***List of upgrade for max HP from V8 LE***

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Zen_master
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Postby Zen_master » Fri Aug 02, 2013 7:31 pm

Is there a standard order of operations for the R51?

For example, is an exhaust upgrade recommended first, followed then by an intake, and then ECU/programmer, only then to be followed by engine internals?


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Clay350
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Postby Clay350 » Tue Aug 06, 2013 9:01 am

The gearing change from 2.92 to 3.36 on my truck did not have any noticeable affect on mileage. It was bad before and bad now. I am running slightly larger tires and that did affect performance and mpg slightly negatively. I can get 20mpg highway if I keep speeds in the 60-65 range.

My feeling on what hurts the performance of these trucks is the electronic throttle system. It just has bad throttle response and is always thinking to much. I would rather have a direct link to my throttle body with my foot instead of my foot to the computer.

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NmexMAX
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Postby NmexMAX » Thu Aug 08, 2013 9:07 am

Clay350 wrote:The gearing change from 2.92 to 3.36 on my truck did not have any noticeable affect on mileage. It was bad before and bad now. I am running slightly larger tires and that did affect performance and mpg slightly negatively. I can get 20mpg highway if I keep speeds in the 60-65 range.

My feeling on what hurts the performance of these trucks is the electronic throttle system. It just has bad throttle response and is always thinking to much. I would rather have a direct link to my throttle body with my foot instead of my foot to the computer.
You'll need to go at least pre-03 to find anything like that.

If you want to get crazy with the VK56 performance, check the TT forums. A LOT of guys there do a lot to better their throttle response. 4" intake comes to mind.

A larger MAF housing is what I did to my Maxima to get rid of that throttle lag and it has helped ever since. I find the PF's throttle to be more touchy/clumsy than laggy.

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Clay350
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Postby Clay350 » Wed Aug 21, 2013 6:07 am

I agree it is touchy and clumsy. My dad was pulling me out of the water on the boat ramp a couple weekends ago. He broke the tires loose. And he knows how to drive.

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Postby Zen_master » Fri Sep 06, 2013 9:08 pm

For those saying the throttle lags could it be the VDC engaging? Maybe it's just placebo effect but I swear I can break the tires free with VDC off but when it is turned on the throttle appears to quasi stall if I mash the accelerator in 2-wheel drive thereby preventing wheel spin.

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Postby skinny2 » Sat Sep 07, 2013 5:16 am

Depending on the situation, VDC does cut power if the wheels spin. It typically applies the ABS to control the spin but if it feels the vehicle isn't going to go the correct direction it will cut power. I have a spot on my commute that is a "short-cut" to get around trucks. The angle of the intersection and the fact I have to hammer on the go-pedal will cut my engine every time. So I have to switch it off and let it get a little lose.

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doctahjones
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Postby doctahjones » Sun Sep 08, 2013 12:43 pm

i've actually only noticed vdc apply the brakes if i'm in 4lo and spin for a few seconds.

in 2hi/auto/4hi i only notice that it cuts power, and doesn't apply brakes.


however, i do agree with at the very least the placeo affect when having vdc off. it seems that if i have vdc on and give it more than about 75% throttle, that i get like 10% less even though the slip light doesn't come on. with vdc off it seems like it's all there

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Postby Zen_master » Sat Mar 29, 2014 8:42 pm

Is a custom exhaust required if one chooses to go with the Doug Thorley headers? To clarify, is the stock exhaust so restrictive it would mitigate much of the benefit of headers?

I've read a lot of posts on these boards about swapping out mufflers. Are these same swaps including the front pipe / head pipe too?

http://www.dougthorleyheaders.com/produ ... uctID/1065

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Postby Zen_master » Sat Mar 29, 2014 8:47 pm

As for the OBX it says they are for 04-08 Titan/Armada and look to be shorties as opposed to the long throw Doug Thorley headers. Any idea if they'll fit a 2011 V8 LE R51 and what else is required to make them fit?



http://www.obxracingsports.com/products.php?pk=1630

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Postby Zen_master » Sun Mar 30, 2014 7:19 pm

NmexMAX wrote:Headers gears 4" intake and a tuner in short.

Head over to titantalk, they've got tons of go fast mods.

The headers don't fit without modification due to the UCA since the engine bay is smaller. A lot of people like LT Doug Thorley's but they are pricey. With that said, the OBX are essentially DT knock offs at a cheaper price, so since they need to be modified might as well go with them vs banging up a nice set of Thorley's. Couple that with the staight b pipes and with either an 18 or 22" muffler and you'll be on your way. Also, an LS series TB seems to be popular over there. Since we have the 08+ VK we also have a better intake manifold but there are some members over there going with the M56 IM since its a little more top end oriented.

There is a V8 Pathy over there with I/H and OSIRUS running 13.8 or 13.6 without gears so the potential is there.

There's always weight reduction.

The above mods put together well would net about 380-390 whp on a dynojet.

