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I'm sure most of us know about this test.

Basically I'm starting to question the validity of this test after seeing other cars dyno and getting very different results. A car that has certain modifications you can pretty much guess what the power curve is going to look like. Even though every engine breathes differently they all have pretty consistant power curves with certain types of bolt-on modifications such as common I/H/C/E upgrades. My problem is that the power curves displayed in this test are not consistant with anything I've actually seen for myself.


The stock torque curve is way too flat and is making almost as much torque to the wheels as it should be making stock to the flywheel. The torque is consistantly 10-15 ft-lbs over any other near stock Type R I've seen dynoed including mine putting the peak HP at 176whp. They said before how they used the SMSP 2.5" exhaust for the stock dyno. Now I know SMSP's exhaust is good, but to give that huge of an increase without a 2.5" exit header I just don't know. I also know the Mustang dyno gives higher numbers than Dynojets, but I didn't think they'd be this much higher.

one of my main problems are the power curves of the 4-1 headers. There is no power loss anywhere on these headers compared to stock. I have never seen a 4-1 header make more or equal power in the low-end before VTEC than a 4-2-1 header in person. That's just not how it works. Every other dyno and track test I've seen since I've started this whole obsession has shown a loss of low to midrange power when using a 4-1 over a 4-2-1.




The big kicker is putting the DC JDM 4-1 up against SMSP's extra long sequentially paired hybrid 4-2-1 header. The SMSP horsepower curve is the thick red line.

(*edit: SMSP vs. stock shown since I no longer have the SMSP vs. DC JDM 4-1 , compare to the DC JDM above. MD.)






Import Builders does a lot of work with SMSP headers, and in every instance they completely blow standard 4-1's like this out of the water in all points of the powerband. Here the DC JDM makes equal or more power in every part of the curve except for the very top. If you go by this dyno all of SMSP's design features mean pretty much nothing.





This dyno done at Import Builders showcases what SMSP's design was made to do, and is like every other SMSP dyno I've seen done. The SMSP dyno done at the great header test is really just something I've never seen before and at Import Builders you see alot of SMSP headers around.

Just some thoughts I had on that "Great Header Test" that most see as the bible of choosing headers. I really don't know what to think of it anymore as it is completely inconsistant with anything I have seen and experienced in person. Any further thoughts?
 

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wow, this would be nice to have cleared up. I just bought a type 1 header, and "the great header test" played a part in my decision to buy it. But for some reason i remember reading that the ITR being tested had the comptech icebox equipped. So that could be the answer, but then again i dont think the icebox give 10-15 lbs. of extra torque....????
 

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the car had an icebox, testpipe on the comptech header only, the rest had a 2.5 in. 94006 carsound cat and smsp 2.5 in. exhaust.

the only downside to the test is whether the car would have run a stronger pull if you had the big headers go on first. the order during the day of when the header was run may affect the output since the motor is more tired at the end of the day, regardless of the number oil changes they did.That ITR engine took a beating. I certainly would not have volunteered my car as a test mule...so kudos goes to the person for sacrificing his engine for the test.

for a 1 day all out effort, you can't fault this as a grass roots attempt to get an answer. it was never done before and no-one ponied up the funds to do it..not even Sport Compact Car or Superstreet who have the cash and hookups to do a proper 3 day test. I know John doesn't think too much of the test and thinks it was rigged. I jut don't see how you could rig it. The differences aren't that much between the headers to show that someone tried to fix an advantage.
 

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Rigged? I don't know. I saw this too when I was looking at the website awhile back. I have to agree with Tuan about the engine taking a beating. They probaly did a header test when the engine was cold after an oil change, then the next two headers got a hot engine. I still don't see how this could create over 10 ft/lb's of torque. I would definitely look into this.
 

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Up to the point of the test, all the Mustang dynos seemed to record lower than thhe Dyno Jets. I believe the dyno operator even made mention of this and gave some reasons why the Mustang was better than the Dyno Jet. It's my understanding that the Clayton dyno is the one that reads high, but I don't have any experience with it.

