XTZ mods and dyno feedback - .: XT660.com

Freez · # 1 12-07-09, 08:55

My friend Jon picked up a new XTZ the other day and yesterday we put the bike on the dyno to see what we could figure out to unleash some more power from the bike.

We fitted a PCIII from his previous XT660R, loaded a zero map to allow the bike to run on the default ECU fuel settings and I gave the bike a few runs until I started getting consistent HP figures.

Note, before people ask why the dyno numbers are low, please note that I run my Dynojet dyno at around 4500 ft above sea level and it is set up to measure torque in Ft-lbs, not NM. It seems to be a common problem with Dynojet dynos at this altitude to not compensate correctly, so if you want to know how much the HP and torque figures will be at close to sea level altitude, add 10 to 12% to my dyno figures. The correct way to do it is to take my HP figures and divide it by 0.9 to 0.88.

The 1st question we had was how this bike's HP and torque output compares to that of a stock XTR's. The dyno run below shows the difference between a stock XT660R and the new XT660Z. Both bikes where brand new with less than 300km's on the clock. The XTZ is the blue line and the XTR red.

As you can see, there is almost no difference in power output between the two. Only around 0.8HP difference at peak, so it is very safe to say that they deliver the same HP in stock form. Actually, in this case the XTZ was slightly better. As said earlier, take my dyno's 37.33HP / 0.88 and you get around 42HP from both bikes.

Next we made a custom PCIII map for the stock XTZ to see how much the fuel mapping would change power output. PLEASE NOTE THE FOLLOWING. The XTZ is running a bit lean (around 14:1 A/F Ratio) in the low to mid RPM ranges when you use less that 60% throttle. Then after 60% it tends to run rich, meaning lower than 13:1 A/F ratio. I strongly suggest that you do not install an aftermarket filter or exhaust without a PCIII or other fuel device.

Below is a dyno run showing the HP gains from the PCIII and a custom map that I built for the bike. Nothing on the bike was changed. Stock filter and exhaust, snorkel in place.

The PCIII with custom map made a big difference. The bike gained around 2.5HP at peak RPM, meaning it would push out around 45HP if I tested this at sea level. Jon who rode the bike with the new mapping said that the popping backfires under deceleration is much less now and it feels quicker when you accelerate. We checked the acceleration times in 4th gear and the new map helped the bike to accelerate from 2200 to 7200 RPM more than a second faster.

Then we played around with removing the snorkel alone, and we gained yet again, especially midrange power. There is a massive gain by doing this. I am not going to post that run as the stock filter did not fit snugly without the snorkel. I will test the bike again with the DNA filter and stage 2 adaptor this coming week and post the results.

We found another mod that really is going to give the bike a jump in HP, but you will have to wait and see.

More feedback coming soon.

Kev · # 2 13-07-09, 02:14

Nice work Freez. Can you run the XTZ without the air filter to see what HP it gains? It looks like to me that this bike needs a lot more air then a fuel adjustment, as there is quite a dip in the mid range HP & torque between 3500rpm & 5000rpm.

Can you also post the fuel map in the Map section or send it to me & I will add it there.

CaptMoto · # 3 13-07-09, 02:54

Hello Freez, please can you check the TPS number code and part number and also same for the ECU, also, rumour has it that the XTZ might have a different throttle body from the XTX/XTR is there any truth in this?

What we are trying to understand here, is what makes the XTZ 99.9% surge free as opposed to the X and R which are still known to suffer from a slight surge from factory, my question is, is this due to a different ECU/TPS and Airbox + filter combination or other?

Thanks for your feedback in advance.

Kev · # 4 13-07-09, 05:07

I also forgot to mention that after seeing a few XT660 heads there is a difference in the castings between the years.

The 04/06 heads have a different casting numbers to the 07 models, the 04 to 06 models have very bad inlet port to valve seat shaping with the valve seat sticking out in the port, where as the 07 head has a almost perfect matched port to seat, this may account for the extra HP on the XTZ up top.

Freez · # 5 13-07-09, 07:37

Will send you the map later today Kev. Please PM me your e-mail address again.

