nikitopo's BRZ OEM+ build

[nikitopo]

Originally Posted by Spec C Wannabe

Thanks nikitopo. That costed alot for OEM header!!

Let us know how it feel once you got it installed.

Without the heat shield it costs less, but yes you have to pay for OEM quality:

https://www.japanparts.com/parts/detail/51411

About the feel, it won't change much in mid range torque. After the 5k RPM the sensation is that you have a VTEC. This is with a combination of the header and the Cosworth stage 1.0 kit. The tune is also strong on high RPM, but I cannot attribute all the gains to the tune. This is a comparison graph of a pre-17 car (blue & yellow) and a post-17 car (red & green). You can see the difference especially after 5.5k with a bump in torque:



In the stock +'17 cars there are a few more changes, but you get most of the feel with the new header, a better air filter and a good tune.

Finally, the sound is more racy on high RPM.

[weederr33]

Originally Posted by nikitopo

Without the heat shield it costs less, but yes you have to pay for OEM quality:

https://www.japanparts.com/parts/detail/51411

About the feel, it won't change much in mid range torque. After the 5k RPM the sensation is that you have a VTEC. This is with a combination of the header and the Cosworth stage 1.0 kit. The tune is also strong on high RPM, but I cannot attribute all the gains to the tune. This is a comparison graph of a pre-17 car (blue & yellow) and a post-17 car (red & green). You can see the difference especially after 5.5k with a bump in torque:



In the stock +'17 cars there are a few more changes, but you get most of the feel with the new header, a better air filter and a good tune.

Finally, the sound is more racy on high RPM.

The Cosworth manifold really helps for the up top zing! It's really great. Also sounds sooooooooooo much better than the stock manifold.

[nikitopo]

Last weekend I finished all the logging of the Cosworth tune. There was a question of how the tune works together with the rest of the changes (throttle body, exhaust manifold). We had to make only a small change in the upper ranges and now I am using a revised tune. Everything else looks very good and the long term fuel trims are within the limits of a good tune. Overall, very satisfied with the Cosworth customer support and the final result.

I'm waiting now for the lightweight flywheel and clutch installation and to start the necessary break in procedure.

[nikitopo]

A couple of days ago I installed the Toda Racing lightweight flywheel. It came as a kit with an Exedy Stg2 clutch disk and plate. I've been blamed in the past that I haven't provided any evidence about improvements on installed parts. Following is a before and after logging using my Ecutek cable and program:




Total gain is 0.34 sec or about 6%. The logging has been done on same road (w/o level differences), same external temperatures, same ignition timing etc.


PS: I have one more log and the accuracy is on the one hundredth of a second. So, I would say pretty accurate.

[weederr33]

Originally Posted by nikitopo

A couple of days ago I installed the Toda Racing lightweight flywheel. It came as a kit with an Exedy Stg2 clutch disk and plate. I've been blamed in the past that I haven't provided any evidence about improvements on installed parts. Following is a before and after logging using my Ecutek cable and program:




Total gain is 0.34 sec or about 6%. The logging has been done on same road (w/o level differences), same external temperatures, same ignition timing etc.


PS: I have one more log and the accuracy is on the one hundredth of a second. So, I would say pretty accurate.

But you didn't even post pictures of said parts

[nikitopo]

I've just found that the same parts were installed in the TRD 14R60 car:

[ermax]

Originally Posted by nikitopo

A couple of days ago I installed the Toda Racing lightweight flywheel. It came as a kit with an Exedy Stg2 clutch disk and plate. I've been blamed in the past that I haven't provided any evidence about improvements on installed parts. Following is a before and after logging using my Ecutek cable and program:




Total gain is 0.34 sec or about 6%. The logging has been done on same road (w/o level differences), same external temperatures, same ignition timing etc.


PS: I have one more log and the accuracy is on the one hundredth of a second. So, I would say pretty accurate.

Did you happen to weigh the OEM flywheel?

