[CThoreal]

Thanks, but I think thats a little overkill. Mr. Bills made some good points, and I think I'll be taking his advice.

I have the exact mods Mr. Bills lists. You will have a noticeable increase overall but it wont be huge. Granted I have 33" tires which numbs everything. Those mods with stock tires and you will notice increased snappiness for sure. Power kicks in around 2100 RPM.

 

[knightrider]

I can't say that I understand your reasoning but I understand the want/need for better response. There is a very pronounced lag in the throttle when compared to cable throttle vehicles. Most people that drive an automatic will not notice this lag, but it's apparent with a manual transmission and it takes a bit to get used to. Your want to increase power I think is a little misguided. Increasing low end torque will not necessarily improve the response, partly because of how the computers that control it were designed and partly because of what the vehicle was designed for (offroad).

ok now for a couple points:

first, ignore chris haynes, he really doesn't bring anything of value to the conversation, not even homeless people want his .02

2nd, there is a bit of power to be made with these engines but I don't really think it's as important as you want to think it is. You keep saying you NEED this and NEED that but I doubt you will be happy with all the money spent to gain said power. Power to weight is what matters and you have a lot of weight, so adding a bit of power won't help much, it will be noticeable but not life changing. The vq40 is no slouch but the xterra is also not a light weight vehicle.

3rd, throttle response will lag on all electronic throttle body engines, because the computer is controlling the throttle, not your foot. Your foot(throttle input) is just making a suggestion to the computer of what you would like it to do, in the end it will do what it feels is best. This is made worse by the addition of the WOT restriction under 40mph and the traction control system, these systems contradict what you want the vehicle to do when you push the throttle to the floor. This computer lag will still be there whether you have 200hp/200tq or 600hp/600tq. There are aftermarket devices that can help with the lag, but they also make the throttle very touchy in my experience.

4th, because the Xterra was not designed to be driven fast or hard, the flywheel is very heavy and designed as a 2 piece unit to absorb shock loads. This causes the engine to rev up and down slowly, quick shifts cause a lot of stress on the transmission syncros since they have to deal with large differences in engine speed and gearbox speed. A lightweight flywheel helps the engine rev quicker, but an oversquare 4L V6 is still not going to rev like a F1 engine.

My advice, from someone who actually drives a manual transmission,
get a BullyDog tuner, add the regular fuel tune(or Premium if you don't care that you need to run premium), and remove the WOT restriction.
Fix the Y pipe restriction in the exhaust and put a high flow filter in the stock air box.
The intake manifold spacer should also be done.

Something free you can do and will probably have the most effect on response and driving a manual transmission Xterra is to disable the traction control, no fun way to do it but you have to hit the button to disable it every time you start the vehicle. This stops the traction control system from cutting power when it detects the tiniest amount of tire slip.

I had the fortune of my steering angle sensor going out which permanently disabled the traction control although the slip light is on all the time. The 09+ ecu is less responsive to power upgrades but the few I have done made a noticeable improvement between my armored up on 33" tires MT 12' Xterra vs my friends stock MT 12' Xterra.

 

[ChrisHaynesUSA]

Close up the thread.
Knightrider has weighed in.

 

[jsexton]

*I did not read the replies in this thread so someone may have already said it.

If you have a 6mt and the throttle response is sluggish, especially with the low end torque, then you are in the wrong gear. I'm not sure there are any mods that will overcome that. Try driving in a gear lower than you are used to. I think you will be surprised by both the responsiveness and how little it affects fuel mileage.

 

[IM1RU]

Too bad you don't want to regear.

What Surf said.... you want it to jump off the line, or get up and go while driving..... RE-GEAR.

The Bully Dog helps yes (I have one), Y-pipe yes (air goes has to come out), IMS.... meh (I call BS... when someone proves it with Dyno-testing with that upgrade only).

 

[JNR]

While these have *decent* power for a 4x4 suv, there is still room for improvement, especially if you add any more weight, including cargo and passengers, let alone heavy steel items and so on.

