ok, i wanna know if this guy is fulla **** or what. he was tellin me that "the more you do to your engine, the worse a JRSC will perform..." now, call me a liar, but basic engine mods (other than i/h/e) such as cam gears, underdrive pulley, and maybe some ITR cams on a b18c1 wouldn't hurt performance. god i feel like a dumbass asking such questions, i apologize. and to whoever wants to know i used the damn search feature on this one too!

 

Obviously you are correct. Engine mods such as IHE will perform better with a JRSC. What this person may have meant is that when you up the boost it doesn't help as much as upping the boost on most Turbo kits. For instance the difference between a JRSC at 6psi and 9 psi isn't as big of a power difference between a t3/t4 turbo at 6 and 9 psi. The JRSC isnt as efficient as a turbo, and combined with the lack of an IC, heats the intake charge more than most turbos at similar pressures.

 

k this is coming from things i have learned on the forum and from my friend who has a JRSC GSR... first yes, pulleys do degrade performance and ITR cams are bad too... FI doesnt work well with high lift cams so the ITRs are pointless u might as well leave the stock GSRs... if anyone else cares to give more of a descriptive answer go for it.. cause i cant

 

The high lift isn't the problem, it's the overlap that is usually associated with high lift cams, that kills performance. -C

 

so it would be best to leave the pulleys and cams as stock GSR yeah? the only reason im asking so many JRSC questions is because i will have to get one if i want FI. i cannot afford to be without a car for as long as it would take to have my motor rebuilt and dynoed and all that **** for a turbo, i have to have my car. JRSC seems a lot simpler and less full of headaches.

 

Underdrive pullies are bad, as they will underdrive the SC. I personally believe that there is some power to be had with ITR cams, cam gears and a dyno. But that's just me.

I personally think that if you just want a NICE boost in power JRSC is a very good way to go. BTW I'll have one for sale in 2-3weeks. I didn't think it would happen but the turbo bug bit me.

 

i couldn't buy your JRSC now even if i wanted to, im flat broke and saving for a swap. im going that way for a reliable boosted car and i don' really have time to build up a motor for a turbo because i need my car everyday to get to work. i don't see why ITR cams and cam gears wouldn't do something positive for my setup. could someone explain to me why they wouldn't? even after a dyno?

 

Ok, you realize that NA there is an overlap between the exhaust valves and the intakes valves. Theory being, momentum and the intake stroke will blow the rest of the exhaust gases out of the cylinder.

With forced induction, you do not want this overlap to be as long if at all. So you need to tune it out. Otherwise, most of your boost will blow out while the exhaust vavles are open.

If you tune out the overlap, you want to make sure you don't go any further than at the end of the combustion stroke. (e.g. the exhaust valves better not open before the pistion reaches BDC, otherwise some of the force of the explosion will escape out into the exhaust, read as loss of ponies).

The large cams are designed for some overlap, that's how NA cars make extra ponies. I'm making the assumption that it might be impossible to tune out enough of the overlap to not lose power in a boosted application with high lift cams.

On another note, I have heard that using the stock GS-R intake cams with an ITR exhaust cam makes a few extra peak ponies on a JRSC B18C (~7whp)

Just my opinion
I could be wrong

 

u sir... are correct

 

that's pretty interesting...

id probably just leave it alone for a while, then start doing more in depth-research on it. i really appreciate all this help, thanks a lot!