I've been lurking here for almost forever, but now I'm looking at building a K20 powered EK road legal race car for a production/street/touring car category in Australia called 3J or Improved Production.

It's very popular and diverse with everything from Silvias, Skyline GTRs, EVO Lancers, Datsun 510, RX7s, as well as Holdens and Fords (Falcon/Commodore/Monaro or Pontiac GTO as you would call it). The racing is kept competitive through the turbo cars running inlet restrictors limiting them to ~400hp, while the 600+hp V8s struggle to put power down through 225mm A048s or 265mm A048s in the hard compound.

Reason I'm attempting to keep it road legal is the restrictions on weight reduction mean we keep standard dashboards, doortrims, glass windows and so on with the added advantage of rather than running ballast I can run luxuries like carpet, a demister, etc.

If you were to build a Honda for 3J, the rules are actually very very similar to the the rules you guys have in Honda Challenge, with the exception engines are considered 'free' and we can do whatever the hell we want. The development of Hondas here is not even in the same league as the Hondas you guys build in the states, and I believe a K20 EK civic street car could potentially be the quickest car in the category.

Running a non standard engine block forces you to run minimum racing weights. That means 2300lbs for up to 2.0L and 2600lbs if I go over that. Not much point retaining the B16 to avoid this as there's very little weight freedoms. Overall, a 2L K20 looks to be the best compromise.

Looking at lap times, you guys have H2 cars that can lap on pace with a stock 997 GT2 (2:00 BW13 with your H1 cars being a bit quicker at other tracks eg. 1:31 Willow Springs). Overall, the most successful cars are generally naturally aspirated RX7s that are about as quick as a standard 997 GT3 (I'm using the Porsches as a comparison tool as it's the only thing thats consistent between us).

The RX7s are SA22Cs (1st generation, live axle and macpherson struts) with bridgeported 13Bs making ~350+hp (flywheel) and weigh ~2250lbs with, usually running 13x50x225 Advan A048s.

A K20A EK would have wishbone suspension all round weighing 2300lbs with 17x45x245 Advan A048s. Whether or not I can achieve as much power while being as reliable as the Mazdas as a 2.0 on a realistic budget isn't really known to me but I'm fairly confident at least 330hp is achievable on E85.

I'm considering a few other, more expensive options:
AE86, 2.2L 3SGE (BEAMS) making ~330bhp or restricted turbo 4AGE making ~390bhp. Weight would be ~2100lbs.
R32 GTR, ~430hp ~3000lbs

Your thoughts?

(I can post a TLDR version of the rules, and/or the rulebook if anyone is interested.)

 

Not sure if that GT2 laptime you posted is by a pro racer. A pro piloting a bone stock s2000 should do buttonwillow 13cw in 2:05 and willow springs in 1:35

 

Are those laptimes on the standard rubber?
The GT2 times are claimed by Road & Track / Steve Millen
1:59.8 and 1:33.6

 

Just so I understand everything correctly here, you're aiming at these first gen RX7s, making ~350 crank hp. They will weigh slightly less, make a bit more power, but (I'm guessing) handle worse?

How long are your tracks and how long are the races? Are there any other FWD cars in the series you can compare to?

Also FYI, the R&T would be run on whatever the OEM tires are typically, and definitely if it is a stock car test.

 

He did mention he'll run 245 width tires versus 225 width on the RX7s, so I'd guess he's thinking this is the primary advantage.

 

I'd punt you aren't going to easily/cheaply/reliably going to be able to make the power u need to to hang

 

My 2 cents:
If you're dead-set on running a Honda, I think you'd be relatively competitive. Why do you want to run the EK though? At least you're off to a good start with the 245 A048's.

Unfortunately, speculation of success or failure is very dependent on circumstance because you'll be running against so many types of cars. If you're a very good driver, I think you'd hold your own against the older RX-7's, 86's, etc - depending on the course. If you're facing off against against a 400whp R32 Skyline that's also running A048's and the driver really knows what they're doing behind the wheel, you'll run into some trouble.

 

Cheers for the responses,

The EG is not as rigid as the EK, and minimum weights mean I'd be just putting ballast in the car (fixed position). Versus the DC2x chassis theres conflicting information from people on both sides of the camp re which is a better base. Deciding factor is that the DC2 is based on a much older platform. (I'm more than open to suggestions)

No GTRs here are going to be making 400whp. It's against the laws of physics with 27mm restrictors. The fastest GT-R dynos at around 330whp in 2wd (our dynos read a little low compared to ones in the US). The rules on fuel have changed and the turbo cars have gained a little more power, but basically, the airflow limit on our race fuels is calculated to be around 430-440 crank hp for a GTR, with about 50% more turbo lag and no usable power above 6500rpm. Single turbo cars have a limit of about 400 crank hp.

We have a pretty large variety of tracks. Some with average speeds of almost 100mph, others under 60mph. Races last between 10 and 30 minutes with a 3 race format and the 2nd race being reverse-grid, however the formats have been known to change.

Theres been a few civics in the category but nothing very serious until recently - a B20 EK Civic that did a 1:48X, 3 seconds off the lap record on one of our fastest tracks.

 

How much power was the B20 Civic running? Do you know weight and tire choice?

 

He's using a B20 block putting him at 2300lbs minimum.

Tyres are A048, I am assuming they are 245x45x17 (widest that capacity can use, and they are definitely no bigger than 17")

No idea how much power, but I've been told the sister car to it is now running a K20. Should be interesting.

 

interesting thread