Perhaps most folks here don't care about extra power, or they have not driven a powerful car(s) prior (that will make you realize how sluggish these feel in comparison ) or for so long they forgot...that's alright, they are content....probably better that way, being it's not wise to drive crazy in such a poor handling vehicle for that task (gets dangerous).

However, there is nothing wrong with wanting more and there are a few things you can do, although there is a wall you hit on n/a on these, since there is not a whole lot of aftermarket support....things like cams, heads and parts that really change and increase the power, etc...

Best bet is supercharger plus real tune...only real 'kit' player is stillen there and its tune that is part of that is not that great...also, things like extra fuel delivery are not dealt with properly, but I could be thinking of another s/c kit on a different vehicle. The one in my mind simply increases voltage to pump, rather than replacing it with say a wahlbro 255 lph. I bet the intercooler could be better, as well...but, it is a bolt on kit, so probably will give you 80 to 100 hp tops. Not bad, just a lot of $$$.

Turbo would work great on these engines, but afaik, nobody makes a 'kit'...besides the plumbing and location of compressor logistics, there is no magic...the tune, fuel delivery and keeping the compressed air as cool as possible would be the trick...also, doubt these plastic manifolds would appreciate any pressure (boost) beyond single-digit numbers, so $$$ for what you will end up needing to do...this is assuming bottom end can take it...a good tune is important, lean = boom time, haha...can be done, including custom manifold if needed, just real custom at that point.

For bolt ons....LT headers > ST for lower to mid torque and on these, pretty much all around. Be aware that Doug Thorley LT's are really more medium length...I couldn't believe how short they were, although made install easier.

Exhaust...catbacks are $$$, and the oem exhaust isnt too bad other than the Y pipe...factory cats are kind of restrictive, but be sure to go with high flow rather than remove (to keep it somewhat clean)...mufflers pretty much come down to user preference on sound...be prepared these are V6's and can sound raspy or ricer-ish with the wrong one, esp with LT's and high flow cats.

Manifold spacer...there is another brand that is better since it is phenolic, but hard to get now, unfortunately....was cheaper, too....do a search at clubfrontier.org (BTW GO THERE TO THE PERFORMANCE SECTION for more info on modifying these engines, as people there are interested in such). Also, I did a dyno before and right after plus temp readings, all being better (go to CF for thread...want to say under CXJ, as it was their's I tested; the other one has never been dyno'd afaik, or at least actual results published)

Port and polish TB...just be careful near the butterfly area where it rests at idle, as in don't increase that part there, or it will suck in too much air, making idling rpm not good....that is, unless you were to replace with larger bf and matching bore hole...we don't have a lot of meat tho and IIRC, the manifold opening isn't that large, nor can it be made larger by enough to make it worthwhile.

DO NOT remove the internal 'straightener' inside the manifold...people will claim it is a screen and it gives them more power, but it is there for a reason, with respect to keeping the air non turbelent and better working in its design. (Hooefully that makes sense)

A freebie is increasing the air box's tube at the fender (again, go to clubfrontier; I made a couple threads on that...may have here too, don't remember).

I *personally* think the "cai" kits are way overpriced and not much better than factory, but it would beni nice to have a better intake tube, just not for how much it is. Meaning, nothing wrong with them on their own, just need to make the call.

Be glad you have a manual...huge difference from the auto (had an auto frontier pro-4x), mostly from the gear ratios, but my 2011 had WOT restriction and you could tell...there is debate on whether 2013 and newer has that...IMO, it doesn't come with that...it can be confusing on when the 'variable intake runners' kick in vs the wot, sincevthere is a noticeable increase after, like the throttle opens more...not saying all cases, just saying.

I'm sure there is something I'm missing, but a real tune should be considered necessary whenever you do something beyond say a muffler or cai, etc...the out of the box ones should work fine until you get into headers and such, but IMO for a little more, may as well get full control (ie Uprev).

