Sam's build thread

[sambb]

legend. thanks! The 2K2 ohm I read about is a bit off the money. Think I'll start with what you did. Our cars are similar vintage. thanks mate.

[teamshaw]

Looking at running some of the NSW supersprint rounds.

Has anyone experienced running a restriction in class 3? http://supersprintnsw.com/wp-content...egulations.pdf


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[metalhead]

Hey Sam, I've got a spare bucket and a new 4 point harness you're welcome to have on loan. They're intended for the passenger side of the Vette ultimately, but I don't see that happening for at least a few months.

[sambb]

[QUOTE=teamshaw;1288296]Looking at running some of the NSW supersprint rounds.

Has anyone experienced running a restriction in class 3? http://supersprintnsw.com/wp-content...egulations.pdf

Did you mean type 3? I'm normally in type 2 class C (our car is 3.1L when the turbo multiplier is applied). I guess I could be put into type 3 with some of my mods. What did you mean by restriction?

[sambb]

Andrew I'm going to be up at Argenton on Sunday around 9pm. Looking at wheels and a HANS 6 pointer for Pete and a seat for myself. Think that might be near the track at Ringwood yeah? I'll flick you a text tomorrow as I may need to take you up on that....just for Bathurst. thx

[teamshaw]

Yeah, I meant type 3 Improved Production. I think ECU tune would put me out of type 2, and would need to run 29mm intake restrictor in type 3. CAMS really don’t like turbos [emoji12]

Might look into this one instead: Home


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[Sydneykid]

Yeah, I meant type 3 Improved Production. I think ECU tune would put me out of type 2, and would need to run 29mm intake restrictor in type 3. CAMS really don’t like turbos [emoji12]

There is no 29 mm restrictor in 3J, the size depends on the racing weight (which includes driver).

https://www.cams.com.au/docs/default-source/manual/race/ra26-group-3j-2019-1.pdf?sfvrsn=4f0e4ee7_5

Single Turbo;
36 mm up to 1225 kgs
37 mm 1226 to 1325 kgs
38 mm 1326 to 1425 kgs
39 mm 1426 kgs and over.

Twin Turbos;
2 x 27 mm up to 1450 kgs
2 x 28 mm 1451 kgs and over

I have no idea how they check weight at the tracks that don't have scales, maybe they will accept a weighbridge ticket.

A 36 mm restrictor will allow around 360 bhp on Pump 98, a bit more on E85.

FWIW I have no idea how I would check for an ECU tune and I'm a National Accredited CAMS Technical Officer. It's an unenforceable reg.

Cheers
Gary

[Sydneykid]

Most guys in Improved Production (A050 is the Category Control Tyre) U2L run 225/50/15's on 7" rims as that is the 3J(a) maximum rim width. Yes, it's a bit baggy but it works. The 3J(b) U2L cars run the same tyre on 8"rims, their maximum width. We run a 3J(a) car (State Championship winner) on 215/50/15's on 7"rims as I'm not a fan of the extreme bag on the 225 (they are 235 mm wide). The A050 Yokohama recommended sizes, width and overall diameter.

205/50R15 86V	5.5 - 7.5	217	587
215/50R15 88V	6.0 - 7.5	229	595
225/50R15 91V	6.0 - 8.0	235	606

Personally I would have no hesitation in running the 215/50/15 on a 6.5"rim.

Best to forget "road tyre" and rim sizing, A050's (and most other R spec tyres) have completely different carcass construction to a road tyre, tracks are different to normal roads (eg; not a lot of potholes) and hence the rules of thumb for sizes don't apply.

We get around 400 to 500 laps (Eastern Creek) of practise, qualifying and racing out of a set of A050's in medium compound. And they are not a lot slower at the end of their life (as in bald) than what they were at the beginning (as in brand new). That's why there aren't lot of 2nd hand ones around, we use them till the canvas sticks out. On a $ per lap basis they are the best R spec tyre I've ever used.


Cheers
Gary

[HaydEn]

Most guys in Improved Production (A050 is the Category Control Tyre) U2L run 225/50/15's on 7" rims as that is the 3J(a) maximum rim width. Yes, it's a bit baggy but it works. The 3J(b) U2L cars run the same tyre on 8"rims, their maximum width. We run a 3J(a) car (State Championship winner) on 215/50/15's on 7"rims as I'm not a fan of the extreme bag on the 225 (they are 235 mm wide). The A050 Yokohama recommended sizes, width and overall diameter.

205/50R15 86V	5.5 - 7.5	217	587
215/50R15 88V	6.0 - 7.5	229	595
225/50R15 91V	6.0 - 8.0	235	606

Personally I would have no hesitation in running the 215/50/15 on a 6.5"rim.

Best to forget "road tyre" and rim sizing, A050's (and most other R spec tyres) have completely different carcass construction to a road tyre, tracks are different to normal roads (eg; not a lot of potholes) and hence the rules of thumb for sizes don't apply.

