Switching exhaust setup for FI
06-28-2009, 11:31 AM
#1
Switching exhaust setup for FI I'm switching my exhaust setup this week from my duals which are 3" straight back on either side, no H or X going to 5" Magnaflow race mufflers. I'm changing to a Kooks ORY, and a Magnaflow catback. My fist idea was to do dual cutouts on the ORY, however, I was thinking today, would it be down on power if I just did 1 cutout in the i-pipe on the new setup or should I stick with the 2 cutout idea? I know it isn't directly FI related, but I'm not sure how much the setup change is similar to doing it on an NA car.
07-01-2009, 10:40 PM
#2
Be interested to hear this feedback also, I run a 'catted' Kooks Y on my street car with a Magnaflow cat back and it is very quiet, almost too quiet, at the track I can never hear myself think against all the open exhaust race cars, although it is kind of fun to out run some pretty decent bracket cars going mid 10's in this car.
I have wondered lately what the capped up exhaust is costing it. I have read other threads where guys say it ain't much, subscribing...
I do know this, the older I get the more I appreciate a quiet street driver.
I have wondered lately what the capped up exhaust is costing it. I have read other threads where guys say it ain't much, subscribing...
I do know this, the older I get the more I appreciate a quiet street driver.
08-21-2009, 05:02 PM
#5
Just for reference on this here is a comparison. With the 3" TD's, straight back to Magnaflow Race Mufflers (not bullets) and no H/X the car made 773 RWHP/709 RWTQ. I swapped to a Kooks ORY (originally a catted but those were gutted), and a Magnaflow catback, no cutouts. The car made 754 RWHP/693 RWTQ. Keeping in mind the Kooks Y has a small crush in it for about 12" but retains a 3" diameter throughout.
I think that is a pretty good result, a MUCH more restrictive setup dropped me about 20 RWHP and about the same RWTQ. It is in the shop right now getting a custom 3" ORY into a 3" to 3.5" Flowmaster merge with 2 cutouts. I'll try and get results for both.
It is also noteworthy that the 773 RWHP pull was just shy of 20 PSI where the 754 RWHP pull was down a couple PSI.
I think that is a pretty good result, a MUCH more restrictive setup dropped me about 20 RWHP and about the same RWTQ. It is in the shop right now getting a custom 3" ORY into a 3" to 3.5" Flowmaster merge with 2 cutouts. I'll try and get results for both.
It is also noteworthy that the 773 RWHP pull was just shy of 20 PSI where the 754 RWHP pull was down a couple PSI.
08-21-2009, 07:12 PM
#7
Just for reference on this here is a comparison. With the 3" TD's, straight back to Magnaflow Race Mufflers (not bullets) and no H/X the car made 773 RWHP/709 RWTQ. I swapped to a Kooks ORY (originally a catted but those were gutted), and a Magnaflow catback, no cutouts. The car made 754 RWHP/693 RWTQ. Keeping in mind the Kooks Y has a small crush in it for about 12" but retains a 3" diameter throughout.
I think that is a pretty good result, a MUCH more restrictive setup dropped me about 20 RWHP and about the same RWTQ. It is in the shop right now getting a custom 3" ORY into a 3" to 3.5" Flowmaster merge with 2 cutouts. I'll try and get results for both.
It is also noteworthy that the 773 RWHP pull was just shy of 20 PSI where the 754 RWHP pull was down a couple PSI.
I think that is a pretty good result, a MUCH more restrictive setup dropped me about 20 RWHP and about the same RWTQ. It is in the shop right now getting a custom 3" ORY into a 3" to 3.5" Flowmaster merge with 2 cutouts. I'll try and get results for both.
It is also noteworthy that the 773 RWHP pull was just shy of 20 PSI where the 754 RWHP pull was down a couple PSI.
Very interested to see what the cat back is holding back. What size primary tubes are your headers? Last edited by conan; 08-22-2009 at 07:23 AM.
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08-23-2009, 12:19 AM
#12
Wow, that's not as bad as I thought the Kooks ORY and Magnaflow cat back was going to be. That is what I have been running, although with a catted Y.
I just switched to this set-up last week and haven't got to the track yet. It will be for the track mainly, on the street I will go back to my other set-up I just took off. I run the Magnaflow cat back on both.
