Celica Forums General Discussion Engine and Performance Porting your header

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 celica.org/forums/showthread.php?s=&threadid=60156

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://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
91octane unleaded

Close-ups of the test subjects


(1280 x 960 high res pic link)https://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://celicahobby.com/gal...ds/DSCN0287.jpg


Stock close-up: (1280 x 960 high res pic link)
https://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.

-Raymund

thats pretty cool

i liked how you wrote this posted i felt like i was there with you high fiving all the guysv

wow, there's this place near downey called extrude hone, and they can port and sandblast anything. I've always wanted to port my header, sandblast that mofo to smoothen out the pipes and ceramic coat it. but it's good to know that the gains are worth it. the only thing is getting off the header can be a Pain. sometimes i wished i owned a honda. my bro swapped a civic si header in 45 min.

so can someone put that in english for me

what are they doing when they 'port it'

what he said ^

this is cool but i would rather have a whole new header and tpr is gonna put that out soon so i will see which is better after the dyno comes out on that

let it be known that this dyno was done on an injen CAI first gen which is notorious for hp losses down low. with a TPR or aem it will garner better results...

does aem make a header for the gts?

yeah...it's called the DC header since AEM bought out DC a while ago

you said it ran 13.6:1 with the p&p and 13.8:1 with the stock header. then you said maybe the celica is designed to run lean. those two numbers are rich readings. maybe im just misunderstanding you and your saying they're leaner than you think they should be. just clarify that up so no one gets lost.
and also the celica should be designed to run at stoich, i think every car is supposed to for emmissions reasons. i could be wrong so somebody correct me.

ill wait for TPR, but good job and congrats on the gains

good stuff. CT

wait wait wait...this isn't MY header...this is just an article taken from new celica.

So is it worth porting My hotshot headers?

you are right about the two numbers being rich, but the fact that the header ran leaner means that it made power. about the celica being designed to run at stoich, well i dont know about that,cause it is a high comp.engine (2ZZGE)and running such an engine lean would be detrimental to the long term reliability of that engine due to excessive detonation. they do sell celicas all over the world where there are diffrences in ambient temperatures and availabilty of above 93 octane gasolene. i dont think the celica is designed to run lean.