The Roadster NA Journey Begins

Magpie · Postby **Magpie** » Thu Aug 30, 2018 7:07 pm

Suspension changes done, alignment done, rear brake pads done, steering angle sensor calibration done, RPM into the CL-1 done!

Was a busy weekend getting everything finished. The pre alignment values were 'interesting', so much for marking the alignment bolts before pulling them out. LR toe +13 and FL toe -26.4mm

Running a slightly different alignment to previous, dialed some rear camber out to help with grip out of the corners.
Front

Caster L/R 4°01' 4°01'
Camber L/R -3°29' -3°27'
Toe L/R -1.4 -1.3

Rear

Camber L/R -2°28' -2°29
Toe L/R 1.2 1.2

Took advantage during the alignment at Hacketts Discount Tyres to calibrate the steering angle sensor. A simple job really, but required the steering wheel to be turned at least 20°and I do not have turn plates in the shed

Steering by Eipeip, on Flickr

Racepak sent over the cable to hook up the RPM to the CL-1. Now have the RPM working which now means I do not have to manually start the recording. Happy to put in another car at the track one day to get thoughts on the CL-1.

SKYHI · Postby **SKYHI** » Fri Aug 31, 2018 4:40 pm

Great to see more progress. Interesting toe settings on the front, don't think I've ever seen anyone run that much. What's the thought behind those settings? Trying to get it to turn in a bit better?

Magpie · Postby **Magpie** » Fri Aug 31, 2018 8:58 pm

SKYHI wrote:Interesting toe settings on the front, don't think I've ever seen anyone run that much. What's the thought behind those settings? Trying to get it to turn in a bit better?

I have been running that for awhile now, was also done by Accurate Suspension. Yes it is for better turn in as well as some high speed stability. Add the F/R toe together and it is almost zero.

Notwithstanding the amount of toe has not caused any increased tyre wear, however maybe lowering top speed. Will see how it goes tomorrow and if needed tweak the alignment. However the AD08R’s will be back on soon and they do not like the settings I use on the AD08R’s.

Magpie · Postby **Magpie** » Thu Sep 06, 2018 9:07 am

Well, the weekend did not go as planned...

Too many changes at once to the car as well as a repeat of the issue at Morgan Park with SDT surfaced again (not car related).

Notwithstanding that I was 2 seconds off my PB times and managed to loose time in the last half of the track which I normally pick time up in the car felt good. Well once I adjusted the tyres and dampers.

Have another session at QR soon and possible another before leaving for Sydney. Hopefully the driver issues will be sorted out and regression to the mean works in my favour on 20/09. Will be setting the car up as per previous days and not trying anything else, will also be reverting to 205/50/15 tyres.

If interested here the article I did for why I was slow... Yes it is on Facebook and yes it is for Team Racepak
https://www.facebook.com/notes/team-racepak/why-was-i-slower/2177992875817965/

Custardtart · Postby **Custardtart** » Thu Sep 06, 2018 11:04 am

That's a really interesting analysis. A general observation would be about the "feel" of the car with the changes you'd made.

If it were me, I'd expect the car to feel more tail happy under braking and entry to the corner. Was this the case? It seemed like this is where you were losing the time.

Possible things to cure this would be add more rear camber, reduce front toe, drop tyre pressure 2 psi but you've identified that you had made a lot of changes so maybe best to hit the reset.

What handing issues were you "feeling" that made you want to make the changes?

Magpie · Postby **Magpie** » Thu Sep 06, 2018 12:00 pm

Custardtart wrote:What handing issues were you "feeling" that made you want to make the changes?

The plan was to always change out the suspension arm/bushes however it took a lot longer than planned to get this done.

The reason for the change in bushes was to remove any 'bind' as well this impact on the spring rate. Plus the bushes had been in there for awhile and needed to be inspected anyway. The previous bushes had no issues.

What I need to do is get some track time to dial in the dampers with all the changes. If necessary a change in spring rates maybe required. I have left my run a bit late and have maybe 2 tracks days to test on before heading to Sydney.

First action will be to 'reset' to my previous PB sessions and start from there. Not possible to reset the alignment, but this can be done after the track day on 20/09 if needed.

You are right on loosing time on corner entry, but I think it was more a grip issue associated with the tyres close to use by date.

