13BT S5
12-11-2007, 06:28 PM
#1
Member
Thread Starter
Join Date: Dec 2007
Location: EastCoast , Florida
Posts: 78
Hello Guy's new to the forum , I have been searching the forum for few days and I have to say that it is a honor to be part of this forum and the valiable information you guy's have on herem. I am currently getting a S5 engine with a t80 turbo on methanol built for all out dragracing by JR Fab AKA Just Racing Frabrication in Port ST Lucie Fl and we are undecided on the exhaust port . I am asking for everyones opinion we went with the 3rd gen rotor housing , we are not sure if to go with early opening or a bit of both early opening a bit on late closing . what you guy's think
Best Regards
Gilbert
Best Regards
Gilbert
12-12-2007, 10:57 AM
#3
Senior Member
Join Date: Jun 2003
Location: Grand Prairie, TX
Posts: 917
Originally Posted by 13BT_Starlet' post='889881' date='Dec 11 2007, 04:28 PM
Hello Guy's new to the forum , I have been searching the forum for few days and I have to say that it is a honor to be part of this forum and the valiable information you guy's have on herem. I am currently getting a S5 engine with a t80 turbo on methanol built for all out dragracing by JR Fab AKA Just Racing Frabrication in Port ST Lucie Fl and we are undecided on the exhaust port . I am asking for everyones opinion we went with the 3rd gen rotor housing , we are not sure if to go with early opening or a bit of both early opening a bit on late closing . what you guy's think
Best Regards
Gilbert
Best Regards
Gilbert
Very cool, Gilbert! My advice is to focus more porting upwards (closing edge) rather than opening edge. The earlier the exhaust port opens, the lesser amount of torque per stroke will be made due to the stroke being shorter. Honestly, in my experience, there's not a real need to make the exhaust port the size of a lemon. Here's how I it:
http://bdc.cyberosity.com/v/EnginePo...xhaustPorting/
B
12-12-2007, 06:21 PM
#4
Member
Thread Starter
Join Date: Dec 2007
Location: EastCoast , Florida
Posts: 78
BDC you preffer you exhaust port to be late closing by raising the port upwards and shaping the lower part of t port with the sleeve . thanks for your opinion BDC . alright where is the rest of you guy's opinion looking for more ops !
12-12-2007, 09:25 PM
#6
Member
Thread Starter
Join Date: Dec 2007
Location: EastCoast , Florida
Posts: 78
Originally Posted by j9fd3s' post='890002' date='Dec 12 2007, 09:26 PM
yeah i like to match the opening of the port to the sleeve, and keeping the factory bevel, or just plain rounding it off.
i dont like to close the port too much later, as i've gotta pass smog
i dont like to close the port too much later, as i've gotta pass smog
well I dont have smog issues here and this is going to be strictly for racing , is the later closing best for my application ?
12-13-2007, 08:07 AM
#7
Senior Member
Join Date: Jan 2002
Location: NJ USA
Posts: 1,915
porting 2mm towards your exhaust opening will help to spool that big turbo you have, and will not sacrifice your exhaust stroke. 2mm is fairly nothing and will not effect your exhaust stroke to much, but the increase in exhaust flow is noticeable and very helpful. Porting towards the exhaust closing increases overlap, and that to me is always y NO-NO...
I have posted pictures of how to port away the factory 2mm bevel towards the exhaust closing, and then port the 2mm bevel back into the closing edge. this way you have increased port timing but keeped overlap down to a minimun.
I have posted pictures of how to port away the factory 2mm bevel towards the exhaust closing, and then port the 2mm bevel back into the closing edge. this way you have increased port timing but keeped overlap down to a minimun.
12-13-2007, 06:30 PM
#8
Senior Member
Join Date: Jun 2003
Location: Grand Prairie, TX
Posts: 917
Originally Posted by Judge Ito' post='890022' date='Dec 13 2007, 06:07 AM
porting 2mm towards your exhaust opening will help to spool that big turbo you have, and will not sacrifice your exhaust stroke. 2mm is fairly nothing and will not effect your exhaust stroke to much, but the increase in exhaust flow is noticeable and very helpful. Porting towards the exhaust closing increases overlap, and that to me is always y NO-NO...
I have posted pictures of how to port away the factory 2mm bevel towards the exhaust closing, and then port the 2mm bevel back into the closing edge. this way you have increased port timing but keeped overlap down to a minimun.
I have posted pictures of how to port away the factory 2mm bevel towards the exhaust closing, and then port the 2mm bevel back into the closing edge. this way you have increased port timing but keeped overlap down to a minimun.
Awww Juan, overlap isn't a no-no. Try telling that to the two-stroke racing community.
B
12-13-2007, 09:21 PM
#9
Member
Thread Starter
Join Date: Dec 2007
Location: EastCoast , Florida
Posts: 78
Originally Posted by Judge Ito' post='890022' date='Dec 13 2007, 09:07 AM
porting 2mm towards your exhaust opening will help to spool that big turbo you have, and will not sacrifice your exhaust stroke. 2mm is fairly nothing and will not effect your exhaust stroke to much, but the increase in exhaust flow is noticeable and very helpful. Porting towards the exhaust closing increases overlap, and that to me is always y NO-NO...
I have posted pictures of how to port away the factory 2mm bevel towards the exhaust closing, and then port the 2mm bevel back into the closing edge. this way you have increased port timing but keeped overlap down to a minimun.
I have posted pictures of how to port away the factory 2mm bevel towards the exhaust closing, and then port the 2mm bevel back into the closing edge. this way you have increased port timing but keeped overlap down to a minimun.
I agree with you on the overlap , thank you for sharing this valuable info with us . I tried serching this pics you mention but did not come across them , do you remeber where you post them ?
Thanks Gilbert
12-14-2007, 03:21 PM
#10
Senior Member
Join Date: Jan 2002
Location: NJ USA
Posts: 1,915
Originally Posted by BDC' post='890076' date='Dec 14 2007, 12:30 AM
Awww Juan, overlap isn't a no-no. Try telling that to the two-stroke racing community. 
B
B