In-Depth testing of 60mm Dual vs. 70mm Single
01-22-2011, 08:25 AM
#201
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Here is the PDF that bpaspi sent. I briefly scanned through it, and see where it talks about why Honda decreased the size of the IM to improve throttle response, but it also says that it still achieves maximum output. I'll read it more thoroughly on Monday. Thanks for sending it!
01-22-2011, 09:32 AM
#202
Originally Posted by gernby,Jan 22 2011, 07:25 PM
I briefly scanned through it, and see where it talks about why Honda decreased the size of the IM to improve throttle response, but it also says that it still achieves maximum output.
"the maximum target power could be achieved."
Honda targeted 250HP for the F20C.
The Intake manifold has the volume for an 1.6 litre engine to achieve best throttle response. It should have more volume to provide more power:
01-22-2011, 10:02 AM
#203
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I saw that chart. However, the scaling of the chart makes it a little misleading. The ideal range for the F20C appears to be about 2.4-2.5, but the actual size is about 2.25, which is only about 6% out of range.
I just did my standardized test of the 70mm HFC with 70mm single. It seems that the benefit from the HFC is really just that it reduces the magnitude of the resonant dip caused by the catalyst on the high cam. The performance seems identical to the OEM cat on the low cam and also on the high cam above 5500 RPMs. Basically, if you have a stock ECU, don't bother with an HFC.
Green is the 70mm TP with 70mm single (VTEC at 3500). Blue is the 70mm HFC with 70mm single (VTEC at 3600), and Red is the OEM cat with 70mm single (VTEC at 5500).
I just did my standardized test of the 70mm HFC with 70mm single. It seems that the benefit from the HFC is really just that it reduces the magnitude of the resonant dip caused by the catalyst on the high cam. The performance seems identical to the OEM cat on the low cam and also on the high cam above 5500 RPMs. Basically, if you have a stock ECU, don't bother with an HFC.
Green is the 70mm TP with 70mm single (VTEC at 3500). Blue is the 70mm HFC with 70mm single (VTEC at 3600), and Red is the OEM cat with 70mm single (VTEC at 5500).
01-22-2011, 12:29 PM
#204
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Originally Posted by gernby,Jan 20 2011, 06:24 AM
I see the dip you're probably talking about on Toda's page, but I doubt it's the dip I'm talking about. The dip I'm talking about happens only if VTEC is engaged below 5500 RPMs, and it happens right at 5K. The car feels like you just drove into a 50 MPH head wind, and the engine starts sounding "bad", then a couple hundred RPMs later, it goes away.
Intakes & headers test later?
Cheers
01-23-2011, 01:37 AM
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Originally Posted by gernby,Jan 21 2011, 06:20 PM
Oh, I would also like to report that the 70mm single exhaust is an ASM. I didn't want to disclose what it was, since I'm borrowing it. I didn't feel comfortable"devaluing" someone else's exhaust. However, since it seems that there is a way to make gains with it.... I'm disclosing it.
I really do like this exhaust, even though I don't find it visually appealing at all. It is so refined! It is loud, and AWESOME sounding at WOT, but is so quiet while cruising. My modified OEM exhaust is the opposite.
I really do like this exhaust, even though I don't find it visually appealing at all. It is so refined! It is loud, and AWESOME sounding at WOT, but is so quiet while cruising. My modified OEM exhaust is the opposite.
Congratulations for your approach to testing. Maybe there is a need for summarizing all this... Keep up the good work!
01-23-2011, 01:49 AM
#208
Originally Posted by gernby,Jan 22 2011, 09:02 PM
I saw that chart. However, the scaling of the chart makes it a little misleading. The ideal range for the F20C appears to be about 2.4-2.5, but the actual size is about 2.25, which is only about 6% out of range.
Nevertheless, I don't want to spam your valuable Thread with this discussion.
01-23-2011, 05:24 AM
#209
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Originally Posted by Taseas,Jan 23 2011, 05:37 AM
I didn't know that ASM exhaust has a Helmholtz resonator. Is this specific one modified in some way? Also the OEM's Helmholtz resonator is replaced with another one. Does this one match the modified mufflers better, since the loop is eliminated? I guess something went wrong with the equation and that's the reason your stock exhaust is "loud" where it shouldn't be.
Congratulations for your approach to testing. Maybe there is a need for summarizing all this... Keep up the good work!
Congratulations for your approach to testing. Maybe there is a need for summarizing all this... Keep up the good work!
Something that I've learned over the last couple weeks is that every configuration will have different drone characteristics. The ASM droned less overall than my modified stock exhaust, but there was no telling what combo was going to drone and what was NOT going to drone. The absolute WORST drone of all came from my T1R header, 70mm HFC, and modified stock exhaust. I just drove around with that for about 20 minutes yesterday, and it was terrible. I believe this is primarily due to using a larger diameter HFC than the exhaust. If I put a 60mm HFC on, I would expect it to go way down. So the value I draw from this is worthless for people to go around saying X exhaust doesn't drone. I believe ANY exhaust will drone if they are mated to certain other parts.
01-23-2011, 05:26 AM
#210
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Originally Posted by bpaspi,Jan 23 2011, 05:49 AM
For an F20C, yes. But I thought you have an 2.2l F22C.
Nevertheless, I don't want to spam your valuable Thread with this discussion.
Nevertheless, I don't want to spam your valuable Thread with this discussion.