Project EP3 Civic Si: Fixing EP3 Bumpsteer with Hardrace

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With all of our suspension finally installed, it was time to visit West End Alignment to have our car set to our specs.
 

Darin Nishimura set our car up to our specs.  We had him dial in an aggressive but streetable setup with 3 degrees of negative camber in the front, 2.5 degrees of positive caster (the Whiteline lower control arm bushings added another half of a degree) and 1/8″ of an inch toe out.  In the rear, we ran 1.7 degrees negative camber and zero toe.
 

The rear suspension was a little tricky, as one adjustment effects both camber and toe, so Darin had to sneak up on our setting which was somewhat time-consuming.

With our car's suspension finally done, we are super impressed with the overall results.  We didn't think that the bump steer and roll center kits were going to do that much but boy were we surprised. Although the bumpsteer kit can only somewhat reduce bumpsteer, as the steering geometry is rather poor, the kit nearly eliminated the feeling of bumpsteer!  

Our car now tracks straight and does not skitter around in bumpy turns. The car is now much easier to drive in high speed turns with undulations in the pavement.  These turns would previously be pretty scary. The wandering we have felt on the freeway is also greatly reduced even with our aggressive camber and toe settings.  Our car is one of the best handling EP3/RSX platform cars we have yet to experience.  

The worst thing about how our car handled is now fixed. With great handling and brakes we will next turn our attention to the drivertrain and powertrain to make our engine as fun as the rest of the car is to drive. 

 

Sources 

Hardrace USA

Westend Alignment

Fortune Auto

Password JDM

Whiteline Suspension

Enkei Wheels

Nitto Tire

Parts Shop Max

Wilwood

Fastbrakes

StopTech

Hawk Performance Brake Pads

Raxles

Centric Parts

www.oemacuraparts.com

44 comments

  1. This EP3 series is awesome. I love all the insight Mike gives into this car’s weird handling dynamics.
    I have a question about replacing all these bushings and roll center adjuster ball joints and tie rod ends: Is it OK to replace these parts on the stock suspension or is a lowered ride height needed for these adjusters to be effective? Thanks!

    1. The bushings and steering rack spacer work fine on a car at stock ride height but the roll center adjusters and bump steer correctors are best on a lowered car only.

      1. ” roll center adjusters and bump steer correctors are best on a lowered car only.” – not true.
        It lovely works also with standard ride height on stock suspension. It worth to invest in it

        1. There are a lot of bolts and items here, if it is Honda, contact your Honda dealer, if Hardrace contact them.

  2. My Civic Si is the ’04 EP3, and Hardrace’s website say the roll center correcting ball joints are for 01-03 only? What parts do I need to replicate this on my EP3 if it’s lowered a 1-2 inches?

      1. So on an 04 si, the type s parts have been corrected or we should still buy hard race correction rod ends and ball joints? Should I refer to your answer above regarding stock suspension for an 04 model year? I have a 5 bolt hub stock configuration, does that make some of the correction work easier?

  3. Hi Mike, I just bought the RCA and Front LCA spherical bearing to replace the OEM parts on my ‘03 EP3, should I replace both or either one. Thanks in advance.

  4. Where can I find the connecting tie rods to relocate them I don’t see this on hard race website

  5. In order to adjust the camber and toe in the rear were there any special parts not mentioned on the article to make these adjustments? such as LCA’s or camber kits I have all the front end dialed in and parts replaced as recommended. I was looking to go get an alignment and figured I’d ask.

    1. My experience has been that to get these Fortune Auto coilovers dialed you will need a camber kit in the rear of your DC5 or EP3.

  6. Alot of comments on height for a ride height specs( where to take the measurement and the proper height. Your article does not address this alingment spec. Front and rear height ( some claim front should be less than rear height by a factor of two. Example floor to fender is 25 1/2 inches rear and front is 24 !/2 on my 2002 EP-3 . Tire is a 24.8 diameter.

  7. Mike, I am truly a fan of your work explaining the logic behind suspension operation, thank you. I nerd out reading these type of articles.

    I’m helping my brother with his 06 SI Coupe. We are working on the shopping list of parts to make his car handle better. He has chosen to install Tein Flex Coilovers.

    I have been copying most of the work you have published for suspension.

    Knowing that the RSX and Civics of that era share may of their components, would you also recommend the Roll Center Correction and Bump Steer Correction for his chassis since he will be lowering his ride height?

    Thank you,
    Gus

    1. Your brothers car has vastly better geometry than the EP3/DC5 but can still benefit from these parts like any macpherson strut car.

      1. Mike thank you for this write up! Do you know the total length of the tie rod for an ideal toe setting? I’m having a hard time dialing this in.
        Otherwise everything else makes the car handle amazing, thanks again!

        1. If its a track car set it for 1/8″ toe out. A street car where you want your tires to last a long time might be better at Zero. I have no idea what tie rod length that is because that’s not how you align cars.

  8. Mike kojima do you have anyone in NYC the fix ep3 ? I need to get the steering to together and the car in general. When you have time can you email back . Thank you very much.

  9. Mike, what torque specs did you guys apply to the hard race inverted tie rod end nuts? I’ve currently got my hands on these for my EP3 and am wondering how tight they should be. Thanks.

  10. Mike, do you know what torque specs you guys tightened the Hard Race tie rod ends to? I got my hands on a pair and would appreciate the info. Thanks.

  11. Hey, so I bought these tie rods after reading through all your posts (This and the steering rack slider were the only things I got). I have a problem however.
    My car is completely stock and the inverted tie rod ends can only screw into the tie rods by only two full 360º turns (Or two threads) before it stops being installable. This is absurd, it’s “hanging by two threads” in the literal sense! (For comparison, OEM threads into 9 threads/9 360º turns).
    So, what the hell is the problem? For reference, it’s a facelift EP4 (1.7 Diesel). Would it being the EP4 make a difference? Hardrace website says it works for all EP models…

    1. im going to say that i belive because your car is not lowered the tie rod ends are not needed, these are for lowerd cars. When stock the legenth of the rods is what its designed to be, the issues that come up having a lowered car makes the tie rod ends longer and angles them up more as the car gets lower the inverted tie rod ends are to get rid of that issue with the increased angle on the tie rods. if you are stock you should just use the slider. and dont worry about the tie rod flip kit.

  12. I have a 2003 RSX-S and will be installing Tein Flex Z coilovers. If I only drop it 1″ do I still need the roll center correcting ball joint or would I be fine with just the tie rods?

  13. Hi Mike
    Loved this series and been accumulating all the parts for my 02 K24a2 with JRSC EP3! No more Fortune autos for this car, so got Feels instead, and such nice guys!

    Question, I also have HONED DEVELOPMENTS (Australia) Adjustable Inner Tie Rod Mount and the new Ktuned Adjustable Inner Tie Rods. Will all four (with your articles inverted and roll center adjuster) of these products work well in conjunction, is it overkill, or just creates even more ability to adjust Toe and geometry etc.

    Thanks Mike and great articles!

  14. Are the inverted tie rod ends just for lowered cars or is that just the ball joints? I have around $2000 of sporty suspension junk into my honda element (dont ask) including the SHG slider and it still drives like ass.

    1. The tie rods lower the tie rods too much, it’s way better than stock but still not totally correct. We are going to get an adjustable rack slider to help with this.

      What is your alignment set at?

      1. At the exact moment my alignment is a mystery because I broke my steering rack again, but I usually have it set to about stock toe and camber. I dont have the adjustability of coilovers since I did an element SC suspension swap as I dont exactly trust that most coilovers for the element had much testing done

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