Re: HP and Torque Curves

["I.Mannix" <mannix@privatei.com>]

At 3:34 PM -0600 05/22/1997, Stephy G wrote:
>Jason Brunberg wrote:
>>
>
>>         So what's the deal with my car, then.  I forgot to mention >that
>>I have
>> drilled out my airbox and added a K&N,
>
>That was a question I posed to a list member but received no answer (ahh
>well).  When you drill out your air box, my question is, does that make
>your engine run lean/burn up your valves, etc.?

No.  Adding more flow/less restriction before the fuel meter does not
change the amount of fuel delivered.  More air past the plate, more fuel -
I like to think of drilling the airbox more along the lines of a bigger
door - it allows air into the engine faster, more of it.  Drilling out the
box won't lean out the mixture.  Drilling out the box will arguably lessen
power, though - hot air horsepower reductions offset the gains in flow.
Dunno.  I have a chopped airbox right now, planning on doing a cold air
deal tomorrow (divisional this weekend).    When I cut the bottom of my box
out, there was a distinct improvement.  I have gotten used to it now, feels
like the same old slow car.  Cool air is important, but the intake hole on
the CIS-E box is small - it is a tossup, or a bit of work to fit a cool air
tube between the ground, tranny and clutch cable.  FWIW, hope this helps!


>Again, from the various mags I've read, a mandrel-bent pipe system
>(equal diameter on all the bends for maximum flow) going into a free
>flowing muffler is sufficient.  Some folks take it a step higher with
>those new-fangled ceramic downpipes (hmmmmm).  Basically, bigger in the
>exhaust department doesn't necessarily mean better torque.  If the pipe
>is too large, bottom end torque is said to suffer [guess those Honda
>guys don't know that :)]  Just makes more noise is all.

Correct.  I made a semi-educated guess on pipe diameter when I had my
exhaust made - 2.5" pipe.  I was looking for peak horsepower, not torque -
I got decent power, but no torque.  My car gets out of its own way, but it
could use a little more low end.  Depending on displacement, there is a
pipe diameter which flows enough - any bigger, and velocity goes down.
Seems to be around 2" for the 1.8.  Sooner than later, I am going to put a
2" pipe between the cat and the axle, see what it does.


Mannix








--
To subscribe or unsubscribe, send email to scirocco-L-request@privateI.com,
with your request (subscribe, unsubscribe) in the BODY of the message.