Just installed hardrace roll center balljoints and reverse tie rod ends then had it aligned with following specs. The car feels a bit twitchy on the straights. I know I want more camber up front, but need to add another crash bolt or purchase my coilovers with a camber plate.

That being said is it potentially the toe out up front? It's so minimal I didn't think it would cause the twitchiness. I might get used to it and will know more after I track it this upcoming weekend. Any pointers would be appreciated.



Front R Caster: 1.7
Front L Caster: 1.8

Front R Camber: -1.5
Front L Camber: -1.5

Front Toe: 1/20 out
Rear Toe: Neutral

Rear R Camber: -1.2
Rear L Camber: -1.2

 

your toe out isn't that radical.
your front camber seems too low for that car assuming you're running 200 tw or lower
your caster isn't excessive-- if anything you might do well with some more

At this point, you should probably elaborate on what you mean by "twitchy"

how does it feel?

 

Second this^^
Twitchy from torque steer? Between shifts (on/off throttle)? Straight line braking/acceleration?

 

Boy if this isn't a circle je--.... yeah

What he said also

and to elaborate-- is it twitchy because of your spring rates being too high? is it twitchy in vertical movement? Is it twitchy in yaw? Is it twitchy in lateral movement? Maybe try playing with dampers if it's induced by springs..

 

Apologize, I should have included more information, car feels twitchy while accelerating straight on the highway, needing more steering wheel input to keep the car tracking straight. It's not truly pulling to one side or the other, but the steering wheel is overly sensitive causing the "twitchiness" feeling and consistent correction. Hope that makes sense.

I asked for more negative camber up front but the shop stated this was maxed out, I'm assuming I need another crash bolt so I have two crash bolts per side to add additional negative camber. Or move to a set of coilovers that have a top camber plate. I'm currently running Tein Basis Z's that came on the car, spring rates are anything but stiff, 336 f, 448 r.

 

How r ur bushings? I’ve had bad lower control arm bushings tear and result in the whee turning one way on throttle and another off throttle and at braking

 

The bushings feel pretty solid, I have poly energy suspension bushings I plan to throw in after the season is over. To add to the above the car didn't feel like this prior to the new alignment, however since I installed the roll center ball joints and the reverse tie rod ends I don't truly have a baseline prior to the changes as I just purchased the car and don't know what specs the car was aligned at previously.

 

^^ haha

I know we have different suspension geometry, but mine was suuuuper twitchy on accel/braking like you are experiencing (torque steer/shifts were awful) and once I changed the compliance bushings out and went to spherical compliance it took about 98% of the twitchiness out of the car. FWIW, these were new hardened rubber that were replaced.

 

The suspension geometry on the EP3/DC5 is funny. What you might be describing could be an increase in "crispness" of the car. So it may feel like it's twitchier, but it could also be more responsive now that you've made the changes you did.

The bump steer on these cars is also much worse than on the older Civics, so changing the camber may have changed your toe curve with height change.

Honestly, keep an eye on tire wear and keep driving it. Something may have drifted after the alignment too-- keep that in mind.

Crash bolts have a habit of slipping and in theory camber will affect toe-- so that could be causing your problem.

 

You have a newer car than most have on this forum.
Not to say that there aren't some competitive EP3's tracking, but most cars here are much older in generation.

Hard Race isn't a bad brand, I use them. Sometimes it takes a day or three at the track to feel better IMO
Especially if you swapped out all the OEM rubber for HR.
Missing elements
Ride height
Engine horsepower...any further HP gains other than stock?

Like all others said twitchy how? your answers are vague.
Id like to see some in car vid of you shifting.
I see you are running a street tire according to the spec sheet, as well as those sorry to say Crappy Dampa Chi street coil overs
Something id never entertain being put in my race car. Even though the shell came from a former TEIN employee in so cal.
Maybe go a 50 series tire while at the track? Great time to get that second set of wheels you haven't gotten yet.
Find some used ones online and get a set of used R compounds as well.
Subscribed to see how this irons itself out.

