What a difference a properly functioning ignition makes !!!! | FerrariChat
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What a difference a properly functioning ignition makes !!!!

Discussion in 'Technical Q&A' started by Kds, Sep 16, 2005.

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  1. Kds

    Kds F1 World Champ

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    #1 Kds, Sep 16, 2005
    An extra 67 rear wheel horsepower in fact.

    My newly acquired 1977 308GTB was backfiring profusely thru the carbs and running rich when I bought it......but otherwise it was not a bad car overall for the money considering I'd have to spend some on it to make it right.

    My mechanic told me the leak down test was between 0-3% in all 8 cylinders and the carbs were properly balanced and functioning correctly. An inspection of the ignition system indicated that the distributor caps, rotors, condensers and points were totally shot (the wires and plugs were OK)......it was probably all original stuff given their visual condition and the nature of the damage as well as the replacement cost for the parts. The original dyno run produced 111 HP at the rear wheels...................after properly setting up the timing and replacing all the ignition parts, as well as a bunch of other small stuff that good mechanics experienced in these cars know how to do we now have 178 HP on the dyno (214 after 20% conversion factor).

    What a great car !! These things are fast if set up correctly. There's another 10 HP there to be had with a little more dyno tuning which will occur next week. Given that these things were rated somewhat optimistically at 255 HP am I going to be happy with 225 "real" HP.........or is there more there ? Has anyone else done this exercise on a dyno ?

    I wonder how many of the older cars are running around out there with ignition bits that are not up to snuff due to the cost of the parts. I spent $1,200 overall in USD for the pieces......and I shopped hard and long for the best deal.....as well as another $1,500 in shop labor.
     
  2. Kds

    Kds F1 World Champ

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    #2 Kds, Sep 19, 2005
    So has no one here ever had their 308 on a dyno......ever ?
     
  3. matteo

    matteo F1 World Champ

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    #3 matteo, Sep 19, 2005
    I never dyno'd my 78 but once I had the ignition redo, it was like a bat outta hell. Get an euro ansa or a tubi and you will gain a extra few. Also, pull your cats to see if they are ok. They might be plugged.
     
  4. Kds

    Kds F1 World Champ

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    #4 Kds, Sep 19, 2005
    Cats....? What cats ? Heh.....
     
  5. snj5

    snj5 F1 World Champ

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    #5 snj5, Sep 19, 2005
    Lots of 308s on dynos in old threads. Very interesting numbers for sure. Your 178 is about what many carb 308s are running. Great job! Usually, the correction factor is closer to around 17%, but rear wheel dyno to dyno comparisons are iffy due to tire/traction losses. They are best for same car tuning as you say.

    Here is a quick summary from a previous thread:

    A quick summary (rear wheel hp):

    308 gtsi - 175
    308 gts w/ 3.0 qv engine - 192
    328 - 210
    328 - 216
    328 - 218
    348 - 250

    Would be VERY interested in any dyno data you have with Air/Fuel information. Especially idle, off throttle and cruise in addition to the pull.
    Many thanks!!
    Russ
     
  6. f355spider

    f355spider F1 World Champ
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    #6 f355spider, Sep 19, 2005
    I got about the same with my 78 308 GTS...it had been recently serviced, with new wires, Crane Cams electronic ignition, Bosch blue coils, 140 main jets, test pipes and K&N filter.

    The 255hp figure is for Euro 308s


    North American 308's were rated as follows:

    75-77 240hp
    78-79 205hp
    80-82 205hp (though some say it was actually much less)
    83 230hp
    84-85 235hp

    I may have the 83 versus the 84-85's inverted.

    Either way, checking/tweaking to make sure your distributors are advancing, and richening the jetting slightly will reap a few more hp, I'm sure.

    Have fun!

    Dave
     
  7. f355spider

    f355spider F1 World Champ
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    #7 f355spider, Sep 19, 2005
    BTW, my 87 328 GTS pulled 214hp at the wheels with a Dynojet, and this was after a major service, Tubi exhaust and K&N air filter. I later replaced all the fuel injector with the newer brass Bosch ones, and the car pulled much more willingly to redline. Never got it back on the dyno, but bet it would have done slightly better.
     
  8. ants2au

    ants2au Formula Junior

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    #8 ants2au, Sep 20, 2005
    I got 173 RWBhp out of my 1978 308 GT4. this was with no air box on the carbs, and the engine lid was closed (nice hot air getting injested).

    I was upset after the run that I forgot to open the lid at least.



     
  9. snj5

    snj5 F1 World Champ

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    #9 snj5, Sep 20, 2005
    More quoted rwhp dyno figures from previous thread. I think the 512 numbers may be switched.

    Another difference is that often Ferrari will use and publish the more popular in Europe DIN hp ratings, as they are a bit higher than SAE thus reading better. If they do not specify, Ferrari numbers seem to usually test out closer to DIN I've found. As said before, factory hp quotes from the 70s and early 80s, especially on US cars, are a bit optomistic.

    In my latest learning adventure, I'd be interested to hear if anyone has numbers showing a difference based on spark plugs. I'm finding they may have a bigger effect than I thought.

     
  10. Kds

    Kds F1 World Champ

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    #10 Kds, Sep 20, 2005
    The car is going back on the dyno at the end of this week or early next week for the tweaking....and I have air/fuel info available as well (according to the shop).....I will post it here later.

    Thanks so far for the replies. Plug info would be interesting to have as well if and when it comes up.
     
  11. enjoythemusic

    enjoythemusic F1 World Champ

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    #11 enjoythemusic, Sep 20, 2005
  12. Dave

    Dave F1 Rookie

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    #12 Dave, Sep 20, 2005
    I put my 77 on the dyno as soon as I got it, before I made any mods.
    In stock form with fouled plugs it put out 179 rwhp.
     

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