 

[jsexton]

The 2015 6mt 100% for sure has the throttle restriction. It's very easy to feel it with the manual if you try.

 

[JNR]

Doesn't seem like my 2014 (manual) has it, but who knows...if it does, then it is not nearly as noticeable as my 2011 was....the variable length runner design is noticeable when it 'engages' (changes) but not as much as that wot change, IIRC.

Btw - OP, don't get a TB spacer, as they are about useless on these, even though it adds a little plenum volume. I had one that came with the IMS and didn't notice anything and didn't like the idea of another potential vacuum leak source if it wasn't going to help power.

 

[Tlrtucker]

...there are many times where a quicker throttle response is needed for safety reasons...

:scratch: That's some interesting logic, lol

 

[Longboardr]

:scratch: That's some interesting logic, lol

Ever ride a motorcycle in traffic? :wink:

 

[itsyvesxterrra]

I moved to Utah from Centreville, VA, so I know what you mean by darting around the Beltway or 66. I got a K&N CAI, had the Y pipe replaced with a Magnaflow, and got the Bully Dog tuner. Having the WOT restriction removed helped a lot with acceleration from a dead stop. I also get pretty good gas mileage too. Around 280 miles per tank around the city, but closer to 350 on the highway. I towed a 5x8 Uhaul trailer from VA to CO and got 330 miles per tank with the premium tune. I'd start with the tuner to remove the WOT restriction. If that's not enough, then do the intake or drop in filter, then the y-pipe. I didn't do a full exhaust because I work nights and I didn't wanna piss of the neighbors. Hope this helps. I don't miss that traffic one bit. I was born and raised in Georgetown, and will never go back. Lovin the Rockies.

 

[dtank]

Its good to see the support for this mod from people who've already done it and glad to hear that it can only bring benefits. So based on everyone's response, it seems like the only mods worth the money are the following:

1. K&N drop in filter
2. Intake Manifold Spacer
3. Muffler (2-in/1-out)
4. Tune for new equipment and removing WOT restriction
5. High-Flow Cats?

Nobody has mentioned high-flow cats, but I'm reading a lot of good stuff about them. Any opinions on it?

 

[dtank]

I have the exact mods Mr. Bills lists. You will have a noticeable increase overall but it wont be huge. Granted I have 33" tires which numbs everything. Those mods with stock tires and you will notice increased snappiness for sure. Power kicks in around 2100 RPM.

Wow! 2100RPM...that's awesome.

 

[dtank]

I moved to Utah from Centreville, VA, so I know what you mean by darting around the Beltway or 66. I got a K&N CAI, had the Y pipe replaced with a Magnaflow, and got the Bully Dog tuner. Having the WOT restriction removed helped a lot with acceleration from a dead stop. I also get pretty good gas mileage too. Around 280 miles per tank around the city, but closer to 350 on the highway. I towed a 5x8 Uhaul trailer from VA to CO and got 330 miles per tank with the premium tune. I'd start with the tuner to remove the WOT restriction. If that's not enough, then do the intake or drop in filter, then the y-pipe. I didn't do a full exhaust because I work nights and I didn't wanna piss of the neighbors. Hope this helps. I don't miss that traffic one bit. I was born and raised in Georgetown, and will never go back. Lovin the Rockies.

Great info! Glad to hear that gas mileage will improve too, and you're one of the lucky ones to leave this God awful place lol.

 

[Mr. Bills]

Its good to see the support for this mod from people who've already done it and glad to hear that it can only bring benefits. So based on everyone's response, it seems like the only mods worth the money are the following:

1. K&N drop in filter
2. Intake Manifold Spacer
3. Muffler (2-in/1-out)
4. Tune for new equipment and removing WOT restriction
5. High-Flow Cats?

Nobody has mentioned high-flow cats, but I'm reading a lot of good stuff about them. Any opinions on it?

