That Base DC5 {Timmy_B}

[Timmy_B]

In need of an update I think....

Got some exciting things coming up.

[Timmy_B]

Haven't really had time to update this in ages. Life has been very busy.

Since late last year when I did the first shakedown of the car after the rebuild I was happy with all the changes but still saw room for improvement. Its drove well and was very responsive round SMSP but there I wasn't happy with the setup and driving on old tyres made things more difficult.



The start of this year I decided to take things a little further.
Starting with getting all unnecessary weight out of the car.
Took the dash out and finished taking the heater core and the rest of the AC components out.
Also tidying up the wiring and removing the last SRS equipment.




I also wanted to start looking into some aero. Last time at SMSP the car would rotate on itself and main straight speed would cause the car to be a side to side. At 200kms + I could feel the cars movement and it was a little off putting.
I chopped the rear bar a few inches above the lip to limit the amount of air that may be trapped in the rear bar from under the car.



I also made the decision to not continue with registration anymore. Its was up for renewal and I think it would of just been easy to do what I wanted and not worry about police and driving it on the road. In the last 12months of rego I drove it 5 times on the street.
But before it was up, I went to make some changed to the alignment.
The previous setup was only to fit the regamasters, and didn't give the car the grip it needed.
Plus the change to bigger tyres meant for better grip.

Old setup was very tail happy but more so to 'fit' wheels.
Front........
Toe -1.2
Camber -4

Rear
Toe +.7
Camber -2.5

New setup
Front.......
Toe -0.9
Camber -2.7

Rear.......
Toe 0
Camber -1.4

Had to really pull the rears to fit


Once rego ran out I wanted to make an exhaust that hugged the new rear bar. The decision to go 3 inch straight pipe was made.
After work one night I towed the car down to the workshop and my mate Shaun got to work.
Pretty basic exhaust with 1 small resonator just to give it some tone.

[Timmy_B]

Started to finish off the aero package .
Front splitter needs a few improvements, but it was well braced and very stable.
Its about 90mm out and 50mm down from the front lip.



To accompany the front aero, I ended up getting a 1400mm INGS wing just in time for my next testing day at SMSP.



SMSP testing went extremely well, after loosing an axel and wheel on the trip down we were left with 3 wheeler trailer. LOL

To get on the trailer the splitter has to be removed but it takes about 5mins so its not too bad.

First session out was more a less to makes sure nothing falls off. I was a little worried that the splitter would move and the air damn would have issues but it went well.
Second session I still took it easy and got a feel for the changes. The car just grips now, its a little daunting at first as I was so use to the old setup and its over rotation that I felt like it had way to much understeer. Turn 1 really knocked my confidence down as I wasn't prepared to carry more speed into the turn as I was afraid off the understeer.
After pitting in and taking to 'the team', we found that the tyres weren't up to temp yet........ I needed to drive it harder and have faith in the car. Its lighter, faster and has aero now, It WILL do it.

I will admit, it was very hard to feel 100% confidence in myself. I wasn't in the right mind frame. Why was I thinking about damage and the cost of rebuilding? It had been a long and expensive build from that faithful day I miss shifted, and it must have been playing on my mind.

Session 3. I gave it a little more than the previous sessions after a talk with Luke and Alex. Finally we got temps in the tyres and could get some real data.
Once again I found myself out braking my markers and taking too much speed off before turn 1.




After lunch I started to feel the car more and wanted to push a little harder.

Session 4, I finally clock 200kmh down the main straight and braking at the 100mm marker, once again taking too much speed off for turn 1, around 145kmh, but could jump on the throttle a lot sooner and getting to 170kms before turn 2.

Session 5 didn't last long as oil on the track from previous group caused for a slow back half of the track and I was nearly out of fuel.
Managed to improve the first section of the track and did one of my quickest sectors.

I called it a day and sat out on the last 2 sessions.




Very happy with the cars performance, I just need to improve and get some confidence back.

I have made some slight changed to the aero and cleaned up the air damn that I didn't get to finish off before SMSP.


Over the years the car as seen a huge transformation. Its really made me learn a lot and doing it all myself has been a huge challenge over the years. Many times I have considered giving up and selling or might have thought twice about how far I have taken it. But at the end of the day its been a huge experience and 1 that I think has taught me so much, given me new friends and new happiness.
As I am getting older, priorities change, work has become extremely busy and takes up most of my time and I try to dedicate as much as my spare time with my wife and friends. Getting time off work to race is great, but its harder and harder to do now days as I have more responsibility and less members in my team. That's life I guess......

[KVZT]

Hey Timmy!
I also have a base DC5, was wondering if you changed your front and rear swaybars to aftermarket ones? Even after coilovers I still get mad body roll
Love the progress, read this from start to finish

[Toddxxx]

Hey Tim
What material did you use for the splitter? Just plywood or?

