Why so much FI insecurity?? It is what it is, the DD is a special engine in automotive history. Deal with it guys.
Left you can see a 3.9l 2V aftermarket piston (for my Espada). Right you can see a 5000S 2V piston. Image Unavailable, Please Login
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That is a pic of piston 001420828 that is 9:3:1 and is found in some 25ths. Since I can't prove something doesn't exist, do you have a pic of this piston style in an open and previously untouched QV block? -mick
Here is a couple of things to factor inn, point 2 in compression in a typical us 500 hp v8,without touching the induction or timing,in general ,gains aprox 1/2% in hp. This means aprox 2,2 hp give or take in the qv case, removing 15 grams from each piston,(180 grams in the qv) equals aprox hp gain ,3 hp, i o w, the lighter pistons gains more,than the added compression, but,here is the best part,lighter recicropating weight also makes for a much quicker and more responsive engine,and saves load on bearings. All in all,perhaps Lamborghini had a plan with this, or put it this way,a dd with fi pistons ,would actually have more hp based on avg rules.
Those are some interesting points, thanks for sharing. As a general rule compression follows the law of diminishing returns. After a certain point the gains you recieve will be relatively smaller in proportion to what you saw previously. The jump from 8:1 - 10.1 will be ok (even then you need supporting adjustments). But .2 at a already relatively high compression like in the CT won't be a huge difference. Small enough in fact that weight could play more of a difference like you said. That being said the timing on the DD is a little more aggressive.
Timing is easy. Interesting part is this. My car has 2 owners manuals Us And row. The US tec spec says comp ratio 9,5 +/-,2. - 1. . Could this poss mean they had a bunch of pistons laying around? Lets use them all, intetesting to get some real facts from real owners) not important beeing it will give at the most 2,5 hp. Poss a loss if You reside in Denver or Kloster. (Altitude) good snd meaningful Countach discussion. To quote my good buddy. Sackey.
Thanks for Posting Dani, I saw both Pistons at my mechanic's workshop, since he had at the same time a DD and FI engine to restore, huge differences, also behaviour was quite different, btw. both equipped with a MSD 7-AL-2. Like day and night as my mechanic discribed. Isn't this the one you got from me? BTW, I have also an original Diablo and F1 Piston, guess what, they are almost identical, but almost identical is not same...
Not really, but whatever makes you happy. I don't but if you have one please post it. Mick, no comment. Dani your observations speak for themselves. Exactly. Good advice. Coupled with the Downdraft's cams and 44DCNF Webers, different worlds.
Night and day? The lighter pistons makes for a more rew happy engine,more so,in fact,than the ,2 in compression ratio difference, factor inn a 35 hp handicap in emission,and 200lbs in added muffler and bumper garb ,yet only,2 sec slower to 60 mph, looking at these nmbrs, shure seems like Lamborghini put more thoughts inn to the fi than the dd.
I bet some Fuelie owners wish you would stop drawing attention to the Downdraft's obvious performance superiority with your comments, all of which are opinions, none of which are proven or independently corroborated. It's basic knowledge that the Fuelie was in fact a production afterthought, a compromise of the original Countach carburetor concept purely in response to a Federal transportation authority emissions mandate. Accordingly, basically, the Fuelie is an EPA Countach by virtue of reinventing the wheel and strangling its performance, and there is no reason for its existence other than to satisfy the US government. Ask everyone @ Nuova Automobili Lamborghini SPA from the CEO to the Chief Engineer to the Chief tester and you find that as sports car manufacturers, the compromised Countach Fuelie was not a variant they consider their best work, and the car's significantly inferior performance was exactly the reason they FIA Homologated the Downdraft instead. FWIW none of the aforementioned points are opinions, and all of them are independently corroborated.
Good one. only reason for its existence? I was always under the impression Lamborghini s whole reason for existence was to make a profit, a bussines.as in a company wich intentions are to make money, also,did not The Mimrans develope the qv head in order to compete with the Testarossa,Porsche turbo, and their likes, or no? IOW the qv was needed for$$$$$$ money reasons,all variants. I Do not think The cost of the Four valve cylinder head was done just in order to satisfy somebodys dream, they needed a better product. Profits dd,fi all in the same category, and on a budget,reason why they kept the old cyl block,with added spacers.
