Aftermarket exhaust cam?
 

Based on the complexity and purpose of the VVEL, it seems very unlikely that the intake valve timing is the limiting part of the air flow through the VQ37VHR. The intake valve timing is likely adequate to the 8,000 rpm range where lightly modded vq37's reach. The maximum valve lift may limit the ammount of torque, and therefore power that the engine makes but it looks like that can be adjusted with the clevis pin in the rocker-foot linkage. Although Nissan tells you not to and that the heads have to be replaced if someone fiddles with this.....but after all.... someone fiddle with it to get it assembled correctly at the factory. If this all sounds like Greek, watch the video below.



In any event, VQ37VRH's with bolt-on's make peak power at 7,000 rpm. I can't imaging that the stock, single profile exhast cam is designed to make power any higher than that. So, chances are that the exhaust cam duration is what causes the VQ37VHR's torque curve to start falling off after 6,000 rpm and that it was designed this way to meet emission requirements. The broad turque curve and slow rate of fall off of the torque curve at high rpm suggests the exhaust cam has a large lobe seperation angle (LSA), although technically there is no lobe seperation since there isn't a true intake cam. Regaldless, it implies that the exhaust valve opens late.

An after market exhaust cam with either 1) earlier exhaust valve opening (lower LSA), 2) more valve lift, 3) longer exahaust valve duration or 4) a combination of those factors, would make more peak torque and more peak power as well as peak power at a higher rpm, all at the expense of emissions compliance and low rpm driveability.

I haven't heard any posts on this topic or even any rumors. It seems like there would be a market for such an item for people wanting more performance, especially those comtemplating track use or forced induction since the pressurized intake overcomes many of the intake limitations and makes the exhaust limitations that much more severe.

Any feedback? Ideas? Anyone think my logic is wrong? Just curious what else we can squeeze out of the VQ37VHR without going to a complete engine rebuild.

-Phim

Interesting!

I've been searching and waiting for a company to come up with a software to control the VVEL, but an Exhaust cam would be nice too.

Aftermarket on the vq37 seems really slow to me, its been out in the G for 2yrs now and there isnt even a supercharger kit yet.. let alone cams.

Economy woos, enthusiasts buying 335is and Skylines have been accommodated because of the price bracket difference than the mid-range cars. Spending several thousand and up isn't uncommon for the owner to install modifications right when the car is new. I feel that the 370 market falls into the I want a sport vehicle but would like to be on a medium budget. I believe it took two years to get the 350z aftermarket product availability rolling from the time of its release in 2003.

Great products will come, we just need to be patient and complacent with some basic bolt-ons for now so we do not have to double spend for horsepower, replacing temporary parts now when the engineered parts that really provide benefits come in the future.

I think Stillen is on the 370z and will be the first supercharger as well as Greddy being the first TT kit, other than these two companies it may be a while before anything comes to surface outside of custom setups.

Nick J.

Greddy won't be the first TT kit. Their's isn't out yet and AAM and GTM have both developed one already... FYI

FYI... AAM or GTM don't have them available yet either... neither has one installed on a 370z. AAM is going to start their first kit on a car they are getting in next week and is install only because they fabricate parts on the actual vehicle, and GTM still won't ship their kit as they are ironing out the details as well. Greddy as well has their 20G 370z kit on the dyno tuning the e-manage for a plug and play base map... check their blog Mr. 600cc.

Nick

:ohsnap1:

I saw the AAM already on a car in their thread so I'd assume you can get it soon but if you say the Greddy will release to the public first then, ok. It has already been mentioned that someone is rolling around with a TT 370Z (470ish RWHP i thought). Don't know about his setup being a "kit" though.

It seems you took my post a bit offensively as I feel your response was a bit hostile but it wasn't meant that way.

Now that I think about it, I didn't see the GTM on a 370 yet so I was wrong there.

Oh and it's Mr. 636cc. Thx :D

Seemed like those were taboo topics on the G37 for a while. Everyone is too scared to get their hands close to that VVEL.

Holy moly that's cool! That's an even better picture compared to the animations.

So does it make sense for one to lower compression with deeper piston dish and optimize with increase valve travel? So the exhaust cam is still the limiting factor, right?

E-mailed TOMEI

:stirthepot:

I want an exhaust cam, plus vvl control.

i might try and mess with the clevis pin in the rocker-foot linkage.

But... if you can adjust overlap and duration, why would we even need a different cam (well, whenever we can, that is)?

All that extra lift that's mechanically possible should mean some nice potential gains in top end power...

Holy thread revival!!!

Subscribed:tup:

what he said

Because the exhaust cam is not variable as VVEL only controls the intake side of the engine. Also, the VVEL mechanism can provide very aggressive intake valve lift while the exhaust cam is mild in comparison.

What Phimosis proposed is to install a more aggressive exhaust cam to more closely match the already aggressive VVEL intake lift and duration.

Yeah, but controlling overlap and duration from intake side will be more than half the battle without opening the head...

soon enough i plan on opening the head anyways, just waiting for the aftermarker to keep up with my thoughts and ideas.

good luck with that !!
I also wanted to do that but I didnt had the balls doing it in case something goes wrong,
but anyway im sure there is enough clearance between the valve and piston to allow some more lift with the screw

I'm just saying, we have an adjustable set of parameters and a non adjustable one that requires fabrication... seems to the first goal should be dealing with the first one and then someone can worry about designing a new exhaust cam.

So, mega bump from the dead.. Saw this on RHDJapan's FB today.

JUN AUTO - JUN AUTO JAPAN - HOT NEWS

Interesting.

Would have been better if they compared stock vs cams only. Some of that power is coming from the higher compression 12.3:1 pistons... and bigger injectors.. and tune..

Very interesting. Looks like a 30HP bump

This could help! Can't wait for more info.

Nice to know someone is on this project. Still I agree with the previous comments, hard to tell how much the cams add when you are running all the other major engine mods.

Nice. Who's gonna be the first.

Well first we need a vendor to get them.

They are going to be expensive, need an experience installer and a tune. With that taken into account, its safe to say that VVEL more likely than not will not be cracked cheaply (full standalone for VVEL) however an exhaust cam that can keep up with the aggressive VVEL will be awesome and help both N/A and FI guys.

$650 the pair

I need a retune as it is, I'd happily be the first if a vendor can get them for me around that price.

I would be curious if these can be thrown in without having to adjust VVEL.
VVEL is fairly smart already and might be able to adjust on its own.

Yea VVEL will adjust for it, the computer does a lot of it's own adjusting. I'm wondering the gains FI people mite see. $650.00 seems decent.

The install will be heavy, probably look to drop the engine, anyone want to guess install cost at an experienced shop?

you shouldn't need to drop the engine. Should just need a raise/tilt.


Most shops will charge 10+ hours for an install

So about 1k-1200 for the install

Ouch!

i am on jun's website where the cams are, and dont see the dyno graphs where u guys are pullng these gains from. might be my camp since there is a big blank white space right below where it says reference.

can u see this?

http://i108.photobucket.com/albums/n...3/canvas-1.png