6 turbo engines, Indy 2.2 liter V6 turbos. Not much low end power to be had with that configuration, so they rev 'em to 12,000 RPM. No pushrod motor will do that.3 tons wrote:Yup, pretty interesting piece of racing history there. With that being said, got to wonder why modern-day Le Mans, Indy, and Formula One cars continue to use OHC engines.
I can still recall the original cast iron, OHV Ford GT 40โs of Le Mans fame walk away from the high revving, sure to win OHC Ferrariโs
โFeb-21-2019 10:38 AM