Hi Guys Took the Dino down to a specialist tuner the other day to see what she put out on the road and moreover to map the ignition timing over the entire engine range. I was never happy with the curves given by BSM as most of their advice was rubbish. To say I was crapping myself would be an understatement. Revving her to 7K+ is unheard of, the old girl is treated with kid gloves at 40 years old and now deemed a historic car. Anyhow on the rolling road they put her through the paces and revealed some interesting facts, first of the black stallion system is a very good set up but rather crude 2D software at only 800rpm increments. The first run gave 168bhp, with some adjustments we got her up to 173.9BHP but was running (worryingly) lean in the mid to upper range. (4000 - 5500) Looking at the jetting which are all factory correct, the tuner was amazed that the air correction jets were so big at 2.20. He has advised to reduce these to 1.80 to enrich the fuel / air ratio a little more in this range. This they say can then allow them to alter the ign timing and hopefully get closer to 200bhp. Which according to them is possible. On the way back the difference was noticeable...or was it my imagination!! Anyhow I will be fitting 1.80 AC jets shortly and taking her back for another run.
Hi Tony, have you fitted high lift cams on your car? apparently my Dino was fitted with these during a previous restoration, and i was wondering what effect this might have on overall performance?
Corrected to flywheel Jim, they are only interested in what the engine is doing. I am concerned that at high rev's the engine is dangerously lean with factory settings and used to often at these speeds could seriously damage the engine. Losing 11% from the quoted 195 claimed factory output after 40 years I guess isn't to bad. However they feel they can tweek it back to this figure. We shall see!! Tony Ps they also say they can dial out the miss that occurs when going around corners. On the way back it certainly felt better and after fitting the smaller AC jets this morning, it feels much much better. However thunderstorms curtailed the test!
I know that this is not popular to say, but the factory horsepowers of almost all Italian Cars from the 60s and 70s are let´s say "very optimistic". Fiat was more realistic with their values. I know several original Cars which had between 175 and 185 Hp on the Dyno.
Without any real evidence its hard to say, but Ferrari did have a habit of exaggerating things a little bit. Its claimed top speed is a little ambitious too. OK for you guys in Germany to explore but the rossers here take a dim view of anyone doing 71.5mph What worries me is the lean condition this engine runs at medium to high revs supposedly correctly jetted by the factory. With smaller AC jets the performance is much better, only a dyno can tell the truth.
Correcting to flywheel HP requires multiplying by a factor to compensate for losses in the drivetrain and tires on the dyno rollers. Since this correction factor can vary with different drivetrains, tires, etc, the "flywheel" number is only a guess and I wouldn't put much faith in it. Even the number from the dyno requires correction for altitude, temperature, etc, etc, so it is not entirely reliable. Probably the only thing that is reliable is change-- so if you reject the carbs and gain 10 HP, that is probably real assuming the air hasn't cooled so it has more oxygen, etc..
Factory jetting was made 40 years ago and fuels worldwide have a much higher oxygen content than when the manual was written. Your problem has more to do with FUEL and not altitude. With modern fuels it is necessary to increase jet sizes and decrease air correctors in order to get proper carburetion.
This makes sense and I have never heard it expressed before. By "oxygen content" I assume you mean ethanol, which has a fairly low energy content. So it makes sense you'd have to add more fuel to get the same effect.
Ethanol is only part of it and referring to modern fuels as having lower energy content is a great way of putting it. One of the big problems is that most mechanics just use the factory jetting because 'Ferrari chose it so it must be right' and then endlessly tune and mess with the speed screws and idle mixture screws to try and get the engine running properly. The problem is that the fuel used today is not as potent as before making it necessary to re-jet the carbs in order to get the best performance. I have started a series of posts on my Dino blog to educate owners on this subject and to give practical advice as to how to tune their own carbs. I have been in a number of Dino's and few of them have really performed. When the carburetion is right there is a night and day difference with most of 'that's the way they are' problems totally eliminated. Carb tuning makes a huge difference and with the right knowledge is easy to do yourself.
Ethanol has a gross caloric value (GVC) of around 30,000 kj/kg and petrol 48,000 kj/kg. A 5% ethanol mix (possibly soon to be 10%) will therefore reduce the GCV on modern fuels hence the need to re-jet to correct the air/fuel ratio I haven't had any chance to get the car back on the rolling road as yet but the engine runs much cleaner, in fact the plugs may be wrong now as to prevent fouling I had fitted many years ago hotter spark plugs. Mapping may be tricky & time consuming but this is seems to correct thing to do, although I have noticed hot starting is much worse, something I have never encountered on my car before. Perhaps the timing needs shifting a tad more, something the tuning guy wouldn't do until I returned with the correct AC jets fitted. Tony good advice on carb tuning Rob, something every dino owner should master although in my opinion the carbs always got the blame for bad timing set up, especially with the mechanical weight system. The programmable system at least has the benefit of being consistent and accurate everytime.
Tony if you are going back to the rolling road be sure to buy the next two sizes up on the main jets, the next two sizes down on air correctors, and the next two sizes up on idle jets. In total you will spend very little and have just about everything you need for a good tune. Changing the jets on the dyno takes only a few minutes and they are totally plug and play. You can tune your programmable ignition between jet changes but the biggest hassle is getting to and setting up on the rolling road so having all the jets you need is the least of your worries. If the person working on the dyno clearly understands what the effect of each change does and knows how to properly work with your ignition system they should easily be able to give your car a perfect tune within 2 hours of dyno time. Here are a few guidelines to consider: - The idle jets control the mixture up to about 3000 rpm so be sure to use larger idle jets if the A/F mixture looks lean below this speed. On Weber carbs the idle jets do much more than just set the idle! - Be careful not to have the idle speed screw set to past 1.5 turns from the point of contact otherwise you start to introduce the secondary progression holes in the idle. - Air correctors work hand in hand with main jets and generally act as the 'in between' adjustment between two main jet sizes. Changes should generally be made one size at a time so if you feel the need to go down two air corrector sizes, the change to one main jet larger should yield about the same result. When you next go to the dyno please post the results. I'd be really interested to see the gains you make. It is not only about absolute horsepower but correct jetting fills in all kinds of flat spots in the power band. Let me tell you Ferrari may not finish a body very well but they sure know how to make a tune an engine. Too bad nowadays so many are borderline anemic in their performance. Properly tuned the Dino is pretty peppy even by modern standards.
Can't figure out what he has in this, is he still using the Dino block, re dissy ? Beautiful Blue with red interior https://www.youtube.com/watch?v=F6DwmJ27dt0
Well it seems like my car likes the following 0.55 idle jets (0.50) 195 Air Corrector jets (220) Everything else as standard ie main jets, emulsion tubes etc. Tuned up very nicely indeed and mid range power is very good. No off idle stumble and certainly a lot of the dino quirkiness of flat spot when cornering has been substantially reduced. Very pleased indeed, I could go a tad further to extract a bit more but I wont push the old girl.
Tony, Hi - may I ask where you get this work done? My car is running fine, but might be nice to get it really fizzing....sounds like you are pleased. I am about to do a long run up to Scotland and if I had time, would make sense to get it looked over before that.
I do the final tuning & set up myself with the use of a rolling road (and his expert to advise of what jets to use.)
