Truenotch's BEAMS AE86 racecar

[Truenotch]

Onboard vid from the City (GA2 City with B18CR, 17x9s with 235 Nangkang AR1s, M factory close ratio kit etc etc). 

The City is ~185hp at the wheels (about the same as my car) and the weights are similar, so they're pretty well matched  .

[Truenotch]

The headers decided to start leaking at Teretonga, which probably explains all the flames out the rear end  

Pulled them off to inspect, and there was a decent sized hole in #3. It would have been pretty thin from port matching and must have cracked and blown out. 

@eke_zetec_RWD made these headers for me back in 2010, so they've done pretty well! I was planning to give them a. cleanup anyway. 

They came up pretty good after a quick sand blast: 

Welded up the affected area and tried to use as little heat as possible: 

And a quick lick of high temp paint: 

Then I spent this afternoon wrapping the headers (another job I've been planning to do for over a decade). I won't be in a rush to do another set.... It's a fiddly job. Should help with under bonnet temps a lot, so it'll be worth it. 

Back on the car:

[Truenotch]

Took this for a run at Highlands on Saturday. The Central Otago Motorsport Club run a sprint on Track C each year. It's reverse direction with the addition of the whoops and an extra corner through the forest, so there aren't many straights and it favours good handling cars.

Suits me! 

It's a pretty busy little section of track... I'd say it's the coolest format of any sprint I've done in ~20 years of motorsport. 

Here's an external view: 

My workmates Brandon and Taz were running the B18CR City, which also suited the track really well. We ended up 1st, 2nd and 4th out of the 48 entries. Not bad

There's a couple more videos on my YouTube channel if you're keen to see more: https://www.youtube.com/@truenotch/videos

 

[Truenotch]

Chase cam from the City in run 3. Skip to 1.05 to see a hairy moment passing a Mini. 

 

[Truenotch]

Look at my massive semi  

I have three more somewhere too. They should be good for the Coronet Peak Hillclimb in November.

[Truenotch]

Bolted this thing onto that thing to get a baseline before making a few changes.

Gave it a couple of quick runs, then swapped the trumpets from the 95mm blue ones to 75mm bronze just to see what might happen.

95mm trumpets are the green line, 75mm white line. The AFRs are pretty messy and we haven't touched any tuning, just swapped trumpets and ran it again, so maybe the shorter ones will work after some fuelling and VVTi changes?

There's a set of 48mm Jenvey ITBs floating around at work and one of the guys has 3D printed a manifold to test. It'll be interesting to see if there's a difference from an extra few mm of throttle plate, and I'll give a few different bell mouths a try at the same time. 

I'd really like to try 50mm or even 52mm just to see if there's any gains.... will see If I can find a set to try.

 

[Truenotch]

Entered a hillclimb in the weekend. I'll come back to tell the story soon... for now, here's some eye candy.

 

[Truenotch]

Took the 86 for its first hoon of the year at Teretonga. It rained, so the day was all about skids. 

Not complaining. 

 

 

[Truenotch]

 

[Truenotch]

Over the weekend I competed in my first actual race meeting in the South Island at Highlands Park with the SS Cup Class. It feels like this has been a long time coming and I was pretty fizzed to have a run at the "A&C" format of the track that has its first turn straight after the start finish line. 

The car was looking pretty good! 

 

Until I had small a moment in qualifying and went lawn mowing... Unfortunately my front bumper tucked as I landed on the grass and got dragged under the car. This is all that's left of it now 😅

Oh well! nothing lasts forever, especially not Fibreglass. Here's some photos from before the excursion: 

I threw some tape around it to secure the flares and went back to it. I'd qualified 10th on the grid (second in my class) and it looked like there would be lots of good cars to battle with. 

 

The racing was definitely good all day long! We had 4 x 8 lap races of different formats (qualifying order, reverse grid with staggered start, reverse finishing order, another reverse with staggered start). I ended up finishing 10th, 7th, 9th and 2nd in the 4 races and was 2nd in class all day behind Josh from Crowesport in his WRX. 

Here's a vid from the last race of the day: 

 

[Truenotch]

Found a front bumper in Auckland, so the next game is relaying it to the South Island over the next little while.

It's a genuine Uras kit and is slightly cut up already, so will be a perfect base for me to modify without feeling guilty.

 

The corners have been chopped to fit N2 flares.

 

I think this time I'll try to make the bumper 2 pieces, with a separate lip thats easily removable for loading on a trailer etc. It'll also allow me to mount the main bumper more solid since it won't need to be removed every time the car goes on the trailer. 

