What upgades?

[Garth]

Am planning to have work done to my Sigma 125 in the Autumn. Have pretty standard set up with adjustable shocks and 15" CR500's. Hope to have the Engine re-worked to head to somewhere near 190bhp.

Also considering the following;

- 13" wheels for track days - will lower the car a little but this should be ok on tracks?

- Have Sierra diff which is quiet enough, but 'backlash' not too good - thinking of converting it to LSD - would appreciate advice on ratios - see lots written on the forum but do not really understand where to go with this

- Have 5 speed box - also see many posts about ratios but also not sure where to go with this

- will probably stick with wet sump with some modifications?

- not convinced it is worth going to upgraded brake callipers, probably just better pads??

 

Generally do 4 or so track days a year and as much blatting as possible. Cheers

[MartinS]

I'm sure this will be contentious, but in my opinion I'd focus on stopping as well as going faster. The AP 4 brakes are very good, so I'd personally suggest you spend the money on that at this stage rather than things like an LSD or different gear ratios. Getting the engine better protected for track days is also important, I assume you can get an Apollo for the Sigma engines? If you go that route, make sure you also get the one way valve from Think Automotive, a quick tech search will throw up the parts.

 

Otherwise have fun! I've spent a small amount on my car upgrading it from a very basic spec, and tuning the engine was the most expensive and in the end the most problematic thing to do

 

M.

[myothercarsa2cv]

If I was in a place to spend a few grand on my car, it would be big brakes all round, probbably hi spec, dry sump and LSD. Don't think you need any more power just for four track days?

[Mankee]

A proper geometry setup (if you've not had one done already) is great value. I've found standard calipers to be adequate for track use, with uprated pads. There's always room for improvement in them though!

[Drumster]

I'm sprinting and hillclimbing with 190bhp, standard brakes and uprated pads and MC and that works well. You don't need to throw money at brakes.......

[Jonathan Kay]

For driving on public roads and for track days isn't good instruction the upgrade that provides the best value for money?

 

Competition might be different, but I wouldn't know.

 

Jonathan

[Garth]

I will be spending some money on tuition, just feel that it would be good to have some more power and make sure the rest of the set up is optimum? Do feel 1st runs out very quickly?

 

Had some time with an instructor on a track day earlier this year - has plenty of experience with Caterhams ans he felt that the standard callipers were generally good enough for track days!?

 

Caterham 'flat floored' and set up the suspension for me.

[Jonathan Kay]

Quoting Garth: 

Had some time with an instructor on a track day earlier this year - has plenty of experience with Caterhams ans he felt that the standard callipers were generally good enough for track days!?

More on that here

 

Jonathan

[Richard Price]

If you're going to get 190bhp out of a sigma, then its likely to be pretty peaky and thrive on revs.

I'd say that a six speed box is likey to give a set of ratios that suit such an engine.

 

A modified 5 speed is likely to give you a fifth gear that is still too high unless you have a lower diff ratio as well.

[Grubbster]

Sounds to me like you're on the right track if you want to get on the slippery slope of upgrading!

 

13" wheels are best and more choice of tyres available, you can always raise the car on the dampers for more clearance, best to get it set up properly.

 

If you modify a 5 speed you can fit a lower 5th as well as a longer 1st. If you switch to a 6 speed you'll probably want to change diff ratio as well. SPC or BGH are worth talking to about gear ratios and the costs involved to change them.

 

LSD will help with traction out of slow corners (and of course donuts if thats your thing 😬).

 

Upgraded brakes give you better feel but unless you're repeatedly braking hard from very high speeds then the standard brakes are quite well up to the job, better with decent pads.

 

I don't know about the Sigma when it comes to wet/dry/apollo necessities.

 

If you want to go faster around a track though fit some decent tyres and spend money on good instruction

[Garth]

Trying to find BGH and SPC contact details - is it BGH Geartech in Kent? Ditto for SPC - is it SP Components Ltd in Redditch?

 

[Tony Whitley]

Yes to both.

[Garth]

Thanks