Originally Posted by Steffo
DOHC isn't all its cracked up to be. Its larger, physically, and weighs more. Lets just compare a 260kW 500Nm 5.4 litre DOHC 32v BA XR8 to a 220kW 435Nm 5.0 litre OHV 16v pushrod AUIII XR8. Both average 14.4s over the 1/4 mile, yet the BA has a 40kW and 65Nm advantage. Why?
Because the BA is heavier car than the AU, nothing more.
Well, that 5.4 in the BA is a much larger engine then the 5.0 in the AUIII, and not simply capacity wise. A 330ci DOHC V8 from a current Falcon is dimensionally larger then a 351ci Cleveland V8 from say, an XY. It is also quite heavy. To match its lighter pushrod sibling, it needs to be making alot more power and torque.
Nonsense. Yes a 5.4 DOHC is heavier than the 5L Windsor, but it ain't heavier then a 351 Cleveland.
Pushrod engines tend to be structurally stronger then Overhead Cam engines are.
Drag Race engines have proven this. Pretty much all Top Fuel cars are pushrod, there is only one exception I know of, Sanity I believe, and they are very slow (5.2s @ 290ish mph is slow for a T/F). The cam drive system is suspect to breaking quite early in the run of such a powerful engine, which compromises the already shaky reliability of Top Fuel and Funny Car engines. Hence why the "old tech" pushrod blokes are running well into the 4s, and the ONLY (note the emphasis on only) OHC example is stuck in the low 5s.
These are blown engines running so much boost and nitro it ain't funny. No matter how the valves were opened it wouldn't matter.
BTW, it's 'Sainty'.
People can blab on about efficiency all they like, but fact of the matter is, Ford's most successful engine ever, the Windsor, was pushrod.
Jeez, and so it should be, it's been around for more than 40 years!
And it is momenterily proving to still be a far superior proposition to the current 5.4litre mill in the Falcon, and the less-insanley-undersquare 4.6 in the Mustang.
What a load of bollocks, far superior to whom, may I ask?
GM seems to be doing well with pushrod V8's, what with the GenIII's success and the upcoming GenIV.
Success?? You call that rough running, oil using bucket of shit a success??
The only thing that has saved the Gen 3 is the fact that Ford offered no competition to it until the BA.
The only reason it outguns the BA 5.4 is because the cars are lighter and better geared. That ain't rocket science.
They do make a DOHC motor, its called the Northstar 4.6 currently only used by Cadillac. If it were beneficial, it would quite easily find its way into GM's beloved Corvette, but they have decided that the GenIII LS1/LS6 and the GenIV LS2 are superior and so continute to use those.
Nonsense, it's all about money.
Not to mention the fact that Holden/HSV seem to be doing better then Ford with their "low-tech" pushrod solutions, what with 285kW 510Nm in the Clubsport now superior to its Ford competition, the XR8's 260kW 500Nm. The 260kW 475Nm Clubby was faster then a BA XR8, the 285kW job brushes it away like a housefly. As does the 300kW 510Nm GTS to the 290kW 520Nm GT. Frankly, myself, I'd have liked to have seen Ford Australia push on with the Windsor V8 at 5.6litres instead of wasting time with the 5.4, or at least adopting the Cobra's Supercharged 4.6.
Well let's just be thankful you're not in charge of making those decisions within Ford OZ.
See above about why the GM product has been hosing the blue oval. Hint, weight and gearing. Compare engines alone and it's a no brainer, Ford in the first generation are generating the numbers to look like a very promising future.
After saying what I've said, I really don't know why I voted "both are as good as each other," but I guess it is the most correct thing. Both have their strengths and their weaknesses. And before anyone starts yapping about DOHC being newer, DOHC was invented in 1917 in France (forgot by who) and the first DOHC V8 was done in 1928 by Ford. Pushrod was done by the Chevy brothers in 1913. Ford decided in 1928 that Pushrod was more cost effective and space efficient then overhead cams, so they dumped the concept from major production until 1996, with the exception of the SOHC 427 "Cammer" V8 of the 1970s.
From the early results of this poll, it seems that the majority of people on this forum are blinded by jibberish about DOHC being newer and more efficient. BA's V8s aren't proving to be that efficient at all.
Well, many other manufactures around the world must be blind also.
BMW, Mercedes, Honda, Yamaha, Kawasaki, Ducati, etc,etc.
You are so wrong it's not funny.
OHC and DOHC have so many advantages over pushrod engines it's just plain silly to even compar the two, hence my first post on the subject.
You can't compare what was developed over 1/2 a century ago to what is being done today with modern metals and manufacturing techniques.
Get back to me with some real 'engine' numbers and not the whole 'vehicles' numbers and we'll go for round two.