Duncan's V37.......race car?

[nickcorr]

Nice big brake kit!! My JDM Skyline hybrid is fitted with the smaller two piston brakes, but basically the same as my V36 370 SP had...

Following to see what is transferable knowledge to my car. 

[Duncan]

I haven't made a lot of progress on this car, per the NSW section thread I've had other stuff on my mind (and to do list...)

On 09/07/2024 at 11:01 AM, soviet_merlin said:

....'m wondering: can you defeat the collision warning systems and other safety features? I've heard they can cause issues when racing modern cars. Don't want the car to start emergency breaking because you are heading into a corner or towards obstacles too fast.

In theory, the AEB is deactivated along with stability control when you turn off traction control...that is one of the main things to check out, they never sorted it on the A45 AMG which looked good on paper but sucked on track. Since the master cylinder is electronic these days I'm assuming I can't just pull fuses if it intervenes

On 09/07/2024 at 9:16 PM, niZmO_Man said:

...Remember folks, this is a luxury car so 1,700kg isn't heaps .

So, on that....luxury or not is really just a marketing term. While things like fundamental suspension geometry will have an impact, it really comes down to how much weight has to be pushed around the corners, and how much chooch it will have.

In production cars regs there is very little that can be done to increase power, especially for na cars. Inlet is standard, exhaust is free from the head (na) or turbo outlet (turbo) back, ECU is free. The big thing is that for turbo peak standard boost can't be exceeded....but that boost can be made elsewhere through tuning/boost control. A key example of this was Evo X ran something like 1.5 bar standard in the midrange, but it dropped off top end from factory; in prod cars they were allowed to run that boost all the way through the rev range which gave them a big top end advantage compared to factory (I suspect the BMW M cars are similar but haven't seen the data).

This is some examples of the cars the V37 is up against, based on current lap records and class points leaders (table sorted by power/weight)

HSV GTS - 436kw, 1880kg - 232

*F80 BMW M3 - 317kw, 1625kg - 195

*Q50 Red Sport - 298kw, 1680kg - 177

*Civic Type R - 235kw, 1430kg - 164

*M135 BMW - 240kw, 1520kg - 158

*Sirocco R - 209kw, 1390kg - 150

*Evo X - 217kw, 1550kg - 140

Toyota 86 - 170kw, 1270kg - 133

(*again, keep in mind the turbo cars likely have a modified power advantage over na under the rules)

So, I'm not saying the v37 will turn up and dominate all, but it on paper it has 3rd best power/weight of the main cars in the category which is a good start. The Evo is the only 4wd on that list so it seems the traction advantage has been eroded over time (noting, that is very track dependent, Wakefield park is 4wd friendly but Bathurst not so much).

[Duncan]

Having done all those calcs.....Infiniti specs lists V37 Red as weighing 1784, and my rego papers say it is 1680.

Seemed like a very reasonable excuse to buy some corner weight scales and check.

It came in at 1774kg with no driver, about 2/3 tank of fuel and all daily driver stuff on board including space saver spare (more to come on that). Unfortunately it is 57/43 front to rear which is not great and will be hard to improve, so those poor front tyres will be working hard.

Corners:

 

Cross Weights:

 

[HYBRID VL]

are you going to basically gut the interior and remove most things like electric window motors and all heavy addons for weight saving?

i have been really interested in this thread and i love it when you post something up.

is adjustable suspension the only way you can modify the weight shift?

[Duncan]

Thanks Matt. Yes, at the end of a long process it will be stripped and caged assuming it all works OK, but I have a few things to sort first; most importantly wheels and race tyres and some track time to see how it goes before I commit too much.

To get there though, first I need to get the spare tyre sorted so I don't need the run flats and can put some decent tyres on either the factory rims or something aftermarket.

So first, size. The depression in the boot is only 660mm wide which limits the height of the spare (for example, the fuga one does not fit)

p9-9 of the factory user manual says Mexico, Middle East and South America got a spare, in 145/70R18 (660mm high). Its not clear if that goes over the Red Sport brakes and in any case I couldn't find a part number so I didn't go genuine. 

Next, the tyre placard for mine says 245/40RF19 (678mm high) but the car has 245/45R19 fitted (704mm). I'm OK with the taller tyres day to day because they help the speedo be a little more accurate (it still reads about 2% over), but they make it hard to sort a proper spare of a similar height.

Then, to sourcing a wheel and tyre. There are spare tyre listings for Infiniti Red Sport in both UK and US, but price+shipping was crazy, so I looked for local alternatives.

It turns out not supplying a spare is the new black, and there are a few options listed for other cars. In particular, Mustang GT comes with big brakes from factory and our friends at ford use the same wheel stud layout as nissan (yes, fitting falcon steelies for burnouts is a potential option...) at 5x114.3

So, I bought this: https://www.ebay.com.au/itm/335566379123?mkcid=16&mkevt=1&mkrid=705-154756-20017-0&ssspo=ormGmo1aTQG&sssrc=2047675&ssuid=dJvnaZ11TB-&widget_ver=artemis&media=COPY. I went to the shop so that I could trial fit it to both the boot space and the car, and they were able to do a little cheaper than the ebay price

That tyre is 135/17R19 which is 670mm high, or about 5% smaller than the other tyres on my car. Guidelines I saw said up to 6% is OK so I'll go with it. 

