Difference a Recurved Dist. Improves Performance

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wsa111
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Difference a Recurved Dist. Improves Performance

Post #1 by wsa111 » Mon Mar 20, 2017 3:19 pm

This is an old dyno test from 1960 on a 352" engine. The numbers show the benefits of a properly recurved distributor does. Highlighted shows the Distributor gains. Test #5
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67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, duraspark II dist. with MSD-6AL. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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Re: Difference a Recurved Dist. Improves Performance

Post #2 by xctasy » Wed Mar 22, 2017 6:12 am

its a typical story that hasn't changed since the first chassis dyno work. Ignition alone an be a 33% er thru the range. It is the low hanging fruit.


If you've not had yourair fuel mixtures checked, and your ignition reprofiled, you could be missing off idle power of up to 33%, and peak power at maximum rpm of 33%+ and never notice it. Peak power missing was 17%, but either side of 4000 rpm, it was twice that.


This Thunderbird Special V-8 made 300 hp at 4600 rpm, 10.5:1 comprssion engine with 600 cfm of vac sec Holley 4-bbl. Between that and the rollers, it lost half its power.


Ak Miller found a 120 gross hp 1967 200 CI i6 made 65 hp at the wheels. It lost haldf its power. But with fuel trim restored to the more ideal, and the igntion reprofiled to suit, it gained 11 hp, and thats 17%.

http://www.cometcentral.com/tech/hm6/page1.html 65---> 75 hp, 10 hp extra, +15%
http://www.cometcentral.com/tech/hm6/page2.html 76 rwhp (=11 hp, +17%)

David Vizard said it best in his third revision of his A series Mini engine book. "I've tuned engines and gained 40 hp on 140 hp engines and the engine still idles and runs fine. You don't notice the difference until its on the dyno". Thats almost 30%.

On Davids stock 1974 California 2000 cc Pinto, he gained 68% more rear wheel hp, and 5 mpg more economy via a series of small tuning operations, plus better emissions. Modifying Fords SOHC.

The bulk of the improvement is just dyno work. 33%......like the a random loss of two bullets in your nice Smith & Wesson Model 29 are gone....


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XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/About-Us.html

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wsa111
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Re: Difference a Recurved Dist. Improves Performance

Post #3 by wsa111 » Wed Mar 22, 2017 10:21 pm

"X" most of the members of this forum purchase a distributor from the auto chain stores, & other suppliers who just give you a generic curve.
The other supplier is the DUI which has shaft oiling problems, advance weight problems heat related problems.
I offer a real HEI which has none of the above conditions.
The Duraspark DS11 is the best ignition available curved to your engine with either MSD, Duraspark Module, GM HEI module & the Chrysler module. Bill


67 mustang,C-4, with mod. 80 hd, custom 500 cfm carb with annular boosters, hooker headers, dual exh.-X pipe, flowmaster mufflers, duraspark II dist. with MSD-6AL. Engine 205" .030" over with offset ground crank & 1.65 roller rockers. 9.5 comp., Isky 262 cam.
2003 Ford Lightning daily driver. Recurving Distributors. billythedistributorman@live.com
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xctasy
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Re: Difference a Recurved Dist. Improves Performance

Post #4 by xctasy » Thu Mar 23, 2017 8:17 pm

I shoulda said...distributor dyno work..... :nono:

The OEM replacement junk getting cranked out needs a reality check, and your it, Bill.

Bill also does carbs. A voice of honesty among the sharks. :thumbup:


Image
XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/About-Us.html

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