Brian C. Franke

Hello everyone. I've been having some pretty good luck autocrossing my ep3, so I thought I'd share my autocross build for you all.

The ep3 and dc5 can run in the STF class in SCCA solo autocross events. STF enjoys a very liberal pax adjustment, so it's quite easy to compete with the big boys out there. I've taken 4 pax wins along with a 2nd and 3rd out of the last 6 events in central Texas. The competition around here is pretty serious with a number of current and former national champions at each event, so I couldn't be happier with the results of the little ep3.

Here's what my build looks like so far,

2002 Ep3 with 125K

CG seatbelt lock (awesome!)

Hawk HP+ will be replaced with Hawk HPS

Metal shifter and shift cable bushings

Injen short ram intake

Progress adjustable rear bar w/brace set at the highest setting (26mm I think)

Energy poly bushings all around.

OTS Koni Yellow's (set a half turn at the front and a quarter turn at the rear from full stiff)

Ground control coilover sleeves with, 8" 425# front springs, and 6" 750# rear.

15mm cam style camber bolt (don't mess around with camber plates, I tried. You'll have to change the tierods to get your toe settings back and you can't do that within the rules)

Ingalls rear camber arm

15x7.5" Konig Lightspeeds with a 32mm offset

20mm spacer and extended studs up front

225/45-15 or 205/50-15 Bfg Rivals (46psi front 36 rear)

Alignment = max camber (-4.5) up front w/ a little toe out - 2.5 degree negative camber rear w/ a little toe in

JDM DC5R Aluminium Front Lower Control Arms and Swaybar
Replacement smaller ball joint sleeve from King Motorsports for jdm lca

Yuasa Ytx-14bx battery

Hondata reflash

MBS 100cell high flow cat

DC Sports short header.

Custom stainless 2.5" midpipe that eliminates the resonator and keeps the stock muffler (which is only 12lbs).

Energy poly engine mount inserts

Just replaced the clutch with an oem excedy unit
and wrapped the headers and intake

Still to do,

Kirky Seats
Suspension Bracing
Lighter wheels and brakes would be nice
Downturn pipe to eliminate the very light 12lb stock muffler
The newest hot 200tw tire

Hope this helps if you're auto-xing, or if you're not you should really consider it, it's a blast.

Here's a video of one of my first pax wins (right after installing the intake, koni's and a softer set of springs) from a road course a few months ago, along with a bunch more at my youtube.

Davidss

It's nice to see someone trying a different car in STF. From the video the cars looks really pushy, all of the times it is loose it is driver induced. You should try maxing out the rear bar.

You planning on doing the College Station/Mineral Wells events?

Xian

Nice! Should be a fun build... I've always felt a little bad for the EP3 as the unloved stepchild in the Si lineup.

Couple comments:
Balance looks all sorts of funky... pushy on throttle and then overly loose off-throttle?
Looks underdamped/undersprung with a ton of oscillation. Thinking you're likely to need more front spring than you're going to as well as more rear spring/bar. May as well revalve the shocks too.
I'd need to go back and re-read the rules but aren't you allowed "just one" control arm in ST? If you've got a rear camber arm and are adding a LCA, I'd think that would be an illegal item?

Best of luck with the build!

siblueg

Needs more rotation, looks like a fun course

civexspeedy

^What they said. If you have an Ingalls rear camber arm, then the rear control arms my not be legal. At least that's the rule for STC, I'd assume the same applies for STF.

Also it's one thing to PAX well locally, it's another to PAX well at a National type event. Try making it out to some National events or look at what the top guys in STF are doing to help you get faster.

Brian C. Franke

The video is from the first event (2nd lap) with the koni's, springs, rear bar and the cone, other than that it was pretty much stock. It is definitely pretty loose still, I don't have much camber unfortunately I'm hoping the new stiffer springs, front lca and a little patience going into the corners will help a bit. I've only auto-xed for a year and a half, so lots to learn still.

I'm really glad I didn't install the rear lower arms yet. Thanks for the rule advice. I thought about that one allowance rule when I was typing out the parts list here, but I didn't want to believe it. Do the old civics have adjustable rear camber stock or something? I know I've seen them with a ton of camber and aftermarket lowers. That's really a bummer because I already bought them.

