CAT California Association of Sunbeam Tiger Owners

DYNO Day - Superior Automotive, Anaheim Nov 17, 2001

Thanks to Chris Thoman who followed up and acted on an idea, CAT held DYNO Day for
the first time.  The Chassis DYNO by Dynojet at Superior Automotive was the focal point from about 9:00 to early afternoon as Members watched, listened and learned. Fourteen different engines, from high compression race engines to a stock 260 (and a Rambler six) put all the power they had to the big rollers in the floor.

We watched the pros carefully rig the tie downs and hook up the connections. Safety was
strongly enforced and there were no problems.

We listened to the V-8 rumble build from a low cruise to full throttle, rpm climbing to the red line.  Incredibly loud race engines screaming over 7,000 RPM!  Powerful street Tigers sounding so sweet powering through 5,000 and beyond.

We learned.  As a participant I knew that Tiger Blue has a strong engine and should
put out more than a HP per Cubic Inch (302).  Fact or fancy?  Turned out to be fact, 318 HP at the crank (Measured HP on at the wheels increased for the estimated drive line loss.).  No substitute for cubic inches! Ken Mattice was "The Man" in street driven cars with his show stopper beautiful and ground pounding powerful stroker motor Red Mk 1A.  Figure 425HP at the crank!  A surprise highlight was the appearance of one of the three Le Man Tigers.  Dick Barker towed it up from San Diego.  Not just a pretty face either!  This 260 has claws.

Note from DYNO Master Chris Thoman:  All readings are at the rear wheels, (for stick trans add 18% for est. flywheel hp).

CAT others:

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"This graph (No pun intended) shows the difference a dyno-day can make.  When taken to the CAT Dyno-Day the car seemed to be running pretty good, but the run showed it was extremely lean in all ranges. Put fresh plugs, etc. in and took the car back for a "dyno-tune" They fixed the timing advance, richened the carb w/new metering rods and springs. The immediate difference was 57 additional HP and 41 ft./lbs. torque.  Bill Graf   (The ragged blue line below is the original pre tuning DYNO DAY run.)

Webmaster Observations:

This is a perfect example of the value of coming out to the Dyno. Bill could see, and he was told by the experienced operator, that Hairbol was not performing up to potential and a lean mixture was the obvious villain.  Less than 220 hp at the crank is OK for a stock 289 4V but not close to what this engine is capable of twisting.  Bill's goals in putting together the components in this 289 might be summarized as fast but hassle free. The finished piece is basically Edelbrock Performer class.  Edelbrock low rise performer intake, aluminum performer heads, mild hyd cam and 600 CFM carb.  Headers (from CAT of course) and a 2.5" exhaust provide more than adequate exhaust.  The result is a very street friendly one hp per cubic inch.

CAT XTC above was put together under a more aggressive philosophy. I expected to live with some drivability problems (comprimises).  Loping idle I felt I could live with.  I run some open track and wanted a usable RPM range out to at least 6,000.  My major compromises for street use were the Compression low enough, 9.5:1 to run pump gas and hyd lifters so that I could avoid the regular chore of adjusting solid lifters. Tiger Blue's 302 is built Edelbrock Performer RPM class plus a wilder grind cam.  The result (so far*) is 5 percent over one hp per cubic inch. About 30 more hp at 4,000 and at least 500 more rpm to use on top is the real payoff on the track.

Watch this space.  CAT XTC is forcing the by-products of combustion through pinched 2" exhaust. Later this year we will cut the clearance and install 2.5 inch tubing and mufflers.  With that and time to "Dyno Tune" carb and timing? Maybe another 10%.

Added 5/07/2002

On a rainy April day CAT XTC went back to her tormentors at Superior for a few more high RPM blasts.

Changes:
 

Results:  A first look a disapointing 5% increase in HP at the peak.  Looking back from the peak the results are better.  Lots more torque resulting in a 20+ HP gain at the rear wheels from 4.000 to 5,500 RPM.  This will be a big kick exiting corners on the track.  I am puzzeled that the power did not pick up more at the top.  Both changes would seem to favor the top end the most.  Maybe the dual plane Performer RPM intake manifold is not optimum for over 6,000 or the World Products, Windsor Junior heads are out of their league at 6,000 plus.

Well at any rate we know what we have and although there is room for improvement I am happy with the end result.  Not much to do from here other than tweaking or starting with a clean sheet of paper.  Many auto enthusiasts brag about their big HP.  Show me the Dyno sheet.

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