Any performance gains from high flow cats will be marginal, particularly in relation to the expense. You should be very circumspect about modifying emissions parts because you may have future issues with emissions testing and/or when selling your truck. Its no fun to have to spend $$$ to return emissions parts to stock, particularly if you didn't get much of a performance boost to begin with.

Frankly, I think @Surf and Snow gave you the best advice of all - pick a lower gear or stay in a given gear longer before upshifting if you want better throttle response from a MT Xterra. It costs nothing.

If you simply must start down the slippery slope of engine modifications, you should make changes incrementally so that you can determine which modifications are worthwhile and which are just burning hundred dollar bills.
As was previously suggested by another member, you could start with the tuner, then do the drop-in filter, then a new y-pipe & muffler, and lastly try the IMS. (I would probably start with the air filter because its cheapest and easiest.) I think you will find that you reach the point of diminished returns long before you get to the point of considering high flow cats as a next step.

 

[JNR]

Its good to see the support for this mod from people who've already done it and glad to hear that it can only bring benefits. So based on everyone's response, it seems like the only mods worth the money are the following:

1. K&N drop in filter
2. Intake Manifold Spacer
3. Muffler (2-in/1-out)
4. Tune for new equipment and removing WOT restriction
5. High-Flow Cats?

Nobody has mentioned high-flow cats, but I'm reading a lot of good stuff about them. Any opinions on it?

High flow cats will give you an increase, but more often because of the larger diameter than stock. On their own, same size as oem and no other changes, probably not going to notice, but coupled with headers, a better exhaust (personally prefer a good Y vs. 2 into 1 muffler) and a TUNE to take advantage of all that, you will see a noticeable increase in not only power but mpg (apples to apples and being realistic with the gas pedal, haha). They will NOT work as well as oem to keep your emissions as low, but can and do work just as good to the ecu, although that seems to be hit or miss. I do not get CEL from the hi-flow cats and LT's I'm running with regard to P0420/0430, which means the rear O2 is reading too close to the same as the front O2, or the cats are not doing their job within the ECU's set parameters [keep in mind those are sensitive values, as you could imagine, so doesn't necessarily mean they're not doing anything].

Do I recommend them as a performance change that is worthwhile? Yes and No...more no unless you are already planning on changing them and running other things like LT's and larger exhaust, etc., as I mentioned. Also, if you're in a smog-county of commiefornia (which are most of them), then keep in mind you will fail the visual being they are not oem. Workarounds, sure, but something that could be a hassle.

Also, keep in mind these changes will make the X pretty loud and much more aggressive sounding. To me, too loud, but I'm also running a Dynomax ProFlo 3" round muffler and no resonator, with the tip going straight out the back, thru the bumper, so that doesn't help things. I *think* with a large turbo muffler, it would be better, but won't know until I go that route (or add a resonator)...just mentioning that to be prepared if you go that route...we have short exhausts and with there being no trunk, or bed, etc. you really hear it inside. I've added some insulation that helped, but not into loud and how this sounds since it doesn't back up the sound, haha. (it does sound really good, just loud and I like to be more subtle when I drive...unless I'm in my 'velle, but that has a large cam and built engine and it fits the car )

As for the filter...keep in mind a K&N is not the best choice if you go off-road...it won't filter as well as a paper unit (hence the little extra power)...you need to be careful not to over oil it and/or let it dry real good, cause droplets can get sucked onto the fine sensing wire(s) of the MAF sensor...easy fix with some electronics or MAF cleaner, but something to be aware of....Also, don't expect much by itself, other than being nice to re-use, as far as any power increase, or such a small amount that it will hardly be noticeable. I'm talking vs. a clean paper unit for a fair comparison...You'd be better off with the modification of the air box (not cutting extra hole, but increasing the inlet tube @ fender + removing silencer portion there) than just the filter change. Add both and it seems to go together well. I've never had a problem running K&N's off-road and in really dusty conditions, although I don't doubt there is more particulates getting by...just not enough for me to worry about, but worth mentioning.

