Gernby

I thought I mentioned that. The 70mm HFC with stock exhaust was terrible. It didn't perform well, and it droned worse than any other combo.

Gernby

I'm kicking myself for not doing more standardized tests with the stock tune. However, I did find some dectent soft dyno files with the stock tune. The blue line below shows the stock tune with the stock catalytic converter and 70mm ASM single. The red line shows the stock tune with 70mm TP and 70mm ASM single. The green line shows the custom tune with 70mm TP and 70mm ASM single. Obviously there are gains, but check out the AFR curves below that ...

TougeS2k

excellent, thank you

Reckon

Hmmm...good point. I'll see if there is a tuner nearby, checking with my local forum. Would it be as difficult to jusify the purchase of a header as well, if no tune is available? I have an 05 so my options are limited in that aspect.

Thanks!! Really good information here!!!!

EDIT: I see from your most recent post that the gains from the TP and Exhaust with stock header and stock tune was still a decent improvement over stock cat and exhaust with stock header and stock tune. Granted, the tuned version is great, but it would appear that the TP and exhaust on stock tune will provide benefits (around 5hp at 7k rpms, not bad for a $70 part).

Gernby

The plot I posted this morning was for a 70mm single. I'll see if I can put together a similar plot for the stock exhaust and 60mm TP. I don't believe the gain is as significant.

Gernby

Okay, so I was wrong about the gains from the 60mm TP being as significant on the stock tune. Here is a plot similar to the one I posted above, but with the stock exhaust and 60mm test pipe. The blue line is stock tune with stock catalytic converter and stock exhaust. The red plot is with a decent tune that wasn't quite "done" with a 60mm TP and stock exhaust. The green plot is the stock tune with just a 60mm TP and stock exhaust.



NOTE: The green and red lines below are reversed! The green line below goes with the red line in the plot above, and the red liine below goes with the green lin in the plot above. Sorry.

Gernby

Oh, and I forgot to mention that all of the plots in this thread were done with a PWJDM intake, Hondata IMG, and some of them were done with larger injectors. However, I didn't overlay any plots for comparison that didn't have the same supporting mods.

takchi

I appreciate your work! Does that test include custom tune too?

Gernby

Yes, I adjusted fuel tuning for any combination that showed more than about 1% change from my target AFR. However, I used the same timing map for everything, which is MUCH more agressive than stock, but not as agressive as it's been for more "permanent" setups. I just didn't think there was enough benefit from full ignition tuning for an exhaust test. If it were a header test, that would be another story...

Swiftoy

Could you run a 70mm tp with a stock header and 60mm aftermarket exhaust would there be any benefit over the 60mm tp? or is it just a waste to go 70mm on that setup. Opinion please.