It seems to be the better alternative so far. a dyno of 5whp peak and overal gain across the power band of 2 whp is more than what we get from the DC header.
wanna learn more: from http://www.new
Curious to see the result on a port matched and polished GTS exhaust manifold, I asked Joe @ http://alaniztechnologies.com/
for help . From his experience and knowledge of head porting and air flow dynamics, I figured, luck was on our side. I chose him because of his respected reputation in the racing community, and the fact, he checks all his work with a Flowbench machine (aka. the bullsh!t filter). I asked if he would be intrested in a bit of R&D work and that I would supply the header in return. He was enthusiastic about it and just as curious. He mentioned extracting more power on todays high-output-multi-valve engines is not an easy task. The 2zz's well designed header piping (minus the merge collector) makes it even more daunting. This is from his experience porting high-specific output Honda dohc v-tec engines and various Intake
and exhaust manifolds a like. He hinted similar traits the 2zz shares with Honda motors and the tedious amount of trial&error to extract note worthy gains. The fact that there is no current aftermarket cams, tuneable ecu, or adjustable fuel systems available to compliment a better flowing header isn't too promising. Even if he was able to improve exhaust scavenging a bottle neck elsewhere might prevent any gains to be realized. Still, these are only speculations. Alaniz and I want hard facts. We want dyno results of the stock header and his p&p version. Of course, that wasn't satisfactory enough for us. We also want same day dyno, same test car, on one dyno and as little time interval between comparison to factor out temp, barometric, and humidity conditions. For that task, We needed someone willing to cater to our special need. A person who is unbiased and willing to give the most accurate back to back comparison. For the task at hand, we went to Church Automotive Testing in Torrance CA (310-787-7123)
We weren't sure what to expect. Will it loose power at low rpm in return for better top end, vice versa, or will it loose and not gain at all? We made 6 total dyno pass. 3 pass with the stock header and the last 3 with the p&p version. At 9:00am, we got our base/stock number yeilding good result at 181whp with 51.8F outside temp followed shortly by 2 more pass of 180whp. At 9:30am, we finished dynoing stock. We promptly start the swap of exhaust manifolds. 3hrs later, the p&p version was instaled. We fired her up once again. By this time, engine temp had grown cold and ambient had risen to 59.2F. We let it warm up a bit before making the first pass. Wow, 186whp! That is 5 more whp difference in peak hp. Alaniz and I are high-fiving each other only to be interupted by Sean's (dyno man in charge) witty but honest remark. He said, "Hold on.. let's wait and see what the 2nd and 3rd pass yeilds. I'm going to warm up the car a bit more and stabilize the engine temp", a while checking the OBD scanner for temp read outs. 2nd and 3rd pass both resulting in 184whp.
We took the best stock pass and compared it to the worst p&p header pass and the result is as follows.. 3whp gain at peak. 5whp gain at 8063rpm over stock and a consistent gain of 2whp from 4100 to 6000rpm. It lost about 1whp from 3500 to 4000rpm.
(1280 x 960 high res pic link) https://www.celicahobby.com/gal...ds/DSCN0297.jpg
The lower plot on the graph shows air/fuel ratio. As you can see, the car ran leaner with the p&p header after 5000rpm which is partly due to increased scavenging effect the p&p header is producing. During full throtle, the ECU is at open-loop and fuel trim is already at maximum enrichment. This is troubling since we may have hit the roof with the Celica's fuel system. At 8063rpm the air/fuel ratio is at 13.6:1 compared to the 13.8:1 stock header. Remember, my car isn't stock. It would be nice to know the air/fuel ratio for a bone stock GTS so we can gauge how much we have strayed away. Remember, 14.7:1 is stoich but not always the best for maximum power. Who knows, maybe the GTS was designed to run lean from the get go! More fuel would be nice at this point, or maybe not??
These are the list of mods during testing. Nothing was changed, altered, or swapped aside from the headers itself.
GTS 2k 6spd:Injen
1st gen CAI
removed catalytic converter
Kazuma race exhaust
Close-ups of the test subjects
(1280 x 960 high res pic link)https://www.celicahobby.com/gal...ds/DSCN0278.jpg
Since the header flange is made of cast iron, a special carbide bit must be used to grind out the ports. Regular high speed steel bits will dull in minutes. It is by far more time consuming than working with aluminum. This is one of the reasons Alaniz dislikes working on "iron" head V8s in general.
P&P close-up: (1280 x 960 high res pic link)https://www.celicahobby.com/gal...ds/DSCN0287.jpg
Stock close-up: (1280 x 960 high res pic link)https://www.celicahobby.com/gal...ds/DSCN0281.jpg
I'm happy with the result and I've asked Alaniz if he would be intrested in providing this mod to Celica owners. His reply, "My specialty is with cyl. head modifications, but if there is enough demand within the Celica community I will consider it."
So, there you have it folks. The facts are on the table, cut and dried. Let Alaniz know what you think.