We get around 400 to 500 laps (Eastern Creek) of practise, qualifying and racing out of a set of A050's in medium compound. And they are not a lot slower at the end of their life (as in bald) than what they were at the beginning (as in brand new). That's why there aren't lot of 2nd hand ones around, we use them till the canvas sticks out. On a $ per lap basis they are the best R spec tyre I've ever used.


Cheers
Gary

That’s a huge amount of laps!

How light is the car?


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[Sydneykid]

That’s a huge amount of laps!
How light is the car?

Medium compound heat treated A050's and more than one car, FWD and RWD. They are properly set up, have all of the right gear and fine tuned every race. At a race meeting we never stop tuning them for the conditions. Weight is between 1,000 kgs and 1100 kgs, with about 300 bhp and they lap at around 1.43's at Eastern Creek (GP). We do 6 race meetings a year, plus 2 practise days with around 60 laps at each. If we didn't rotate them, on a FWD car the right front will do around 250 laps, the left front around 400 laps and the rear pair around 650 laps, for an average of 480 laps for the 4. On a RWD it's a more even spread of wear, but the average for all 4 is similar.

On a badly set up car with average gear they can chew through them in a day. A car that does decent lap times over a race length usually looks after it's tyres very well, so they last a long time. A one lap screamer can do a similar time but the tyres are sacrificial.


Cheers
Gary

[sambb]

So I got my self a pair of aluminium seat mounts from Revolution Racegear. I needed these ones because they are symmetrical. This would allow me to switch the rail (2nd pic) to be able to get the seat right in against the centre console which centres it with the steering wheel ie the OEM seat is hugely offset relative to the floor mounting points. If they hadn't been symmetrical (drilled holes and front vs back of mount heights are often different) then the heights and fwd/back positioning of the seat would have been different on each side when I switched them.
My problem is that the inside centre console side mount will bolt directly in, however on the sill side the mount doesn't reach the floor mount bolt points. The seat mounts are high grade 6mm aluminium. I have a sheet of 8mm aluminium and I was planning on welding or bolting the seat mount on top of that full length sheet so that it would have the extra width necessary (30mm) to reach the mounting holes. I would raise the inside mount by the same height too obviously.

So that's what I need advice on. I don't believe I need a full sheet to be mounted to the floor and then the seat mounts bolted to that because
a) on the centre console side the bolts will go straight into the floor holes b) on the problematic sill side, the 8mm sheet I have will be sitting flush along the full length between the bolt holes and also supported on a centre rib that runs across the middle of the floor pan in that spot. That'd have to be rock solid yeah?

Strong enough????

[sambb]

I just spoke to a local engineer who was a racer as well. You might know of him Gary his name is Andrew and used to run a Silvia with an atmo SR20 in NSW IPRA. He said seat mounts cant be welded as welds can fatigue. They must be bolted. I told him about my idea using a length of 8mm aluminium under the mount to bridge across to the mounting holes and showed him the pic etc and he said that'll be legit/strong/ and pass scrute. So tonight at work, there will be much milling /cutting etc.

[Sydneykid]

The extension/flat alloy plate will be fine, that's what we all do. I use the same thickness alloy as the seat brackets (6mm I think). I bolt the extension plate to the seat bracket with 4 x M10 mushroom head high tensile bolts, evenly spaced. With the heads underneath and the nuts (nylock) on top and with a flat washer under the nut.

Andrew Cherni, used to run a rapid (but fragile) blue S14. Now owned by Jason Hendy, he's made it a bit less fragile but that meant bigger/stronger components (diff etc) so it's a bit heavier. Still goes good.

The further in you can get the seat the better for weight distribution, the bonus is it's a bit safer from side impact. Plus when you put the roll cage in the side intrusion bars will fit

Cheers
Gary

[sambb]

sweet sweet sweet. Two people in the know who say it'll be ok that way so I'm happy. I love having peace of mind!
Yep thats the guy. It was blue in the pics he's got up on the wall.
Yeah I must say when I had the seat dummy fit in the car it felt a hell of a lot safer with the seat surrounding me, well in from the door and much lower too. The steering wheel ended up on the lowest furthest in setting for the pedal reach to be correct at that low height and it all felt great. And it'll be about 9/1/2kg plays 23kg (totals including bases etc) so the left right weight distribution will even out too and overall much lighter.

Oh and Hayden you were dead right re the airbag resister value. It meters at 2 ohms or something but I put a 4.7 ohm 1 watt resister in and its been fine for nearly a week now.

[HaydEn]

Oh and Hayden you were dead right re the airbag resister value. It meters at 2 ohms or something but I put a 4.7 ohm 1 watt resister in and its been fine for nearly a week now.

Good to hear! I haven’t quite mastered the rattling loose thing. So will get the light come on randomly every now and then


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