Vintage Race 2.4
 

Ok, as some of you know my dad and I got a 1973 911 T Targa to be our vintage racer project. I'm sure arguments can be made whether that's an ideal starting point or not, but it seemed like a good idea at the time, and it's what we have (and it's sure fun!!). One of the things I want to get into is the engine, both because it's old, "T" spec, and I'm an automotive engineering major, so it's just fun stuff for me.

Anyway, as with any project there seem to be a baffling array of variables here. Our last project was a hot rod 1955 Jag, and we found a good supplier that did his own vintage racing etc and he helped us out a lot and it turned out pretty good (it's just for fun not racing so rulebooks weren't an issue). Anyway, some fairly major questions... are coming up.

I'm a fan of high compression, and twin plugs... what CR is good for this set up?

Cylinders: Nikasil seems to be preferred around here in general, and I understand Porsche has been using this for a while... I was turned off to Nikasil a few years ago, because Jaguar used them, and had issues that poor quality fuel (high sulfur) would disolve the lining... I believe BMW also had similar issues. Is this a complete non-issue? I was thinking the "biral" cylinders would be good, but reading on here people seem to think nikasil is more durable?

Is it feasible to expect ~200HP from a 2.4?

Will the stock "T" crank/block hold up to 200HP?

I think that's all for now.. just thinking bottom end to start with.

Distinguish between Nikasil, which has been a phenomenal technology since it was invented for the 917, and Alusil, which is the issue that plagued the Chevy Vega and the ill fated BMW V-8. Huge difference and well documented here.

Biral v. Nikasil is a question of heat rejection. Porsche achieved 190 HP with the 2,4S which is your engine with different heads, cams and pistons (and the rods are different but I wouldn't worry about that) and a different space cam in the MFI. That said, the Nikasil cylinders are much better at shedding heat and the bonus is that they are now available in 84mm. A 2,4 T crank is the same as an "S" in 1972 and 1972 only. Preferred lingo is "case" as there is no "block" per se but I know what you mean.

But those are really later stage issues. The first issue is: what do the rules say you can do for displacement? What sanctioning body. The rule book drives ALL decisions.

Targa? Ok, you get to put the engineering degree to work designing a cage that both complies with the rules and stiffens the poor floppy Targa chassis. Old 911s are bad enough compared to a modern car in terms of torsional stiffness but cutting the roof off doesn't help. That said there are many successful targas racing, it's the nut behind the wheel that counts.

Good luck!