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1980’s gas vs 2010 fuel tuning

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Capt Fiero View Drop Down
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Joined: 12 February 2007
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    Posted: 09 June 2009 at 5:05pm

 

          While I was reading over the new owners thread from Vlad's car, something just clicked.

                      Our Fiero's the 2.8's to be most specific were designed and built to run on 87oct GAS, not methanol, not this that or the other stuff, but normal gas.  20-30 years ago, what came out of the pump was drastically different that what we get out of the pump today.  Now new cars have much more advanced computers to compensate for almost anything right up to E85.         

          It never really dawned on me until I was reading over that post, when I said, most people are running there V6 cars at 12' timing vs the 10 that was recommended in 1985.  The fuel today frankly has changed so much, even the EPA admits the new ethanol fuel has less punch.  Which causes many people to lose power and fuel efficiency.  It really just occurred to me, why some Fiero's especially, the ones that I have "tweaked" are seeming to run much better.   I run my 88GT at 12' timing and have the fuel pressure raised a few pounds over stock.  It seems to run amazingly better.  Easily pulling off 30mpg, where as some people are struggling to make 20mpg.  I recently tweaked Nigel's car in a similar manor to what I do to other cars and oddly enough he said the car has never ran this good, saying it felt like a new car.  Also pulling off the best mileage he has ever gotten in the car.

                 The gear heads in the Fiero world know this, but I am not sure that everyone else is even aware, the 85 Fiero V6 was 8.9-1 compression and the 86-88 was 8.5-1 compression.  That extra 1/2 point in compression always gave the 85 motors an edge in the performance arena, and hence had to be tweaked just a little different, but none the less the same is holding true.

     If we are trying to set our cars up for best efficiency, wouldn't it stand to reason that, we can't tune for fuel that has not been used in about 20 years and fuel that is currently out there.    Data logging with a wide band, and dyno testing would obviously be the best.

       However, common sense says, we need a bit more timing to make up for the fuel difference, and we need a bit more fuel to compensate for it, even opening the spark plug gap up a smidge from .045 up to .050 helps.    

                Has anyone ever really stopped looked at the whole picture regarding tuning our cars.  I have never seen a stock Fiero to date that did not run better at 12' timing vs the stock 10'.  Obviously engines that are pushing the 10-1 compression ratio should be set back to 10 and altered timing and fuel curves should be used.

 

         Input?  Suggestions?  Arguments?

Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.
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