is it worth it to switch the front diff from suretrac to helical?
 

New member here from Australia, figured since I signed up I should ask for advice.

I have a bugeye sti, I have the opportunity to purchase a OEM STI helical front differential to be fitted in, but the costs with that and the labour costs are not cheap.

My current drivetrain setup is the stock suretrac differential in the front, cusco tarmac gear (35f/65r split open diff) in the center, and OEM 2011 STI helical in the rear.

The car is mostly a daily driver, I do plan to attend some track days, but have not yet had the time other than the drag strip. Car really doesn't see much gravel or off road use, only really if the roads I am going are not fully paved, but no motorsport that isn't on tarmac.

My gut feeling is it might not be worth the upgrade since the car is very heavily rear biased, and even switching from the suretrac rear to the helical, the only major difference was how smooth it was, but I wouldn't call it a major improvement even under hard driving. The front still pulls around turns, and I can feel the differential working but I'm not sure how much of an improvement if any a helical differential would give me over the suretrac.

Any advice would be greatly appreciated.

Welcome to Scoobynet from the UK. Just found this it's been a busy week. Helical would be better and what I'd recommend if you had an open set up. BUT it isn't worth the cost of the upgrade. It won't be that much better to justify it.

Good luck, happy to help anytime, call if I can helpm in the future.

David APi Impreza [ Was once connected to APi in Melbourne - not any more though ]

www.apiimpreza.com

Hey David,

Thanks for the reply, I had a feeling that it wouldn't be worth it, as I feel the suretrac isn't being overwhelmed by what I use it for.

Cheers!

Mine was great when new, but after about 30,000 miles it felt weak and useless. Went to a late model DCCD set-up.

dunx

Got over 112K Km on mine...still feels strong to me, but in my car it's the rear that will break loose not the front...and when I replaced the suretrac in the rear with the torsen, it was a very minor difference, nothing major. I'm curious to see why people think it could feel weak and useless after x amount of miles, looking at the design and schematics on how a suretrac is built I find it very hard to believe that it would get weak over time.

FYI, I've scoured and used my google-fu and this post and another post of yours from a couple years ago are the only posts I can find of anyone saying that their suretrac feels weak after x amount of mileage or even is less effective. This includes all the north american, australian, and european subaru forums. However, my google-fu may not be that great.