A question for those running JRSC...

My understanding of losses in that system (boost) are attributed to cam overlap; this being boost being lost because the exhaust valves and intake valves are open at the same time. Blow-by, I believe it is called.

So with the JRSC for the ITR, boost is set at a mild 5psi (please correct me if I am wrong). Is there a loss of boost due to overlap with stock cams? Is there a way to reduce the level of overlap, and increase the manifold boost pressure by dialing out overlap? Can one utilize larger cams, and still retain a reasonable amount of boost pressure by installing a smaller charger pulley?

The reason I ask this is because I would like to introduce a supercharger onto my B18C5R, which has a relatively high CR, and large cams. Ideally, it would be nice to see about 6psi boost and retain reasonable thermal efficiency. I understand I am probably having to go to a stand alone engine management system, but I would like to try and figure a great deal of this out prior to jumping into this head first.

I have recently seen an S2000 with a non-intercooled SC on it, so I am confident it can be done.

All input is appreciated. thanx.

 

Overlap can be minimized by the use of camgears. Buy some and tune it on the dyno.

 

Hmmm.... supercharger w/minimized cam overlap.
Can anyone say Miller Cycle (as in Mazda Millenia S)?

I'm thinking of using some Toda Gen II cam gears on my soon to be boosted (Drag III) 97 R.

 

You can keep your aftermarket intake cam, but replace your exhaust cam with your stock one. That should also reduce overlap a little.

 

That is interesting.

As I said, I am just trying to work out some of the logistics, so any further input would be appreciated.

Cheers.

 

ok, then how do you reduce overlap on a SOHC???

 

Goto: http://www.hostboard.com/cgi-bin/for...gras&number=40

However, JRSC, 8psi pulley, Hondata, and 440cc injectors seems to be the hot, yet reliable ticket now... for a B18C5 and your case, add cam gears and some good dyno tunning to the tune of a 240+whp with OE reliability... kinda cool to take off from a parking lot in 3rd gear just above idle... off idle torque is a beautiful thing on a grocery getter... ie my 4dr...

 

Grind a new cam.

 

Zeus,

I still would like to utilize my Spec B's.... this is why I am concerned about the overlap.

Any thoughts on that?

 

keep the cam gears within 0-2 degrees.
thats what ive done with my Spoon Cams

 

if you need some cam gears, i have some new ones for sale. still in plastic and in box. polished silver and black. fits all 1.6L and 1.8L DOHC engines. i would get em! $200 shipped. or $190 if youre from the bay area.