Zbuzz

iTrader: (1)

A while back I got a great deal on a new-in-the-box throttle body for the 350Z. As you guys know, from the factory, the bore is 70 mm. I had a reputable shop bore it out to 72.83 mm. They did a beautiful job on this, by the way.

Anyway, I've got pretty much all the Nismo engine pieces available on the car at this point (CAI, headers, cams, flywheel, clutch disk and cover, LSD, as well as high-flow cats from Japan), a UR underdrive crank pulley and a Unichip for engine mgt.

Does anyone have any experience or opinions on the bored out throttle body being added to the mods I've already done? Benefits? Problems?

I've heard some horror stories about fooling around with the throttle body on the Z33.

ZU L8R

iTrader: (84)

Prob only beneficial if your FI

xlr8r

iTrader: (8)

It can be helpful as long as he has portmatched the intake manifold neck for a smooth transition from 72.83mm back down to 70mm. Also the benefit depends on the the inner diameter of the intake piping. If they are 70mm then the benefit of a larger t-body won't be felt.

Generally larger throttle bodies improve throttle response & given then mods he has (cams, headers, etc) it will probably give a slight bump in power & torque throughout most of the powerband, as long as the intake piping diameter is larger than 72.83mm.

ZU L8R

iTrader: (84)

He'll get a couple hp no doubt. Just don't think he'll get more than 7.

Kwame

iTrader: (78)

I had the 350Evo version a few years back and it was a nightmare. My idle was insanely rough and my car was throwing codes left and right. I cannot comment on performance gains because the driving experience was a nightmare as well.

2004Black350z

iTrader: (37)

? is whats beneficial with HFCs from Japan? JDM

Zbuzz

iTrader: (1)

I had thought of that as far as the intake and manifold piping. I'm guessing it could end up causing more headaches than help. Kwame, I've heard the stories about the uneven idle and thrown codes on bored out factory TBs as well. Main reason I've had the TB in the box for almost two years is that my gut tells me it would be more problems then it's worth, HP-wise.

Zbuzz

iTrader: (1)

2004Black,

I had been considering HFCs for awhile, and was looking at Random Tech's HFCs. About a year ago I stumbled on a pair of Nismo HFCs that a guy in Oregon had purchased and imported from Japan, installed and ran for about 10 dyno pulls, and then took off because he decided to take his Z in a different direction.

I won the Ebay bidding, and ended up paying a bit less than if I'd bought the RT HFCs. Had a local performance exhaust guy (gotta love his name, "The Muffman") install, and they're great. Gave my exhaust a throatier note, and a couple of horses, same as any other HFC would do, plus it gives my car something that's a little unique.

IIQuickSilverII

iTrader: (13)

have some ***** and Try it out


seriousloy...it would be great contribution to the Z comunity


the powerlab kit comes with a pretty large intake pipe... you would need to work on the neck of the stock plenum to see if you can get it closer to 72mm too
After that id strongly suggest a standalone ems

ke0ki2k

iTrader: (2)

how much are you pushing at the wheels? ditch the throttle body....UTEC, let Sharrif tune it, and 3.917 final drive. then go beat STI's and Evo's, videotape it, and spam it everywhere. **** off all the AWD-Turbo boys

xlr8r

iTrader: (8)

I just realized after reading about the headaches that people have experienced is that the MAF is the choke point (diameter) & probably the cause of ECU issues since it's not aware of the larger T-body (and larger piping if placed in a larger intake pipe). I'm too accustomed to MAP tuning that I forgot the Z's have MAF sensors. It seems like the best/only way to take advantage of a larger T-body is with some form of tuning. It's hard to believe that an extra 2.83mm is going to cause problems though.


On a side note, as I'm narrowing down my intake manifold decision for my project I think I'm going to be modifying a stock Intake Manifold with a new/larger elbow (swinging to the passenger side) that will allow me to put a 80-90mm T-body on it since 70mm seems to be on the small side for 3.5 liters at 6500 rpm; if you consider the HR engines for example, that have dual 60mm T-bodies which are the equivalent of a single 85mm T-body. Granted the HR's rev higher, but I think we all agree that 70mm is a bit small for the DE's.

