[vdubturbo]

I wasn't sure where to post this, so I'll start here.
I'm bulding a 16v 1.8l turbo and was wondering if anyone has adjusted their exhaust timing to reduce valve overlap. If so, how many degrees?
In this situation, it would seem to me that an adjustable cam gear would be pointless b/c it won't adjust the 2 cams independenly of each other, just move the overall valve timing relative to the crank. Sound Right? TIA! http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


[Modified by vdubturbo, 10:14 AM 11-29-2001]

 

[89turbrio]

Re: Adjusting Cams for less overlap... (vdubturbo)

yeah, true, but the best you can do is time the valves to breed more power in the upper rev range- retardig the cam timing will allow all those spent gasses to escape while the intake side is still force fed, it gives you an advantage up top. I run -3' for this reason.
Luck

 

[vdubturbo]

Re: Adjusting Cams for less overlap... (89turbrio)

quote:[HR][/HR]retardig the cam timing will allow all those spent gasses to escape while the intake side is still force fed, it gives you an advantage up top. I run -3' for this reason.[HR][/HR]​

I haven't torn down the head yet, can you simply retard the exhaust cam by a tooth or two?

 

[89turbrio]

Re: Adjusting Cams for less overlap... (vdubturbo)

Wait, you don't have adjustable cam gear? I thought you did. But anyway, It's fun to play around with in a NA car, They're pretty cheap, so the investment is minimal for maximal adjustability. But, Why don't you just get a forced induction cam set if you don't already have cam gears, that way you'd wouldmn't have to worry about adjustments at all -with the turbo that is-

 

[BUNNYLOVE]

Re: Adjusting Cams for less overlap... (vdubturbo)

An adjustable cam gear will just move your power band to a different RPM range. It will not effect overlap. So your right.
Internal cam gears can adjust your overlap allowing you to adjust your cams independently. If you have stock cams I wouldn't worry about the overlap.

 

[vdubturbo]

Re: Adjusting Cams for less overlap... (BUNNYLOVE)

Does someone make a forced induction cam set!?

 

[BUNNYLOVE]

Re: Adjusting Cams for less overlap... (vdubturbo)

Not that I know of unfortunately. People are getting some really good numbers with stock cams IMO.

 

[killa]

Re: Adjusting Cams for less overlap... (vdubturbo)

i think schruck did, anywaym get the kent cam adjustable chain gears, you wont be able to jump a tooth and reduce overlap unless u do it in the chain inside the valve cover. eurosport sells the kent set.

 

[2035cc16v]

Re: Adjusting Cams for less overlap... (vdubturbo)

Kent sells individual cam timing gears...

 

[vdubturbo]

Re: Adjusting Cams for less overlap... (2035cc16v)

Is there any advantage to these other than ease of adjustment? Like, can't I just retard the cam one tooth inside of the chain?

 

[killa]

Re: Adjusting Cams for less overlap... (vdubturbo)

like i said, if u wanna reduce the overlap you'll have to do it at the internal chain that drives both cams, if you skip a tooth, you'll have to measure the degrees that the tooth measured, it'll prolly be way too much for you to do that. The regular cam Gear(timing belt gear) won't let u adjust overlap, you'll move both cams at once.

 

[vdubturbo]

Re: Adjusting Cams for less overlap... (killa)

Am I mistaken or did I see adjustable gear sets and cam chain sets as well? Are there 2 options for internal head adjustments?

 

[killa]

Re: Adjusting Cams for less overlap... (vdubturbo)

quote:[HR][/HR]Am I mistaken or did I see adjustable gear sets and cam chain sets as well? Are there 2 options for internal head adjustments?[HR][/HR]​

there's adjustable CAM gears (the timing belt one) and the internal chain gears(these let u adjust one at a time), the internal chain gears are the ones u want.