Thanks for the feedback on the article. It took a while to put together.

madjak · Postby **madjak** » Thu Sep 06, 2018 6:24 pm

Tyres make a massive difference to times. Why aren't you prepping for WTAC on Advan AD08's given that's what you'll be running? Even older AD08s would be better to a difference size and brand tyre regardless of age.

Also I now run 0 toe on all corners and find it is great. The car has a little less directional stability but nothing that causes any problems. All of my other alignment settings are pretty similar to you with around 3.5 degree camber up front and 2.2 camber rear, just no toe.

Last event I also dialed back my rear wing to a lower angle. I think when I first set it up I managed faster times every time I upped the angle but I think that was more due to me gaining speed each run than better downforce. Since I dialed it back I've been setting way faster times again, although I was also on fresh rubber. But it goes to show you shouldn't rely on a single setup and to constantly re-assess your settings to see how the car handles.

Magpie · Postby **Magpie** » Thu Sep 06, 2018 6:31 pm

madjak wrote:Why aren't you prepping for WTAC on Advan AD08's given that's what you'll be running?

That is what will be on from now on. Agree on the toe settings, may dial this back after 20/09 if things are no better. Already aware of the wing impact, however, I may dial it back some more. At WTAC last year when the rear wing was dialed back I was slower so it was reset and not been touched since.

Just going back to AD08R's will require setup changes anyway.

Magpie · Postby **Magpie** » Fri Sep 21, 2018 9:58 am

Had a quick test of the car at QR yesterday as well as scrubbed in the WTAC tyres. However, the 'best' part of the afternoon was having a friend of mine take the car out for a few laps AND provide some feedback. Not to mention it is the first time in a while I have heard my car from the outside as well as the opportunity was taken to watch Trent's live times from Racepak's CL-1. The live data also gave the predictive time so it was possible to see, in real time if he was on a hot lap or not.

Trent managed a 59.99 where as my best was a 60.78. Trent was almost 0.5 seconds faster than me through T2 to T3 by carrying almost 10 kmh more speed. I did not think that it was possible to carry that much more speed!

By the end of the day I managed to almost get the tyre pressures right (old set of AD08R's), however the temps still indicate that they are under-inflated, They were started at 26 cold , then adjusted down (hot) to 29, 28, 27.5 then back up to 29.5 and 30.0 (hot). Both Trent and i did our fastest laps with them on 30.0 hot.

The feedback given is invaluable and I will be working on the main issue this weekend.

Trent's lap
https://www.facebook.com/mx5na6/videos/330466867704230/

Custardtart · Postby **Custardtart** » Fri Sep 21, 2018 10:31 am

To get accurate pressures smash the in lap

Magpie · Postby **Magpie** » Fri Sep 21, 2018 11:07 am

Agreed, however I do have the surface tyre temps to use when on the track as well as when in the pits.

It was just a while since I had used those rims (6.5") and the car had been through a few changes. Notwithstanding all the changes have been in the positive direction. Trent getting a 59.99 on the sprint with 12 month old 205/50/15 AD08R's on 6.5" rims was not easy.

The observation I have when scrubbing in a set of 205/50/15 AD08R's on 8" rims when compared to the 6.5" rims is that 6.5" rims are compromising the tyres performance.

Anway, depending on what happens 2019 will see 17x9 or 17x10 rims on the car...

Custardtart · Postby **Custardtart** » Fri Sep 21, 2018 11:17 am

Nice re. your tyre temps monitoring set up,
I once got a Porsche works and British GT driver to test my car, similar result to you :mrgreen:

there’s no substitute for talent but horsepower helps :lol:

A word of caution, having just fitted 9” rims my car did have more grip but it was much harder to do a lap time and less fun!

Magpie · Postby **Magpie** » Fri Sep 21, 2018 11:29 am

Yep the 9" will be a lot more heavier. Only alternative is to go to AO50's as they come in 225/50/15 however this would imply open class at WTAC and without some other changes not a smart move. Maybe staying NA and putting a 100-150 nitrous shot....

Nankang will have a 245/40/15 soon hence another reason to stay with the 15's...

Agreed, have another person drive your car allows feedback and a baseline to be set.

plohl · Postby **plohl** » Fri Sep 21, 2018 12:07 pm

you have as much chance winning wtac in open class as you do in club sprint - may as well do what you want to the car and just run in whatever class they put you in.
I'm with madjak thought - if wtac your aim, probably should stick with the control tyre all year round.

Great that you got trent to drive it. Dude can pedal. Hopefully his data will help push you towards a faster lap time.