Flat6 Innovations

Its never one limitation that makes a combination perform a certain way.

Shortening the stroke will generally change where the power is made, not the overall power output. I have extensive experience with this, most recently while developing my R51 engine combination.

stroke/ rod ratio/ port configurations, net flow, and all those other things come into play.

Pushrod engines can see insane RPM with enough valve spring/ valve control. I've spun one to over 9,500 RPM. It takes some serious development to do this, especially when considering the deflection the pushrod sees with over 600# of open spring tension.

The beauty with OHC is lighter valve train parts can be used, as there are fewer parts reciprocating. The engine can see the same RPM with roughly 1/3 the valve spring tensions a pushrod engine, for revs over 6,000 RPM.

I love building pushrod engines to do crazy things, because its a real challenge. In times past I've used silicon nitride (ceramic) lifters, and other crazy things to achieve this. Thats why doing crazy stuff with an M96 is so damn easy for us.

Esfoad

Very interesting read. I'd like to see an updated version with current technology now that NASCAR finally allowed fuel injection and the latest F1 engines.

RMG

LOL ... thank you for making my point.
All started with this statement "Raise the limiter on an LS3 engine”, giving the impression this is very easy.
I didn’t say high rev pushrod engines don't exist. But there are limitations and it’s not easy to build one. It makes more sense to build a DOHC engine instead. This is why the high rev push rod engines today are only used in competitions where a pushrod engine is mandatory.

Esfoad

When you say build an engine, you are actually referring to modding an existing engine, correct? Rather that building an engine from scratch? I would imagine that NASCAR and F1 engines are ridiculously expensive to build but probably more is spent in F1.

gmgracing

I was very confused by this for about 15 seconds.

Small note to contribute.

I used to head up product development at a well known vintage bimmer supplier, and got rosy-eyed when some producers called saying that they were doing a new show for discovery called "Lord of the Car Hoards". I ended up supplying the drivetrain and suspension for the car under the verbal-promise (big mistake) that there would be great product placement complete with interviews, etc. We were on set, took part in the "unveil", everything. It was pretty exciting at the time, but you can guess what happened when the show actually aired .... nothing. Not even a mention in credits, and the rest of the car was barely cobbled together (all the expensive trim ended up being taken off and sold to "fund" other parts of the car). Learned my lesson. The ironic take-away was learning that the most honest, genuine, guy there was Chuck Palumbo.

On the other hand, about two years ago while at the same shop, I had a friendly gentleman who came in the tiny reception area. We chatted for a good 15 minutes. He then introduced himself as Mike, and that he was working on a 2002Tii for a car show (Wheeler Dealers). I immediately got wary (don't watch much tv, and didn't know the show at the time), but he was very upfront that they didn't need any "sponsors" and were not looking for handouts. They just needed some bits. Sold them the parts and helped consult during their sympathetic restoration. Overall a great experience and VERY different than the first run-in with show business.

RMG

Both. The main problems with a high rev OHV's are pushrod valvetrain complexity and (lack of) stiffness.

5CHN3LL

I made no suggestion that increasing redline by 33% is easy. I was merely pointing out the fallacy in the comment made by M3Driver: "The GM ls series motors are hands down some of the best motors ever produced, and with no question are better than any motor Porsche ever even thought about"

Yes, you can build a monster LS3. That isn't the point. The claim was that the entire line of LSx engines are better than "any motor Porsche ever even though about." I believe the CGT engine, which spins to ~8000RPM and makes about 107HP/liter is better in a number of ways than an LS3 making about 70HP/liter and a max useful RPM of approx. 6200. Incidentally, that's an engine Porsche actually BUILT. I bet they "thought of" even better ones.

The LS3 is a solid, reliable, mass-produced power plant. Those three attributes - solid, reliable, and mass-produced - are also why it isn't better than the best engines Porsche engineers can "think of."

Esfoad

Agreed with all comments comparing LS3 to Porsche motors. Still, the torque provided by the LS3 rather than the ultimate HP is or should be better than the DOHC format, so for typical street use, there's the initial shove off the line but then overtaken by the freer revving DOHC motor. Always will be an interesting comparison but the OHV V8 days are probably numbered based on how many DOHC 2.0L turbos are now available from virtually all manufacturers in the quest for MPG's and efficiency.

