Considering a Cossie GT86.....

[Muckyman 1]

Hi all,

just joined up as I'm considering a Cosworth supercharged GT-86 as my next run around - although there's not many of them for sale at any given time.

 

Am currently driving a pristine JDM Toyota Supra TT (if anyone with a Cosworth Supercharged '86 fancies a swap, drop me a line)  :-)

Previous cars have included (in no particular order)...

BMW Z3M, VX220 (supercharged), MX-5 (turbo), MR2 SW20 Turbo, MR2 AW11 (x3), Clio 182, TVR Chimaera 450, Mitsubishi Evo V, Celica GT-4 (x2), 350Z, Audi TT etc etc.

 

Have considered a GT-86 Cosworth conversion for a while now, and joined up to look into owners real world experiences and to check common issue / upgrades etc

 

cheers

Michael

[Leeky 84]

Just curious, but did you end up getting one?

Was tempted by the Cossie Supercharger myself, but for the kind of extra torque/power/weight added to the car you’d need bigger brakes, better cooling, better suspension etc to do it right and it soon becomes an expensive final package.

I’ve instead decided to stay NA. But keen to hear from those that have gone Cossie SC to see if they tell me good things to change my mind

[Subota Boy 402]

The thing that appealed to us about the Cosworth package was that the test car that we drove had standard brakes, standard wheels with primacy tyres, standard suspension.  Only upgrade apart from the S/C was the exhaust.  We both ragged that car and that was when my wife said I was allowed a supercharger, because it would not require all the additional costly upgrades, and she felt that it did not spoil the way the car drove.  It just complemented the original DNA.

After a year running  with that layout, I had found that, trying to do a 0-60 time was a massive failure with std tyres as traction was difficult to apply, even with a spare wheel in the boot.  Clutch smell lasted for a while too!

I also had occasion to brake hard under full acceleration once, and the standard brakes had a hard time dealing with all that forward thrust.  Other than those 2 aspects, the std car coped very well with the S/C.

[Ade 517]

The standars brakes are actually off a subaru wrx and have no problems on the road with 300hp and a mild pad upgrade.

The suspention is also excellent for what is it and can handle a grippy tyre very nicely. Most poeple only change to colivers to reduce the arch gap.

On track then yes everything is stressed harder. I ran stock brakes with project mu clubracers and couldn't fade them after 30mins. More of a race pad though so you'd expect them to be amazaballs.

For a road car all is recommend changing when adding the SC kit is a mild pad upgrade to handle a bit more heat before fade, decent tyre like PS4s and change the oil to 0w30 millers nanodrive.



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[Willtl 54]

I've been thinking about the Supercharger because I feel the BRZ needs a fair bit more power. The problem I have is that I can't change the exhaust because my head can't cope with anything louder than stock.

Not sure if anyone can answer this but interested to know whether the Supercharger has any significant impact on noise (even with a standard exhaust) as I can't risk an expensive upgrade that loses me money through scrapping or selling the car due to it becoming unusable.

That aside, are there increased maintenance costs and will I notice a decrease in MPG through normal driving?

The other thing I'm considering is just trading the car next year either for a 2.3 Mustang or a 280HP Alfa Giulia.

[Rich 378]

On 02/06/2018 at 8:37 PM, Ade said:

The suspention is also excellent for what is it and can handle a grippy tyre very nicely. Most poeple only change to colivers to reduce the arch gap.

I think I got more out of the camber adjustments than the coilovers themselves.

14 minutes ago, Willtl said:

I've been thinking about the Supercharger because I feel the BRZ needs a fair bit more power. The problem I have is that I can't change the exhaust because my head can't cope with anything louder than stock.

Not sure if anyone can answer this but interested to know whether the Supercharger has any significant impact on noise (even with a standard exhaust) as I can't risk an expensive upgrade that loses me money through scrapping or selling the car due to it becoming unusable.

That aside, are there increased maintenance costs and will I notice a decrease in MPG through normal driving?

The other thing I'm considering is just trading the car next year either for a 2.3 Mustang or a 280HP Alfa Giulia.

Supercharger is a couple of decibels extra noise. It won't be crazy at all with the stock catback.

MPG will probably be decreased a little, though how much you can alleviate that through moderating your right foot I'm not sure. Most folk with superchargers will use the extra power, which obviously uses extra fuel.

I wouldn't trade it for the Mustang personally, the extra weight will dull things down too much, without even the V8 to make up for it.

Something to consider, a supercharged GT86 (280 bhp) is 224 bhp/ton, the 2.3 Mustang is 194, the Giulia a little over 200. The GT86 has the best handling chassis of all three too (lightest and lowest).

[Willtl 54]

From what I read, the Cosworth super charger with stock exhaust is 240bhp which I think will be slower than the 280bhp Giulia.

 

 I found the Giulia more comfortable too.

 

 

 

 

[Lauren 2259]

4 hours ago, Willtl said:

I've been thinking about the Supercharger because I feel the BRZ needs a fair bit more power. The problem I have is that I can't change the exhaust because my head can't cope with anything louder than stock.

