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260DET

The Z31 Project - Race Car

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Pics are always good so below are some taken with the engine and transmission still in which show the huge amount of space for big tyres in the wheel wells. Those are the race Hoosiers off the 280 which bolt straight up with no clearance problems, F 9" rims, R 9.5". I'm bloody rapt, so much space for bigger wheels and tyres.

 

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The project itself should start next week with filling in the T top openings and adding some structural bracing across the top of the door openings.

 

Seeing that it's a turbo model the brakes look like they have Z32 rotors, just need some decent calipers. One thing I've learnt is that suitable brake pads are very important, proper race ones will withstand extreme temperatures and actually brake much better. Having stock rotors means that they are not expensive to replace too. The rear axles are second generation CV jointed and for the R200 diff a reasonably priced Quaife LSD centre is available. Keeping all the stock type suspension, the rear will be interesting, I have some fairly dramatic mods in mind to get the semi trailing arm setup working satisfactorily

 

So the project is going to be stock based except for the engine and auto trans. 

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Good looking Off Road racer spec suspension in those pics!!!

You dont like the very strong, braced ally calipers these cars have?

Same as fitted to R32 GTR, but rotors and calier throat a bit narrower, therefore caliper bridge is stronger!

Save your $$$, stick with the stock clutch pack type LSD, but replace two plates each side, with the slightly thicker Isuzu Rodeo plates, you'll be able to set a higher breakaway torque, without verstressing the stock Belleville cups

 

You still sticking with those QFM Race pads, the ones with a high metal content, that absorbs mousture from the air, and then they turn to crumbled Fetta cheese, at the next meeting???

( same as Ferodo 2500's do!) BSM Motorsport in Murrumbateman ACT might do Pagid RS's for these, r se what the R32 GTR fanboi's use!

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This one has sliding calipers both ends Jason, I suspect that Z32 calipers will fit although I might go for better ones in the front. Gave up on QFM pads long ago, will be trying Project Mu club racer pads on the 280 next to replace the excellent Carbotech's, the retardation these sorts of pads give is something to be experienced.

 

You wouldn't be referring to the semi trailing arm suspension Gordo, eh eh :) It's going to be interesting but I love a challenge, the easy way out would be to replace the lot with a S chassis setup. Otherwise I'm quite confident it will all turn into a decent race car, certainly bang for buck wise. Fibreglass doors by themselves rip out weight.

 

Generally, the way S30 prices are going I think that projects like this will become more common, unless a S30 is being built for a specific purpose like Group C or P to P it will become just too expensive to justify. There should be items of general interest in this build, like the T top fill in, full wiring kit installation, electric steering and so on. Hope so anyway.

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the retardation these sorts of pads give is something to be experienced.

 

 

As if you needed anymore Richard.

????

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I run Project Mu H16-03s in my JZZ30 Soarer race car and they are freakin unreal. I think you will be very impressed with them. Apparently the RC09 has a similar bite but can't sustain the heat for long periods (but i'm talking multiple hours). I'm going to run them in my 400rwhp Rx7 for doing sprints.

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I see that those Mu H16-03's are a full race pad, a bit hard on the rotors?

 

Tip for anyone thinking of a Z31 project, get the Series 2, for a start the guards are wider and will take wider wheels. Want wider still? The S2 below with flares looks the biz. And finally I noticed that the Nissan sponsored Z31 which used to race in the US, Paul Newman used to drive one, was a 2+2. Z32 too, apparently the little bit of extra weight was offset by better corner stability from the longer wheelbase.

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I run Project Mu H16-03s in my JZZ30 Soarer race car and they are freakin unreal. I think you will be very impressed with them. Apparently the RC09 has a similar bite but can't sustain the heat for long periods (but i'm talking multiple hours). I'm going to run them in my 400rwhp Rx7 for doing sprints.

aren't these the brake pads that crapped themselves at Wakefield, and allowed you to sail off into the kitty litter and smack the wall?

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They aren't hard on the rotors at all in my opinion. Raced for 16 hours and the rotors were still in roadworthy condition. Could have done another days racing if you wanted and they were just DBA T3s.

 

aren't these the brake pads that crapped themselves at Wakefield, and allowed you to sail off into the kitty litter and smack the wall?

 

It wasn't a problem with the pads, it was a combination of a faulty set of KU36 tyres that made the ABS favor one of the brakes (front left at wakefield) and it simply ran out of pad on one side and the pistons fell out of the caliper. The pads on the right hand side were fine. The tyre carcass failure caused a heap of problems and we didn't figure it out until the next round at QR. It was only our second time running the car at QR so the first time at Wakefield we didnt know what was normal.

