<VV> August 1975 Hot Rod Magazine/Remember Corvair Sand Buggies?

[Garth Stapon]

Andy:

If there were a post of the month award, I would nominate yours as one of them. On topic, interesting and well written!

Well done!

Now back to Olympic hockey!

Regards, Garth Stapon
Chairman VV

-----Original Message-----
>From: Andrew Allen <andyman260 at yahoo.com>
>Sent: Feb 19, 2006 12:02 PM
>To: VirtualVairs at corvair.org
>Subject: <VV> August 1975 Hot Rod Magazine/Remember Corvair Sand Buggies?
>
>Greetings,
>
>Bob Helts 'Corvair Secrets' is a pretty cool book in
>that it's kind of a display of Mr. Helt's long history
>and gathered wisdom regarding the Corvair. I think
>it's a nice companion to 'Corvair Basics' and is
>essentially a collection of briefs.
>
>One brief entitled 'Building a Hi-Performance Engine'.
>In the brief he debates the relative effectiveness
>deviating from a stock engine and going whole hog on
>modifications in search of more horsepower and/or
>torque. Mr. Helt points out that unless you are
>equipped with all kinds of diagnostic and testing
>capability and, apparently, all the time in the world
>you will be hard pressed to beat a basically stock
>engine.
>
>The August 1975 issue of Hot Rod Magazine has part two
>of a sand buggy article that compares five differently
>modified Corvair engines on a dynamometer. This
>artilce is metioned in the brief to back up Mr. Helt's
>opinion and experience.
>
>The article tests five engines. Engine one is a stock
>140 out of a '65 Corsa and is tested three ways. This
>engine was provided by Bob Helt.  First with the stock
>carbs and linkage and the result is peak horsepower of
>120 at 5000 rpm and a broad torque range that peaks a
>about 150 ft/lbs between 3000 & 4000 rpm. Additionally
>"High speed engine misfire was observed about 5500 rpm
>and was attributed to valve float." This same engine
>was then tested using the IECO and Edelbrock 4 bbl.
>set-ups resulting in a 4% gain in HP and 7% gain in
>torque in the same rpm range.
>
>Engine two belonged to the author and was essentiallya
>stocker 140 running with four primary carbs and the
>Crown carb rotator linkage, signifigant head work,
>high lift cam and exhaust headers. The result?
>A shift in the torque output and 4% gain in HP.
>"Certainly not much of an advantage over a stocker to
>justify all the modifications."
>
>Engine three has .60 bored barrels, bored primary
>carbs using the Crown linkage, wild cam and individual
>zoomie headers. The result? Overall loss of BOTH HP
>and torque. "It may be speculated that the
>long-duration, high overlap cam used somehow went
>beyond the breathing limits of the heads, and the long
>individual exhaust pipes provided no scavenging or
>extractor effect to further impair breathing. But of
>course this is pure conjecture. We are still
>scratching our heads on this one."
>
>Engine four had heavily modified heads with welded on
>Motive Vair tunnel rams each sporting a Holley 500cfm
>2bbl, .60 over, a high lift, long duration Crower cam
>and a Vertex magneto set. Yikes! Well...140 HP at 5600
>rpm with torque, predictably, down and peaking at
>about 145 ft/lbs between 4000 and 5000 rpm.
>
>Engine five was provided by "3 Liters Corvair"  and
>was the most modified of all. 3 1/2" barrels for 195
>cu. in., milled heads to provide 11:1 compression and
>heavily modified intake and exhaust systems. "The
>stock intake manifolds were replaced with a custom ram
>tube connected directly to each intake port from a
>common center mounted log manifold supporting three
>two-barrel 210 cfm Holley 1929 carbs."
>The exhaust system was really tricked out too. They
>had some fuel starvation issues during testing this
>engine but recorded 210 ft/lbs torque at 3200 rpm (!)
>and predicted it would have showed HP in the range of
>200 if they didn't have the fuel starvation problem. 
>
>The conclusion is you have to get totally nuts with
>the mods and be REALLY dedicated to beat the stocker
>in any meaningful way.
>
>Whew! I'm getting the July issue.
>
>Cheers!
>
>Andy
>'66 A/C Corsa
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