exhaust question

by **JvR** » Fri Aug 21, 2009 5:47 am

Midias wrote:
JvR wrote:Sorry (my english is not so good) but a catback is the last part of a exhaust? (what you see at the back of the car)

I get a dual exhaust

are you getting 2.5 inch dual exhaust?

The catback is everything after the catalytic converter back all they way to the exhaust tip.

Not really ...more like this:http://www.octanemotorsports.com/images/RMS-0893071549.jpg

by **Midias** » Fri Aug 21, 2009 8:54 am

2.5 into that should be just fine.

by **JvR** » Fri Aug 21, 2009 10:30 am

Thanks a lot!

by **RON** » Fri Aug 21, 2009 2:34 pm

jetbtkng wrote:3 in is the only way to go, im making 284.5 hp, and 270 fpt, with the obx complete exhaust, no cats, that was with stock air intake, manual tranny,

and 6lbs..

Ok..as you know I'm going to dyno at same place (with 5.5lb) and 2 1/2" (Y pipe and cat back)...in fact I have ony 2" Cat inlet/outlet that's flared out to meet the 2 1/2"

. Should be VERY interesting to see my #s. I'm planning the dyno in a couple weeks.

ron

by **JvR** » Sat Aug 22, 2009 2:03 am

I have googled around and found this:

http://www.mk5cortinaestate.co.uk/calculator5.php
http://www.autolounge.net/calculators/e ... izing.html

My conclusion is:2.5inch is fine till around 300hp (not WHP)
So if a s/c does not run over the 6psi this 2.5 exhaust will be fine.

Do you make the same conclusion?

@Ron:
I am very curious ....i hope you will test it in the coming 3 weeks :wink:

It is funny,i thought i just ask a "simple" question what have been discussed before :lol:

by **JvR** » Sat Aug 22, 2009 2:06 am

I have googled around and found this:

http://www.mk5cortinaestate.co.uk/calculator5.php
http://www.autolounge.net/calculators/e ... izing.html

My conclusion is:2.5inch is fine till around 300hp (not WHP)
So if the s/c does not run over the 6psi this 2.5 exhaust will be fine.

Do you make the same conclusion?

@Ron:
I am very curious ....i hope you will test it in the coming 3 weeks :wink:

I'm a bit afraid to do a run...then i will found out my car is not that fast/in good condition :roll:

It is funny,i thought i just ask a "simple" question what have been discussed before :lol:

by **RON** » Sat Aug 22, 2009 12:20 pm

JvR wrote:I have googled around and found this:

http://www.mk5cortinaestate.co.uk/calculator5.php
http://www.autolounge.net/calculators/e ... izing.html

My conclusion is:2.5inch is fine till around 300hp (not WHP)
So if the s/c does not run over the 6psi this 2.5 exhaust will be fine.

Do you make the same conclusion?

@Ron:
I am very curious ....i hope you will test it in the coming 3 weeks
I'm a bit afraid to do a run...then i will found out my car is not that fast/in good condition

It is funny,i thought i just ask a "simple" question what have been discussed before

That web link you gave shows 300 HP requires 2.7 diam (1 pipe). We'll see when I dyno. I got 261 WHP last time on another dyno and this one (at Church) *should* read around 10HP higher (to the hubs). If so, then I'm not that far off Franks 285 with 6 lbs and headers and bigger exhaust with NO CAT.

Ron

by **JvR** » Sat Aug 22, 2009 1:22 pm

what is the differences between 2.5 or 2.7......

If the 2.7 piping has many curves and rough weldings....it will maybe preform less then a smooth 2.5 piping.

so i think, 2.5 is good enough for 6psi...i hope :lol:

And it is always better then the original :wink:

by **jetbtkng** » Sat Aug 22, 2009 3:16 pm

well ron if you get 10 more ponies you'll be on par with bbq bobs 272.2 hp, as shown with bobs dyno chart,

.....and hes an auto., 5.5 psi............................... :drinking:

by **Mole** » Sat Aug 22, 2009 4:02 pm

if no smog regulations, go as big as possible.

by **JvR** » Sun Aug 23, 2009 1:58 am

akora12 wrote:As for the a/f bung, it needs to be before the cat in the y-pipe. Make sure it's mounted at an angle as well.

Sorry i forgot to ask....I think the tip of the sensor must be pointing against the flow, but at what angle?

Mole wrote:if no smog regulations, go as big as possible.

In the Netherlands a car needs to be check every year. (called APK=General Periodic Inspection)
On that inspection day the check everything on the car..... mostly safety things (doors,belt,brakes,lights etc.) but also the (4) gases.
(the same as in California)

When the power is increased with more then 40%, i can not drive till it passed a road holding test.

Thanks again!

by **Midias** » Sun Aug 23, 2009 7:54 am

What is a road holding test

by **1gSE** » Sun Aug 23, 2009 8:24 am

JvR wrote:Sorry i forgot to ask....I think the tip of the sensor must be pointing against the flow, but at what angle?!

between the 10 o'clock and 2 o'clock positions

by **JvR** » Sun Aug 23, 2009 11:43 am

Midias wrote:What is a road holding test

haha, a stupid translation error. :lol:

I think you call it road handling test :roll:

1gSE wrote:between the 10 o'clock and 2 o'clock positions

So,10 o'clock=
_______\__________________
-------->\ (with the flow?)
_________\________________

So,2 o'clock=
________/______________________
------->/ (against the flow?)
______/_______________________

I don't understand it,sorry :oops:

by **RON** » Sun Aug 23, 2009 1:14 pm

..JvR

Our cars look alike..see my link at the bottom.

Ron

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