valve springs for FI- which ones and who's gottem?
 

so, now that there is the discussion of changing the valve springs and leaving the cams stock...anyone want to chime in on this...
how much $$$ are we looking at here, who's got em...and what are the best kind for a 550whp forged 350z motor???

JWT makes valve springs, you could always get custom Ferrea valve springs as well. SGP Racing sells JWT valve springs.

SGP has JWT springs I believe . I got the Nismo springs [$240 I think ] also going with there cams also . Got them thru Performance [Jason ]

I have the JWT valve springs with my cams...with the shims they costed $238 + shipping.

Aaron

Re: valve springs for FI- which ones and who's gottem?
 

We have the JWT in stock :D

$240 for springs and shims

woah...quick feedback...thanks guys
also, what type of time (labor wise) is involved with switching out the springs? any other parts needed???? ANYTHING

Time I would say about 3 hours if the head is already off the car. I would also look at the TI retainers more then the springs. It would really suck if you sink a valve on that nice new forged block because the cheap aluminum one on the car gave.

I had JWT springs that i was going to use, then I decided that they were a little on the stock side. If you look at their specs on the JWT you will find... 43lb@on seat & 136lb@12.5MM lift

Thats hardly more than a factory style spring. As a matter of fact, the pressure on the seat when valve is shut is actually WITHIN factory valve spring specs.

Tommarow I will be adding all the Ferrea equiptment that I used in my heads on to my website with pricing, we are direct Ferrea dealers and have used their parts for years.

Ferrea single valve springs for the VQ35DE are almost twice the pressure on the seat. If your gonna rev higher and run higher boost, I would recommend the Ferrea units... Ferrea also has a lightweight retainer to use with their single spring.. available in 2 sizes, one for stock valves and one for the 6mm Ferrea stem valves. The ferrea retainers are reengineered in form and are much lighter than other retainers. For a super crazy engine they have dual valve spring setups for the VQ also... but I dont think there are many here that are gonna need that. Pricing on the Ferrea stuff is very good, I bought it all first to compare it and its very nice stuff.

I would not use the tighter Ferrea springs on stock aluminum retainers. The Ferrea stuff for this engine is affordable and soon it will be the standard... most people dont even know they have it out yet.

-Charles
CJ Motorsports

I just decided to go pretty much all in...

JWT springs and camshafts
1mm oversize valves
and the Ti Retainers...

Im gonna go the overprotective route and get a better headgasket too... probably nismo... the way I see it... if you're doing an engine rebuild why skimp out on a pretty cheap piece that is kinda important.....its not that much more when you look at the whole picture... just my thoughts

Looks like I need to update my sig... I will be going with the Ferrea springs and retainers as opposed to the JWT.

Why would you need different springs unless you are running a higher lift cam or spinning the motor to a higher RPM?

As far as installation, there are kits that allow you to install springs with the head still on the motor. Don't know about the VQ35 though.

phunk:
what do these cost? do you have them in stock?
thanks!
TODD

Sorry for being off topic but do you need any type of headwork to install 1mm oversized valves? I would like to get cams, valves, and springs. Thanks

For just cams and springs alone , headwork is usually optional.
However; larger valves definately require some port work.

I'm doing a fairly aggressive set of cams on my buildup heads (NA, not FI), and my machinist specially told me not to bother with the springs or retainers and that the stock ones were more than sufficient.

For a really high spinning motor, it would be a worthy investment (I'd go Ferrea too - it's all they do!)

Adam

Are springs, retainers and valves really necessary if you are keeping the stock rev limiter on a boosted motor? I was under the impression the springs/retainers/ etc were for those upping the RPM limit.

if your staying stock on the rev limiter and then you probably dont have cams and you probably dont plan on making insane power which means you probably dont plan on running high boost... in which case you have no need for springs or retainers.

RPM isnt the only thing that causes one to require a tighter valve spring. higher boost, higher exhaust backpressure, and agressive cam profiles alone can create a need for tighter springs. Even if your not spinning faster.

I got the Ferrea page done for my website with pricing and everything... the last thing i need to find out is if one of the 2 ferrea single valve springs is compatable with the factory style retainer... in other words, if people with SGP retainers can use the ferrea springs, since SGP retainers are dimensionally identical to stock. I would not recommend stock aluminum retainers with tighter valve springs.

Within the same dimensions, aluminum is actually lighter than titanium. But titanium is strong enough that you can engineer the part to be small enough to loose weight over aluminum and still be stronger.

is 550rwhp w/ 16-19psi of boost considered high to you?..or are u talking 650+?
thx,
TODD

You don't need to change the springs unless you actually bump up the rev limiter, and rev higher. THe stock springs are good enough for a FI setup, unless you are running Super high boost, in which case you're probably built anyway.

Charles, the Ferrea link on your website did not work.