Audi A4 BTCC / STW engine specs - 305 bhp from an N/A valver.

Discussion in '16-valve' started by A.N. Other, Mar 23, 2009.

  1. mr hillclimber Club GTI Supporter and Sponsor

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    It is a big torque jump from the previous years 188. A friend of mine see's figure in that later ball park from big capacity XE's, with comfortably over 300hp... so the numbers sort of add up, but it's a lot for a 2ltr... though I would'nt have thought Audi had much to prove by stretching the numbers.
     
  2. lufbramatt Forum Member

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    yep, and they twisted the gearbox right round so the diff was at the top and ran the propshaft through the V of the block to get the engine to sit as low as possible in the car :)

    "It was originally a 2.5, but we reduced it to 2.0-liters to fit with the regulations," says Wilcock. "We used a standard casting, but the cylinder head was completely revised. Forty individual parts were welded to the head and the process was so complex that just one in three of the heads we produced was of sufficient quality to be used on the car. The rest were just thrown away. At the time, a Touring Car cylinder head was more expensive than those used in Formula One."

    "Back in 2000, power outputs were guarded with feverish intensity. The manufacturer quoted 300 bhp, but Wilcock admits that the true output was 315 bhp, with 221 lb-ft of torque. Given that the Mondeo has a weight of 2,326 pounds including the driver, the power-to-weight ratio is an unspectacular 299 bhp/metric ton but these cars were built for agility rather than straight line thrust."

    "The drivetrain and suspension could then be added to each completed shell. The engines used are Mazda derived 2500cc V6 taken from the Ford-USA Probe model. Cosworth Engineering were responsible for the race engine design, selecting the V6 due to it's excellent 24 value twin cam head design and larger piston area compared to the available four cylinder units. The all alloy 60 degree V6 was also light and compact (only 457cms) so could be fitted well down in the chassis to improve the car's center of gravity."

    "The rules stipulate the use of the standard production block and cylinder heads, but Cosworth replaced virtually every other component within the engine with their own custom built items. An all steel crankshaft and connecting rods were topped with aluminum pistons, the engine capacity being reduced down to 2000cc limit by changing the length of the engine stroke. "

    pd4.jpg

    sorry its a bit off topic, but it still interesting :)
     
    Last edited: Mar 28, 2009
  3. s1m0n Forum Member

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    Actually Cosworth "lost" the engine at the end of 98, Prodrive had been running the cars and Cosworth had been providing the completed lumps, the results had not been coming so for 99 Prodrive took over the engine as well... The results of this in 99 & 00 speak for themselves.

    But your right about the drive coming though the V of the engine, all the super tourers had really high diff outputs because of the 19" wheels and low ride height, that V6 was spectacularly low (and back) though.

    Bit more on topic, I know the "numbers" seem ridiculously high but I know what that little V6 made and there was certainly no exaggeration going on, it would surprise me if the Audi figures were fibs

    Cheers

    Simon
     
  4. lufbramatt Forum Member

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    also supports the suggestions earlier in the thread that new lumps of metal were welded into the head castigns to revise the airflow to the valves.
     
  5. s1m0n Forum Member

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    Can't speak for the VAG head (though it looks "different") but the V6, yes, very much so.

    Cheers

    Simon
     
  6. infinity

    infinity Forum Member

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    not 100%, but did the more powerful lump go into the later not so successful front wheel drive version of the A4.

    I've asked for pictures of the pistons and dimensions to confirm the 85mm bore.
     
  7. Neal H Forum Member

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    Different car I know, but the Group A mk 3 kitcars had 84mm bore and 90mm stroke with an ABF block.

    Looking forward to seeing the pictures of the pistons. I will try to post a picture of the 85mm headgasket I have...
     
  8. mr hillclimber Club GTI Supporter and Sponsor

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    I'd imagine so if it was the later development, though that car never really looked right.

    I expect the bore dimensions were right (the numbers add up), but I would'nt want to run a standard block that thin... one off castings, well that's different.

    I also remember Audi claiming at the time that the cars were "totally" stripped after "every" race and re-built, so if all the block had to do was last a weeks testing/qualifying/racing...
     
  9. mr hillclimber Club GTI Supporter and Sponsor

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    Would like to see that gasket, I'd imagine the fire rings are thin. Same goes for the rally engines, they only have to make it to the end of the event, not a few years like we need to see when we're paying for it out of our own pockets.
     
  10. infinity

    infinity Forum Member

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    As promised some pictures of the pistons

    piston_1.jpg

    -84.87mm pistons points towards an 85mm bore.

    -The M is the manufacturers logo (Mahle Motorsport)

    -Notice the massive cut-outs for the valve reliefs
     
    Last edited by a moderator: Oct 30, 2017
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  11. RobT

    RobT Forum Junkie

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    wow - thats a race piston and a half - like fitted to high revving race bike engines, next to no skirt

    great find - looks like they were probably special block castings then
     
  12. davidwort Forum Member

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    KR and 6A for comparison

    116-1623_IMG.jpg

    116-1621_IMG.jpg
     
    Last edited by a moderator: Oct 30, 2017
  13. FaTT mk1 Forum Member

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    Why is the bottom of that block missing? In the bottom pic?
     
  14. drunkenalan Paid Member Paid Member

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    did you read the entire thread??
     
  15. FaTT mk1 Forum Member

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    Yea but theres no REAL reason?
    is it just a brace then?
    It looks like it holds the crank in like a one piece big end bearing plate.
     
  16. drunkenalan Paid Member Paid Member

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    to stop the block flexing, it can be a problem on large bores and high revving engines.

    basically its a brace yes, aswell as acting as a crank scraper etc
     
  17. King Kwik

    King Kwik Forum Member

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    Fantastic thread I never thought I'd see anything like this on here.
    Does anyone know the conrod length or R/S ratio?
    Some shots of the exhaust manifolds and collectors would be welcomed too.
     
  18. Neal H Forum Member

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    One 85mm headgasket...

    DSC01467.jpg

    DSC01468.jpg
     
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  19. mk1g60turbo Forum Member

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    Cracking thread!!! Not much meat left on that gasket!
     
  20. mr hillclimber Club GTI Supporter and Sponsor

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    That is tooooooooooooooo thin... the bores would wobble like a bastar% with anything like decent power on a bored out standard block. All these big bores are worthless if the bores distort and the ring seal is broken. I'd suspect the BTCC block where indeed special cast items with altered bore spacing.

    Great pic of the gasket though Neal, Cometic are exellent gaskets, but leave that one in the packet.
     

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