# How to: "Bolt-on Header mod"



## ValBoo (May 19, 2003)

Ok lets do it,
Manuelga asked for it and Terranismo keeps talking about it so here it is:

I finally completed my Header mod two weeks ago.
Since our engine QR25DE is the same as the famous "Sentra Spec V" which has all sorts of goody aftermarket bolt on accessories, good performance parts are easy to obtain.

The compatibility of the parts was kindly confirmed by Terranismo who was my source for this information and who also has LOTS and LOTS of mods.

The bolt on was quite easy. My only problem was the stripped threads on my front oxygen sensor and as you probably read in previous posts, a replacement part was sourced out of Mexico by our good buddy Manuelga (thumbs up!) since Dealer couldn't help me.

To get to the stock header you first have to remove some heat shields, remove the O2 sensor(s), remove the passenger side wheel, loosen the belt drive, move away the alternator and finally remove the stock header.
In reverse order reinstall performance aftermarket header.

I went with the header manufactured by HotShot.
This mod was explained in detail in NPM a few years back when the Spec V came out.
Here is the link with detailed description of the install on the Spec V:
http://www.nissanperformancemag.com/may02/specvmay02.php 

As you will see the engine showed gains of approx 12 HP at the wheels.
The stock header also contains a pre-catalytic converter which the performance header does not have.
On the Canadian X-trail there are two O2 sensors: one before the pre-cat and one after. Since the performance header does not have a cat you have to relocate your second O2 sensor, luckily the car has a second catalytic converter under the car, you should extend the wires of the sensor and relocate after the second cat, (If this is not done, you will get a check engine light).

My impressions:
You definitely feel much better power from the engine.
Noise from the engine is slightly different, but barely louder.
There is a slight 'tingy' noise around 4000 rpm.

What I really like:
When I had done this mod on my Spec V, there was some very slight popping noise (backfire) when shifting or letting off the gaz pedal. Amazingly the X-trail has none of this whatsoever.

here are some pics of my installation:

finished install:









O2 sensor install:









Old and New sensor (sent by Manuelga):









Relocation of second O2 sensor after the second Catalytic converter under car:










Since this is install I have also added a cold air intake system and a lighter aluminum drive shaft pulley, but since I have no pics yet I will keep these mods for another day...

Happy X-Trailing Easter egg hunt to all!

ValBoo.


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## ViperZ (Feb 9, 2005)

Valboo, thanks for posting pictures :thumbup: It looks very nice in there and the increased HP is excellent. I sure would like to know how a system like this would affect my LE-VDC system if at all  Everybody with an XTy could always use 12 extra HP, well maybe not so much the owners of the XT-GT in Japan  


Good Job!


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## manuelga (Dec 14, 2003)

I've seing that O2 Sensor before  

Really, thanks a lot for the info, I guess after I change my Sentra Header (It's more "necessary" in that tiny engine), I'll go for the X-Ty one.



ValBoo said:


> O2 sensor install:
> 
> 
> 
> ...


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## Terranismo (Aug 31, 2004)

Valboo great to see your truck is running great. :thumbup: If you want even more power take off the secondary cat and have a custom downpipe made up. You will feel almost the same difference than when you put on the header. I went with a 4-1 header for more top end. What kind of CAI are you running I'm using an AEM right now.


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## ValBoo (May 19, 2003)

*replies...*

Viper,
Thx. I do not know enough about VDC to say it would be affected by a header. Off the bat, I can't see how an exhaust mod would affect this system but I could be wrong. I'll try to search around...

Manuelga,
Thx. Couldn't have done it without your help with that sensor!

Terranismo,
Thx. I will be working my way back slowly changing the exhaust. However, I will keep the Catalytic converter for the environment and also because our X-Trails have two O2 sensors (And I would not want to have a check engine light on all the time... I know there exists some O2 simulators, but I will keep the second cat).

My cold air intake system is also from HotShot (stainless). Install was a breeze... I will post at a later date about this.

ValBoo.


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## aussietrail (Sep 24, 2004)

*Dyno*

Hi Marc (ValBoo) and Terranismo,

With your power enhancement modification experience, can you please advise me on the following:

Is it safe to run an automatic exy on a 2WD dyno while left in 2WD mode?
Is there something else I need to do to ensure the rear wheels wont start to
have drive/power transferred to them?