I too was surprised at the results, especially of the Comp Tech header. This header has primaries that start out smaller than the USDM DC 4-2-1.

Let me clear up the test procedure here once and for all.

-The bone stock ITR that was offered never showed up.
-one of the would be spectators offered his (canukR???)
-We then changed his oil/filter with Mobil 1, installed a new cap, rotor and spark plugs.
-The donor car had a Spoon 4-2-1 with a Godspeed test pipe. These 2 items were replaced with a stock header and a 94005 cat built by Tom Payn I believe and were bolted up to a bone stock ITR cat back.
-The car had a CAI, Comp Tech or AEM I can't remember.

-So the baseline was done with CAI and 2-1/4" cat, peak whp was 178.58. This and the following peak numbers were taken from the data file not the graph that had a smoothing function applied to the data.

-A JDM header was not used with the stock exhaust which was a big brain fart by all of us.

-The stock header, 2-1/4" cat and 2-1/2" cat back made 179.25 peak

Then the JDM headers were tested with a test pipe (cat only used in the baseline runs) and 2-1/2" cat back. Below are the peak numbers recorded after about 3 runs for each set up. We all know that peak numbers mean jack but here they are anyway.

DC JDM 187.04
ITR JDM 185.56
JUN 186.57
Comp Tech 187.19
Type one 186.22
Toda 190.04
Spoon 187.41
SMSP 190.28
MuTech 187.11
Mugen 186.34

The best dyno jet numbers I've seen on a stock ITR engine with CAI, ITR JDM header, 94006 cat and a 2-1/2" cat back were 182.4 on George Knighton's car. Which is less than all the above, even when running a test pipe. As for the test weather, we stayed between 55-60 in the shop all day from what I remember.

Bottom line is be careful in comparing one dyno graph to another, even the same brand. Because the conditions can be different and the condition of the dynos can be very different.
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"for a 1 day all out effort, you can't fault this as a grass roots attempt to get an answer. it was never done before and no-one ponied up the funds to do it..not even Sport Compact Car or Superstreet who have the cash and hookups to do a proper 3 day test. I know John doesn't think too much of the test and thinks it was rigged. I jut don't see how you could rig it. The differences aren't that much between the headers to show that someone tried to fix an advantage."
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MD, I think if the test was rigged, one of the headers would have blown all the others away.
 

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i emailed the website, and this is what they had to say:

The hp is high for this type R. It was a very strong motor. The dyno is a mustang dyno, not a dynojet. So it is a realistic number. Some of the mods that he had done: he eliminated the power steering, some brand of intake and a few other minor bolt-ons. Sorry, but I cannot remember all else he had done. The original car we were going to use never showed up, so we used his as a replacement.

Also, even if the car is higher then a normal typeR. The headers were all tested on the same car, same day, same everything. So it would clearly show which header performed better because all of the other variables are the same. So you are comparing header to header. The dyno if very accurate. It is calibrated every 2 weeks and has been used in the past by car and driver and road and track to test vehicle hp with manufacturers claims. I hope this info helps. And all in all. The type1 header would be the one to get. When all the headers were compared to each other the type 1 was an exact copy of a spoon header. Which is why it put down similar numbers. The spoon might flow a little more because the welds were cleaned up. But that is something you can do also. More work = more money.

Thanks,
Jeff

note that the only reason he is talking about the type 1 header is cause i mentioned that i just purchased it.
 

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Discussion Starter #10
That's what I don't get. SMSP's header should have blown away the 4-1's in low end power if anything else. But the the DC JDM 4-1 did better than the SMSP everywhere below 6900 RPM. That's what really gets to me, because the whole purpose of the hybrid extra long 4-2-1 like SMSP is to give killer low to midrange while still leaving it open for the high end. But in this dyno test it really didn't do anything, kind of throwing out all that header/exhaust theory stuff out the window. It just doesn't match anything else I've seen before, which is why I've been concerned about it.
 