This setup pictured below is louder for sure under WOT, but not too much more at idle although the exhaust smells big time out the back. The converters really cleaned that up with the other setup. With the cutout open it sounds nasty, I mean sort of like **** IMO.
I will probably go back to my Kooks catted Y and stock Magnflow I pipe after I put this thing into the 9's. which I'm hoping to do at the current 9 psi setup.
I replaced this out of Kooks ORY I bought used on here.
With this. FM 3" to 3.5"
DMH 3.5" electric cut out
I just switched to this set-up last week and haven't got to the track yet. It will be for the track mainly, on the street I will go back to my other set-up I just took off. I run the Magnaflow cat back on both.
This setup pictured below is louder for sure under WOT, but not too much more at idle although the exhaust smells big time out the back. The converters really cleaned that up with the other setup. With the cutout open it sounds nasty, I mean sort of like **** IMO.
I will probably go back to my Kooks catted Y and stock Magnflow I pipe after I put this thing into the 9's. which I'm hoping to do at the current 9 psi setup.
I replaced this out of Kooks ORY I bought used on here.
With this. FM 3" to 3.5"
DMH 3.5" electric cut out
08-23-2009, 04:18 AM
#14
Nice! I'll get pictures of the new y pipe this week. I like it a lot! 3" custom, dual cutout with a flowmaster 3" to 3.5" merge. Oh, new numbers too, my car seems to really like the D1-SC: 808.65 RWHP / 730.95 RWTQ 
, SAE and smoothing at 5, no tricks other than a big fan in front of the car. No icing etc. And the dyno is a lil stingy. It is shy about 10 rwhp than other dynojets around.
Edit: This is cutouts open, 1 7/8" coated Kooks, 3" collectors.
, SAE and smoothing at 5, no tricks other than a big fan in front of the car. No icing etc. And the dyno is a lil stingy. It is shy about 10 rwhp than other dynojets around.Edit: This is cutouts open, 1 7/8" coated Kooks, 3" collectors.
08-23-2009, 07:35 AM
#15
Nice! I'll get pictures of the new y pipe this week. I like it a lot! 3" custom, dual cutout with a flowmaster 3" to 3.5" merge. Oh, new numbers too, my car seems to really like the D1-SC: 808.65 RWHP / 730.95 RWTQ , SAE and smoothing at 5, no tricks other than a big fan in front of the car. No icing etc. And the dyno is a lil stingy. It is shy about 10 rwhp than other dynojets around.
Edit: This is cutouts open, 1 7/8" coated Kooks, 3" collectors.
, SAE and smoothing at 5, no tricks other than a big fan in front of the car. No icing etc. And the dyno is a lil stingy. It is shy about 10 rwhp than other dynojets around.Edit: This is cutouts open, 1 7/8" coated Kooks, 3" collectors.
. 54 hp / 37 tq gain is crazy. So do you feel the catback is the biggest restriction or the Y pipe? Meaning more gain from the cutouts VS the 3' to 3.5" merge?
08-23-2009, 09:33 AM
#16
Nice! I'll get pictures of the new y pipe this week. I like it a lot! 3" custom, dual cutout with a flowmaster 3" to 3.5" merge. Oh, new numbers too, my car seems to really like the D1-SC: 808.65 RWHP / 730.95 RWTQ , SAE and smoothing at 5, no tricks other than a big fan in front of the car. No icing etc. And the dyno is a lil stingy. It is shy about 10 rwhp than other dynojets around.
Edit: This is cutouts open, 1 7/8" coated Kooks, 3" collectors.
, SAE and smoothing at 5, no tricks other than a big fan in front of the car. No icing etc. And the dyno is a lil stingy. It is shy about 10 rwhp than other dynojets around.Edit: This is cutouts open, 1 7/8" coated Kooks, 3" collectors.
08-23-2009, 11:53 AM
#19
Unfortunately no races this weekend. I was out of meth by the time it was done on the dyno but it will be out next weekend! That was with 18 psi and 2 more degrees of timing. I dont think the exhaust was as much a factor as the timing. I'd say 40% of the gai. From the exhaust and 60% from the timing. That is with the converter locked 
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