Kwame

iTrader: (78)

Please let us know WHERE your going to find a 80-90mm throttle body that is compatible with our drive by wire system. Wherever you do tell them you have two more people waiting with money in hand (Adam and I would love this on our NA builds! )

In addition we offer 3" MAF housings, if you really think that is the root of the problem.

ACEMAN

iTrader: (29)

Im running larger pieces with a Utec right now.. Plan on getting the setup dynoed on the 12th

Here sizes of all the pieces

Stock figures are:

Maf ======== 72mm
Intake pipe ===72mm
TB ==========70mm

Larger Pieces

Maf =========80mm
Intake pipe====85mm
TB========== 2mm oversize at 72mm, with the inlet enlarged to 78mm.


Later
Todd

2004Black350z

iTrader: (37)

I understand and thats Neat you have JDM HFCs I guess but maybe he just said that in the ebay auction 2 sucker sumbody into Not tryin 2 be a dik but GL with ur TB question

Zbuzz

iTrader: (1)

Hmm, lets see. I think most would understand that hi-flow cats are a fairly straightforward mod on the Z, where if done correctly, will give you some nice sound and maybe a little extra HP/torque.

On the other hand, with the throttle by wire set up, messing with the TB is a bit more complex of a mod as I understand it. Sorry if my question offended your delicate sensibilities. We all can't be expert, I guess.

As for the Nismo cats. Anyone who buys on-line has to do as much due diligence as possible, and understand that there is some chance they'll get ripped off. When I first saw the listing, I had doubts as well; I had seen quite a few listings for "Nismo" cats on ebay myself. The guy I bought them from had a reasonable story, had good answers to my questions about the parts, and had excellent ebay feedback.

Once I had the cats in hand, both myself and my exhaust guy were impressed with the quality of the products themselves, and they've performed well since they've been on the car. I'm sure you'll have a cute remark to this as well, but they were embossed with the Nismo logo very similar to the way my Nismo headers are.

At this point, I have no reason to think they're counterfeits, and if you think they are, oh well. I couldn't care less.

xlr8r

iTrader: (8)

Sorry man, the VQ is going into a 510 so I'll be using a cable Throttle body so there are plenty to choose from. The cost & time to do a 90mm is the same (if not cheaper than going 80mm, so I'll probably be going 90mm).

I did notice an some 80mm & 90mm(LS2) drive by wire T-bodies that may be possible to use for VQ's if the parameters are the same. You can also convert your 350z to a cable, though from my understanding you'll need an aftermarket ECU in order to take care of the TPS sensor changing, but if you're going with a much larger T-body then you probably already have tuning.

xlr8r

iTrader: (8)

Based on those #'s a 72.83mm T-body should work fine & I doubt it will that much of a difference power/air wise to throw the ECU off. I think zbuzz should give it a try & if the results are good then people can bore out their T-bodies to 72mm for a little more pep.

Zbuzz

iTrader: (1)

xlr8r,

Based on that, I think I'll give it a shot. After it's in, I'll post and let everyone know how it went. Thanks to everyone for the excellent feedback to my question.

GrayG35

iTrader: (2)

good luck im hoping for positive results so i can do it too!

Q45tech

Why not measure the oem TB restriction at WOT at various high rpm with an accurate manometer to arrive at the restriction in inches of water column so you can mathematically derive any expected gains.

On a NA 1psi [27.7" W.C.] is a 6.8% restriction. The few dozen TB I've measured [various Nissan] run ~~ 6-7" W.C. or 9.8/4 or 1.7%..............NA TB improvements are always less than 1%.

The larger the TB the less crisp the throttle response which is limited by electronics in the first place.

As with any NA HP each costs $100-$150.