i'm trying to find out which one i have i think i have a vented optispark on my 94 camaro, i replaced it 3 years ago and didnt know anything about cars but now i'm thinking its a vented and i have no vacumm harness? whats the best way to tell?

 

you have a 94, you have an unvented opti

93-94: unvented
95-97: vented

 

A vented opti has a hose that runs from it to the left side of the intake manifold.

 

 

Is this conversion a MUST when doing heads and cam? And if it is...why?

 

Its not a MUST but if your car has some miles on it and you are going to be in there anyways then if you have the money then i say you do it.....

 

I wasn't going to change mine either when doing a cam install untill I learned that over 6000 rpm you need a heavier duty timing chain and I didn't want an electric water pump so the only option was to go to the vented opti so I could run a lt4 ex duty timing set.

 

rkussy, can you explain a little further? I am in the middle of a rebuild so I'm debating over what to do with timing chain, opti, waterpump. I think I'd like a Meziere, why don't you want one? If I'm to replace my opti, can I just buy a 95-97 (cheaper) or do I have to get an older one and modify it to be vented? What timing chains fit with what opti's and waterpumps? I need to upgrade to a better chain too but would rather opt for something cheaper than the extreme duty if possible. If I go the Meziere route how about the Lunati timing set? ($109.00). The extreme duty is made for stock waterpump .....I see now looking in this Jegs mag ....

 

i have an aftermarket opti i think i forgot to mention it does have a tube in the bottom like kind of the one from where the coil hooks up. and theres no vacum hoses attached to it.

question! could you put a vented opti on a 94 camaro alone no other modification ???

 

you have to cut the dowel pin on the cam down .. but it will fit

 

i did'nt do that and it fit or maybe thats why it has a nasty stumble and a missfire

 

Vented opti is cheaper to buy!

 

The reason I did't go with the electric water pump was after reading so many posts about life of the pump worries about it failing and not being aware it failed I decided I could deal with a little less hp and possible leaks to have a pump I could rely on. The Lunati chain is a link type just like the stock one so there doesn't seem to be any advantage to that. The ex duty is a little pricey but with 6400 rpm shifts it is needed. If you are willing to use the electric water pump then you can use a true double roller for less cost. Your own preference.

 

Hi Charlie

The '94 opti can only be used with the stock "stamped" chain

to convert you need a bunch of parts listed here
http://para.noid.org/~muttvette/opti.html

the benefit of converting is to be able to use a better timing chain

I'm going to an agressive cam heads combo and wanted a better timing chains and have done the opti conversion so I could install ED timing chain.

if you want a double roller and/or cloyes set you need to have an electric water pump.

no major cost benefit as the elect water pump plus the cheaper chains is close in cost to the ED set. basically a function of the age of your existing water pump. i just replaced mine so I did not change it.

As far as Hp savings - I can not believe the small WP sproket is a huge drain of HP

The problem with the elec pump is that they may leak and fail without warning - but you can putin a warning light in case of failure and a proper install won't leak.

to convert you need to change the timing cover - do not get a '97 as it has the crank sensor - the '95 cover is best ~$60 new
opti is ~$200.

I sold my vented opti for $175 so the cost of conversion was not to bad (but my opti had low miles on it)



email me if you want more info

 

if you are thinking of doing an electric waterpump know that it does out flow a mechanical one during idle.. but at WOT the crank driven out flows it.. I did the mez and was having horrid heating issues because I would drive at sustained high speeds and high RPMs.. I wasnt getting the flow I needed..

and an vented is best as far as optis.. You dont want to have to replace it over and over..