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

they are for an audi

 

From the angle of the throttle bodies in those pictures, I would be surprised if there has been extensive remodeling of the inlet tract as such. If the valve centres have to remain as standard you will not be able to get very big valves in there either so 305 is very impressive.

I wonder how they managed to get an extra 30 lb/ft between 96 and 97. Seems like a big jump to me, too big...

 

its hard to believe but just did a couple quick calcs

305hp at 8250 means they have to be making 194 ftlb at 8250.......thats a lot

max torque will probably be about 7000, which means 289hp at 7000rpm

maybe.......

BMEP is 240psi......WOW, thats one seriously efficient engine

 

Cracking info. On a rummage around Google, I found more:

Click - the 80 STW-spec car was raced in '94, possibly in the German and Italian championships:

Wiki:

STW - wiki



And a press shot:


From Pirro's website:


Anyway... bit of history on the engine/car origins

 

Arn't the drive couplings higher to allow the engine and box to be fitted lower in the chassis?

 

Suspect so

 

A couple of more gem's

A4 / 80 BTCC 2.0 block (believed to be from a 9A ~ 6A casting) or bubble block ??



End View (notice the main bearing size!!




My Stock ABF block for comparison




With the conditions this engine was likely to see, a proper lubrication system was required!! Fully integral dry sump, for a Longitudinal set-up of course.

 

So nothing resembling an ABF there, which is what it could be based on.

Anyone with a 9A / 6A block pic?

Alloy skirt is weird, but looks OEM - not on any ETKA info?

 

Look at the short length of the BTCC block. The iron stops at the join in the main bearings, the rest is alloy by the look of it...

 

Feels like a more 'involved' version of the block girdles you can buy from Eurospec:

 

I was thinking more in terms of reducing the total weight of the engine, rather than for structural purposes. Could be for both I guess, but you can't really tell from those pictures...

 

I'd agree, it's doing both.

 

Just reading this interesting thread and thought i'd throw in this

I think the blocks based on a 2.0 ltr ACE code
put one into my rado about 6 months ago , i know ive a better shot of the rear of the block somewhere , but from this shot it does look similar




Ive just had to take it out due to an excessive oil consumption problem , will get some better shots of the rear .

 

Looks nearer- it's that upper cross ridge that's closer to the block deck than on infinity's ABF.

 

It's the same valve cover and very similar looking vernier etc as this:


Which was quoted as being an 'audi motorsport head', I always thoguht the v8 left bank cover looked very similar.

I've also got some pictures of a head I planned on buying from a french guy with a stock of ex STW parts. Different throttle assemblies, slide throttles, dry sump bits etc. Some of it's in the porn thread from a while ago.


RobT,i agree with regards to the bmep figures. I did some calcs and thought 240psi is mental. 108.5 lbft per litre NA is pushing the envelope. I have to say a lot of the other super touring stuff is often thought to be exaggerated, manunfacturers outdoing each other etc, and i'm sceptical of 305.

Chris glad you bought it up spent a lot of time trying to research these engines and never really got anywhere. Other than the spanish hillclimb A4 rebuild thread where a lot of these pics are from. I translated a lot of it even the bit about the owner getting the engine rebuilt, but it was all really vague. Not really any help.

 

Cracking - those inlet ports on those are massive Injector cut outs are also missing. I suspect the heads are ringer castings with altered water jacket areas, to allow that sort of porting.

Nissan were quoting well over 300bhp for the Primeras...

This is where I suspect some of it comes from - bespoke toothed intercam wheel on the LHS:

Means the timing chain can be junked and the timing set as marginally as possible, yet valve contact avoided at high rpms.

Useless for production - that straight cut wheel will make a serious whining racket.

Cam lobes are extra thin - friction?


Whatever other pics from STW parts you have, do post them up


Btw, credit to inifinity for all this - firmly his idea.

 

That block posted above presumably has a main cap ladder similar to a Millington Diamond or the AER 'mazda' LM engines. It's fairly common practice it seems on really high spec stuff. Means you can also compartmentalise the crank case and have seperate scavenging for each one. Helps greatly with modelling and controlling windage etc. apparently. To me it looks like they've cut the bottom off. You can see where they've cut through the lug on the right. The ladder would be held together by main studs primarily anyway.



These are not all from the same place. The last one is from that south african vento with a claimed 280bhp which was for sale on race cars direct for ages. The wet sump one is(or has been converted to)s2000, which was offered with the head, as is the stand off injection stuff.

 

Chris you're right about cam gears. Makes it a headscrew as the inlet then turns the wrong way and the cam looks out of place at tdc.

wierd cam cover again, 3rd different type of v8 head? makes me wonder about fitting an rs4 head to an fsi block.




That's all i can find for now.

 

jimmy those are some excellent pic's keep em coming!! Anything with NNE on it is the equivalent of VWM part numbers

Looking back at the block, I've found the following spec's

AUDI SPORT BLOCK

BORE = 85mm

STROKE = 88mm
(although info is a little sketchy as some people have said 88.6 and 88.7mm, but these sizes may take it over the regulated capacity??)

So quick calcs indicate the following capacity

Area of piston X Stroke

Area = 56.71 cm 3
Stroke = 8.8cm

Capacity of 1 cylinder = 56.71 X 8.8 = 499 cc

Capacity of 4 cylinder = 499 x 4 = 1996 cc


Audi was clearly trying to make this motor rev and accelarate as quickly as possible, big bore and destroking.

boring a 9A block to 85mm isn't unheard of, there has been talk on vortex about it and a couple have sucessfully carried it out.


Now lets look at VW Motorsport's 2.0 16v ABF specs


BORE = 84mm
STROKE = 90mm

Carrying out the same calc gives

Area of piston X Stroke

Area = 55.39 cm 3
Stroke = 9.0cm

Capacity of 1 cylinder = 55.39 X 9.0 = 498 cc

Capacity of 4 cylinder = 498 x 4 = 1994 cc

In terms of power, I was visiting an engine builder a few weeks ago and they were verifying the power on a nissan STW primera it produced 329 hp, wish i'd taken a camera, awesome sight and I've heard nothing like it

 

Unbelievable bore outs! 85mm

Very interesting to see how they've gone charging after a square engine/shorter stroke configuration.

^^ any ideas what that cam cover is supposedly off? Again, looks dry sump modded, though production style, very Mk4 Polo....