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I can see how the long primaries on the JDM 4-1 will give the exhaust gas a lot of acceleration, but other than that there is practically no anti-reversion effect. There is something screwy in that test, damnit.
 

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From the looks of it the 4-1 jumps at just around 5k right??? im thinking of going with the DC 4-1 i know in my MR2 i rarly go under 4-5k when doing twisties and off the line i hit 4ish as well never going under that.

i dont know... any insight on these tests that would change my mind?
 

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Im loking for this test. And any more info about it? I cant find this test online anymore..can someone provide me the dyno pictures?
 

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The website is no longer available.

There was a long long thread about it over at honda-tech and I don't know if they still have it in the archives.





Basically, it was a bunch regular Joe's like you and me getting together, donating & collecting money for the dyno time (actually Chad did an amazing job organizing it), both regular honda owners and shops loaned their header for the test, and a member (not attached to any shop or agenda) volunteered his ITR to be the test mule.

They changed the oil a couple of times during the test.

Histrorical perspective:

there was the first "Great Header Test" done by Sport Compact Car in Oct 1999 using a gen 3 GSR with an AEM CAI and stock cat, and a 2.36 in. exhaust, no tuning, done on a dynojet on various days.

this second one was done on an ITR with a Comptech CAI on a Mustang dyno and the details are described by SMSP who was there in the post above, including the fact that they weren't hampered by a stock cat. The good thing was that it was all done on the same day but the down side was like first test, no fuel/ignition tuning was done to harmonize the engine to each header. There was no Hytech in the competition. There was a Mutech though LOL: a Mugen 4-1 header which had to be repaired after it's primaries were crushed from a low ground clearance hit and had the back part of a Hytech with a 2.5 in. collector attached.

The questions of heat soaking and lack of tuning did come up, since the differences between the headers were negligible and the fact no major differences were found in the different powerbands among the top headers using different design layouts didn't make sense, as Surfer raised here in this thread. It was a great effort though by the grassroots enthusiasts like you and me and shows you what people (complete strangers to one another) can do if they come together in a common project to try to get answer that the companies won't answer or weren't willing to answer. They deserved an "A" for effort for sure.


The top 3 headers were the Toda, SMSP, and Spoon but the difference was hardly noticeable.


The third Great Header Test was done by Titan Motorsports and we have a copy of the thread here if you search under "great header" in the performance forum (but the dyno pics are lost). The good thing about this test was: there was fuel/ignition tuning for each header, it was done on the same car, on the same day, on the same dyno, using a full 2.5 in. exhaust system. This one by far is the most accurate of the 3 in terms of methodology of measuring power as best you can accurately. Hytech won that test. However, there was no SMSP in that test.


Remember in dynos you are looking at the relative changes. You look at the difference between the headers and not the absolute peak number for each header since we know each dyno can vary in calibration, wheel inertia added, correction factors, and dyno operator sampling method.
 

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if you want to see a good example of how much longer the hybrid header is compared to the stock length headers, you have it in the pic that I had posted of the Great Header Test 2 headers all lined up in a row there . And that's one of Dave's shorter SMSP headers. LOL

You know what added length does (see Header Tech article here).

He makes them even longer than the one in that test now and for the 2L people the collector options include both 2.5 and 3 in. OD.

John at Hytech also has a longer header and 3 in. collector.

To show the same idea more vividly, here's a comparison of a Hytech street header to a USDM Comptech, stock-length, street header taken from my old header article over at automotivetech.org:




So for people who are getting more serious about their hobby, the hybrid header design is the mainstream now because the comprimising between top end gain vs. the powerband width is minimized.
 

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Has John at Hytech gotten the patent on that design yet since he was the first to come out with the longer hybrid header?
 

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you'll have to ask John. I have no idea about his legal stuff.

I don't know if it's going to make a difference anyway since the cat is out of the bag and there are a ton of hybrid headers on the aftermarket that don't look like his but have the same basic design layout features which isn't a patent violation.
 
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