When buying JWT cams the for sale add says to use JWT springs is that necessary or will any performance spring do?
272 is getting pretty lumpy. Would think that idle/spool would be affected significantly with these yes? They are considered 'lumpy' on our 3SGTE's in the MR2's, anyway. And I don;t think the extra duration really gives much if anything more up top compared to a set of good 264's.
You would think they are lumpy based on specs. A mate of mine Jeremy has them in his zed. The idle is surprisingly still good and well able to idle at stock speed. I got R4's originally cause I was worried about this. I sold them off ages ago after seeing how Jeremy's car runs with the R5's. I would have no hesitation in using them even in a road car. The extra air flowing through the more open valves WILL lower spool onset slightly, But its at the top end you really see they shine. But if you are hesitant the R4+'s are a good compromise.
THIS IS THE PART i'M WORRID ABOUT .. Its a fact that the bigger the duration the further the powerband is pushed up .. (power starts later and ends later at least on an aspirated engine) also think that the extra air flow will help spool but a member on 300zxclub ztuner changed from 400+ to r5 and noticed a few hundred revs later spool but better top end
When I drove Jeremy's car after he put the R5's in and the GT28r's IS AMAZING. Its just scary fast on 14 psi. You just HOLD ON TIGHT then all hell breaks loose. As I am shoving the R5's in the race car all I really want is mid/top end. But as road cars maybe you guys need the R4+'s.
R5's hit you in the back of the head like a shovel. Go with R4's to keep your torque lower in the rpm. Heads ported R4's JWT springs Ferrea stock size valves Stock manifolds, ported well 3" expansion dumps 3" to 2.5" test pipes with 200cpi cats 28rs turbos 0.64 exh housings wiseco's eagles balanced 740's japtek coolers arp stud kits top and bottom S2 cam gears Nismo reg New oem pump job done.
This is a way cool quote I like that Your list looks about right Eric 400 RWKW race car should work just FINE.
Either is fine, the ferrea's require more machine work, hence more set up cost which is not really needed for these cams and a reasonable amount of boost.
lol how do u expect 1mm oversize valves 2 fit !!!! big job involves pressing in new valve seats !!! u can go 0.5mm oversize on stock seats
i meant the double valve springs, thats what we were talking about, i know the over sized valves needed machine work
JWT 400+ 264/375" vs JUN 66 264/9.5 Just going over some specs again (because you guys opened a can of worms for me and considering the 264 duration again ) now in measurement they are both 264/9.5 but anyone know if are they the same or one is bigger eg 220@.050? cant find any other details on them
They are both ground to be used with hydraulic lifters. I would say a pretty accurate guess is ramp rates are very similar. I would be suprised if either had a noticable benefit to the other. What may come into play is how the cam card says to dial these in, this effects LSA which has a pretty good effect on power curve shape.