I chose an aleternate route in that I like and want the low end power so any of the above wouldnt do much when on the trails.
And did I read this correctly, as in wheel horsepower? Flywheel or to the pavement?

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Re: ***List of upgrade for max HP from V8 LE***

Postby palmerwmd » Mon Nov 08, 2021 3:28 pm

Zen (if you are still around) sorry this thread fell asleep on you.
Its certainly a great topic.

Based on experiences in other Nissan performance applications I personally would start with hiflow cats and a uprev osiris retune on a dyno.
Our intakes are not terribly restrictive and intakes are IMHO a money waster for many vehicles.
Of course since our cats come in assemblies with the manifolds it makes sense ot go headers same time.

Now in February I have replaced a drivers side cracked manifold which of course the assembly included a new cat.

I dont want that money to be wasted so I will wait as a minimum until the other side cracks or the drivers goes again (which could be years but I intend to keep this truck a long time)

Then I will go headers, hi flow cats and a retune on a dyno.

Based on experience with modifying other Nissan products I expect an extra 60 to 70 whp from that; with completely intact reliability for the engine.

Been our transmission should be fine with this, mine is however high mile (174k right now) and has been used hard for towing as evidenced by one broken rear spring, two shot rear shocks and both rear wheel bearings needing replacement when I purchased the vehicle.

So I do not know how the tranny would fare since this one has been clearly abused if even the rear suspension was damaged from repeat heavy towing.

But the engine will be just fine.

Also here is the white paper on this engine as presented to the SAE:
topic21121.html

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Re: ***List of upgrade for max HP from V8 LE***

Postby Zen_master » Mon Nov 15, 2021 2:26 pm

Thanks, Palmer. Do you have your eyes on any particular header setup? I've heard long throw are preferred but they do cost more. There's also some debate about relocating the oxygen sensor depending on which brand one springs for.

On this topic of performance parts, Jim Wolf Technology makes a few performance items for the VK56DE. According to JWT, for the 2007+ VK56DE which should have the intake cam phaser mechanism the correct cams are part number VK56-07CS2. To run safely to the factory rev limiter they advise a set of Jim Wolf Technology intake valve springs (part number AVK07-SPINT) for the 16 qty intake valve springs.

Not sure if anyone on here has tried a cam swap on the V8 and can report what gains, if any.

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Re: ***List of upgrade for max HP from V8 LE***

Postby silverarrow27 » Mon Nov 15, 2021 6:34 pm

Preformance Racing's website appears to be down at the moment, hopefully not permanently, but according to their R51 V8 drag strip warrior...intake manifold. $$$$ though. Try to reach out to them as they personally drag race their R51 Pathfinder with a manual transmission conversion.

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Re: ***List of upgrade for max HP from V8 LE***

Postby palmerwmd » Mon Nov 15, 2021 10:45 pm

Zen_master wrote:
Mon Nov 15, 2021 2:26 pm
Thanks, Palmer. Do you have your eyes on any particular header setup? I've heard long throw are preferred but they do cost more. There's also some debate about relocating the oxygen sensor depending on which brand one springs for.

On this topic of performance parts, Jim Wolf Technology makes a few performance items for the VK56DE. According to JWT, for the 2007+ VK56DE which should have the intake cam phaser mechanism the correct cams are part number VK56-07CS2. To run safely to the factory rev limiter they advise a set of Jim Wolf Technology intake valve springs (part number AVK07-SPINT) for the 16 qty intake valve springs.

Not sure if anyone on here has tried a cam swap on the V8 and can report what gains, if any.
Great to see you are still on the board!
Its been years :D

I think I will start slow and deliberate with any performance improvements.
Right now the car is still undergoing what amounts to a restoration of near new condition mechanically (I am there I think) and (eventually, making progress) cosmetically.

I think my first performance mod will be an Osiris UpRev tune.
The only thing that bugs me I should probably do a breathing improvement of some kind first to make the uprev more worthwhile.

Typically for Nissans which tend to have fairly open exhausts most of our breathing restrictions are not in the exhaust , but in the cats.
Now this is a Cali car so I am unsure if I will get a check engine light if I put in hi flow cats. :?:
But fundamentally the most immediate bang for the buck would be hi flow cats followed an uprev tune on the dyno.

But if I find a maybe used 350Z Turbonetics kit I might try that.
The turbo is slightly small for the 5.6 but thats ok.
Capacity was never a problem with these on early 350Z but engine internals were.
But our internals are strong almost like Nissan intended forced induction from the beginning.

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Re: ***List of upgrade for max HP from V8 LE***

Postby palmerwmd » Mon Nov 15, 2021 10:57 pm

silverarrow27 wrote:
Mon Nov 15, 2021 6:34 pm
Preformance Racing's website appears to be down at the moment, hopefully not permanently, but according to their R51 V8 drag strip warrior...intake manifold. $$$$ though. Try to reach out to them as they personally drag race their R51 Pathfinder with a manual transmission conversion.
Yes that intake manifold is interesting . As you said it does sound like $$ ...


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