Build 2012 - LSD, Power Steering, "The Wing", and more

It's been a while since we updated the evolution of the CRX. We have been busy racing the car at local and National level SCCA Solo (AutoX) and Pro Solo (AutoX drag start style) events around the country for the past couple of years. The main focus has been to improve our driving skills but in the Winters we make adjustments to the car to make it more competitive in the SCCA Street Modified class. Locally, we generally run in Super Street Mod as it is more competitive but nationally we run in Street Mod FWD which is where our car naturally belongs.

Power Steering

Call us whimps, but I challange anyone to drive a car running sticky Hoosier A6 15 275 35s in the front to drive a 2100lb, 361whp fwd vehicle in a precise and reproducable manner through a technical autocross course. This was the biggest complaint from everyone who drove the car, kind of like trying to ride a bucking bronco. All our National level competitors also strongly suggested that this was a necessary mod to be competitive. So how does one get power steering in a CRX? The easiest way is to source an EF PS rack from a Civic sedan or wagon. The PS rack also requires the PS subframe which is slightly larger to accommodate the fatter PS rack. Now, this is not an ideal setup for AutoX and the PS rack is only slightly faster then the stock manual rack, but we were willing to accept that to gain the advantage of PS.

The bigger problem was the pump. On a K-swap CRX the pump will not clear the hood, so either come up with another solution or cut a hole in the hood. We opted to use an electro-hydraulic PS pump sourced from a 91 Toyota MR2. This is a popular solution for many custom PS setups so the pumps are not easy to find and can be expensive. Brian at Karcepts helped us out here, and in other waysas well. He routinely sources the pumps from the UK to provide to his customers. There is plenty of info on the basics of how to set this up, for example, checkout the Karcepts article for the EG here. Of course, locating the pump in the already cramped K-swapped, super charged, intercooled, engine compartment was another problem. In the end we mounted the pump in the rear of the car as shown in the pics (where our OEM fuel tank used to be!). A switch on the dash allows manual activation of the pump, which can draw a huge amount of current and requires special wiring. In fact the load is so great turning the wheels standing still at idle can put such a load on the alternator that it can stall the engine.

Was it worth it? Absolutely! The car is so much easier to drive. Remember, in Autox, your swinging the steering wheel back and forth continually, and the PS assist allows one to navigate with much improved accuracy, comfort, and confidence. Like I mentioned, the rack is slower then we would like, but thats a trade-off we are willing to accept.


Clutch Type LSD

We thought our OEM gear type LSD was pretty good. We have heard arguments for staying with the gear type LSD (reliability, zero maintanence) but we also heard arguments for clutch type diffs (improved locking). What turned our decision was when Brian drove a friends boosted EG with a clutch type diff. The word back was "remarkably improved traction allows the power to be put down more effectivly, especially in turns", which is of course what we do all the time. After much research, and a great discussion and support from Mark Mendoza at Toyota Tsusho America (US OS Giken distributor) we went with the OS Giken LSD. Some of the reasons where supposed reliability, and lack of the need for any special break in. Installing the OS Giken was relativly easy, and we used the OEM honda tranny fluid (you can tune the diff with alternate fluids) and we performed no special break in, we just went out and raced. The difference, for our car, was dramatic. Even straight line traction was dramatically improved, so much so that we had to adjust our launches at the drag race style Pro Solo events. Most impressive was the grip on corner exit, it is remarkable how effective it is at pulling you out of the corners so much earlier. Definately an A+ upgrade. Again, this may not be the way to go for all cars, but in our high HP front wheel drive autox car the change was dramatic.


"The Wing"

One issue we have always had in our setup was the car liked to "snap spin". You want the setup to allow you to rotate the car to efficently navigate the tight turns, but always in a controlled manner. In our car it was always a fine line to walk between getting rotation and spinning the car. This is in part due to the short wheel base of the CRX, and the increased front end weight from the swap. But this was a issue we never could get comfortable with. One possible solution was to add a wing to increase down force and improve high speed stability (high speed in autox is over 45mph or so) which is legal in our class. There are many arguments against the effectivness of wings at low autocross speeds, but discussions with fellow racers and just a "butt of the pants" feeling made us think this might help. We wound up going to Ciro Design for the wing. Rick at Ciro supplies many of the Nationally competitive autox cars with his wing, and if you ever saw a triple roter RX7 setup for Super Street Mod, you were likely looking at a Ciro wing on back. Rick was great, and provided custom support brackets to set the wing in a legal position, but we still had to make a mounting surface available for the brackets from the small deck of the CRX hatch (rules stipulate the wing must not interfere with opening the hatch, so it had to be mounted to the hatch). You can get an idea how it was done from the pictures below.

So, does it really work? It worked way beyond our greatest expectations. THIS ABSOLUTELY MADE THE CAR! The car is so much more settled you can now fly through the slaloms and sweepers at a much higher speed. In low speed elements where the wing is not very effective, you still get good rotation, but at high speed the wing works its magic. If anything, the car now pushes a bit at speed, but this can be addressed in the future with a bit more aero. Want proof? How about top 10 pax times (SCCA handycap) in our very competitive New England region events, a class win at the Toledo Pro Solo against the fastest SMF drivers in the country, and 3 National trophies at the SCCA National Championships in Lincoln, NE this year. Not bad for a car that barely sniffed a trophy spot at a National event in the past. So yes, the wing was the final piece to the puzzle. Certainly the LSD and PS contributed significantly, but the wing made the car easy to drive with confidence at higher speeds. Ask anyone who has seen the car race.

Other Stuff

We have done a lot of other things to the car as well since our last update. Some of these included going to a custom lightweight exhaust to help us meet the strict sound policies in our local site as well as to proved clearance to our new adjustable ASR rear swaybar. With the exhaust change we retuned the car on the dyno (thanks Rick at Kinetic for both the exhaust and the tune!) and got a few more horses out of it, not that we need them. More importantly was just making sure the tune was "safe". We also went with a light weight 5 gallon (our legal limit) fuel tank and new fuel system to shed a few pounds. We have also done some suspension tuning to help things along. All in all, we feel good about the car now. It is still street legal, although it doesn't see the street that much anymore (but it is still a hoot to drive on the street!), and it rides to most events on a trailer (things break on Street Mod cars). We still have some ideas, but mainly we need to learn to drive better, but thats coming along as well, and driving skills are always the real limiting factor.

The wing was mounted on a extended bracket that was fastened to the "deck" and braced on the bottom of the hatch.
MR2 PS pump mounted in rear