I am planning on the college station and mineral wells scca events this year Plus all the other college station and most spokes / sasca events, so if you're in the area come by and take a ride.

Xian

It didn't look loose... looked pushy in general and then loose off throttle. Aren't these cars prone to bump steer problems? Maybe that's a contributing factor?

If by "old" Civic's you mean God's Chariot, no. There's no stock camber adjustment. Those cars "should" only have an aftermarket rear upper control arm. You can change camber that way. If they have an aftermarket lower control arm then they'd have to be changing camber with offset UCA bushings. It can be done with the offset bushings but is more hassle than it's worth, IMO, and there's no advantage to the aftermarket LCA's.

Brian C. Franke

"God's chariot" that's funny I'll have to ask the stc guys around here about their shady mods. With the lca's I was just hoping to save a little weight and get a stiffer bushing, but I guess I'll have to forget about it.

I've only lowered it less than an inch, so bumpsteer isn't really an issue. The balance is pretty natural really, a little left foot to weight the front and the back comes around nicely. There are some off camber spots on this track so it took a few laps for me to realize I need to slow down a bit more.

Xian

Definitely talk with them... could be that they're not running the upper rear arms and are running lowers instead (no idea WHY they'd do that but they could).

FWIW, I really am interested in seeing how your project turns out. All the second hand info I've heard through the years on the EP3 and DC5's is that they're really, really tough to get into a handling happy place (due to geometry and motion ratios).

Todd00

I tried the EP3 and so did another guy that I know. Granted, this was back when STF did not exist (only STS), but we came away with a few bits of knowledge:

1) You may *think* your car is rotating well, but in reality when you get on a really grippy course it will push like a pig.

2) You need about 5 to 6 degrees of static camber in the front to really get the car to turn-in good. This is not possible with that platform given the current ST ruleset. The problem is that the tierod/steering arm strut thingys (forget the Honda name for them) that you *must* keep because of geometry considerations in ST don't allow enough adjustment in the ends. You will run out of thread and have a car that can't be aligned properly.

3) No less than 1:2 ratio for springs. That means if you want to run 500lb springs in the front, you'd better be around 1K in the rear, minimum. Motion ratios suck for that chassis. (1:4 is more the norm, so 500 front, 2K rear).

4) Lowering and rear suspension binding. The rear geometry sucks and you will get binding in the rear if you lower the car anymore than 1" from factory specs.

There are many other issues, but those are the main ones that keep folks from running the RSX/EP3 nationally. On paper it looks like a winner, but once you start dissecting it you'll realize that it will never be more than a "decent" regional car.

We went round and round (STAC) with the front suspension changes back in 05 and it was determined that it would open a can of worms if allowed for the RSX/EP3 so it was left as-is.

Do a search on here or sccaforums.com. We've covered this car in-depth before. Unfortunately, this is just how it is. But, that doesn't mean the car can't be fun...just don't let it frustrate you when you realize that certain aspects can't be fixed.

10cjennings

iTrader: (1)

Anyone give the 05-06 type s a shot? Figure the power alone would help and I thought they made the rear geometry slightly less crappy on those over the 02-04 which was an improvement over the ep3. I don't see it being enough to take the minis but might have a better shot.

Todd00

This is not correct. The RSX/EP3/01-05 Civic suspension pickup points were not changed at any time.

The only "geometry" changes on the 05-06 RSX were the front springs that were wound differently, and those are obviously legal to change in ST. Struts remained the same.

The 05-06 RSX-S also gained about 80lbs from the 02-04. So while you got slightly more power and better gearing, you are saddled with extra weight.

Funny note...the OEM A-Spec Suspension accessory deals with the front tierod/camber issue, but even it is illegal because it is a change in geometry and being an accessory part and not factory off-the-boat arrival, you can't use them.

mattbatson

I know IPG parts runs/ran one in SCCA road racing for a bit, and they reportedly got it to handle just fine

might ask to find out what they did to it...

