I just ordered a Jun 3 cam complete with springs, TI retainers and the cam gears. It might take two weeks for delivery. I was planning on getting CTR pistons for it but still undecided. I did the calculation for the loss in dynamic compression and it seems to fall slightly below the stock no. The tuner who sold me the Jun cams said he tuned an ITR JDM with stock compression and he got 225 crank hp. He said that Jun will email him the correct cam adjustment specs. He does'nt use the degrees indicators in the cam gears but uses a dial guage to determine TDC and adjust the cams accordingly. I don't know if it makes sense because I am not a mechanic. He told me stock compression would be good enough.

But while I was going thru the Jun catalog, I noticed a section wherein they sell engine packages like stage 1 to 4. The stage 1 package puts out 225 hp(probably crank hp) but what caught my attention is that compression was at 12:1! It now seems that I have to go for CTR pistons. The tuner said that the Jun 3 cam will have a slightly lumpy idle when it is set properly. But when searching thru this forum, almost everybody says idle is very stable and just like stock. Is the tuner correct that stock compression with the cam set right will yield good whp nos? Any inputs will be highly appreciated. I will be using chrome to tune my JDM ITR.

 

no the tuner is wrong IMO, i have personal experience with that same JUN set up and you DO need to up the compression to get the most out of the cams you're using 12:5.1/12:6.1 is optimal but you could get away with anywhere around a CP of 12:1 and still get decent HP out of them... PM on the way

 

12.5-1 comp w/ 84mm roller waves and jun 3's is good for 230+whp on a good tune

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by camlob &raquo;</TD></TR><TR><TD CLASS="quote">I just ordered a Jun 3 cam complete with springs, TI retainers and the cam gears.</TD></TR></TABLE>


You are correct in that you will need 12.5:1+ to see optimal numbers from those camshafts.....

Also take into account the fact that jun valvesprings (at least the older ones) will coil bind if just plainly installed with these camshafts. You could shim down the seats for them to have enough room, but it's more trouble than say purchasing valvesprings which can handle the lift with stock install height - toda valve springs come to mind as working well with these cams.

Expect ~200whp with jun 3's and ctr pistons.

Your mechanic is good though - he's degreeing the cams when installing and not just going by 0,0 on the cam gears to start with. I'd spend the few extra $'s and have him clay the motor to see how much adjustment you have +/- on each cam (this will be very helpful when you go to tune the motor).

 

Muchos Gracias guys. The guy who I bought it from said that Jun makes OEM cams for Toda! He visited Jun in Japan and thats what he found out. Probably true given the amount of outsourcing done in most industries. I never knew Jun started out as a machine shop.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by camlob &raquo;</TD></TR><TR><TD CLASS="quote">Muchos Gracias guys. The guy who I bought it from said that Jun makes OEM cams for Toda! He visited Jun in Japan and thats what he found out. Probably true given the amount of outsourcing done in most industries. I never knew Jun started out as a machine shop. </TD></TR></TABLE>


This is the first time I've heard such a thing.....

afaik, toda makes all of their own cams in house.....

http://www.todaracing.com/about/technology.html

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">TODA Racing uses the latest design and manufacturing equipment to produce TODA products. All product design is carried out using the IBM CATIA (CAD/CAM/CAE) which is the same system used by Honda, Boeing, Ferrari, and other high technology manufacturers.

All TODA products are manufactured in-house by TODA. Having an in-house manufacturing capability means there are no compromises in design or manufacturing. Product testing is carried using advanced analytical software, engine bench testing (engine dyno), and race testing.

</TD></TR></TABLE>