Gulliver

You may well be right. However, at my garage (and many others', I suspect), there is no "quest for MPG's and efficiency". None.

AzCoronaDog

I respectfully disagree, and am willing to bet the simple pushrod V8 will still be around for a very long time.
As with virtually everything about business, it simply comes down to money.
I do love the complex flat six in my 911, but I loved the humble LS1 in the Camaro SS I sold to buy the Porsche too.
The LS series of motors are simple and reliable, and much cheaper than the Porsche motor in terms of horsepower or torque per dollar.
As mentioned many times in this thread, they are different animals in most ways, and cannot easily be directly compared.
As long as GM, Ford and Chrysler can build cars nearly as fast or faster than most Porsches in a straight line, for a fraction of the price, the low tech pushrod V8 will not go away.
I believe that government regulations around gas mileage will be the biggest factor in reducing the number built.

As for Fast and Loud and GMG, I enjoy the show a lot. I am a serious motor head, but I realize the show is all about entertainment so I am not expecting much in the way of them sharing technical knowledge.
I like some fairly mindless entertainment after dealing with the complexities of earning a decent living so I can keep my 911!
So the V8 911 build was interesting to me, and appeared to work out better than I expected.
Would I buy it, nope - I'd still rather have Richard's 911 Turbo S...

m3driver

I am all for dohc engines, and in fact I can't believe GM still pursues push rod motors, but there is one undeniable fact they have perfected them. High revving ls engines are readily available with off the shelf parts and they can spin those rpms and be reliable. But the real promise of those motors is there is no need to spin that high. In the world where I come from (ultra4 cars) there are many teams running ls engines spinning 7500rpms under the most extreme situations and they last for years.

jz993

A Porsche without a Porsche engine is not a Porsche anymore, even if it is faster.
The LS engine is lighter, simpler, cheaper, makes more power, and uses less fuel doing so. I loved them in my Vette and F-bodies.
RR is the perfect jackass for TV, an empty shell. I wouldn't be him for any amount of money. Too bad Disc.Ch. won't air what Renegade Hybrids told them when they asked for a free conversion kit. Also, the Porsche logo was conspicuously absent on the boxes for the $11k body conversion kit. Genuine parts probably more like $22k.

bpu699

I dunno...

I have owned and loved Porsche since the 80's... Owned a 996 and boxster S also...

I would gladly buy a 996 with a V8 conversion. The 996 motors just aren't that great. Its not an issue of being cheap, or ruining a car.

I keep seeing guys on here contemplating doing a v8 conversion, and the chorus always is that the car wont be worth anything...

Yet, I don't see any $15,000 996's with swapped V8's for sale...

Busted 996, replacing motor with rebuilt $15-20k. Total cost for owner $40k all in. Cars still worth about $15-20k...

Busted 996 with V8 conversion? Total cost including car, probably about $40k to do it right. Car is worth way more than $15-20k...

If anyone has a V8 conversion 996 they see for sale for $15-20k, let me know. I can find 996's for that price all day long, and even for less...

Putting a V8 in a 930/911/993? Not a great idea. Financially or philosophically. In a 996, totally viable.

ZuffenZeus

Hey, thanks for that contribution. Unfortunately, many of the production companies don't want to fork out money for "Props" because they feel it should be a privilege to be on their show. They considerate it a form of advertisement, but as they say, "An oral contract is a good as the paper it's written on" and so I hate to hear you got the stiff, but it doesn't surprise me. I just wish all production groups worked the show like "Wheeler Dealers". Again, thanks for story!

shanghai_todd

Reason I posted this topic was to see the bearded wonder would come up with and was hoping to see more custom fabrication like they did on their twin turbo Pantera but instead it was simple Renergade kit that has been around for over decade and they got ripped off on a 997 frontend conversion. Entirely to much bitching and complaining in this episode.

Regarding LS swaps..well I love them and done several and just started a 997 C4S project (see link). For me it was a no brainer, picked up the car cheap and already had an LS1 and parts. All-in I will have less than $20k invested, it will put down 450hp AWD and will have body mods of a GT3 wide body.

http://ls1tech.com/forums/conversion...s-ls-swap.html