|02-23-2013 08:37 PM|
|vinniekq2||The rear axle ratio needs to match the purpose of the car. I use a 3.50 gear with 27 1/2 tall tires with a standard. floor it in first or second and the tires break loose.|
|02-23-2013 08:33 PM|
Have you ever seen a race car with mufflers go faster than a similar car with open headers? 3 inch!
also if your engine revs 6500 rpm,your headers are also too small
|02-23-2013 05:40 PM|
Bert, what car? Approximate weight? Trans/converter? More 1/4 mile or 1/8 mile? Significant street driving?
Then I can answer that. As much "detail" as you're willing to share. What style rear axle?
X 2 on the "X" pipe. A lot of our Pontiac guys use Pypes. I've heard good and bad. The X-pipe definitely makes power, though.
|02-23-2013 04:59 PM|
2.5" mandrel bent pipe with x pipe..
from the x junction you have 5" for thet pulse to feed to.. more than anough for a 406
|02-23-2013 04:43 PM|
|02-23-2013 04:38 PM|
|macrobert68||dart shp 72 cc|
|02-23-2013 04:21 PM|
Yes, there will be a loss of low-end torque with a larger system (this engine doesn't appear to make much low-end, though). We tend to recommend, for maximum performance, and not necessarily the "sound", stay with 2 1/2" pipe until CID gets up around 500.
Particularly with smaller headers like you have, you need that "step" in the pipe to increase exit velocity. For "driving" (street use), this is important. If it's a dedicated race car that requires an exhaust system, then yes, 3".
BTW, those headers are awefully small for a 7,000 RPM 400. Just my opinion. I'd like to see 1 7/8" units on there. Upper end power would significantly increase. Regardless, this car will need some "stiff" gear to be a decent driver. What heads are they?
|02-23-2013 11:49 AM|
For your setup I would go with the 3 inch..I don't think you would lose that much on low end and your engine setup is for midrange and top end power..
|02-23-2013 10:58 AM|
but i cant remember if the larger the exhaust is for top end speed or low end tork.
|02-23-2013 10:54 AM|
You are going to get a lot of theory, and ideas on this, and some of the advise may actually be true.
But with so much misinfornation existing, and being reproduced by people on the web, the only way to know is to spend lots on time on a chassis dyno, with different exhaust configurations.
|02-23-2013 10:33 AM|
what size exhaust is rite ?
Hello everyone .My 406 has a 3000-6800 Rough idle, upper mid-range & top end power cam
10.3 compression flat top pistons
duel welind tunnel ram with 450s
Header Finish:Silver ceramic coated
Primary Tube Diameter (in):1 5/8 in.
Collector Attachment:3-bolt flange
Collector Diameter:3.000 in.
and im looking a
pypes Stainless steel
Intermediate Pipe Diameter (in):3.000 in.
Tailpipe Diameter (in):3.000 in. Pypes Street Pro Exhaust Systems SGG13S
Is this to big and will it rob power at low speed?