CRX Engine for Road / Autocross

14453 Views 16 Replies 11 Participants Last post by incomplete, 1 mo ago

LemonStain

Discussion Starter · Apr 18, 2017

What is a good engine for the CRX that would be very good for Autocross/Road racing? I want to feel like it has some nice power but also feel some good power for the straight shot.

I am not looking to completely break the bank either.

Long story short: My first car was a CRX when I was 16, as well as my 2nd car. I got out of the car scene for a long time cause when you are young, money doesn't come as easy as it was. I was into the drag scene, but recently got a taste of road racing (with super cars) this weekend and loved it.

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jfrolang

· #2 · Apr 19, 2017

The champions of autocross favor a supercharged D16, because tight, technical and relatively slow autocross courses prioritize engine torque with minimal weight.

For road racing you're less likely to see consensus. Honda built the SiR with a B16 specifically for road racing, but these days you may be better off with a K-series. If you're racing competitively the rules for your class will be a big part of the decision making process, along with budget and your capability.

raffaelli

· #3 · Apr 19, 2017

Before you open your wallet, figure out what you want to do, what class, what club, what you want to tinker with, what you want to be able to tinker with. Worst thing you can do is spend some money and then figure out there isnt a class for you.

I am currently running my 91 CRX with a D16. The engine build didnt break the bank, lots of fun and is fast enough in my class (SCCA ITA, EMRA ST7).

Dave_Darling

· #4 · Apr 20, 2017

Step Zero is always to RTFR--Read The Rulebook.

In some instances, engine swaps can add the requirement that you use a lot more safety equipment than you might otherwise need. While more safety equipment isn't bad, it can be a pain to live with in day to day driving.

Usually engine swaps will put you into classes where you will need to do an awful lot to the car in order to be even close to competitive.

If you're not willing to do a crap-ton of suspension work, adding lightness, roll cage fab, and so on, it may be best to stick to the stock engine.

Besides, you have have an awful lot of fun in a basically stock CRX...

--DD

jwharnish

· #5 · Apr 26, 2017

raffaelli said:
Before you open your wallet, figure out what you want to do, what class, what club, what you want to tinker with, what you want to be able to tinker with. Worst thing you can do is spend some money and then figure out there isnt a class for you.

I am currently running my 91 CRX with a D16. The engine build didnt break the bank, lots of fun and is fast enough in my class (SCCA ITA, EMRA ST7).

I agree with determine which class you want to run in, and if you still plan on driving the car on the street. If the car is to be street driven plus Autocross competition, you have a choice of Street class, or STS. STS is more rewarding, and unless you build it to the limit, can still be a good street driving car. STS 2016 SCCA National Champion was an 88 CRX.
A stock class CRX can be made to work, but requires some expensive shocks, 15x5.0 rims, and a decent rear bar. Either choice will give you an good, reliable, fun to drive car, with the original d16.

I currently run my 88 CRX Si in HS, and can run with most of the best HS cars in the country.

Jim Harnish
1988 CRX Si 74K original miles.

Mista Bone

· #6 · Apr 26, 2017

Another thought is to not worry about class rules and build a safe HPDE car, aka the Honey Badger CRX.

<<< Transmission builder for road racers and autocrossers, I have the easy job!

cboutilier

· #7 · Oct 22, 2017

I know, up here, any Honda/Acura motor swap into your CRX will automatically put you in SMF class. And if you're in a region like me, you'll end up in SM due to numbers.

Mista Bone

· #8 · Oct 22, 2017

Just a cylinder head swap will put you in SMF

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cboutilier

· #9 · Oct 22, 2017

Mista Bone said:
Just a cylinder head swap will put you in SMF

It's a good class for those of us that like to swap and stuff. It pretty much allows for all of the usual street car mods we like to do, except traction bars.

daveb91

· #10 · Oct 22, 2017

engine that came with car then,upgrade driver mod, tires, suspension then power.

I started out with a SC d16 and it was great power for small autox tracks but could have used more seat time.

cboutilier

· #11 · Oct 22, 2017

This past event I was at, the second fastest raw time went to a 93 Civic Si hatch with stock engine. Only car that could beat him was a wild k24 swapped Miata.

hispanicpanic

· #12 · May 15, 2018

D series engines are the lightest by a fair margin, almost 100 lbs over a B series and 200 over a K series. Which is nothing to scoff at!!!

Your best chance at hitting an optimum HP/weight ratio is with a Turbo D. But don't pay attention to internet wisdom when it comes to these setups. Get a decent turbo (Borg warner EFR series with a mixed flow turbine), and a 9-10:1 compression ratio. Turbo D pistons commonly used bring compression ratios down to something like 7 which is utterly retarded. Make sure your cams and head are spec'd for turbo flow, and invest in a good engine management system and a professional dyno tune. Vtec is irrelevant, mostly, depending on cam choice.

With this setup, turbo lag on the EFR is literally non-existent, so there's no reason to supercharge. It's the only way to hit 300+ HP under 200 lbs. And depending on the amount of head work and turbo choice, you can still run more reasonable levels of power in the 200 range. Stock d16 rods are good for nearly 300 hp. Of course you'd want solid pistons to be hitting those levels.

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88k_crx

· #13 · Jul 17, 2018

I am running a SIR b16 with a greddy td05-18g turbo charger and i road course.

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88k_crx

· #14 · Jul 17, 2018

hispanicpanic

· #15 · Aug 6, 2018

edit

Mista Bone

· #16 · 2 mo ago

Snot Rocket build if you can find the info. Last I heard my head and cam was doing fine, I've had the transmission twice and heard it needed another FD because TQ and sticky tires break parts.

incomplete

· #17 · 1 mo ago

daveb91 said:
engine that came with car then,upgrade driver mod, tires, suspension then power.

I started out with a SC d16 and it was great power for small autox tracks but could have used more seat time.

TL;DR: start as the car came, upgrade the driver first, then suspension, then think about power.

longer version: i really can't agree with this more. when i started doing HPDEs etc i ran a bone-stock (except for brake pads/tires) RSX-S for many years. only after i knew the car inside and out did i start the suspension upgrade path, and didn't touch the motor.

run whatever motor is in the car til it explodes. better yet, yank it and rebuild it (hot tank, head/block planing, cylinder re-bore). this will be ~$3k if you don't do it yourself, and ~$1k if you do. i did the latter w/a friend, and it was nerve wracking and very long, but now i know how everything works.

the D series vs B or K is also important to keep in mind. we built an enduro crx w/a D15B2, and it just happens to be an autox ninja. the extra torque is amazing, and not needing to "keep it in VTEC, yo" lets you focus on the corners rather than shifting.

of course, first thing i'd go over the car and rules for whatever class you want w/a fine-toothed comb and replace bushing, bearings, belts, hoses or whatever else needs attention.

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