[Timmy_B]

Hey Timmy!
I also have a base DC5, was wondering if you changed your front and rear swaybars to aftermarket ones? Even after coilovers I still get mad body roll
Love the progress, read this from start to finish

Thanks Mate,
Yeah Front sway has been changed to EP3R
Rear remains the same.
What coils are you using?

Hey Tim
What material did you use for the splitter? Just plywood or?

Yes, as this was a 'trial and test' splitter its made from just ply.
I found that my mounting points aren't identical on both sides, so when the splitter is mounted its ajar to one side and as you go round the splitter it changes -15mm
This can be fixed by drilling into the chassis and nutsert for better fitment.

Also I found I need more bracing. There is slight flex in places that the bracing is more than 100mm away from the edge. On the track it was very solid.
When I am happy with the design and changes I will make it out of aluminium

[Apu]

That's a lot of bracing! I have the PCI kit on my car and it's just he two brackets plus clips that hang on to the lip. I have added turnbuckles to tighten up where it sags (mainly for aesthetics) and that works fine but my splitter only protrudes about 8cm from the lip at max.

I'll be cutting a new splitter from 10mm ply which will be stiffer, but I'll also have it reach out by about 10cm...that might change things a bit. I really like using ply - cheap and easily replaced. I did want to do it in CF but the number of times I would have cracked it...plus I'm less concerned with looks as it's a track car only.

[Timmy_B]

That's a lot of bracing! I have the PCI kit on my car and it's just he two brackets plus clips that hang on to the lip. I have added turnbuckles to tighten up where it sags (mainly for aesthetics) and that works fine but my splitter only protrudes about 8cm from the lip at max.

I'll be cutting a new splitter from 10mm ply which will be stiffer, but I'll also have it reach out by about 10cm...that might change things a bit. I really like using ply - cheap and easily replaced. I did want to do it in CF but the number of times I would have cracked it...plus I'm less concerned with looks as it's a track car only.

Yeah anointed aero has a similar design. Its mounts from the subframe and has adjustable length.
The only issue I could see with this is Limit in bracing and I would never have to adjust the height of my splitter as that would make my air dam useless.
Although there is only 2 main points of strength.
I had a good chat to him when he saw what I had made. I asked if his brackets would be better and he said "I would still suggest bracing as you have done for track use."

I have 6points its bolted to and have braced the point at least to another point.
Ideally, I would make a 'box' with my bracing and at the front (see picture above) I would then connect each to the point of where the air dam sits.
This also helps with not choosing a massive thickness in ply (or what ever material you may use) for strength.
Thicker = more weight
Also I have used small 8mm bolts to hold it on. If I happen to crash or something happens, its the weak point and I wont be destroying/bending my chassis.
Although driving over it can't be good, Its the better outcome.

[KVZT]

Thanks Mate,
Yeah Front sway has been changed to EP3R
Rear remains the same.
What coils are you using?

Ah, did you feel any change with the swap to EP3 front sway?
I'm on Function Forms, not the top teir but I'm definitely, definitely not as serious as you

[Apu]

I have 6points its bolted to and have braced the point at least to another point.
Ideally, I would make a 'box' with my bracing and at the front (see picture above) I would then connect each to the point of where the air dam sits.
This also helps with not choosing a massive thickness in ply (or what ever material you may use) for strength.
Thicker = more weight
Also I have used small 8mm bolts to hold it on. If I happen to crash or something happens, its the weak point and I wont be destroying/bending my chassis.
Although driving over it can't be good, Its the better outcome.

Good points...I was just thinking about using an ABS sheet today as you can scrape it, and it won't break in chunks like ply does. Going to a box brace as you describe it will allow me to use ABS an stiffen it!

[Timmy_B]

Ah, did you feel any change with the swap to EP3 front sway?
I'm on Function Forms, not the top teir but I'm definitely, definitely not as serious as you

I can't say I noticed a difference just from the sway bar as I had changed multiple things at once.
BuddyClub RSD also have stiffer spring rates which would help reduce body roll.
I noticed the biggest changes when I upgraded all my bushings to SuperPro and Hardrace RCA.
Everything felt so solid after I did that.

Good points...I was just thinking about using an ABS sheet today as you can scrape it, and it won't break in chunks like ply does. Going to a box brace as you describe it will allow me to use ABS an stiffen it!

Yeah its all trial and error. Find out what works and what needs improvements.
Just make sure the ABS can't 'flex', otherwise its pointless.

The biggest advise I can give people who want to build a 'track car' or looking into aero is this....... (and I don't consider myself an expert on any of this shit, I just have done hour of reading and research on different things)
You want to make your car 'slippery'!
With that in mind, look at how much power you are putting out. Most of us on here have underpowered Honda's.
With this in mind, we shouldn't be looking for 'downforce' but more so stability.

