andy-gts

Question for all,
I have the devek level 2 headers and 3 inch dual exhaust on the stroker that Greg built and I am thinking of switching to the header exhaust that Greg builds but wonder is the 2.5 inch duals he sells with the cross over further back ( to move the torque peak a little higher in the rpm range) will cause any increased resistance to flow substantial enough to cause any top end or drivability problems?????

I doubt it , is my first feeling but I have no math to back up my feeling>>>>

any one with any knowlege on the subject.?

wont know until I compare on the dyno?


thanks in advance

andy

SMTCapeCod

" A section of straight pipe the length of a typical muffler, rated at the same test pressure as a carb (10.5 inches of mercury), flows about 115 cfm per square inch. Given this flow rating, we will see about 560 cfm from a 2.5-inch pipe. If we have a 2.5-inch muffler that flows 400 cfm, the engine reacts to this just the same as it would a piece of straight pipe flowing 400 cfm. "

http://www.superchevy.com/technical/...h/viewall.html

Opinion: I'd go 2.5 duals all day long, unless you're over 550HP.

andy-gts

I am a little over 610 at the crank before optimal tuning..

AO

Wait for cooler weather and you'll have plentyof torque. Dibs on the Devek LII headers is you decide to sell them. My new Euro needs them!

andy-gts

cfm at max 6800 rpm is 624 cfm. hmmm.

torque is excellent now, I just see the header exhaust that greg makes and surely if anyone can make something better .....he can and did with his super snake exhaust!!!!

andy-gts

I just got off the dynomax web site and found an interesting muffler with a spring flapper inside that cuts out drone but open wide open with increased full throttle flow....

anyone ever seen this muffler used and dyno'd?

terry gt

Called dynomax VT , got a pair on my car . no drone ,I have pictures in a drone thread

andy-gts

did they have any negative effect on power,,,,,do you has an additional rear resonator just before exit???

this sound great as I have quite a drone still with the devek system and cant carry on a conversation....

I will do a search for the thread!!!thanks

andy

AO

Andy,
I was looking into one of those myself when I was doing my exhaust, but saw some people complaining about the noise of the flap. IIRC there were some YouTube reviews that illustrated it.

I decided to go with Magnaflows which I have been super happy with. I believe Greg uses them too.

Rob Edwards

Andy, your engine ran on the dyno with both the Devek Level II's and a set of Greg's headers. There was a roughly 5 hp/10tq difference in favor of Greg's , though the setup wasn't exactly one you'd be able to replicate in the car (the post-collector dumps are what, 5"?, and those 8" spacers were so the headers would clear the engine cart)






Greg's catback setup is an H-X design and does use Magnaflows. I have the slightest of resonances at 1800 rpm, an rpm at which I never drive, so it is a non issue. It's as quiet as stock, until you get into it....

BC

Unrelated, but after my 27 hour return trip from England Rob, can I add to your quote in your sig?

Maybe like "I would still rather spend 48 hours driving a 928 than 27 hours in an airport and airplane"

Sorry, off topic.

GregBBRD

Andy's headers (Devek Level II) also had to have a rather large "ding" added, in order to clear the starter motor, on one pipe. That's the major "power reduction", once they were installed in the vehicle. (That "ding" wasn't there during the dyno.)

My headers are designed to clear the lightweight starter....and of course, Roger's latest "heavy duty lightweight starter" hangs in the middle, clearing everything.

BTW....I hadn't seen this picture of Andy's engine running on the dyno, before. Pretty cool looking....especially proud of the wiring!

Rob Edwards

Sorry 'bout the less than flattering wiring, Greg, it was the first picture that came to hand that showed the spacer pipes and Roger's sewer pipe exhaust setup (As I recall didn't Andy's engine blow one of the joints apart in the house exhaust ducting? Such an amazing sound in that room....)

https://webfiles.uci.edu/redwards/pu...%203-16-11.mp3

andy-gts

very cool picture, I will pm to see how much mooola for the whole schebang...maybe for christmas me thinks...and then I will do before and after dyno

thanks for the pic, i had never seen glowing red headers like that before. real eye opener.

terry gt

Andy ,pictures of the system . Tryed it with magaflows first but the drone was very uncomforable . I was going to the dyno today but got delayed , but the power is there