 

[Tlrtucker]

Ever ride a motorcycle in traffic? :wink:

I have, for many years. But last I checked the Xterra wasn't a motorcycle >

 

[JNR]

Speaking of which, there were a few times that driving a high performance, good handling car came in handy to avoid an accident...People not paying attention and darting out right into your lane, or from an intersection, where some throttle and really quick swerving was necessary and brakes were not the answer (once on the freeway especially clear in my mind). Something the X wouldn't have been able to avoid.

I do miss the instant power with the blip of the accelerator, but do have to say this X (with minor mods and manual) sometimes does put a smile on my face with it moving pretty nicely; usually when it's (rarely) cool out. Just with it sounding the way it does, I can't get on it much because then people think I'm racing and want to pace me. It's an SUV, people, c'mon

 

[alabamatrailboy]

start taking weight off. Remove the spare tire, rear seats, roof rack cross bars, roof rack if you're bold enough or like the look. easiest way to get more pep out of any vehicle is to lose weight where you can.

 

[dtank]

High flow cats will give you an increase, but more often because of the larger diameter than stock. On their own, same size as oem and no other changes, probably not going to notice, but coupled with headers, a better exhaust (personally prefer a good Y vs. 2 into 1 muffler) and a TUNE to take advantage of all that, you will see a noticeable increase in not only power but mpg (apples to apples and being realistic with the gas pedal, haha). They will NOT work as well as oem to keep your emissions as low, but can and do work just as good to the ecu, although that seems to be hit or miss. I do not get CEL from the hi-flow cats and LT's I'm running with regard to P0420/0430, which means the rear O2 is reading too close to the same as the front O2, or the cats are not doing their job within the ECU's set parameters [keep in mind those are sensitive values, as you could imagine, so doesn't necessarily mean they're not doing anything].

Do I recommend them as a performance change that is worthwhile? Yes and No...more no unless you are already planning on changing them and running other things like LT's and larger exhaust, etc., as I mentioned. Also, if you're in a smog-county of commiefornia (which are most of them), then keep in mind you will fail the visual being they are not oem. Workarounds, sure, but something that could be a hassle.

Also, keep in mind these changes will make the X pretty loud and much more aggressive sounding. To me, too loud, but I'm also running a Dynomax ProFlo 3" round muffler and no resonator, with the tip going straight out the back, thru the bumper, so that doesn't help things. I *think* with a large turbo muffler, it would be better, but won't know until I go that route (or add a resonator)...just mentioning that to be prepared if you go that route...we have short exhausts and with there being no trunk, or bed, etc. you really hear it inside. I've added some insulation that helped, but not into loud and how this sounds since it doesn't back up the sound, haha. (it does sound really good, just loud and I like to be more subtle when I drive...unless I'm in my 'velle, but that has a large cam and built engine and it fits the car )

As for the filter...keep in mind a K&N is not the best choice if you go off-road...it won't filter as well as a paper unit (hence the little extra power)...you need to be careful not to over oil it and/or let it dry real good, cause droplets can get sucked onto the fine sensing wire(s) of the MAF sensor...easy fix with some electronics or MAF cleaner, but something to be aware of....Also, don't expect much by itself, other than being nice to re-use, as far as any power increase, or such a small amount that it will hardly be noticeable. I'm talking vs. a clean paper unit for a fair comparison...You'd be better off with the modification of the air box (not cutting extra hole, but increasing the inlet tube @ fender + removing silencer portion there) than just the filter change. Add both and it seems to go together well. I've never had a problem running K&N's off-road and in really dusty conditions, although I don't doubt there is more particulates getting by...just not enough for me to worry about, but worth mentioning.

Ok, so basically since I'm not upgrading the headers or exhaust (other than modifying the muffler/y-pipe), high-flow cats are unnecessary because the gains would be very little and wouldn't be worth the money.

Why do you prefer a y-pipe over the 2-in/1-out muffler?

When you say "increase the inlet tube @ fender", are you saying I should make the hole at the fender bigger (with a dremel?) and replace the current tube with something with a bigger diameter?