[nikitopo]

Originally Posted by ermax

Did you happen to weigh the OEM flywheel?

OEM flywheel is 9.34kg/20.6lbs. Toda Racing flywheel is 5kg/11lbs.


EDIT: Total weight of car is around 2620lbs.

[nikitopo]

Last September I installed the Sachs performance coilovers. I don't drive this car during winter and the new suspension was for a long time in a break-in period. Last week I realized that the settings were too aggressive for the road. The setting was from the beginning -5 clicks from full stiff instead of +5 clicks from full soft. Overall, this kit has 20 clicks and it was set up like this by the person who installed it. So, I changed now the settings to the softer side and I expect an even better result. Tomorrow I'll install also the +'17 rear stabilizer bar which is a bit bigger. Reason is because the rear spring rates are a bit on the soft side. Pictures of the new bar and bushings on the first page. I'll post an overall review after the installation.

[nikitopo]

I had the chance to check the rear sway bar and the ride is definitely flatter and overall better. I didn't notice any difference in comfort, apart from the rear wheels being now a bit more dependent. My springs are progressive, but on average give a 35.8N/mm rate front and rear. The stock '+17 suspension has approximately a 30N/mm rate front and rear, so I would say the new rear bar is within specs.

Source: https://documen.site/download/zf_pdf

[nikitopo]

After having the car for a long time in the garage and after fixing an issue I had with my overpipe (broken stud), I did a few more road dyno runs. Following are the findings ...

Here is a factory dyno comparing the newer and the older header design. The red torque curve is of the +'17 MT header and the blue one of the older. Notice that there is a noticeable bump in performance in the area of 5500-6700 rpm:



Here is a 3rd gear virtual dyno graph with a similar increase at same rpm's (marked in red boxes):



The torque curve is pretty much similar and accurate. Even the small decrease in two points @6000 rpm is because I had to change lanes during the run. Otherwise, the curve would remain same up to 6700 rpm. So, what are the conclusions ...

First of all, you can get the complete gains of this change without a re-tune of the engine for the particular header. Secondly, factory focused on the higher rpm's area and not trying to fix the torque dip. Such a decision is certainly good for performance on the track, but not for a day to day driving where a flatter torque curve in mid rpm's would make more sense. Finally, the JDM +'17 MT cars are spec'ed at 207ps with a peaked difference of 7ps if you compare with the blue torque curve. If I make the same assumption and compare my own curve with a flat curve in the 5500-6700 rpm area, then I have the same gains and maybe a bit more because of other changes.


Overall, I would say that Subaru did a great job if we consider that older and newer headers are catted designs. Well done Subaru!

[Prodigalson]

nikitopo, you are in Germany? I'm here in Germany for a four month assignment..I'm in the Stuttgart area.

[nikitopo]

Sent pm. Thank you.

[nikitopo]

Originally Posted by tomm.brz

your words:


http://www.ft86club.com/forums/showp...89&postcount=8


"My own car feels of an equivalent 250-260hp car and I don't think it has been ruined somewhere."
and more recently you bumped up to 270hp "feel", just can t find the post or lazy to find it, but i m sure a lot of people remember you saying that :ç )))

I am moving this discussion here ...


Where in my words can you find the 280bhp number? I said about 250bhp if someone measures a base '13 car to be around 190bhp and 260 if someone goes with the official catalog number. And these numbers are not actual, but more about a feel after working A LOT on specific NA power mods and weight reduction. All the details can be found in this page like how the new exhaust manifold gives a power bump after the 5.5k rpm range or how good the Cosworth tune works in comparison with the stock tune. On weight reduction I was just lucky because my car was already lighter (-35kg) from the factory and I didn't have to make a lot of modifications to reach my weight target. I bought the bare bones trim level which was available in certain countries in Europe up to year 2015. If you check the first page you can see that the boot interior was already stripped from the factory. So, the 270 or 280 numbers are your own words and interpretation. At least if it was not well understood in the past, then I believe that it is clear now.