In advance....yes, I searched

What I'm wondering is...why does the Hondata reflash for the Si's K20A3 make almost 20whp more than the base RSX reflash? Why does the Si get a rev limit of 7700, while the RSX gets 7300? These are both K20A3s....if there were something significantly different in the engines themselves, I would think Honda would've reflected that in the engine codes....

I ask because the EP3 is really looking like a better option than than a base RSX, at this point...but I'd prefer to buy an RSX. I'm hoping there's an easy explaination for this

 

No CAIs on either.





Base RSX with CAI (still doesn't come close to the EP3)



Confused!

 

In the Tuning Notes before the Si with I/H, it says "Two cars were used for testing. A totally stock Civic Si, shown in the graph above, and another with CAI and header."

I posted the totally stock graph. I don't get it. Even the RSX with the reflash and CAI doesn't come close to the Si with just the reflash.

 

Ah, crap. I just had some info and it got
bunked.

Trying again:
(I think this is from Shawn Church, where they
dyno'd the first reflashes at)
"The EP3 uses a higher rev limiter simply because it can take advantage of it. With the base RSX there is simply no point in revving higher. You'd be slower than if you shifted at 7300 rpm. The EP3, OTOH, hangs on to the power much better and Hondata has set shift point so you have a bit of revs past the power peak, which means that you maintain good average top end power when shifting at the limiter."

Still looking for more info for ya (really just
trying to sway you to get an ep3, but oh well. )

 

Still confusing, I was under the impression that a K20A3 is the same motor as a K20A3

 

More info:
"The intake manifold is the key difference. The Si has a bigger TB and an intake manifold better suited to high rpm. It holds onto the power better and therefore can make use of the extra rpm. The base torque drops off so fast, there isn't any point in revving higher."

http://forums.clubrsx.com/show...+base

Aren't I just a ***** today?
EDIT: sorry to switch it up on your regal, just figured I'd delete my senseless posts.

 

That's interesting...and even the stock Si is making 10 more whp than the RSX. That's kinda shady that Honda lists both cars at 160hp even though EP3 seems to be significantly stronger!

 

Yup. The Civic has the same intake manifold as the Type-S and the same sized throttle body as the Type-R!

 

Thanks everybody

 

that is because the two cars are very different. the base has a cheap *** intake manifold and it can not handle much. the si ecu is design for more power and more tq compare to the base rsx. the si is a faster car, the gear ratio is much closer than the base.... that is why the difference is there...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by weoassface &raquo;</TD></TR><TR><TD CLASS="quote">that is because the two cars are very different. the base has a cheap *** intake manifold and it can not handle much. the si ecu is design for more power and more tq compare to the base rsx. the si is a faster car, the gear ratio is much closer than the base.... that is why the difference is there...</TD></TR></TABLE>

LOL - wow, very informative

The base has a dual-stage intake manifold which gives it better midrange torque than the Si (secondary runners open at ~4800rpm). The Si has a larger TB and its single-stage IM is slightly shorter/wider than the base's secondary runners. These two factors allow the Si to breathe better near redline, giving the Si slightly more peak HP.

The base doesn't have the extra balancing shaft that the Si has (giving it a few hp), but on the other hand, the Si has electric power steering (which saves a few hp).

Those are the differences between the two engines. You can't compare the two dynos done by hondata. In fact, as a general rule of thumb, you don't compare dyno charts of two different cars done on two separate days.

On average, most base RSX's dyno between 132-136whp and most Si's dyno about the same, maybe 1-2 whp better. The RSX's always have a fatter midrange and the Si's breathe better up top. It is for that reason that hondata's increased redline helps the Si more than the base RSX.

Also, the hondata-flashed Si dyno on their website is NOT a typical result. I'm not saying they BS'd their results, but if you go to ephatch.com, you'll see there is constant debate about how effective their reflash is (although everyone seems to like the 7700rpm redline).

Between the Si and the RSX, it's as close to a drivers' race as you'll see. The Si has better gearing, but the RSX is lighter and has more midrange torque. The fastest stock track times for both cars that I've seen is 15.6.