I think it is for sale too

Todd00

This was Realtime's solution for the rear, lol.



Not quite SoloII ST legal.

10cjennings

iTrader: (1)

Is that just based off the manf weights or from your own experience?

If its the manf #'s, a decent amount of that 80lbs might just be from the bigger wheel/tire combo in the 05-06 vs the 02-04. Also the Z1 has a significant bump in power over the A2 (I have graphs somewhere....), and I think the Z1's FD would be preferable as well.

Either way if the weight between the ep3 and type s is remotely close, and the chassis is essentially the same, all that extra power is going to be helpful to have a chance in STF.

10cjennings

iTrader: (1)

and ^that's awesome, is the sway bar run through the cabin?

Todd00

It was basically 80 lbs worth of NVH additions, 17" wheels, a few more supports, interior "enhancements", headlights, rear wing, etc. That was factory published specs and real-world weights sitting as-is. I'm sure that after applying rules, the difference would be more like 60lbs as the only thing you can legally shed is the wheel weight.

As for power...the new Type S motor didn't really make anymore midrange torque. It had more power up top for sure, but the time spent accelerating above 7000rpms on an autox course with that car is very small. Midrange torque is the key and they were roughly equal in that regard after tuning.

Regardless, you're putting all of that "power" down through a max 225 tire in STF with an open diff. Even the 02-04 found traction limits *very* quickly when accelerating out of corners. Not to mention that you are working with about 1.5 degrees of static camber...you can quickly see how more power is not really going to help you with that chassis.

That and until the Toyo 195 goes away because any car that can run that tire (mini, Mazda2, etc) is going to be the car to have.

10cjennings

iTrader: (1)

Goes away, or is "re formulated" with +60 magic UTQG points and all the same grip lol?

I don't really think an rsx would have a good chance of doing well, just that it might have a better chance than the civic on the right course where it could use it's power advantage over the mini and mazda.

Todd00

I owned a Type S and an Ep3 and truth be told, the EP3 rotated a bit better. The wheelbase was the same but the EP3 had a lot less overhang front and rear and more weight was based toward the middle of the car (look at the rear hatch/window area, for example). Perhaps this made for a lower polar moment to some degree, but also in the real world I just felt the EP3 rotated a bit better.

Let's keep in mind though, "a bit better" needs to be put into perspective. If I compare that with a 89-91 Civic Si, I'd say the Ef Si was infinitely better

If you're looking for the lightest car in STF trim, I'd say the 02-03 Si with the 4-lug would probably be it. It also has EPS (which I hate), but it is a bit lighter. Although I found that sometimes the EPS in the EP3 was unable to keep up with certain fast steering inputs.

Basically, its a toss-up with positives/negatives between the RSX and Ep3, but it still boils down to the chassis having too many issues. That's too bad because the motor and tranny was so sweet in the RSX-S.

mattbatson

I remember an article done by grassroots motorsports about 10 or so years ago.
They had a project ep3 autocross car, and they compared it to an EF autocross car.
I don't remember all the details, but the EF was pretty much faster in every way...

they blamed a few things on the high center of gravity and suspension, etc...I don't really remember the details...

I just remember it was interesting as the ep3 had so much hp on the EF...
in autocross hp can only get you so much...your constantly turning after all

rick_rabies

^i remember that. or was it they compared it to a fit? same car almost. drum rear brakes 1.5L et etc.

mattbatson

I'm pretty sure it was an ef hatch si...
I had an 88 crx si at the time is why I remember...

rick_rabies

no i mean they compared EF to the fit. might have been a different magazien

mattbatson

gotcha...
I seem to remember a fit comparo in there also, but the one I'm talking about was an ep3 that grassroots took on as a project car for autox. They were trying to make it competitive in whatever class at the time (sorry, I don't really autox).
they were comparing it to the class leader at the time, the ef hatch.

they did some testing with both cars on an autox course, and the ep3 just couldn't keep up.

Xian

I recall that GRM did a comparison of the EF CRX vs. the CRZ. They may well have done EF vs. Fit but I don't remember it...

Size wise, they're about the same length but the Fit is way taller.