 

Agreed, it could be an increase in sensitivity/responsiveness which may be a good thing in the end. I'll know more after this weekend. I drove it straight from the shop and noticed it immediately, something could have slipped, but imagine it's just the new specs. I might bring it back for them to check. Thanks for the replies, much appreciated.

Thanks for the reply, as mentioned above it could just be a change I'm not used to. Can you help me with the stock height of the EP3, fender to hub center f/r? Currently there is about a 1 finger gap between wheel well and tire, but I'd like to measure from fender to hub center if possible. Based on what I've read I'm thinking the car is actually lower than ideal height, but need a baseline to adjust. Haven't been able to find that info anywhere. Agree this set of Tein's are not ideal, but that's what the car came with so I'll make due until I can upgrade. Currently car is mostly stock with just intake/exhaust.

I explained the twitchiness in more detail in a reply above. I will try to get some in car footage from the track. Currently running P Zero Nero GT street tires. I'll look at another set of tires as this will likely turn into mainly a track car.

"Apologize, I should have included more information, car feels twitchy while accelerating straight on the highway, needing more steering wheel input to keep the car tracking straight. It's not truly pulling to one side or the other, but the steering wheel is overly sensitive causing the "twitchiness" feeling and consistent correction. Hope that makes sense."

 

Measure from your jack points and compare that to others that have tracked EP3s and set it to where they were most successful. With different tire and rim sizes, its tough to know where the best height is based off of your geometry measuring things that way.

 

^^ this + Annotate all changes you make to the car no matter how small they may be.
Since you have a newer car than most here search out the EP3 forums and if I recall there was a car back east that posted in this forum.
If memory serves me they got that car set up pretty good...
This is the car, now back track this in this forum using honda-tech in the search string (google)
IPG Parts Blog :: IPGParts.com :: IPG SCCA STL Class 2004 Civic Si EP3

research and google is your friend.

 

Thanks, I read a bunch of his threads, but I'll need to reach out and grab some more details from him, can't find too many details outside of parts list.

The weekend went great, car handled just fine, actually felt like it turned in better and I learned a lot. I think the steering input was more sensitive than I was used to. Progressed and shaved 5 seconds off my lap times on each course over the weekend. I'll throw some videos up, the driver POV didn't come out that great, need a different attachment for the GoPro.

 

Feel free to critique and let me know what I can improve on. Threw it together quickly, so feel free to skip through.

 

"reverse tie rod ends" … were these hardrace as well? "some" folks (in the older chassis) have had issues with how stiff these are and how much it transfers to the steering wheel.

 

They were Hard Race, I did read about some folks having issues with them in the past on the older chassis, but couldn't find too much about the EP3, although I did find a post that said reverse tire rods could increase toe steer in the dc5, which would translate to the EP3. I believe they are spherical bushings, but didn't notice anything too out of character in how the car handled, like I said just a bit more sensitive to steering input than before, which seems like a good thing. With the change in balljoints to the taller Hard Race version it's hard to deduce how each part is contributing to the feel of the car. I'll probably buy one more crash bolt and see if I can have the alignment shop dial in -2.5 degrees camber on the front and call it good.

It looks like you're part of IPGparts.com, do you have more details on the EP3 you all were running?

 

IPG Parts has been supporting my Honda Challenge effort during my rookie year. I know James was dropping the new ITR off for a cage install so he might not be in the office... but I would reach out to them. They have been extremely helpful via email.

 

Awesome, sounds good, thanks Kaan.

 

Not too bad!
Dont remove your hands from the wheel, don't look at your instructor.
Drive the car, look through the turn and the car will go there.
You paid to use the track, use all of it.
Didn't hear Vtec crack but that's ok for now.
Good deal.

 

Thanks, yeah I know I have some bad habits I need to work on with hands and looking ahead through the turn. What do you mean "vtec crack"? It's i-vtec so less noticeable than b series and other k series.

 

Randomly came across a video of the guy behind me for 1/2 of the session, definitely gives a different perspective vs being in the car. I felt like I used more of the track than I did and turn in points could be way more consistent. This was also my first solo session.

 

I guess it doesnt crack like you would hear from other engines.