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What to expect out of a VG33+ and VG34


MY1PATH
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I noticed a nice improvement with my KA throttle body with a Z31 intake. Better throttle response and mid range grunt, driving around I don't even need more than an 1/8 of the pedal to get up and go pretty quick.

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I may have been a little over reactive on my previous post; it's simply a mod I will not be doing to my N/A Vg33. A 60mm or 62mm TB (stock is 58mm?) would certainly add a more snappy feel to a pathfinder (or a z31) and probably be of no harm at all compared to what I described above but a 90mm is too large and entirely unnecessary unless you are making like 300+ HP. Speaking of the 300HP the Q45 VH45DE with a 90mm TB uses a special linkage mechanism to slow the opening of the throttle at light throttle to give more precise control and prevent lunging.


The thing is, installing a bigger TB tricks a lot of people.

Say you have a 60mm TB and you replace it with a 90mm TB... The opening is 66% larger. Now when you drove around at 1/8 (13%) throttle with the 60mm and then you do the same with the 90mm its really more like driving around with 20%
By the same token if your engine reached is flow capacity at 100% throttle on the 60mm then the engine will reach its flow capacity at 66% open with the 90mm

Better throttle response yes, but You can duplicate the same effect without changing your TB by just pushing the pedal into the floor a little faster.

 

A TB is nothing more than an air flow control valve and for controlling small amounts of air smaller is more accurate. Example: If you go too large you lose some of your light throttle control. I you are trying to just CREEP up a rock it will be more difficult to be gentle on a larger TB because the changes in airflow are more dramatic.

 

So why did nissan go to larger for the 3.3? My guess is marketing: If it feels snappier it must be faster. A good example is The VG33ER with its 8:1 compression ratio, choked down cam and restrictive manifolds is quite sluggish before it gets into boost. To cover this up nissan uses a super aggressive throttle linkage found only on the ER TB that whips it into boost from closed throttle almost instantly.
I think this is also why you find the larger TB's on the smaller 4 cyl engines; Make it more snappy so it feels faster than it is lol.

Edited by MY1PATH
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Yep, that sums it up. It is mostly a gimmick, but a slightly larger one can improve the driving experience. We all know the actual power isn't there past a certain threshold, which is why being able to get up and go with a smaller amount of skinny pedal makes things a little more livable.

 

It's like Ford with tuning their drive-by-wires so aggressively and touchy. Makes the vehicles feel more powerful even though they aren't. It shows when you try and command more power but nothing is there.

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Yeah i would never go 90 mm q45 throttle body. That's way too large for an NA VG33. I plan to boost my vg33e further down the road with a remote mount turbo and will also be upgrading to n60 maf and the vg33e intake manifold and tb. The stock is 56 or 58 mm and the vg33e is about 62 mm so it's not a massive jump but it will be enough to make a difference, especially when boosting. Plus... the vg33e intake mani and tb are free mods since I already had them so might as well take advantage! :)

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Yeah i would never go 90 mm q45 throttle body. That's way too large for an NA VG33. I plan to boost my vg33e further down the road with a remote mount turbo and will also be upgrading to n60 maf and the vg33e intake manifold and tb. The stock is 56 or 58 mm and the vg33e is about 62 mm so it's not a massive jump but it will be enough to make a difference, especially when boosting. Plus... the vg33e intake mani and tb are free mods since I already had them so might as well take advantage! :)

 

I've had the 3.0 and the 3.3 manifold side by side before. I don't remember all the differences but I remember deciding that the 3.0 is better. (I Wish I remember reason why)

 

One thing to take note of is that the TPS on the 3.3 TB speaks a slightly different language. You can fit the 3.0 TPS on there but it requires some machining and a shaft swap. I did a writeup on it but I think I only posted it to Z31P... Maybe I posted it here too, I can't remember. (did it on the 3.3 TB on my supercharger)

Edited by MY1PATH
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Yeah i actually just figured that out a few weekends ago when I was bored. Machined the tb to fit the older tps and swapped throttle shafts. Also had to add a sleeve to the end linkage area so the throttle actuation was nice and smooth. I studied both manifolds pretty extensively and decided the vg33 was better lol. I don't like to how the plenum ends on cylinder 6 on the vg30 manifold. The vg33e has much smoother transition from the body of the plenum to the end cylinders and also has larger flow paths through the throttle body area. Only time will tell which one is better for making power once I finish acquiring parts for the tuning and wideband setup

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  • 4 years later...
On 6/13/2013 at 11:22 AM, MY1PATH said:

Good luck, I think JWT S1 and some headers should get you the same numbers but you will not have the same low end unless you raise the compression ratio.

Donno how I wound up back here but while I am, I gotta correct myself...

 

I have a set of JWT s1 in my 3.0 1993 PF and the torque comes in really early. I just bought a second set as my cam of choice for my next build.

 

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Finally some input on mpg after 3.0 came and other hp upgrades. At first I stuck with 3.3 cans because I wanted the more low end torque but lately I've been wanting to swap over the 3.0 cams that I kept and have been sitting in the garage. I'd like the truck to be a bit quicker for better drivability. 3.3 seap was nice to reduce shift, upgrading it would be even better

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14 minutes ago, Charlie_Brown said:

Finally some input on mpg after 3.0 came and other hp upgrades. At first I stuck with 3.3 cans because I wanted the more low end torque but lately I've been wanting to swap over the 3.0 cams that I kept and have been sitting in the garage. I'd like the truck to be a bit quicker for better drivability. 3.3 seap was nice to reduce shift, upgrading it would be even better

For your MPG interest, More details on my 1993 top to bottom:
3/8 intake manifold insulator
Jim Wolf Tech stage 1 camshafts
Stock block 308,000 miles
Gibson 2.5" cat back

Chevy 16" (19lb alloy) with P225/75r15 tires (nearly 100 lbs less rotating mass than most sets of 31's)

 

Depending on driving conditions we've seen 20+ MPG but 17-19 is more common for our mixed driving which is 75% highway. I hope to keep or improve this when she goes 3.3.
ON the flip side my (MPFI) 89 does worse on MPG. But its lifted, extra wide wheels, typical D/E-rated 31x10.5" tires, heavy bumpers, fender liners are missing (air pockets). It also mostly does short trips with very little highway time and I think the Euro cam with its really long duration is an efficiency hindrance for the lower engine speeds.

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