Tuning the VR6 continued...

[Chris VR6nos 0]

There's been a lot of debate of late regarding the lowly VR6 12v engine and what constitutes a well tuned or 'Race' engine.

 

I did a thread some time back with a shopping list of juicy bits you could use to tune the VR6 engine, however there was one main thing that was missing, simply because i couldn't find any at the time!

 

These are essential for tuning the engine or in fact any engine really.

Well here is an example of these illusive things.

 

VR6 Vernier timing gears

 

If you find and better or sexier looking ones, or indeed and cheaper ones then post up your findings

These are part of the sharp end of tuning and a way of getting it 'exactly' right!

 

 

 

Chris

[Claret Badger 0]

nice but not essential

 

A hot pair of cams and a branched manifold - twinned to some headwork is the difference maker.

 

 

Get the air in

[Kevin Bacon 5]

Good find Chris! The elusive VR verniers have materialised at last :-)

 

£246 though!!

 

Why do the Americans always have all the good stuff?

[Chris VR6nos 0]

well i guess i could get them made but at what cost etc?

 

The thing is, Claret Badger, the gains can be very noticeable.

I put the cams in on H8RRA's engine and got one of them about a tooth out and it was harder to start and ran lumpy and produced noticeably less power!

On investigation i found the cam timing to be out and the cause of the trouble, the car would have ran happily and another person prob wouldn't have given it a second thought!

It wasn't a full tooth out as they wouldn't line up exactly so with a vernier pulley kit you could adjust things and realise possible the same gains of an exhaust manifold and some head work alone!

After market cams are notoriously out of timing, just look at the range of piper cams and the range of verniers to go with it.

Anyway i'm not arguing about it, i've seen it for myself and it's a good addition if you want the best from what you buy with your hard earned cash!

 

 

 

Chris

[Kevin Bacon 5]

Vernier results speak for themselves on the dyno.

 

For example, quite a few years ago, Vince found an extra 10lb/ft torque across the range on an old Audi 2.0 16V engine from just a vernier pulley and nothing else.

 

There's no guarantee you'll get the same from the VR6, otherwise loads of people would be making VR verniers, but for fine tuning cam timing, you can't beat them.

[Henny 0]

My G60 found somewhere in the region of 10BHP due to having the vernier fitted and setup by someone who knows what they're doing with it... 8)

[Chris VR6nos 0]

Yeah the verniers gears are all fine and well but you need to be very critical and know what you are doing.

A Dial test indicator is essential and a 360degree protractor and off you go

 

 

 

Chris

[DaveVR6 0]

Anyone care to explain about 'verniers gears'? for the laymen's!

[gaz the geezer 0]

Anyone care to explain about 'verniers gears'? for the laymen's!

 

basically, the standard cam pulley is an iten that has a keyed boss in the centre to allow positive fitment to the cam and the circumference of the pulley has teeth for the cambelt, the cam timing is fixed with this type of set up ( standard 1 piece), the cam timing can be altered ( or dialed in ) if the pulley is made up of 2 parts, the keyed centre is fixed to the cam as usual but the outer circumference can be altered by releasing / tightening the fixings on the pulley allowing the outer edge to move a few degrees clockwise/anticlockwise independant of the centre 8)

[Chris VR6nos 0]

The reason for this is that due to variations in the cam timing such as chains and tensioners with wear and the cam or sprocket keyways not being machined perfectly but within tollerance.

These variations can put the cam timing out sufficiantly to alter power and torque results but can be corrected by resetting the timing to where it should be regardless of the presence of wear in the componants.

 

 

 

Chris

[DaveVR6 0]

ahhh i see. so are you really actually 'gaining' anything more? or just getting the maximum possible?

[Chris VR6nos 0]

Good question, i think the best answer would be to say that you are trying to limit what the losses are.

 

 

 

Chris

[vdubjb 0]

Good find Chris! The elusive VR verniers have materialised at last :-)

 

£246 though!!

 

Why do the Americans always have all the good stuff?

 

http://www.catcams.be . Belgians been selling them for quite a while. Not terribly easy to access. Great for old cams that wont line up.

[Chris VR6nos 0]

vdubjb, the link isn't correct, i deleted the dot from the end and i got onto a site but simply couldn't find the timing gears, can you post a direct link please?

 

 

 

Chris

[steve_16v 0]

Go here click on English, then cam pulleys in the window that pops up

[Chris VR6nos 0]

Champion, Cat Cams seem to know thier stuff, looks very good and there's cams over 300degree duration too, excellent!

 

 

 

Chris

[vdubjb 0]

I'm running Cat 268°'s. Love them, but havent had a chance to rolling road them yet. Cheap from the states if you can avoid VAT.

[Chris VR6nos 0]

What did it end up costing and where is the power band etc?

 

 

Chris

[vdubjb 0]

I got them for about £200 a few years ago. Power is concentrated above 3000 rpm's. And lasts till redline. I have a turn2 intake and big valve cylinder head, so I never experienced just cams. Mind you, the 268° grind was dropped in favour of the 263° they offer currently. For what they cost, they are a tremendous deal.

[Chris VR6nos 0]

Wonder what the lift etc is, do they do cams specifically for forced induction?

 

 

 

Chris

[vdubjb 0]

The old Cat specs are in the faq here . The new ones are on cats website. Honestly, you can use any cam w/ forced induction, provided you can fuel them. Someone swapped his stock cams for Schrick 268°'s in a high psi vrt and they made more power higher up, just like in an N/A application. The key is aftermarket fuel management. The overlap was apparently not a problem. If you are simply going to use a turbo chip, I'd stick to the 256°.

[Chris VR6nos 0]

I'd use a bag of sperm if it works properly!

Surely the overlap won't help if it's too much though, and a correctly ground cam woould be better, mush have a chat to these guys sometime!

 

 

 

Chirs

[veeDuB_Rado 0]

Rrright, getting my hands on a garret T3 turbo, no real point putting it on the 16v so I'll put it on the vr6 when I get one...

 

I wanna be able to run it all safely and so that the engine isn't under too much strain from it, what I want to know is, what equipment will I need to accomplish this?

[DaveVR6 0]

Money!? :wink:

[veeDuB_Rado 0]

Saving me pennies, plus, you lot should know insurance costs don't matter to me :D