I hope the aftermarket companies are going to be all over the new 3.7 in the g37 so when the new z's come out aftermarket will be readily available.

 

Whats the differnce between the VQ35HR and the VQ37HR besides displacement?

 

I know a few details:

VQ35HR
*Twin throttle bodies that open independently of each other...one first than the other (not at the same time). Good thing is they share a single plenum, so FI "should" work. Tuning....??

VQ37HR
*Completely different valve system. Similar to BMW's. "Infinitely" variable lift so no need for throttle bodies, but they're there for some emissions reason. Significantly more HP compared to current generation VQ's

Just some news I got from the service manager at our local Infinity dealer.

 

The throttle bodies work independently of each other? Can anyone confirm this?

 

Well, the only reason I know this is because we discussed on one particular 07 G35 that was having awful cold start/run issues (really cold) where it would run like ****. Going through the flow chart and service manual provided this information. They eventually fixed the car, but I don't know the specific repair. So yes, they work independently of each other. One opens first and when additional flow is needed passed a certain threshold, the other opens.

Pretty fancy, huh.

 

That doesn't sound like it makes much sense.
Let's just say the setup was
--T--123--T
-I---456---I
F----------F

With F = Filter, I=Intake, T=Throttle body, obviously.

Wouldn't it make more sense to have them both open, if the left side opens first it looks as if cylinders 1/4 might be a little starved or at least that having both open would benefit the car.

 

and lose about 15hp or more til then?

 

How is that possible? I was there when JT dyno'd her car, he removed her y-pipe so that her cats were open, and her car went from 265whp to something 274whp instantly...that was with nothing after the cats! I don't think strapping on an EVO TT will do any harm NA

 

^ there's no friggin way an na car with minor boltons will run right with a evo tt

 

Why not? I full heartedly disagree, but don't have any facts to back up my opinion

 

where you get your backpressure for the evott? hopes and dreams? people should not be running that huge of piping on a NA z.. you don't have to take my word for it though.. it's your z...

 

It sucks that Z owners have to wait till 2009 to get the vq37hr. I was thinking all things equal between the vq35hr and vq37hr besides displacement you could just buy a brand new vq37hr shortblock and slap it on to the vq35hr and bump displacement. I used to have a STI and a lot of the 2002-2005 wrx owners used to buy ej257 blocks (2.5l sti block) and slap it on to their wrx heads and boom you have a 2.5l wrx.

 

what the hell are you talking about? Granted they will loose low end power but gains will be seen on the top end. It has nothing to do w/ back pressure. It is all dependent on exhaust velocity. How do you think a FI'd car runs when they are out of boost? (they are running in vaccum just like a NA car).

granted its not the ideal setup for a NA Z, but if he is buying the exhaust w/ plans of going FI then it is certainly fine

 

edited

 

Both throttle bodies share the same plenum. There is only one plenum feeding all 6 cylinders. Get it? Regardless of which throttle opens, all 6 cylinders get the air. The individual actuation of the throttle bodies have something to do with response down low and VE/Balance at the top end.

I don't know how, if at all, this will effect FI.

 

 

dude you can post up cutesy pics all you want, but you obviously have no clue what you are talking about. A perfect example of this setup being operational is having a NA car that is runing a exhaust cutout (ie no exhaust past the headers). Now i personally know that this setup is fully operational as i have owned one before. Hell you could run around with open headers and the car will operate fine. Granted the car will sound like *** ,but it will drive fine!!! Like i said this will net you a gain in top end power, but the bottom end of the power band will suffer.

Increasing power with a exhaust is all dependent on increasing the volume of exhaust gases expelled. When you have a large exhaust the lower part of the power band suffers due to the fact that the exhuast velocity is not high enough to move the exhaust gases out quickly enough, but at higher rpm's the exhaust velocity is substantial enough to remove a larger volume of gases than the stock system netting a gain in power. NEEDING BACK-PRESSURE IS A MYTH!!!!

BTW what do you base your opinions on? I have read alot of your post and 90% of the time you are mis-informed.

 

you can flap your jaw til your hearts content.. 3" exhausts should not be used for an NA setup, mr. google-search man. 90% of the time I'm misinformed huh? you get this from reading all my off topic posts?

 

IF HE IS STAYING NA HE SHOULDN'T RUN THAT EXHAUST, BUT THE OP STATED HE PLANS ON GOING FI. The greddy evo tt is 2.75 inch dual and if he is planning on going FI in the future then the exhuast will be fine, not optimal but fine while NA.

 

y don't u do some research before posting stupid, ignorant, uninformed comments

https://my350z.com/forum/engine-and-drivetrain/260222-our-first-2007-350z-vq35hr-baseline-dyno-3.html

check out post # 51

incase u don't know how to read a dyno chart, let me break it down for u

the stock and the evoTT equiped runs show equal power from ~2200ish rpm to 5900ish rpm, above that the evoTT equiped goes on to make 10 more whp and below that it make just slightly less power, which is still plent for driving around town. and if one needs to go faster, then s/he won't be below 2200 rpm