Your help and guidance is much appreciated.

Aah, by the way Marc, I didn't comment on your mods above, because I'm still digesting and comparing to similar mods done in Australia, once I complete my research, I'll let you know  It's a great mod however and you've done a great job. :thumbup:


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## ValBoo (May 19, 2003)

*Caution with AWD system on Dyno*

Jalal,

I did not think there was any problem to have car in 2WD mode sitting with front wheels on dyno rollers UNTIL I READ THE BELOW from the electronic service manual (see the very last caution note):

-----start quote-----

4WD MODE SWITCH

AUTO mode
 Electronic control allows optimal distribution of torque to front/rear wheels to match road conditions.
 Makes possible stable driving, with no wheel spin, on snowy roads or other slippery surfaces.
 On roads which do not require 4WD, it contributes to improved fuel economy by driving in conditions close
to front-wheel drive.
 Sensor inputs determine the vehicle's turning condition, and in response tight cornering/braking are controlled
by distributing optimum torque to rear wheels.

LOCK mode
 Front/rear wheel torque distribution is fixed, ensuring stable driving when climbing slopes.
 Vehicle will switch automatically to AUTO mode if vehicle speed increases. If vehicle speed then
decreases, the vehicle automatically returns to direct 4-wheel driving conditions.
 LOCK mode will change to AUTO mode automatically, when the vehicle speed exceeds approx. 30 km/h
(19 MPH). The LOCK indicator light keeps illuminating.
NOTE:
If there is a significant difference in pressure or wear between tires, full vehicle performance is not available.
Tire conditions are detected, and LOCK mode may be prohibited, or else speeds at which LOCK mode is
enabled may be restricted.

2WD mode
Vehicle is in front-wheel drive.
NOTE:
 If front wheels are slipping in 2WD mode, do not switch to AUTO or LOCK. This can cause difficulties for
the system.
* Even if the 4WD mode switch is in 2WD mode, the 4WD control unit occasionally automatically change to AUTO mode depending on the driving condition (For example; Depressing the acceleration firmly). This is not malfunction. However, 4WD indicator lamp dose not illuminate.*

-----end quote-----

This being said, I will not try it (unless there is some way of electrically disconnecting the AWD system... I'm sure there is.)

Perhaps Terranismo knows?

Later.


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## aussietrail (Sep 24, 2004)

Thanks Marc. It is risky I agree.


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## Terranismo (Aug 31, 2004)

You only have to remove both back wheels and have the rear suspended on jack stands. Or you can also use an AWD dyno (which are plentiful in Australia). I was going to dyno mine this month but instead I'm using the money for more mods  I'll try next month :fluffy:


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## aussietrail (Sep 24, 2004)

Thanks Terranismo.


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## thetimster (May 6, 2005)

ValBoo... any chance you can edit the pics in this thread so this can be a sticky? It certainly is sticky quality.


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## Sergei_dekker (Jun 4, 2005)

aussietrail said:


> Hi Marc (ValBoo) and Terranismo,
> 
> With your power enhancement modification experience, can you please advise me on the following:
> 
> ...


Y would u want to have 2WD when u can have all the benefits of having 4WD traction???


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## aussietrail (Sep 24, 2004)

Sergei_dekker said:


> Y would u want to have 2WD when u can have all the benefits of having 4WD traction???


Sergei, not all dynos are 4WD capable and the ones that are, usually very expensive, hence my question above, but it has been sorted.

I'm not gonna convert my exy to a 2WD only machine LOL 

Hey guys, don't know if you have noticed yet, but we're missing 2 of our key players in this forum *Terranismo* and *Viper* I wonder if they're OK and if anyone has heard anything from them? It has certainly been a while since they last posted in this forum.


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## thetimster (May 6, 2005)

Yup Sergei. Jalal was just talking about performing dyno tests on the X at a place that might not have 4-wheel dyno capabilities. 

And I agree Jalal... 4-wheel dyno probably best and safest. Though as Terranismo mentioned, you can just take off the rear wheels if you wanted to do 2-wheel testing.


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## nbhms (Apr 27, 2008)

*Pictures . . .*

Does someone have the pictures for this HOWTO post? They seem to be missing . . . 

Also, would the SPEC-V Nismo headers work on the X-Trail QR25DE?


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