I currently autocross a '97 Miata in CSP and am looking to switch to a CRX for next season. I plan on using the off-season time to do a build-up, and the car will not be street driven. Here are my ideas and assumptions...please comment or point me to some better resources...

- I plan to start with a 84-87 CRX HF - - lightest model, fastest steering rack

- Which motor has more potential, the DX EW3 or the Si EW3? Remember that I can only overbore +1mm and can't increase compression other than through mild head shaving and block decking.

- What are reasonable HP expectations for a built EW3 (+1 overbore, gasket match, head shaved to spec, block decked to spec, balanced, headers)?

- What is the consensus on carbs vs. EFI? I'm thinking TWM manifold w/Weber DCOE carbs on a DX EW3 motor, mainly to avoid the additional complexity of ECU and wiring.

- I assume that the tranny from a 86-87 Si will bolt up to any EW3 with no problems and would use one to benefit from the improved gearing.

- Planning on 13x8 wheels, 4x100 bolt pattern (probably Diamond Racing steels). What backspacing works? 4.5" or 5"?

Thanks in advance for any help that you can give...

-chris

 

I would personally go with an '89 or '90 HF with a B18c engine...better suspension and handling...light, engine is way better.

 

there are on like 3 owners of first gens here im one and still learning but u know the front has torsion bars and teh rear has a axle....theres not alot of afteramarket support anymore for teh first gen but theres a lil the si is a ew4 not a 3 and as for changing all this it will change ur class to like super wutever i forget...and u will need to wire in all the ecu and motor sice teh hf is carbed not injected if u descide to use the si injection u will need teh whole harness and ecu....u can use a d16a1 from a 86-87 teg witch is as close to a zc as u can get without searchig for a few years since the first gens zc is rare anymore... u may want to start with a 88 hf witch isnt alot heavier but its injected already... witch may out weigh the whole wiring thing...the first gen is a dying breed i love mine now if i can only finish it

 

Yes, the HF chassis is generally the lightest, otherwise try to find an 84 Dx model without a sunroof.

The Si engine has the most potential since it does not have the CVCC head. The SI crank I believe is forged so should be slightly stronger. I run an ITC CRX (DX) and am told that this should crank out ~105 Hp with the 34/34 mm weber carb. A similar Si setup should be slightly stronger. Jackson racing claimed in an old catalog that a stock Si with a header, exhaust, and cams would make 120 Hp at the crank.

With regard to carbs vs FI, it seems the faster guys are either running Webers/Mikuni sidedraft carbs or a custom EFI setup (electromotive ??). The carbs will probably be easier since it does not require a laptop, etc to tune.

The 85 to 87 CRX Si trans will bolt right up to the DX or Si engine. The only difference between the SI and DX trans is the final drive. The Dx is 4.2:1 while the Si is 4.4:1. The later Si cases are slightly larger and will accept the 4.9:1 aftermarket final drive.

The only difficulty I have found in locating parts is trying to find decent performance exhaust system. Several places still make torsion bars, shocks, sway bars and engine parts, etc. King Motorsports (Sullivan, WI) knows these cars well as does OPM Motorsports near Atlanta.

good luck and let me know if you have questions.
Devin

 

There are a bunch of auto-crossers on my 1G forum. Link is in my sig.

I have an 85 DX with a black top ZC, and I will be doing rookie Solo II this year, probably in BSP, due to all the mods.

 

You should have asked this question in the comp. forum because this thread is full of crappy answers (no offense, but don't reply if you don't know).

The car to have for CSP is a 84-85 car (HF, DX or Si). 86 and 87 have the heavier bumpers (and sunroof in Si), so stay away from them. In CSP, you can update/backdate with anything in the 84-85 cars. So even if you start with a Si, you can use the HF rear seats, interior, etc.

Now, the CRX Si had a better FD than any model, even the 86-87 Civic Si hatches (which you can also use parts from in CSP because of the way the rules are written). You cannot use a 4.9 aftermarket FD in SoloII SP (you can in IT, but not here)! FD must be a honda part. Clutches, diff, etc do not have to be though.

You really need to pick up a rulebook to see what you can/can't do. remember, if it doesn't say you can, then you can't. Also, there is still a lot of info out there about the 3rd gen civics/1st gen CRXs because they are a popular CSP car.

You cannot do motorswaps in CSP unless the car originally came in the USDM market with said motor, so ignore the BSP and B16a comments.

Basically, RESEARCH before you do anything because soloII SP rules are tricky. I know a decent amount about the 84-87 cars, but I don't have the time to put all of the little things to watch out for in this thread. Talk with someone who actually autox's the car on a national level and not the local guys.




[Modified by Todd00, 5:25 PM 4/30/2002]

 

Thanks to everyone for the answers, especially Todd. I've been able to dig up some additional sites and info since I posted, so some of my questions have been answered more than once. I guess I got the engine codes a bit hashed up though...some of those sites aren't especially accurate.

The next step is to keep my eyes out for that perfect HF donor car....

-chris