I'm targeting DP class for my '73 2.0L and my motor is getting rebuilt. What's the largest piston/cylinders I can run and still be legal. Rules state...

"The block may be rebored no more than 0.0472” (1.2 mm) over
standard. US-produced six-cylinder and eight-cylinder engines
may be rebored no more than 0.060” (1.52 mm) over standard.
Alternate blocks which are of the same material and nominal dimensions
as standard are allowed. Critical dimensions for piston
engines are deck height, cylinder bore, cylinder spacing, vee angle,
and distance from crank centerline to cam centerline. Critical
dimensions for rotary engines are epitrochoidal curve, working
chamber volume, and eccentric shaft location."

The way I read it, I'm stuck with the OEM jugs - unless my math is wrong

Yes, stock jugs, then overbore them and get custom pistons made to fit.

The rules are the rules...

What you can't gain in displacement, you can try to make up with compression.

-Josh

Unless XP is in the cards, you are stock with stock displacement plus 1.2mm overbore. I had a rather extensively drawn up DP plan that never came to fruition. PM me if you're interested in details. Hint: T1/T4 hybrid in an overbored 1.8 configuration.
Mark D.

Make your power in Heads EFI and exhaust. You need 70MPH in 3rd so gear it LOW.
Make the car faster with lighter, and pimpier suspension. It needs to pull near 2 G's and be able to do it while accelerating.
Avon Slicks on Bogart wheels (DP width)?
Fox shocks sway bars are open so make the big
Cage it and tie into all suspension pick up points a stiff car is a fast car.

Did someone say JUGS?

Click to view attachment

DP is OWNED by the Miata boys. Brit had to go to Subie power (400ish HP) in his XP car to beat the local guys scratch(top 3 or so at the Nats) When the car was 2.7L 6 powered & 1750 lbs (in XP) we were a couple seconds off their times while winning our class regular like at National Tour events. Reality sux, BTDT.

Good luck....he said to the snowball in hell.

Oh crap!... Now someone is saying it can't be done. Am I gonna have to finish my build now just to prove a point?... Because we all knew an FP 914-6 couldn't win either.
Mark D.

Try GP (limited prep).

There is $100K (or thereabouts) in that FP 914. All it needed was a driver. It was FS for years @ $50K. What's in your wallet?

Sorry you don't like my version of reality. Lemme try again.

Sure, go for it. Them Miata boys are just hype. You can wax em'.

I would guess that just about every front running FP car out there has roughly the same amount of $ into it if you were to add it up. I'm rather intimately acquainted with the Bjoin (Larrson built) BMW, and I know it does. And I'm not saying it would be easy to develop a DP 914 to beat the Miatas, which have been so extensively developed for years. However, same as in FP, if the same budget and effort were invested as the competition, I'm sure a T4 914 would have a good shot of taking home the big win. It's just an attitude that is pervasive in autocross. 'Nobody is doing it, so it can't be done.'
Mark D.

The 914 was designed in the late 1960's. There is more problems than just the engine. The suspension design is from the stone age.

"Intimately acquainted" and "intimately involved" are different. The latter means you're spending your money. I was intimately involved with my 914 and we beat that
white 914 more often than not....for half the cost. Your "pervasiveness" is drivel.
Try it on someone who has not BTDT.

Ah. The good old 'You haven't lived my life, so anything you say is automatically disqualified' argument. No. It wasn't my money in the Larsson car. So what? I've run 50 events the past three years fielding and developing a car in an attempt to be top dog in class that's much more tightly contested than DP or FP. I've given everything I've had to give. All my spare money went to that project. Any time I wasn't working, I was working on the car or racing/testing it. That experience doesn't count? Just because I realize up front that I don't have as much coin to lay out to compete in Prepared classes, I guess that means I'm incapable/unworthy of analyzing the situation and offering intelligent commentary. It's all 'drivel'.
My whole original point goes back to a saying I heard once. 'Those who say it can't be done are usually interrupted by someone doing it.' That was the case in FP, and I was saying the same thing back when that debate was going on these boards. It just irks me when people get their jollies from trying to shoot down other people's plans due to their own deep seeded bitterness about their own failures. Same reason I don't race with PCA anymore. A bunch of grumpy old farts that think that offering a negative opinion makes them sound smart.

And Ury, you're right. I was actually quite surprised when I took a look under the FP car and saw how little was changed. The front was converted to coilover, and there were custom fabbed lower arms, presumably for more camber, but it didn't look like any of the pickup points were moved on the whole chassis. He was even running the stock rear trailing arms. I was surprised it did as well as it did. Which means there may be some more speed capability there!
Mark D.

[quote name='BMXerror' date='Oct 27 2013, 11:18 AM' post='1947493']
[quote name='J P Stein' post='1947381' date='Oct 27 2013, 05:10 AM']
My whole original point goes back to a saying I heard once. 'Those who say it can't be done are usually interrupted by someone doing it.' That was the case in FP, and I was saying the same thing back when that debate was going on these boards. It just irks me when people get their jollies from trying to shoot down other people's plans due to their own deep seeded bitterness about their own failures. Same reason I don't race with PCA anymore. A bunch of grumpy old farts that think that offering a negative opinion makes them sound smart.
[/quote]

So, trying to factually pass along my years of autocrossing with SCCA, PCA, up & down the West Coast makes me a "grumpy old man", embittered by my failures, eh?

You, sir, are a fool.

Thanks for the advice all. My ambitions are pretty mild. Two to three years to shake the car out, driving at regionals, then on to the Solo Tour events. It's a long term, spread the cost out, build. I'll start with the 2.0L displacement, then move to the suspension.

Have you seen this months issue of SPORTCAR that gives the results of the Solo II nationals for DP?

I'd go the other route. Do the first big iteration of the suspension first. I know it's not as glorious as gettin' a big motor in the car, but the suspension will have a longer life time than a race motor. If you're building this project over years, by the time you're ready for suspension, the race motor will also need refresh or rebuild. And then you find yourself stuck with a perpetual project that might never get finished...

BTDT

Just my $0.02...

-Josh2