The XT660R we compared it to was an 08 model, so the head should be without the bad casting flaws of the earlier models. I have found that top RPM power is very much fuel dependant. A little bit off and you loose 1 to 2 HP easy, so in stock form the XT660R might not be tuned as well as the XTZ. Also tyre pressures and tread can cause that extra little bit of a gain. The XTZ and XTR come out with different tread tyres.

Will try and see if I can spot the ECU, throttle body and TPS numbers, but these things are hidden behind a bunch of cables, tubes and frame parts. Maybe it will just be easier to see if the parts numbers are the same as the XTR's from Yamaha. Will give feedback on that.

About the no filter test. When I dyno a bike to see what gains we can expect I removed all filters and other intake air restrictions and then use that as a base line. I then start installing filters and so forth, but try and get it back to perform as it should without filters. If you saw my initial mail I mentioned there is one mod that we are looking into. Problem is, no bolt on kit exists to make this an easy upgrade, but we are working on that already. It is air related and the gains will be MASSIVE!!!

jiauka · # 6 13-07-09, 11:02

Quote:

Originally Posted by Freez

If you saw my initial mail I mentioned there is one mod that we are looking into. Problem is, no bolt on kit exists to make this an easy upgrade, but we are working on that already. It is air related and the gains will be MASSIVE!!!

Sound great!!!, is there any chance that you PM me with that mod?

have fun,

j.

Kev · # 7 13-07-09, 11:03

Quote:

Originally Posted by Freez

Will send you the map later today Kev. Please PM me your e-mail address again.

The XT660R we compared it to was an 08 model, so the head should be without the bad casting flaws of the earlier models. I have found that top RPM power is very much fuel dependant. A little bit off and you loose 1 to 2 HP easy, so in stock form the XT660R might not be tuned as well as the XTZ. Also tyre pressures and tread can cause that extra little bit of a gain. The XTZ and XTR come out with different tread tyres.

Will try and see if I can spot the ECU, throttle body and TPS numbers, but these things are hidden behind a bunch of cables, tubes and frame parts. Maybe it will just be easier to see if the parts numbers are the same as the XTR's from Yamaha. Will give feedback on that.

About the no filter test. When I dyno a bike to see what gains we can expect I removed all filters and other intake air restrictions and then use that as a base line. I then start installing filters and so forth, but try and get it back to perform as it should without filters. If you saw my initial mail I mentioned there is one mod that we are looking into. Problem is, no bolt on kit exists to make this an easy upgrade, but we are working on that already. It is air related and the gains will be MASSIVE!!!

As I expected.

What did you do with the O2 senor when you made the XTZ fuel map?

Freez · # 8 13-07-09, 18:37

The DNA filter and stage 2 adaptor arrived today. After a quick install it was time to build a new PCIII map to see what gains we will get.

Below is a dyno report comparing the stock bike with my custom PCIII map (red) versus the same bike, equipped with a DNA filter and stage 2 adaptor with a new custom map I made (Green).

From 3500 to 6000 RPM there is a gain in HP and torque with the DNA filter and adaptor, but below 3500 and after 6000 RPM there was a slight loss in HP and torque.

The next run shows what potential there is if my next upgrade pans out correctly. This mod will release a lot more power. Green line is XTZ with DNA filter and stg 2 adaptor versus the next upgrade (red). Both cases I used the stock exhaust system. As you can see there is a very nice gain in HP and torque from 4500 to the limiter. Again slight midrange lost, but a gain in the low end.

The last dyno run shows a stock standard XTZ versus the power output I am aiming for. Will update you all once we get there.

Exhaust might follow in the next few months, not sure what Jon has in mind for the exhaust system.

Both PCIII maps for the stock and DNA equipped XTZ can be downloaded from the Kev section. Kev will post it shortly. Note you have to be an XT660.com supporter to get the maps.

Freez · # 9 13-07-09, 18:42

Kev, I used the standard O2 eliminator for the XTZ, same as I have always used with the XTX and XTRs. So far so good, no errors. We used a sump plug to block the hole in the header where we removed the O2 sensor.

Kev · # 10 13-07-09, 23:14

Nice gains.

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