I don't know if this has been posted here, but whenever I hear ricers talk about how low tech OHVs are, I say to myself two things:[list=1][*]This guy is an ignorant fool.[*]How come GM has no OHC for its sports cars?[/list=a]Doesn't OHC technology make an engine rev higher? If an F5 V8 had DOHC, do you think GM would design an variable valve control program (or something like VTEC)?



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--David--
1995 white Firebird 3.4 V6 A4 w/ T-tops
Mods:Kenwood KDC516S stereo, front and rear Alpine speakers, Flowmaster 80 series, Firebat and Autografics decals, Moroso CAI, Rally Foglights, Painted interior (Silver Metallic), 3 10" MTX Thunder 6000 subs, BMR STB, Zaino, !speed, !horsepower Help CT get a dragstrip!

 

High-Tech doesn't necessarily mean high speed. I'll vote for whatever is the most efficient (i.e., the most HP and MPG for the least $.)

All things equal - I'd rather have an OHV making 30 MPG and 350HP than a SOHC making 26 MPG and 275HP.

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If it breaks, it wasn't high performance enough.

2001 Mustang Bullitt GT
2000 Jetta M5

[This message has been edited by WERM (edited July 24, 2002).]

 

Camaro will get whatever the C6 gets. That said, I'd be shocked if GM converts to OHC engines in its performance cars now. The development of the OHV LS1 in '97 leads me to believe that GM still believes in pushrods.

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Mark

94 Z28, Red, A4, 3:23
Lone Mods--LPE CAI, !Lapeer Dragway.
(Hey, I'm a college boy I can't afford gobs of bolt-ons!)

Best time: 14.658 @ 95.1
with SES light on and Driver off! (First and only time at track)

The F-body will NEVER die.

 

OHCs are expensive, complex (meaning expensive to work on), and offer no advantage over OHV engines.

OHC can rev higher, you can engineer trick technology (ie: variable valve timing), and you can generally go to smaller displacement. However, smaller displacement OHC engines tend to use as much fuel, produce less torque, and...did I say more expensive(?), than the larger OHV engine of the same horse power.

Just as an aside, if an OHV engine warps it's heads, you have a good chance of simply machining them a bit & bolting them back on. If OHC heads warp, because of the in-head cam(s), they will be unusable.

 

The reason for OHC is to allow for more valve area. The twin-cam XV8 works well to do that with three valves per cylinder.

This is just a theory I came up with, but perhaps OHC's typically high power band is that way for the same reason that having short, fat intake runners gets you mostly high-end power and little low-end when building a regular engine -- larger (wider) flow area...

 

Exactly. If its not broke, don't fix it. GM has proven that OHV can be used in modern day applications just as OHC.

Look at what GM80's OHC V6 did to the cost of that platform, and that was with two fewer cylinders!


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-Joshua
1997 Bright Red T/A WS6 M6
I was thinking dagger. -Steve Nash

 

XV8 gets my vote. Gm had tons of tech in that engine adn even if only half of it makes it- it'll be awesome! Dumb ricers won't know what to think! "Two underhead cams???" hehe

Make a nice 302- 330hp....hmm....make it lighter and that would easily keep up with and maybe beat the current SS/WS6

 

There is supposed to be an engine set to debut in 08 that is like the performance mack daddy at GM. I am willing to bet it is the next generation small block built on XV8 architecture

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Branden-Founder-www.GMInsidenews.com-The #1 GM News Site on the Net!
1995 Firebird A4 White with red leather! SOLD 1979 Firbird Formula 400HO!
Visit my homepage!

 

What about the lt-5, 4 OHC. it is a nice engine, but expencive.

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1994 Green/Grey matalic Camaro Z28 !CAGS-CAI-Ported MAF-AZSM 52mm TB-1LE Elbow-UD Pullies-Ported MAF-HI-6 + LX92 Coil-B&M Ripper-RKSport Headers-SLP Y Pipe-Random Tech Cat-Borla Cat Back-160 Therm-'98 Front Brakes-Eibach Pro Kit W/Blistein

 

I like the OHV set-up. I like changing 1 cam not 2 or 4 cams.

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I WOULD RATHER PUSH A CAMARO THAN DRIVE AN IMPORT

1983Z28
Superramed roller 406 10.5 compression, AFR 195's and custom cam.

future mods:
N20 waiting to be installed

Wifes new car:

1995 Z28
AT, leather, T-tops bone stock for now. 250 RWHP 300 RWT 14.0 @ 99 MPH on a 2.2 60'

future mods:
header to tailpipe replacement and a cold air intake. Then I am just going to leave it alone (maybe)

 

OHV.

 

technologies like OHV and variable valve timing aren't nessesarily mutually exclusive. the problem which causes the perception that pushrod engines are 'lowtech' and less efficient than their OHC counterparts is because most of them are. now hang on one sec, here's what I mean. In the sea of brand NEW OHC engines there are perhaps one or two truely NEW OHV engines on the entire market and even those are now over 5 years old. Engines such as the 3800S2 are truely holdovers and stopgaps that have been propegated from the 50's and 60's because GM was too stupid and cheap to invest in their engine development programs and instead only 'updated' engines which shouldn't even be produces anymore in the world's first automobile market (if we lived in china or india all bets would be off).

So you can see how a neglect of the OHV platform and perpetual advancement of OHC has helped cause a perception that OHV engines are inferior and just OLD, because most of them truely ARE. If manufacturers put as much money and tallent in the development of OHV engines as OHC, the market wouldn't be as scewed on the whole issue. But then again, if you think about it, there must be a reason the OHC layout is the choice of most of the world's manufacturers...

Give me an example of a reletively small displacement OHV engine for a midsized sedan which is as smooth, quiet, reliable, and powerful as its similar displacement OHC counterpart and you win a prise because such an engine does not exist.

As far as the next GM muscle engine, I'd be surprised if GM would break with tradition... plus the XV8 looks really promising.