Gernby

[I looked through that thread, which only has 5 pages with my settings. Can I assume that you were referring me to this post that had videos?

If this is the post, then let me tell you why I think it's inconclusive.

1) I couldn't find anything about the "controls" that Gilly_S2KFreak put on the test to get valid results that actually represented something meaningful. They might have just done a single pull on a cold or heat soaked car, then installed the exhaust and did a "real" dyno test.
2) I'm not familiar with the Megan exhaust, but then again, I don't care about it either. My test is about how the stock exhaust compares to a 70mm single when there are other supporting mods AND a good tune.
3) I didn't see any AFR curves or any mention of them. How do we know that the Megan exhaust caused the car to run excessively LEAN due to it being so awesome that it made less power than the "crappier" Berk 3"?
4) That car put some seriously crappy numbers down on that DynaPack. I've never heard of an S2000 making such poor numbers, so there's NO TELLING why the Berk exhaust made them slightly less crappy.

Regarding the 2nd part of your post, which I missed earlier. I don't just "believe what I want". I argue what I believe until the argument comes to a conclusion. I think that's the only way to really learn anything. If you aren't arguing, then you're just memorizing. I am a very analytical person, who went all through school arguing with teachers until I really understood what they were teaching. By truly understanding something, I didn't have to memorize anything. I actually went all through college without even reading a single chapter of a text book. This didn't work for History calsses and such, so I repeated a few of those ...

Gernby

I'll admit that my belief that it's impossible to never have vacuum inside an intake manifold is based on intuition. It just seems to me that if you were to suck air through a plenum with a filter on the end, there will be a restriction that causes vacuum. Maybe there would be some exotic intake manifold that would prevent this.

However, I'm certain that there's nothing "wrong" with my intake manifold that isn't also wrong with every other '06+ AP2 intake manifold. I'm also certain that whatever restriction my intake manifold creates, it also created it when it was bone stock. It also did not prevent me from making much, much more significant gains with an intake, header, fuel injectors, and / or test pipe. Basically, I don't see any reason to think that we can blame the intake manifold for preventing the 70mm from making any gains when it didn't prevent anything else from making gains.

There is at least one more test that I will do before returning the exhaust. I will put the OEM catalytic converter back on, and test the exhausts again. I'll also try testing a stickish tune with them. Since my car runs so damn lean, I think I'd gain power by restricting exhaust some to richen it up!

chef-j

I'm sure you saw this dyno sheet from AWDmotorsports. I believe it's AP2 stock expect inj/3" headerback/haltech tuned, but ran race gas. why do you think we see so diff result from yours? I have not seen any 2.75" vs 3" dyno yet, but i wouldn't say it is much diff. Or do i missed something.

chef-j

[QUOTE=b.r.i.a.n.,Jan 13 2011, 02:23 PM] in this case though, this soft dyno can help you get to the vicinity of mbt but like i've said before there are way too many variables to take into account.

H22toF20

Their has to be something we missed. This is the first out of many results that have lost power with a bigger exhaust. Heck, I've saw a B16 make power with a 3" over a 2.5".

Endyne even states that the OEM intake manifold chokes a "healthy" motor.

crazysupratt

Very strange that even adding the 70mm testpipe that it didn't improve. Every car is different but when I added the exhaust, it showed and felt quicker. Here is the edyno and softdyno of the change after the exhaust installed.



This is the log inputed into the softdyno software:

Blue is with 70 mm exhaust and red is stock exhaust.





The only other mod that I have is injen cai intake and 70mm test pipe.

Hirevs2k

i don't have any dyno plots or anything coz it's not worth showing or braggin. anyhow, i used to have a 2.5" bluddy club spec III exhaust and it is weaker than my new set up which is greddy 70mm ti-c. granted, the peak whp wasn't much of a gain but the fact was, i didn't lose any hp over 2.5" exhaust. and in fact, i gained a shit ton of midrange whp. however, i did not do a baseline on stock, just the two exhaust.

gernby, even if your data was true. how would you explain to others how they have gained more hp over 2.5" exhausts when they have dyno'd and street race the same cars?

Gernby

I saw that dyno, and it is impressive. However, the baseline dyno was done weeks before with a totally stock, untuned car, IIRC. Then they spent weeks really geeking out on the tune to achieve 100% of the gains they could get. They did this with E85, which I'm sure also required an injector upgrade. Based on my results from performing the same upgrades (injector upgrade, E85, tune, and exhaust), I think the exhaust is clearly the least significant change they made.

I've performed tests like the one I did for the 70mm exhaust for tuned vs. untuned, then also for OEM injectors vs. 630cc Siemens Deka injectors, then also for E85 vs. E10. They all showed more significant changes than this 70mm exhaust and 70mm test pipe.

All of the tests that I've done have been for a single change at a time. I don't see any value in a test whee multiple changes are grouped into a single test. You could have 1 thing cancelling out another thing, and assume neither change did anything. It's just bad practice, and leads to false beliefs ... like the belief that a 70mm exhaust and 70mm test pipe will always perform better than a 60mm test pipe with a stock exhaust...

Gernby

The eDyno plot shows that there was no SAE correction, and I don't know which version of the soft dyno you are using. Did it have SAE correction, and was it enabled? What other steps were you taking to "standardize" your datalogs for consistency? Same day, similar climate, exact same vehicle weight, same road? Did you retune the car after swapping the exhaust?

As I've mentioned a few times in this thread, the weather conditions here right now are unbelievable for power. If I turn off SAE correction, peak torque jumps 12 ft-lbs and peak power jumps 17 hp.

Crackerballer

Gernby, great tests and we appreciate your efforts, but you will never be able to please everyone on this board. There are so many people who would rather try to prove you wrong then help you move forward to valid conclusions or ideas for future testing that you would go insane if you worried about them all.