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Registered
Join Date: Sep 2003
Location: MI
Posts: 425
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Dyno numbers, not too impressive
I have a 79 SC with a 3.0, upgrades include Bursch headers( no cat), Bursch muffler, MegaSquirt EFI, and a 3.2 intake.
On the Dyno I hit 104 H.P. and 100 FP of torque at the rear wheels at 5500 RPM, I was a little disappointed. I am using a narrow band EGO so I am not sure if tuning is at its peak. Between 3200 and 4200 theres a flat spot then it climbs steadily. Any suggestions? Mike
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79SC driver 77S targa work in progress 
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05-28-2006, 01:02 PM
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Registered
Join Date: Feb 2001
Location: Ottawa
Posts: 786
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Mike,
I posted in the other thread you replied, but let's keep this one going. My car is very similar to yours 78SC, 3.0L, backdated exhaust. The only difference is the intake. I got the chopped up CIS box and runners. Compared to my car you are short by about 80HP to the wheels. Something is seriously wrong. Find a nice long road and do a couple of WOT datalogs in 2nd or 3rd gear. Send me a datalog and I'll have a look to see if there is anything obviously wrong. Cheers,
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Tony '78 911SC with BITZRACING EFI conversion kit |
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05-28-2006, 02:49 PM
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Location: a wretched hive of scum and villainy
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What does your a/f ratio curve look like?
For HP numbers that low I would suspect either an ignition system that is way out of whack or your mixture is way off. Have you pulled the plugs to have a look see? Without more information I can't really help except to venture a WAG that it is way too rich. |
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05-28-2006, 03:02 PM
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Join Date: Mar 2004
Location: Windsor, CT
Posts: 2,119
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A bore stock SC, with CAT, should give you 155-160 rear wheel hp. so all that work and 104 should say a big problem
A compression check and leak down would tell you if the pumping side is OK. A/F ratio sould tell you your are way too rich (or lean). I agree with tbitz, you are about 80-100 Hp off. for the work that was done.
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Mike '82 911SC, SSI, 22/29 tbars, 22F/22R Adj swaybars, Bilstein Sport, Elephant polybronze & monoballs, Cambermeister bar, turbo tierods, Carrera oil cooler, front brake cooling ducts, Sparco Sprint 5 & Recaro SRD PAX seat, Teamtech harness, DAS Sport rollbar. |
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05-28-2006, 03:13 PM
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Join Date: Feb 2003
Location: Black Rock, CT
Posts: 4,345
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How did it feel? Uneven? Bucking, or smooth? Sounds asthough the ignition isn't firing on all cylinders, or the Megasquirt is off.
Check the A/F numbers...very important that it's not lean.
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Jake Gulick, Black Rock, CT. '73 yellow 911E , & 2003 BMW M3 Cab. Ex: 84 Mazda RX-7 SCCA racer. did ok with it, set some records, won some races, but it wore out, LOL[/B] |
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05-28-2006, 04:42 PM
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Stranger on the Internet
Join Date: Apr 2004
Location: Bradenton, FL
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My stock 78 SC last year was 161 RWHP. Something wrong with your car, or the test.
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Patrick E. Keefe 78 SC |
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05-28-2006, 04:46 PM
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I ran my carbed 3.0 SC with back dated exhaust on the dyno today, it was so lean we shut it off at 5500 on the first run. On the second run I upped the idle jets but didn't have any mains with me, still the A/F was close to 15 at full throttle. I only got 152HP and 168 ft/lbs. Knowing the car should be 155-16 stock, and more like 180 with the mods I have I was disappointed at first but between the A/F being far too lean and having not checked the timing in over a year I'm pretty confident I can get it up where it belongs.
That flat spot sounds like it's too rich to me. My buddy was there today with a his Ford and it was too rich between 3000 and 3600 rpm and the HP dropped of signifigantly. I've always found the sweet spot to be 12.5-13 at WOT with around 36 degrees total timing for naturally aspirated cars.
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Email me about 911 exhaust stud repair tools, rsr911@neo.rr.com 1966 912 converted to 3.0 and IROC body SOLD unfortunately  1986 Ford F350 Crew Cab 7.3 IDI diesel, Banks Sidewinder turbo, ZF5 5spd, 4WD Dana 60 king pin front, DRW, pintle hook and receiver hitch, all steel flat bed with gooseneck hidden hitch. Awesome towing capacity! |
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06-17-2006, 05:38 PM
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Location: MI
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Well it turns out the dyno is having issues, It should be recalibrated by the time I return from the USGP. With the help of Tony Bitz and the folks at MS I have got it tuned where I want it. Presensly I have the O2gas running in the low 5's, averaging 22-24 MPG. It is my driver so this suits me fine. When it goes back on the dyno I can put the fuel to it and see what kind of HP she puts out. I have not played with timing, I know I'm not at 36 degrees. Is that number close to where I should be?
Mike
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79SC driver 77S targa work in progress
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06-19-2006, 05:09 AM
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1966 Porsche 912 1981 3.0SC
