Is the Auxilliary belt Tensioner really needed?

As above, has anyone ever just got a correctly fitted belt made up?

I wonder how much expansion these could possibly go through and if it would be ok to run a custom size belt instead, taking the aux tensioner out the equation, would it hold up in track use?

I'd like to just run my Water Pump, Alternator and Power Steering Pully off it, along with the Crank Pulley ofcourse,

Anyone know of a company that makes up the custom belt sizes?

It seems Gates in the U.S will be able to sort me out with a custom size, but my reasoning for doing away with the tensioner is this,

I know this is worst case scenario but if it failed, it would likely be in the direct path of my timing belt, there is more chance of mine in particular failing as I have to do away with the little tensioner adjustor to accommadate my different belt after removal of my aircon, so why not just remove it altogether

Worst case scenario of the belt snapping or relaxing while on the track I would discharge my battery then lose power and the ability to pump water and then my ability to steer as easily,

I could offset that with fitting an electric water pump, ok the battery will drain that little bit quicker but at least I'll have less of a deterioration in cooling,

I just wonder how long the belt would last, even if it lasted the abuse of a trackday then it would be worthwhile imho, Goodyear do Gater belts, they look pretty sturdy

could you get the belt tight enough not to slip?

I was thinking of putting the alternator in the location of the aircon, I could use an elongated hole on the bracket to secure the alternator in place and torque it tight

Or if I was keeping the alternator were it is, I could just undo the nut for Power Steering Pulley and stretch it into place before tighting

The Green with Envy car has the alternator in this location, leaves plenty of room for the IC pipe:cool:

You need a tensioner.

If you ever saw a high speed film of how much these belts flap about you would never believe it. Also, standard belts stretch a lot in their service life. The tensioner is partly there to take up the slack.

"Stretch" belts that do not require a tensioner do exist, might be worth enquiring about those. TBH I've never seen one on a long FEAD like the Supra's.

The Goodyear "Gator" belt is designed to be quiet - not necessarily uprated. Its certainly not a stretch belt to my knowledge.

How would a broken belt or tensioner get into your timing drive it it broke?

Lets be honest the whole assembly is not gonna fail, in the pic below if those two bolts that hold the upper shock arm assembly, managed to shear (probably 100k to 1 chance:innocent:) then it may fly off into the timing belt, its not gonna happen...but it could:p

http://www.mvpmotorsports.com/merchant/catalog/jdm/t/supramkiv/p/ttc/02.jpg

I'll check out those stretch belts, if I had an electric water pump the belt would be very small, as the path would be Crank Pulley, Power Steering Pulley and Alternator(in place of the aircon).

Check CRD's, granted it's a drag car and doesnt see daily use, but wonder how long their belts last,

http://caldermotor.co.uk/cars/STK1256_3.jpg

Lets be honest the whole assembly is not gonna fail, in the pic below if those two bolts that hold the upper shock arm assembly, managed to shear (probably 100k to 1 chance:innocent:) then it may fly off into the timing belt, its not gonna happen...but it could:p

Only because some numpty has taken the timing belt cover off in that pic.

Lets be honest the whole assembly is not gonna fail, in the pic below if those two bolts that hold the upper shock arm assembly, managed to shear (probably 100k to 1 chance:innocent:) then it may fly off into the timing belt, its not gonna happen...but it could:p

 

Do you work for Toyota? Did you design the engine? Have you invested millions of £ to back your claim up? I feel the answer is no to all of the above. Its there for a reason and when they designed the engine they felt it was nessasary for it being there.

Mine sheered yet did not damage anything, perhaps you are mixing up your belts?

Just leave it in place it harms nothing.

I wouldn't bother myself, but if you are worried about those two bolts you could always use one from an Auto TT - they don't have that silly shock absorber affair on the belt tensioner.

its not the bolts that worry me, on my old supra the arm on the tensioner broke and when smashing into pulleys, through the cam cover, whole movement caused cam belt to jump 4 teeth. luckerly no whole in radiator.

the give away it was the arm by the way was it was in a few peices, one had the spinning wheel, other bit still on block and the belt was still in one peice!

I wouldn't bother myself, but if you are worried about those two bolts you could always use one from an Auto TT - they don't have that silly shock absorber affair on the belt tensioner.

Interesting as Mark at Phoenix insisted I change my Auto belt tensioner to a 6 speed on the new engine as he had seen issues with the Auto item having the belt come off during spirited gear changes (i have gone from auto to 6 speed), I think I remember him telling be the auto tensioner is designed to operate with the smooth changes an Auto box delivers rather than the more snatchy manual ?

Do you work for Toyota? Did you design the engine? Have you invested millions of £ to back your claim up? I feel the answer is no to all of the above. Its there for a reason and when they designed the engine they felt it was nessasary for it being there.

Thats a pretty pessimistic way of looking at things, Toyota designed the car yes, its a combustion engine, like every other, they also designed it with twin turbos and a couple of cats, should I keep them in too as there were obvious reasons for them aswell....

Back on topic, my 'it could happen' was tongue in cheek, anything could happen, I know its not going to shear, but it was more my extra bit of reasoning to myself,

Is the Auxilliary belt Tensioner really needed? - I suspect no, as long as I can get a belt that can go about its job under expansion, as I need a custom size made up anyhow, I may aswell check out other avenues

Interesting as Mark at Phoenix insisted I change my Auto belt tensioner to a 6 speed on the new engine as he had seen issues with the Auto item having the belt come off during spirited gear changes (i have gone from auto to 6 speed), I think I remember him telling be the auto tensioner is designed to operate with the smooth changes an Auto box delivers rather than the more snatchy manual ?

Yeah seen a few in the U.S go that route,

Mark at Phoenix insisted I change my Auto belt tensioner to a 6 speed on the new engine as he had seen issues with the Auto item having the belt come off during spirited gear changes (i have gone from auto to 6 speed), I think I remember him telling be the auto tensioner is designed to operate with the smooth changes an Auto box delivers rather than the more snatchy manual ?

Can't see it myself. You'd have to making some really bad gear changes for it to have a even the slightest chance of coming off, surely?

I wouldn't bother myself, but if you are worried about those two bolts you could always use one from an Auto TT - they don't have that silly shock absorber affair on the belt tensioner.

That aint actually that bad of an idea if I still wanted to keep the alternator on the exhaust side of the engine, it would take that dampener assembly out of the way

I think they were a couple just cracking and halfing in the U.S when manual conversions where being done, but that could have been a number of factors, fatigue in the part initially being one