Here's an old picture with the front lip split off the bumper. I'll come up with a plan to make the lip lap over the bumper and might make the lip section from carbon fibre... we'll see 🤷

[Truenotch]

Bumper arrived today thanks to @Stu for hustling to get it here.

Someone left me a few notes on the packaging 🤔

I had a good giggle! 

Anyway...

Now to do some jigging, poking, mounting and repairs to get it looking like the last one. 

[Truenotch]

I mucked around with the front bumper mounts today. I'm thinking I'll leave the front bumper as Uras intended this time.... because it drives onto my trailer as is and my ideas for modifying it were getting too complicated.

My last bumper took weeks of nights after work and I know if the juice will be worth the squeeze a second time around...

The new plan is something more like this 👆. An easily removable splitter that mounts independently of the bumper. 

Here's a hotboy S13 that kinda illustrates what I'm thinking: 

I have an experimental idea for making the splitter/undertray too. Two sheets of 10mm foam core ACM stacked together (it's super light and rigid) with aluminium angle sandwiched between the layers for mounting and then wrap the whole lot in Carbon for extra strength and wank factor.

Aaaand now I'm thinking about aero, so it's time to revisit the rear wing idea 😁

The idea is growing on me...

[Truenotch]

Info dump from the rabbit hole I went down last night. 

The extruded wing blade I have is an older PCI race wing - this was their original style and is was advertised as a low drag wing and was mainly used for FWD cars. The cord is 220mm and I had no idea what the profile was, until last night when I found a note about it on an old website that said the profile is an Eppler 421. Airfoiltools has a huge list of profiles: http://airfoiltools.com/airfoil/details?airfoil=e421-il 

I plotted it against a photo of my wing (which has some parallax error, so doesn't perfectly trace it, but you can see it's close). It was a common profile for old can-am cars and seems like it gets used for some fixed wing drones and helicopter blades too.... Which means the extrusion is available on Alibaba if anyone wants to go into business selling wings 😉

Current plan of attack is to build the wing stays and test with this wing, then add a gurney flap to see how much effect it has... And then possibly add a 3D printed second element later if I want lots of downforce (this profile is a common base for dual element wings).

The other rabbit hole (vortex?) I fell into was 3D printed wings and the range of techniques people are using to create strong wings. This is too interesting not to try at some stage.... It's such a cool way to experiment with different wing profiles. 

Most people make them from 3D printed sections with aluminium tubes that slide through the length and aluminium sections at the mounting surface to get a strong mount: 

 

And some people are having success with carbon skinning and vac-bagging the wing afterwards using as little as 5% infill on the prints to keep it light. Some people have said their finished wings are as light as 2.5kg, others add more material and it gets as high as 7kg (still not terrible). 

The results look pretty impressive tbh, so I'm keen to give it a try. 

Ok, back to the grind.

[Truenotch]

Got sticky repairing the lower corners of the URAS bumper last night. After scheming different ways to do it, I ended up going the simple way and threw masking tape on from the outside to get the shape, then covered that with packing tape for structural integrity. 

Couple of layers of glass from the inside and some patches on my flares where the screw holes blew out: 

And it looked like this when I peeled the tape this morning: 

There's a couple of dry spots in the glass (access to that corner was tight), but it's good enough to clean up and get it looking straight. We have another AE86 project at work at the mo, so we'll get this bumper straight enough to take a mould off. 

[Truenotch]

Just riffing through splitter ideas at the moment. 

I'm thinking about forming some small tunnels here. It would be fun to test them (I can block them off for a session to see if they work).

I think ~50mm of poke out the front will be about right:

This material is a polyurethane foam ACM. It's 10mm thick and super rigid I'm planning to double stack it for extra strength (glue two sheets together with panel bond). 

I have a few other ideas on how to make this work better... I'll update on those ideas if they work out 😄

[Truenotch]

More figuring out while I wait for my repairs to cure, no exciting action yet...

In these pics, the splitter is roughly placed ~85mm from the ground, which is close to the minimum allowable under MSNZ rules at my current ride height (bottom of wheel rim is the minimum ~80mm).

It's currently about 10mm lower than the old lip was (the sheet slots straight under that bumper... it would have worked perfectly 🥲 R.I.P).

It needs a notch for the sump so I can slot it right back to where it needs to be. It'll need to be able to move up and down a bit so I can adjust the pitch. 1° over the length of the blade is about 14mm of fall.

and it looks like the tunnel location should work out well. A 6" straight tunnel will send most of the air inboard of the wheel. I could possibly go wider with the tunnel, but I think basic straight tunnels will be plenty for a first test.