My experience with this is....
SMSP - 0 Aero (No wing/no front aero)
Main straight - Top speed of 215km/h (Car feels very unstable and at high speeds moves side to side)
Cornering - Car feel 'floaty'

SMSP - 1450mm INGS wing (no higher than roof line), Front splitter(100mm and back as far as front engine mount) Spaced bonnet (30mm spaced to get trapped air OUT of stock bonnet)
40mm Spaced fenders (Mainly to fit tyre but also helps escape air from wheel arch.)
Main straight - 200km/h (VERY stable and planted, top speed has dropped 15km/h due to added drag created by aero)
Cornering (Exit speed is higher and can get on the throttle earlier, also can feel the car being planted to the road)

Now I know this is only an experience I had, plus the factor of me being more comfortable behind the wheel at SMSP and the changes to alignment would have also assisted.

If I made changed to the rear wing and went to a 1700mm wing, with a massive blade, I could only imagine the amount of drag that would have produced. Sitting wider than the car and higher than the roof would create a huge drag coefficient. If I had the power of an EVO this would be fine as I could 'pull through' the drag created.

Hope this helps people think deeper about aero needs and wants for a Honda.

[Apu]

Absolutely true about drag vs downforce.

That said, smart aero can really help - regular track goers in Melbourne might have seen a white MX5 with a fastback hardtop and "ridiculous" aero (undertray, splitter, diffuser, rear wing) but still runs the anaemic n/a 1.8L (<100kW)...but it beats much more powerful cars around the track.

I've been careful with mine, and chose to go with the PCI kit - it's got a relatively small wing with a gurney flap, which help produce more downforce but with less drag.

I'll add a rear diffuser at some point and thinking about doing a flat underbody as well...one step at a time!

Are you going to Circuit Club in December? Would love to see your car!

[Timmy_B]

I'll add a rear diffuser at some point and thinking about doing a flat underbody as well...one step at a time!

Are you going to Circuit Club in December? Would love to see your car!

I'd do a flat floor first, then rear diffuser. From what I have read and researched, a rear diffuser can't properly 'diffuse' the air from underneath the car without the aid of a flat floor.
The air would already be disturb by the design of the under chassis and the diffuser can't work to its full potential.

This comes back to my 'slippery' thinking. If you have splitter - flat floor -diffuser, the air continually flows underneath in a smooth pattern till it hit the diffuser and is pushed upwards - creating downforce.
There is some pretty amazing builds around that show how effective airflow can be. One thing that has really stuck with me is not fighting air flow. don't block off bumpers and potential benefits of air flow.
People have created channels to guide the air within the engine bay into coolers and brake ducts, but one of the coolest things I have seen is internal canards or scoops within the engine bay.
Air coming in through a light or floglight hole guided to a cooler then guided to a aluminium scoop that curves to the vent in the bonnet. The flow of air is all contained in this amazing aluminium box and is sealed once the bonnet is closed. The scoop curves upwards just above the wheel arch - effectively causing downforce right on top of the wheels.
All this stuff is HUGE $$$$$$$$$$ engineering and cost to create, but the concept is very basic when you think about guiding air and using it as an advantage.


Was going to do the EXE day in Nov but have taken on a huge project at work and am unable to take leave before xmas.
I was thinking of doing the 6th December but that is looking like the date we move house now.

So things are a little slow with the car but its ready to go when I have time.
Maybe will be bringing it to the CITR bbq if I can park the trailer somewhere. LOL

[plAythiNG]

Keen to understand how the Gurney flap works to add further downforce without the same amount of added drag. I've seen this comment a few times on the web so I guess it works due to multiple track goers commenting the same things as Bryan mentioned, but keen to hear the theory behind it.

Good to read discussions on the aero setups etc.

I know alot of S2000 guys in Australia and around the world all tend to go for the 1700mm wing give or take 100mm depending on car. What you are saying about the added "drag" I believe is correct in theory, but IMO that theory has to also take into consideration what type of car this aero is going on. I think the reason why these S2000 track goes run such a "massive" wing is to help with stability, just exactly as you mentioned. I believe the reason why they run a larger wing compared to your DC5 is the S2K is rwd and alot less weight on the rear wheels compared to a bigger chassis like the DC5 hence the reason why the S2000 often sees a giant wing.

Personally for me, I will eventually get a wing. But for now I want to get used to driving my car with the new suspension/tyre setup, and I also still have a thicker aftermarket sway bar to go in before I even consider a drastic change by including a wing.

How much of a weighting would you guys consider aero in terms of dropping laptimes? IMO I think aero is last in terms of chasing quick lap times, tons and tons of seat time would be at the top of the table in terms of where to spend my money to go quicker, with other areas of spending before aero.

[Toddxxx]

1. Seat time
2. Suspension/braking/handling
3. Power
4. Aero

In saying that I got a wing straight away and a voltex front bar :P