♦ ♦ ChargeR's DC5R Blog ♦ ♦

[dnapol]

"Massive update"...
Glad to see the legend lives

[air23box]

Massive update. I had to move my car to my new place so I fitted up a new intake pipe after discovering the old one was split. This is the third OEM intake pipe so far for this car. The car is still as great as I remember it being when I last drove it 12 months ago.



All fixed. Excuse the dusty engine bay, it's been a few years since it was washed.



I've got a couple of other new OEM parts for this car, so I'll update again when I fit those. Unfortunately the N1 shocks are still sitting in a box in the back of the car, so it will be some time until I hit the track again in this car. I'm aiming for later this year though.

Better make it fast bro.......miss your awesome ride and the old time.......~!

[plAythiNG]

Hey Tom, how is this car going?

[ChargeR]

Hey Tom, how is this car going?

No change, still very dusty. Had to borrow a couple of small parts off it for the CR-X, so will order replacements for those from Amayama and then maybe take it out for a drive once I fit them.

[ChargeR]

Back from the dead.

Over the weekend I pushed the Integra out of the corner of the workshop and made a start on getting it track ready. 2017 is the year of 3 track cars. Since it's been more than 5 years since it's last outing it definitely needs some tender love and attention. First up I decided to get on to measuring a few things that I'd always wanted to know, but always seemed too busy buying new wheels to bother with. Focusing on bumpsteer since the DC5 is well known to have shortcomings in this area.

With the car up on stands I set to work measuring stuff to get a baseline to see what could be improved. The DC5 suspension cops plenty of harsh criticism, with the suspension geometry being blamed for ill handling of all sorts. Much of the time it's probably user error. Rather than listen to fools on the Internet I decided to see what I could learn myself.



Starting with the rear bump steer and camber curve:



The resulting rear bumpsteer is graphed below. Since the rear trailing arm attaches to the suspension upright at two locations it provides all the toe control; Toe is effectively defined by the arc the trailing arm travels through, and making changes to the upper control arm does nothing. The upper link only dictates camber and resists lateral cornering forces. The measured toe change is small through the whole travel, around 0.3mm per 10mm of bump travel. This is a good result because there's not much that can be done here without re-designing the whole rear suspension.



Things aren't as ideal with the rear camber curve and motion ratio though. the graph below shows the camber change. The large change in camber of the rear suspension in bump travel is clear, and the curve becomes more steep at the lower end of bump travel which is the range of suspension a typical lowered DC5 is right in the middle of. Matching this large negative camber gain with a flawed front MacPherson strut design with minimal camber gain results in a tendency to understeer!



While cycling the suspension I measured the rear motion ratio as 0.48. This is much lower than ideal for good ride and damping, and interestingly a bit lower than the 0.5 to 0.55 numbers that I've seen quoted for the DC5. Again there's not much that can be done without a substantial re-design though.

Then I got started on the front. Excuse the state of the underbody, it's been a long time since the car has been washed.



Below is the bump steer curve of the front:



The overall amount of toe change that the front end experiences is much more than the rear suspension, and tends in the toe-out direction on a lowered car. At a typical lowered ride height the toe changes up to 1.5 to 2mm per 10mm of bump travel. This is pretty poor compared to many of the earlier double wishbone cars, but not as bad as I expected. This contributes to the poor steering feel and turn in performance that many DC5 and EP3 owners complain about, and with wide low offset wheels impacting the scrub radius the issue only gets worse. Based on these measurements we'll focus on correcting the bump steer at the front end, which will make the car much more manageable.

From what I measured I've identified some clear areas where we can improve the DC5 chassis, and it's certainly not the basket-case that people would have us believe. At the top of the list of changes will be a bumpsteer correction kit similar to the kit Honed already make for earlier models. First up I'll be giving brakes and suspension a good freshen up, and the Mugen N1 shocks sent off for rebuild.

[Shakeel]

Ooo this has got me tingling. I'm definitely interested in what changes you make to what was an already epic car!

Are those the same mugen n1 shocks which were supposedly meant to be sent for a rebuild many years ago?

[ChargeR]

Ooo this has got me tingling. I'm definitely interested in what changes you make to what was an already epic car!

Are those the same mugen n1 shocks which were supposedly meant to be sent for a rebuild many years ago?

The tentative goal for the car is to run the same times I used to on racier tyres on a street tyre like AD08Rs or RS3s, so not going to make wholesale changes, just optimise the package and refurbish some parts of the car as funds permit. Yeah the shocks were meant to be sent years ago, but we're not all baller like you Mr "I've got the whole Amuse catalogue on my car" .

[Jayden95]

Woo, One of my favourite build threads coming back to life!


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[ChargeR]

Bump.



Shocks are now in a box ready to head to our friends Mugen. Have some concepts in mind for some geometry changes for this car. Rumours that the DC5 suspension is irrecoverably bad are greatly exaggerated. Going to drop off one of my sets of SSR Type Cs to be stripped and repainted, then have some fresh street tyres fitted, most likely RS4s in 225 and 245 variety. Looking forward to showing all these K swapped cars what a Honda Stream coupe version with supposedly janky suspension geometry can do.

[plAythiNG]

what a great bump!

Love what you are doing with Honed Tom!

[Shakeel]

Darn it Tom! Surely it doesn't take ten months to package and ship out a set of shocks

Can I just fly down to Melbourne and do it for you?.. I may be speaking for myself but I'm sure a lot of us are desperate to see things happening on the red devil!!

[ChargeR]

Rough to do list on the car for my own reference:

- Refit shocks upon arrival back from Mugen
- Wheel alignment
- Strip and paint a set of SSR Type C
- New tyres - Most likely RS4s as economy is more important than outright speed so I won't be going for the RE71R or Rival S like on the CR-X
- New front pads and discs. What's the current pick of the Project Mu street/track pads? Last time I had the car out I used their LM700s which are now discontinued. Has anyone used the P Mu Club Racer compound?
- Replace gearbox oil, engine oil, power steering fluid, brake fluid and coolant
- New fire extinguisher
- Replace serpentine belt
- Rinse the dust off
???
- PBs

Darn it Tom! Surely it doesn't take ten months to package and ship out a set of shocks

Can I just fly down to Melbourne and do it for you?.. I may be speaking for myself but I'm sure a lot of us are desperate to see things happening on the red devil!!

It does when you've got 5 cars all crying out for your attention like needy children! Thanks for the offer, but maybe I'll just get it done then drive up to your neck of the woods and run some laps at WFP and SMSP. Long trips won't be so bad in a car that has air conditioning and at least a little sound deadening, and Winton is a bit boring lately.

what a great bump!

Love what you are doing with Honed Tom!

Thanks mate, appreciate the support.

2018 will see some S2000 and DC5 Honed parts I expect, so I hope you guys like what we offer .

[Toddxxx]

Pmu street/track pad is the hc+. Great pad that many people use. CR is more aimed towards track day only but can still be streetable.

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[ChargeR]

Pmu street/track pad is the hc+. Great pad that many people use. CR is more aimed towards track day only but can still be streetable.

Thanks for the input Todd, I've driven some cars with the HC+ and I don't think it's enough for me. The car won't really be driven on the street, like all my other cars it will just drive to the track and back. I think I'll try the CR.

[Toddxxx]

Winmax W5? Rated the same as pmu CR but about 25% cheaper, when I bought mine anyway. That's what I'm running on the s2000 and love them. I've done 10 track days on them now and I'm at about 50% pad material remaining so excellent quality for the money paid. Outside of temp range they are quite loud and aggressive on rotors though but if only to and from the track you'll be fine

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