 

 The pic of the tyre is after about 10 minutes of racing.

 

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Kumo tires, worst track tire ever, can NOT handle the heat. I've had bad experience with them. Will never buy again. They are Cheap, and there's a good reson for that.

 

The pic of the tyre is after about 10 minutes of racing.

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Kumo tires, worst track tire ever, can NOT handle the heat. I've had bad experience with them. Will never buy again. They are Cheap, and there's a good reson for that.

The pic of the tyre is after about 10 minutes of racing.

THOSE are the cheapest crappiest fooly sic bro Kumho "sport" tyres you can get!

Try some V710, or V70A , you'll change your thinking very quickly!

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Bad luck there Gordo, that would thoroughly piss you off :( Hankook's and Yoko's seem to be the semi of choice up here for lap times and heat cycles. There is a new semi available but only in 18" so far, Nankang's from Taiwan. Hella cheap and they work well apparently.

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I was running KU36s due to having to have something that had a treadwear rating worse than 180 so basically road car tyres for Lemons. Gordo were those 245s 45 17s by any chance? Our 255s seem to be fine with it but went through 3 pairs of 245s and they all did the same thing... Grip from them isn't a patch on a semi, but i dont think they are marketed as such either.

Edited by d3c0y

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Yer guys, don't want to high jack the thread. I wasn't expecting great grip or time from them, (tires). But didn't expect them to go out of shape. Haha. Cheers.

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Still ripping junk/weight out of it, somewhere under there is a half decent body with plenty of stiffening potential, it has enough wiring in it to connect up a small town. Anyway, besides the boring stuff I've been thinking and researching interesting things, like what mods to do to the dreaded semi trailing arm suspension. It could be modded the usual ways but where is the fun in that? 

 

So how about copying the Group C Bluebird arrangement which itself was derived from the OE semi trailing arm setup. What is that I hear you ask? Susprog representation below.

 

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Why dont you just leave it all as is, build it up, go and play in it, then see what it needs, to get it better.

The USA SCCA and old GT boys are all over how and what to do. She aint rocket science, unless you wanna play Space Cadet, and go shooting off into orbit!

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Jason, the best STA suspension mods I've seen are made here in AU for 1600's, there is not a lot available in the US for the Z31 that changes the operation of the suspension like is available for P cars and BMW's. There is no rush for this build so I want to get everything sorted as much as possible, I hate doing fabrication mods after a car is built too, build it properly in the first place so that the basics are right and only bolt on stuff is maybe required later, like say a brake upgrade.

Edited by 260DET

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Have ordered a set of race spec coilovers made specifically for the Z31 so I'm pretty excited about that, other than bolting them in the fronts have to be welded onto the lower part of the stock struts. The term 'race' is over used these days but these seem to be real, comparison dynograph charts with Ohlins below, what do the experts think?

 

 

Edited by 260DET

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Proof is in the pudding I guess. Really at the end of the day it comes down to the fact what of what does it need to be better than? Even if they are 1/10th slower than the Ohlins but half the price who cares? I'm sure they will be great.

One thing I realised when doing sprints with my 350Z was that I could have spent a million dollars modifying it or just try and get the best possible time I could from the stock setup.

All that changed would change was the lap time on the print out.

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The Ohlins has 15 more clicks..... That's gotta be better right?????

 

The shock dyno shows that the dampers work, but what about your spring rates, heights, geometry, wheels and tyres used and so on.

 

Suspension set up is part science, part common sense and bark black magic voodoo stuff that only level 15 and above wizards like Gandalf understand. 

 

You really need to look at the set up as a whole rather than take one piece in isolation. What may work well for one person may not work for someone else.

 

Unfortunately Richard you are on a journey of discovery and wonder on your own as not many people have tracked the Z31, and as you have found out there are bugger all off the shelf parts.

 

A bit like my old 180B 3J car, plenty used for rally, but no one really circuit raced them and with the rules I had to run to was rather limited in what i could do, so ended up with very different suspenion to any other 180B in terms of dampers and springs, something like 900lb springs in the front and 1200lb springs in the back to control the trailing arms on the bum of the car while running the standard 5" wide wheels at the standard ride height.

 

When we moved to IPRA spec, the ride height dropped, the wheels went up to 7" wide and the spring rates only got higher as we cut the coils to help control the trailing arms again.

 

My only advice, do the sensible changes and make lots of notes, get the best out of the car and you before making another wholesale change, so when the car goes better or worse you will know whether the time was due to the set up or you.

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