MG trackday Z-car dilemma

[Wicker Man]

I bought an MG ZS 180 for use as a trackday car last year, which was fun. I was planning to loose some weight from the still standard cars 1285Kg over the winter but haven't yet had the heart to rip out the perfectly good interior.

Plus a ZR 160 is only 1145Kg to start with, so could probably be under ton without too much effort, so I've just bought this:



which has an even better interior and a perfectly good VVC engine. But I really fancy a (heavy) tomcat conversion. So what's it to be?

ZS 180 Standard/stripped out
ZR 160 standard/stripped out
ZR 200bhp tomcat standard/lightened?

Target date is Marham at the end of April and it's freezing in the garage!

[Wicker Man]

They both handle very well but the ZR is more chuckable, probably due to the lighter weight.

[Wicker Man]

Thanks Roman. There's some useful stuff here too:
http://forums.mg-rover.org/showthread.php?t=378420

I'm a big fan of the Rover Turbo and dropping a T16 in a ZR looks pretty straight forward. So today I bought this kit of parts:





The body work is past its best but the engine runs sweetly. And the 16" alloys might be a useful alternative to the 17s on the ZR 160.

Next, I just need to make some space in the garage!

[Wicker Man]

Thanks for your comments guys.

I managed to give the Tomcat a proper look over at the weekend and it really is tatty inside and out. It has an MoT but God knows how. (It's the first time I've seen an advisory with three exclamation marks!) To be honest, I'm not certain that the engine is up to trackday use, and there is some DIY plumbing on the boost circuit that needs looking into.
So the engine swop can go on the back-burner for a bit while I prep one of the Z-cars.

I had a ZR 160 as my main car for ~3 years. It was the best handling car I've had, although I never took it around a track. Before that I have a Turbo tomcat for 8 years; fantastic torque, bulletproof engine; and a hedge-seeking-missile on cheap tyres. Where are you now M908ACL?

I am accutely aware that I could easily bugger up the handling of the ZR so will proceed with caution. I've read that the K series weight 95Kg and the T series 170Kg, so I need to loose ~75KG from the front half of the car - just to stand still. I may have to lay off the pies a bit!

So Plan A is to use the ZR with the VVC (initially) but loose the fog lights, air-con, move the battery to the boot (maybe fit a small Redflash Gel type), and swop the seats for these lightweight buckets that have just arrived:



I quite fancy the idea of acylic windows too, but that might wait.

Edited by Wicker Man on Tuesday 31st January 13:54

[Wicker Man]

Roman said:

Have you considered building a VVC Metro/Rover 100? Standard 3dr 100 is only 815-885kg to start with
http://www.talonsportscars.com/100rt.php

Yes, I've seen that Metros can make very effective trackday cars. In particular, it was being overtaken by Fast Eddys' one that got me thinking:





I noticed that the lightening extended to removing the bonnet stiffeners and replacing the inner door handles with wire loops. The K-series engine apparantly has a solid cam. No idea what the power was, but it sounded very healthy screaming down the staights.

But Metros don't do it for me, so a Z-car it is.

[Wicker Man]

I took the ZR round to the local weighbridge today:



The weighbridge resolution seemed to be 10Kg and I was assured the accuracy was spot on.



I also tried the front and rear split weights; these two add up to the total, so the numbers can't be far out. Maybe I'll try the corner weights next time. The numbers were:

Front: 700Kg
Rear: 380Kg
Total: 1080Kg



So after subtracting 10Kg for a 1/4 of a tank of fuel, I recon the current weight in completely standard trim is 1070Kg. That's over 200Kg lighter than the ZS 180 and a full half tonne lighter than my old ZT 190!

[Wicker Man]

Thanks for the tips Eddie. I was hoping to have tried it out at the Marham trackday by now but sadly that was cancelled. And RAF Wittering clashes with Glastonbudget! Ho Hum.

Kermit power said:

You don't seem to have subtracted the weight of the snow!

Good point! Plus, I think there may be a couple of kilos of grit jammed behind the sill finishers etc. My new seats have saved 10Kg apiece, thanks largely to the DIY subframes; What a pain fabricating those was - some mechanical skill required my a**e.

(The OH was not in the car when the above weights were taken btw - probably best not to go into that!)

[Wicker Man]

Great pic Leigh, but how come your wheels are still touching the ground? - or have you just landed?
What does yours weigh? I think 800Kg would be going some, even with the paint removed! I been weighing the various bits and bobs and am surprised how light everthing is. Even the rear seat base is only a couple of kilos.

[Wicker Man]

fast eddys said:

Plenty of other oportunities to have a play. Woodbridge with Javelin on the 19th.Eddy

For some reason I thought Woodbridge was a sprint venue. I now see that its a really twisty circuit and that would suit a light and nimble ZR... (with bugger all torque!)

I was just about to book, then remembered that I've got an important reunion tomorrow, so an early start on saturday might be 'logistically difficult'.

[Wicker Man]

Well, the ZR 160 had its first trackday outing at last! The venue was a warm and dry Woodbridge airfield in Suffolk. Javelin has once again set up an excellent circuit. Plenty of challenging twisties but still enough straights for the more powerful cars to get by. The high speed chicane leading into a sweeping 180 at the end of the runway was fun, as was the very complex complex just before the exit.

In the end; preparation consisted of: oil change, check over, bucket seats and harnesses, new disks and pads, four wheel alignment, Mot, and the removal of 'loose articles' - ie mats, parcel shelf, rear seats etc. I arrived with four good tyre albeit the random rubbish the car came with - three different makes, none of which I'd heard of!

Having clocked 130 track miles, mostly in 2nd and 3rd gear and at 5-6000rpm, I'm pleased to say that the car ran faultlessly. (Others in the paddock were less fortunate - wheel bearing failure, broken drive-shaft, overheating/HGF?, engine mounts probs, etc)

The verdict on the ZR 160 in a word: Brilliant! The sheer chuckabilty of the car meant that by the afternoon I was circulating at a respectable rate and even passing other cars. (Last year in my ZS180, I was usually the slowest car on track } Being able to carry speed through the corners certainly compensates for modest power – I can certainly see the merit of adding lightness.

So the ZR 160 has passed its' trackday audition with flying colours. The next outing is Marham on 18th August. With its two Vmax straights the ZR might be found wanting for more power, so I'll not put the Tomcat in the classiieds just yet. And in case the VVC objects to spending another day at high rpm, the ZS is on standby.

Here's what the tyres looked like at the end of the day:



To be continued...