The US market was probably a major reason for the QV heads existence, Lamborghini needed this market bad, but with the old 2 valve head,in combination with EPA, and other restrictions, the Countach was not living up to its looks, a slightly modified Corvette(perhaps even stock) would beat it at the stoplight, Make no mistake about it, the FI,was as big part of the QV developement,from the get go,as the DD, The carburated model was launced first simply becuase there where carburators readily available,and the car was late to the party,it was needed to beat the Testarossa.
And the Homologation, really? You honestly think that was even part of the profit plan for Lamborghini as a company? Do you really think Chrysler gave even the smallest crap to the Homologation, probably did not even know, anything can be submitted for homologation,its cool they did it, but why,is another question.
joe im agreeing with most of your views here, however there are many cases why cars are homologated for racing purposes. porsche homologated the rally weapon SC-RS in 83-84 not because it was spec'ed out solely with highest output motor. it reverted to the old 3.0 motor rather than the new 3.2 since the former qualified as a "evo" model which you only had to build 20 or so extra examples. there are many other examples of an oems reasoning to homologate a particular spec car. The ability to produce a certain number of cars within a timeframe is a struggle even with porsche with a well know quantity like a G-body 911. you dont have to go very far from modena area to see all the high profile failed attempts at homologation for racing. from the LM, Gr 4 bora, early stratos they had to run as prototypes though the intent was street gt cars due to failed homologation. Sant'agata first attempt was a dismal failure with the E26 or BMW M1 in which lamborghini was delayed in the delivery. lamborghini only built 5 or 6 examples out of 400 making the M1 ineligible before everyone moved on to gr5 and gr4 became defunct. eventually it ran in a bernie circus called "procar" series. its makes sense that they chose the DD since it was the first 4v built for the road and the market was more predictable and stable than usa. performance wise dcnf's are better than CIS but im not sure if there were any cars still running with webers on a international level in the 2nd half of the 80's. CIS leaves a lot to be desired, its issues for hindering performance are well know (well with the exception of this crowd.. ) since for a decade and a half it the predominated injection used. But you race what u can homologate.... with the porsche 934 and 308 GrB, it has proven you can win with CIS too. my 2cents
I have never understood why these 2 variants are referred to as Fuelie and carbed when in fact that is only one of the differences between the two. As a number of people have suggested there are many differences and some have even stated "completely different cars". To me they have always been, emissions/DOT compliant and non-compliant cars. It's common sense that any non-compliant vehicle will perform better than a compliant vehicle, so for anyone that believes otherwise I feel they are misinformed. I don't agree that the Fuelie was a production afterthought but instead a production necessity. They wanted the US market but more important the factory knew what was coming down the road with compliance to emissions and safety standards. I would say the company was evolving with the FI Countach and in fact it was the beginning of the end for carbed cars as they had become obsolete by that time. I also don't agree that Fuel injection is a compromise of the original Countach as I do not feel that FI was a realistic option for the original car, but there are many other changes along the way that you could argue are a compromise of the original concept. I think there are a couple of points most would agree on, the non-compliant cars look much better and fuel injection is a better way to deliver fuel to a combustion motor, there's a reason Lamborghini has not produced a production car with carbs in decades. I appreciate them both for what they are and I don't feel one is better than the other, just different. The end of a great era and the beginning of another.
As always, lots of opinons and guesses, yet few facts. You really do make this stuff up as you go along Did you ever ask Patrick Mimran what his agenda was? I did, personally, not through an intermediary. He authorized publication of his viewpoint in the July 2017 edition of Classic & Sportscar magazine, and his thoughts on this specific matter are printed on page 119. What part of "We weren't bothered about outperforming the Testarossa" as stated by Nuova Automobili Lamborghini SpA's CEO himself do you not understand? I like your take on the Homologation perspective, but really, all I seek to underscore is what you have already stated about CIS. I agree with a lot of what you say, your logical presentation of your thoughts helps. That said, again, much of what I am asserting is what you have have said as in "It's common sense that any non-compliant vehicle will perform better than a compliant vehicle, so for anyone that believes otherwise I feel they are misinformed".
Really,not bothered by outpeforming your biggest competitor?,not to mention the att the TR got when released, yup, call it my opinion, i am ok with that,
I am made to understand that this is a very original LP400, if so, much respect to the car's connections the past 40-plus years for not modifying the car, one of few LP400 in Japan that has remained original. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login