Back in February, the World Challenge 2004 regulations said you could have an 1842 cc engine. Now the displacement limit has been increased to a whopping 2007 cc. The rules are contained in the VTS sheet
http://www.speedvisionwc.com/c....pdf re-issued in March 2004 and in the Appendix A
http://www.speedvisionwc.com/c...4.pdf the latest one from Aug 2004.

The engine specs from combining both documents are as follows:

Displacement : 2007 cc (an 11.7% increase over the stock 1797 cc)
Stroke: 87.2 mm (stock ITR) which gives an 85.6 mm bore (stock 81.0 mm)
Is this even possible?
Compression: 12.5:1 (2004 beginning year spec ws 12.0, 2003 spec was 11.0:1 and stock US ITR is 10.6:1)
Cylinder Head Combustion chamber: not specified (was 45.5 cc min.)
Pistons: free (but getting up to 12:5 will require a large piston dome of 7.7 cc vs stock ITR value of 3.6 cc for stock 42.7 chamber volume)
Head: stock with port matching to manifolds for a max of 25 mm into head or manifold.
(No mention of blending in seat a max of 0.75" from seat as in 2003)
Throttle bore: 62 mm (and it used to have a restrictor to make it slower and let the other guys catch up!)

And some surprising parts:

Cams: Skunk2 305.05.0150 (or equivalent) which is Stage III (2003 was stock ITR cams)
Intake Manifold: Skunk2 with no part # (beginning of year a GSR manifold, likely a typo)
Rev limit: 9000 RPM

Weight limit 2350 lbs with driver, assuming no dry sump system.

While the ITR no longer seems competitive in WCTC, does anyone have a similar 2007 cc engine?

For comparison, the latest Honda/Acura limits are with no dry sump:

ITR 2007 cc 2350 lbs
RSX 2045 cc 2500 lbs
TSX 2422 cc 2600 lbs (is 2422 cc possible?)
Civic 2007 cc 2350 lbs (2002 or older)
CTR 2045 cc 2400 lbs

 

they finally figured out that not allowing the ITRs to increase as well were causing them to get murdered on the straits.. I'm sure lots and lots of complaining from some of the small teams still running R's prompted this..

in case you hadn't figured it out, the rules favor bigger, factory sponsored, teams in World Challenge.. or whatever the hot new car is..

/rant

 

Sleeving a bottom end will allow you to get to the 2007cc limit, as well as custom pistons. With these options you should be able to make a 240-250whp car that is fairly reliable.

Austin

 

So is such a motor a very rare bird on the track, or have people made such beasts and made them reliable?

If you are right about the power, such a 240-250 whp engine with a 2350 lb car+driver limit would give you a 2200 lb car (say 150 lb driver) with 250 whp or about 294 crank hp (assuming 15% drivetrain losses), or about 7.5 lb/bhp. That is 146 hp/litre, not too shabby if you can do it reliably, vs the 108.5 hp/litre for the stock ITR motor. This would be a seriously fast machine. In comparison, a 2004 GT3 road car (not the Cup car) has 380 bhp and weighs 3043 lbs, for a 8.0 lb/bhp rating, and they are very fast on track.


Modified by descartesfool at 4:12 PM 8/17/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by descartesfool &raquo;</TD></TR><TR><TD CLASS="quote">..., vs the 198.5 hp/litre for the stock ITR motor. ... </TD></TR></TABLE>

typo.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by descartesfool &raquo;</TD></TR><TR><TD CLASS="quote">So is such a motor a very rare bird on the track, or have people made such beasts and made them reliable?</TD></TR></TABLE>

The N/A drag guys do 85mm, 86mm, or even 87mm bores. The answer to this question might be found in their forum. I'm not sure if any of those big bore engines see many miles.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mos &raquo;</TD></TR><TR><TD CLASS="quote">

The N/A drag guys do 85mm, 86mm, or even 87mm bores. The answer to this question might be found in their forum. I'm not sure if any of those big bore engines see many miles. </TD></TR></TABLE>

I know of a few engines that are 84.5MM, with ~230-245, 10,000 plus miles, 15 track days, and 50+ drag race runs...

Austin

 

Austin,

do you know of any links to builds of such engines?