Not sure if anyone can answer this but interested to know whether the Supercharger has any significant impact on noise (even with a standard exhaust) as I can't risk an expensive upgrade that loses me money through scrapping or selling the car due to it becoming unusable.

That aside, are there increased maintenance costs and will I notice a decrease in MPG through normal driving?

The other thing I'm considering is just trading the car next year either for a 2.3 Mustang or a 280HP Alfa Giulia.

A supercharger will make the exhaust louder. A turbo will make it quieter. Maybe consider that option? Why not just keep the stock exhaust? It'll be pretty quiet that way whatever you do.

You will definitely notice an decrease in mpg. More power= more fuel. It has to come from somewhere.

I'm not particularly impressed of your choices for a next car.

[Willtl 54]

A supercharger will make the exhaust louder. A turbo will make it quieter. Maybe consider that option? Why not just keep the stock exhaust? It'll be pretty quiet that way whatever you do.

You will definitely notice an decrease in mpg. More power= more fuel. It has to come from somewhere.

I'm not particularly impressed of your choices for a next car.

I will have to keep the stock exhaust, changing it is not an option as my head can't deal with any decibel increase.

 

I know putting my foot down will increase fuel usage, but my question really was whether under normal running (i.e. not excessive right foot usage) fuel usage would remain similar.

 

Fortunately you won't have to drive my next car so it should be OK.

 

[surrey86 352]

On 6/2/2018 at 8:37 PM, Ade said:

The standars brakes are actually off a subaru wrx and have no problems on the road with 300hp and a mild pad upgrade.
 

I had one of the Impreza WRX's with the same front calipers and around 260hp and they were pretty borderline tbh, upgrading to STI Brembos was common.

[Ade 517]

I had one of the Impreza WRX's with the same front calipers and around 260hp and they were pretty borderline tbh, upgrading to STI Brembos was common.

Just becuase it was common doesnt mean a good pad wouldnt work. Much like alot of people that go to forced induction and feel the need to go to bigger brakes for road use on our cars.

Also 260hp and 1400kg? Vs 190hp (okay 220hp with few bits) and 1250kg.

I can see how a 325mm disc would help with that weight.

BBK only required if you do trackdays imo.

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[surrey86 352]

I never meant to imply a pad couldn't improve things, but the front brakes were a very well known weak point on the WRX. In my experience of driving one for three years, they were just about adequate for road use on my PPP model. 

The Impreza wasn't even a heavy car, a tank of fuel is half the difference. Add stuff like a supercharger and a sound system and an 86 isn't that far off.

[Ade 517]

You must drive pretty hard on the road then. I didn't think there was a problem on the road with stock brakes and cossy.

Mine was 1255kg with half a tank before the sound system was installed. That with cossy sc kit, Ohlins and cat back.

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[Lauren 2259]

5 hours ago, Willtl said:

I know putting my foot down will increase fuel usage, but my question really was whether under normal running (i.e. not excessive right foot usage) fuel usage would remain similar.

 

It will use more fuel. Such things are inevitable. 

[Ade 517]

Fwiw I noticed motorway fuel eco drop more when switching to AD08Rs than adding the SC kit.

I still get around 36-38 on long runs in the summer if I stick to 3k rpms

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[MartinT 514]

On the noise front, have you tried blocking the sound tube into the cabin? That'll make the car even quieter than stock.

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[Willtl 54]

On the noise front, have you tried blocking the sound tube into the cabin? That'll make the car even quieter than stock.

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Yes, but unfortunately didn't give me the relief I was hoping for.

[Benoxen 0]

On 7/6/2018 at 2:04 PM, Willtl said:

I know putting my foot down will increase fuel usage, but my question really was whether under normal running (i.e. not excessive right foot usage) fuel usage would remain similar.

As I understand it (might be wrong) but the extra power comes from having a better fuel/air mix. The fuel pump and injectors remain the same so if you drive it normally it shouldn't use any more fuel. 

[Kodename47 446]

1 hour ago, Benoxen said:

As I understand it (might be wrong) but the extra power comes from having a better fuel/air mix. The fuel pump and injectors remain the same so if you drive it normally it shouldn't use any more fuel. 

Under cruise the ECU targets a set AFR, 14.7:1. While a bypass valve will be open so there won't be any positive pressure you are still having to spin the compressor which takes away some economy.

[Rich 378]

On 06/07/2018 at 4:57 PM, maurice said:

The Impreza wasn't even a heavy car, a tank of fuel is half the difference. Add stuff like a supercharger and a sound system and an 86 isn't that far off.

How much fuel are you carrying?! 75 kg of petrol is 100 litres, which is about double what a GT86 will carry without jerry cans.

[surrey86 352]

Impressive delayed pendantry 

[Benoxen 0]

On 9/10/2018 at 8:05 PM, knightryder said:

Under cruise the ECU targets a set AFR, 14.7:1. While a bypass valve will be open so there won't be any positive pressure you are still having to spin the compressor which takes away some economy.

true say bro