V-12 Deathmatch...

Back in the days when IDA's and DCOE's were in competition with SU's.  An XKE 6 cylinder made 15 more horsepower on DCOE's over SU's 

 Most  of that was credited to straighter intake shot for the Weber's than the SU's. 
     
    As far as an Aston Martin V12 goes, I don't know any that used SU's. Or even Weber's.  I never could see spending that sort of money.  But then I haven't studied Aston Martins.  I could be completely wrong. 
 As far as simple goes, yes carbs are extremely simple for an old Geezer like me.  Mechanical Fuel Rejection is too.  Electrons and Lucas magic smoke though, well I wouldn't wish that on my worst enemy. 

In reply to frenchyd :

In 2021, hell in 2010, it seems like you have to buy three or four pairs of SUs before you get a good one.  Had a nightmare of a time getting a 240Z running because of the lack of non worn out SU carbs on the market.

If NEW carbs are available, the short term expense outweighs the long term pain in the ass of dealing with worn out junk.

In reply to Pete. (l33t FS) :

The only real wear on a SU carb is the throttle shafts.  They sell oversized shafts and reams to fit them.  The rest of the wear parts come in the maintenance kit.  
     What I love about SU's is the ease it is to richen them up.  Once the ignition is in order if the car is backfiring at a certain RPM  take a piece of fine emery paper, put the needle in a drill and fix it. 

All but the Jag V12 in this thread would require significant fabrication just to use a single 4 barrel carb.  Let alone 6 or 12 carbs.  The BMW and Merc V12's were only fuel injected.  So running them would carbs would be pretty complicated.  I'd bet that they are similar to the Aston in one key aspect- no distributor.  If you are going to have computer controlled ignition, might as well do fuel injection, too.

FWIW, the first Aston V12 used a pair of EECV's that were mostly the same as one used in their host car, the Taurus.

In reply to alfadriver :

Yes the BMW requires 2 systems while the Mercedes Benz requires 3.  Us Luddites like carbs  and distributors. But even I will admit real power comes from Turbo's and that requires EFI. 
    I honestly don't know anything about either one. Maybe they are as cheap and easy to work on.
  I doubt it since I don't have near as many metric tools as SAE tools.  I still think in terms of three barley corns from the middle of the ear.  
    I just don't think the BMW or Benz can go as big as the Jaguar for as little cost. Again I may be wrong because I haven't spent any time with them. 
     I seriously wish someone who has raced and modified BMW & Mercedes V12's could come and help me learn.  
    What are parts costing? Are there affordable replacements, or racing parts?  How much wear shows on a typical 100,000 mile engine? I've heard BMW made some manual transmissions but are they common?  What about adapting other manual transmission to a Mercedes Benz? 

Well since the 90s Mercedes has had 3 different v12 in production.

The cheapest you'll find is a 2000-2002 m137. Those cars were crap and had terrible electronic issues and build quality. The engine wasn't particularly powerful compared to its siblings, 5.8l 362 hp and 390 torque. But, you'll find these s600's for super cheap with fixable issues. Their not particularly liked because 2003+ 600's are better in every way with the sacrifice of buy in. 

Then, the 6.0l m120 (my favorite) from 1991 to 1999. Pre-1996 had biodegradable harnesses and wiring in the electric throttle actuators which made diagnosis and troubleshooting basically useless. After 95 they didn't have this issue. Ran off 2 ecu's and a gazzilion computers. The 1992 engines made 402hp and 428 ft lbs torque, all other years made 389hp and 420 tq. They're famous for being used in the Pagani Zonda. They have the best sound in my opinion and would do well with an aftermarket ECU and using regular throttlebodies. 

2003+ is the m275, 5.5l bi-turbo. In their lowest form they were rated at 493hp but often dyno'd over 500hp in stock form. Mercedes underrated them at 493hp because their flagship S class S55 AMG only made 493hp from a supercharged v8. They didn't want to undercut their AMG. The m275 can reliably 650hp and 800ft lbs of tq just from a tune, intake and exhaust mods. Good luck finding one for challenge price. 

If I wanted a v12 hotrod, I'd go m120 and convert it to throttle cables and megasquirt or something. Otherwise, the jag v12 converted to carbs would be more simple. If you like electronics and have the talent and space, a m275 would turn any car into a rocketship.

With that said, I've owned 2 v12 cars in my life. A 95 Mercedes s600 that I got for free and fixed with $46 worth of fuel pumps. It had corroded harnesses and I sold it for a few grand. I currently have a Jaguar XJS V12. Tough and well built engine in a stupid package with even more stupid cooling and fuel issues. 

If you want to own and actually drive a v12 car, don't get a project car lol. YMMV

In reply to frenchyd :

I think Jag, Mercedes, and BMW all built strong engines as far as internals and being able to last a long time. All 3 companies suffered from overly complex solutions when it came to everything around the engine, in typical European fashion. 

None of them are easy to modify with off the shelf solutions. Even with the jag v12 and your cheap (but not really cheap) and simple (but not actually simple) power gains/mods claims. They aren't as simple or easy as you nostalgically remember. They are 70-89s goofy and complex vs the other two 90s too many computers complex. 

Parts are getting thin on the ground for all of them. Affordable and v12 doesn't go together with available "racing parts", because there's none. 

There's manual transmission solutions for all 3. Mercedes didn't have any factory manual solutions like Jag and BMW but there's aftermarket kits for $$$$ lol. 

I know someone who turbocharged a Toyota v12 and swapped it into a Mercedes. They blew it up at less than spectacular power levels.

Edit: The m137 and m275 will bolt to 6spd manual 716.667 transmission. Commonly found on v6 Mercedes and Chrysler Crossfires.

Anyway, I'll leave this thread to be Frenchy'd lol. 

Should we throw in the Falconer V12:

 
You can even strap a prop to them

here is a pic of a Jag engine they modified:

In reply to yupididit :

I gave you a thumbs up for that information. Thank you. 
    I suppose for Jag the street cooling issues you mention are valid.  The fueling  issues are  also valid for the street.  I'm taking your word for it.  I'm a racer and messing with cars like this to drive on the street never made sense to me.   
The speed limit and public safety, limit all cars to transportation modules for the street as far as I'm concerned. 
      I like to push things right to the very edge. Hold the line as we race through a corner side by side as fast as the car will go. Not just squirt the throttle for a few seconds and slow back down. 
      If that's how you judge cars then it's valid for you. I'm different. 
 However Rob Beere sells Jaguar V12 stuff for racing and while it's not junkyard cheap it's at least off the shelf and very good.  AJ6 engineering also sells Jaguar V12 performance things.  As do a couple of people in America. 
      

aircooled said:

Should we throw in the Falconer V12:

That's a Jaguar.  I thought the Falconer V12 was a 90 degree Chevy V8 with 4 extra cylinders. 

Yeah,  my goof.  It was a pic on their site.  I edited my post.  Nice looking Jag motor though.

In reply to aircooled :

 I've never seen one painted before and I love the detail and color.  
     I'd love to see one all polished  up. That all aluminum motor would be stunning.  

Saw a project where someone had put a BMW V12 into a TVR 2500M but couldn't find a pic.  Nice smooth engines, not super high output and had rather expensive electronics.  IIRC the engine was out of an 850i