by Chris DeLay

The E Prepared class changed completely in 2015, with the rear-wheel drive cars (e.g., Toyotas and Datsuns) moving to other classes. This left EP as a FWD class almost entirely made up of Honda Civics. The previous E Prepared shop manual still mostly applies to EP as a whole; this guide is specifically aimed at people like us who liked the Limited Prep rules but didn't know where to begin.

The Guru(s)

OK we aren't actually Prepared gurus, and that's sort of the point. We spent several years driving a 1989 Honda Civic on street tires, and always wanted to play with in Prepared, but there was never a really good fit for our car. We were also a bit nervous about the cost and complexity of building a prepared car. That is, until the introduction of Limited Prep rules.

So in 2015, Patrick Washburn and I had a crazy idea... let's take our old Lucky Lugnut Racing ST(S) civic and turn it into a Limited Prep (LP) EP car. Unfortunately due to some "real life" challenges, we didn't get the car built until August, which meant we only got two shakedown events in the car before Nationals. Some people have asked us what it really takes to build an EP LP Civic, so I thought I would share our experience.

The Pitch:

The basic concept is this: take a fully built STS Civic or CRX, bolt on some slicks and lose a lot of weight, and you’ll have a fun (and maybe even competitive) EP LP car. We ended up doing a whole lot more than this, but I think the basic concept is still true. If you want to play on slicks, and/or you’re tired of chasing the "hot new street tire" every year or two, this is the easy button. The first question is, are you already towing your STS Civic to events? If so, you have already overcome the most expensive part of moving to Prepared. Of course, if you don’t have a trailer and a tow vehicle, that’s going to be a costly barrier to entry for some people.

The Scoop:

So let's assume you already have a trailer and you don't mind taking your Honda off the road permanently. Now what? Obviously in Prepared you can do things your own way and there are almost limitless combinations… but here is a basic guide if you want to get in the class and don’t know quite where to start.

Weight Reduction: This is the easiest and cheapest way to make your STS Civic or CRX into an EP car. Take out the whole interior and replace all the glass with polycarbonate. Thickness should be .125" minimum for the windshield and we used .060" for the side glass. Got a sunroof? Pull that 35 pound cartridge and replace it with a piece of plastic. If you have an '89 Si Hatchback, removing the front and rear bumper structures alone is worth 51 pounds. Removing door panels and cutting out the steel reinforcements in the doors nets you another 49 pounds. At Nationals our car weighed in at 1640 pounds, which is 50# overweight, but that’s with a full tank of fuel.

Note: leave at least the driver’s side of the dash in place if you don’t want to mess around yet with a custom dashboard and gauges yet. Although we do recommend water temp and oil pressure gauges if you don’t have them already.

Wheels: Here you have a decision to make: 13"or 15"... as Chris Raglin once explained to us, 13" wheels will be less common and therefore more expensive, but if you go with 15" the tires will cost more. We went with 13" and picked up some used sets of Panasport 13x9.75" wheels, although there are other lightweight 13x10 options from REAL, Bogart, and Spin Werkes among others. Warning: be aware that if you go with 13" tires, gearing will become a challenge.

Tires: EP for years has been dominated by cars on Avon tires, although Hoosiers are still competitive. Expect to spend $300 or more per tire. Yes, this is more expensive than street tires, but then again you don’t have to buy multiple brands and spend your season tire testing like many do in STS. Plus, slicks are so much more fun!

Engine: The first question people always ask us is what we did to our motor. Honestly due to time constraints, we didn’t fully build our motor in 2015, and we still had a great time and did pretty well. Our basic recommendation is at a minimum, get a custom cam (conforming to the LP EP rules) and drop high compression pistons into your stock D16A6. We used eBay P29 pistons and rings (1st Generation Integra), ARP rod bolts and head studs, and used head gasket thickness to get us to the 11:1 compression limit. If you get a cam you will also need to upgrade your valve springs.

Everything Else... Ignition system, fuel system, distributor, electrical, this all can remain stock for now. You can always upgrade these things if you want to, but it’s not required right away. Yes, a fully built LP EP motor will be more expensive and more complicated, but the point is, you don’t have to spend a ton of money to come and play. Pistons, cam, and valve springs... that's enough to get you started.

Engine Management and Tuning: We upgraded our ECU to a HONDATA S300 but this is not a requirement; it just made it easier for our tuner and gave us more flexibility for the future. Unfortunately this meant converting from ODB0 to ODB1 so that adds some cost and complexity. It is likely that any adjustable ECU you are running in STS will be good enough to get you started in E Prepared.

Transmission: We started with our standard Si transmission, and picked up a clutch-type limited-slip differential from MFactory. The complicating question is: did you choose to go with 13" wheels? If so you will want to swap out the final drive unless you love shifting to 3rd all the time. To do this, you need to pick up a DX transmission and swap in the final drive and countershaft into the Si tranny. Or, you could use the transmission from a DX but then you would have to use a different LSD compatible with a 35mm differential bearing. On second thought, maybe you want to use 15" wheels after all? While you’re at it, you can get a lighter flywheel and upgrade your clutch if you feel so inclined.

Suspension: You can leave your full STS suspension alone for the most part, just pick up some heavier springs. Yes, you can replace all your bushings with sphericals but this can always be done later. When you do, we recommend you talk to Chris at Kingpin Machine... he makes great stuff. Again, the choice to run 13" wheels can complicate things, because lowering the car so much results in too much negative camber. So we had to use adjustable upper control arms to dial in 3 degrees of positive camber just to get back to where we wanted.

Exhaust: You can remove the Catalytic Converter if you like, but otherwise you can leave the exhaust system alone.

Brakes: Leave them stock.

Steering: We used a Quaife quick-ratio kit (which requires a non-Si steering rack) and that was a good start. However we quickly realized that power steering of some sort would be a VERY nice upgrade. We would recommend you consider adding power or electric-assist steering right away, or at least have a plan to add it later if your arms get tired.

The Price:

If you already have an STS Civic, we won’t talk about how much you already have invested in the car. It's best that way. The good news is all the shiny parts you already have, like shocks, camber kits, header, intake… all that stuff is still good if you come to EP. The big ticket items are probably $1k-$2k to upgrade your motor, $1k for LSD, and $2k-$2.5k for wheels and tires. Steering could be another $300-$1k depending on if you want some sort of power assist. As always, you can spend much, much more if you like... but that's up to you.

The Honest Truth:

Yes, you could theoretically take an STS Civic or CRX, bolt on some slicks, gut the interior and come have fun in EP. That said, if you want to be nationally competitive, it’s going to take a lot more work and certainly more money to build a top motor even within Limited Prep rules. Will a limited prep car ever be able to match a full-prep EP car like Tim Smith’s Civic? We hope so... but honestly nobody knows yet! We are still learning, but we had a great time at Nationals in 2015 and are looking forward to a great 2016 season! Come join us!