[Duncan]

And that's where the problems started

So it turns out that despite the Mustang having big brakes, they are lower profile than the Red Sport ones, and the 19x5 + 5 offset Mustang spare fits the rear OK but fouls the caliper in the front.

A 5mm slip on spacer cleared the brake by 0.3mm (according to the feeler gauge) but not only is that way to tight for my liking, there was only about 3 1/2 threads (5mm) for the wheel nut which doesn't meet the rule of thumb as the same width of threads as the diameter of the bolt (12mm in this case)

So, I grabbed a 15mm bolt on spacer that I'll carry and use if the front is flat (not required for the rear). It gives plenty of clearance and fits fine,  https://www.ebay.com.au/itm/166584112103

Unfortunately they come with 19mm nuts for the spacer to hub so I need to carry a 21 to 19mm adapter in the car as well. https://www.ebay.com.au/itm/194044924912

And final complexity, although the PCD for Skyline and Mustang is the same, the hub bore diameter is not. While that wouldn't worry me too much for general wheels, I wasn't happy with the spare only being located by the studs, so I bought a hub adapter as well to centre the wheel properly. https://www.ebay.com.au/itm/221759295514

All in all, a bit of a pain, but better than being left with a flat one the side of the road...

[Duncan]

So, that gets me a usable spare front and rear so I ditched the run flats and got a set of (chinese) Pirelli Powergy 245/45R19 to replace then (the rears were down to the wear markers so it was due.

Interestingly the run flats were 31kg per corner (wheel and tyre) and the regular tyres are way lighter at 26kg per corner. Yes, 20% lighter in the same size on the same wheel!

[Duncan]

Next was to address securing the spare. I don't think it will go anywhere unless I roll the car (which I'm not intending to do until *after* i start race/rallying it  )

While there are quicker options if I had a hoist (like welding a nut under the floor and securing through the wheel stud hole  or even a central bolt wide enough for the hub bore, I went the easy option on the floor.

I took 2x stainless M6 eye bolts

And put 2 M6 rivuts through the floor, the secured the wheel with a very short rubber strap

There is nothing under the floor to worry about on my car so I just picked a flat section so the rivnuts would sit nicely.  I did initially drop the exhaust heatshield but where I actually put the rivnuts cleared that anyway

*flicks strap* "that ain't going anywhere!"

[Duncan]

Now, thanks to sonicii, onto the uneven floor from a tyre sticking 100mm into the boot space.

I looked into options to raise the floor to the level of the tyre, and ended up going Extruded Polystyrene (XPS). EPS is what I normally think of as polystyrene, the annoying tiny balls that get glued into a flat sheet but XPS is quite different, much firmer and doesn't crumble if you touch it with anything. I also looked at things like heavy duty seating foam but XPS seemed like the right way. I picked up 3x 1200x600x50 sheets for $40ea.

Initially I was looking for 100mm sheets because I needed to make up a 100mm gap, but as it turned out 50mm was available, much easier to work with and made it simple to store the tools

I used a simple 15cm foam cutter to make the shapes. With some practice I was able to make reasonably clean cuts but I don't think Clark Rubber are going to be calling me to offer a job. https://www.ebay.com.au/itm/405092315205?var=675175481574

First layer in place, 3 dimensions are tricky!

Second layer in place, bringing it to level with the top of the spare

Cutouts in the top layer for the tools

With floor back in place, nice and flat with 100mm stolen but no real impact on usability

[The Bogan]

My only regret with the NC MX5 was no space for a spare, even a space saver doesn't fit in

I do have a couple of those puncture repair spray cans, but if I get a large puncture, or sidewall damage, I'm screwed until a tilt tray turns up

I'm thinking I might get one of those 4WD style of puncture repair kits that have that rope stuff and glue, whilst it will kill any hope of saving a tyre, it might help getting me out from some backwoods road far enough to find a actual tyre shop if the first can of tyre fix doesn't work

I'm keen to see how your new toy pans out Uncle Duncan, I'll be moving to the Highlands next year, you'll need to shout out if your heading to Wakefield, whilst I've lost my balls for happy laps, I still love watching those that can

[GTSBoy]

Am I correct in thinking that even if you flat a rear, you'll have to fit the spare to the front anyway? I'm thinking that the LSD will thank you for not inflicting a massive permanent speed difference on it.

[Duncan]

2 hours ago, GTSBoy said:

Am I correct in thinking that even if you flat a rear, you'll have to fit the spare to the front anyway? I'm thinking that the LSD will thank you for not inflicting a massive permanent speed difference on it.

I'm sure you're right....but I bet when I'm at the side of a narrow road, running late and swearing in -5 temps that I just put the spare on the back and take the chance that it doesn't kill the LSD

@The Bogan.....good luck with that....we were moving to the Highlands too until we found out the prices for everything that didn't have some major issue (asbestos contaminated fill down the back fence was my favourite)....so here we are in the beautiful Tablelands instead  No regrets from us though

Except rural roads seem to be littered with self tapping roofing screws

[PranK]

Damn, thats a tidy solution. Looks great! 

I carry a Slime repair thing with the air compressor since I ditched my run flats. It gives me a little bit of calm but in the past any blow out I've had was way worse than Slime could fix. 

I don't have any space under the floor at all in mine so I couldn't do what you have. Lots of folks just strap a wheel in the boot as out of the way as possible. 

Nice work! 

[Blakeo]

Hey Duncan, 

What you did with the boot is mint, I'm going to do the same with my R33. 

Do you no longer like the R-Chassis?