What size TB and EGR for S-trim?

By-Tor · 02-04-2010, 07:52 AM

I am looking to run a S-Trim into a Comp-Poly intake. 306ci,GT-40p heads, B cam. What size TB and EGR should I look to run?

Thanks!!

SlowGT · 02-04-2010, 08:11 PM

what size is the opening on the box? ideally you'd like to maintain good air velocity through the TB and on into the intake runners but with the box you lose some of that velocity as the air expands trying to fill it up. however, maybe not so bad with boost. a B-cam 306 with an S-trim will work fine with a 65mm. i'd use a 73-75mm air meter. don't expect to see a lot of bottom end with such short intake runners. but it should come on nice in the 3800 neighborhood with the blower.

xr4ti85 · 02-04-2010, 09:48 PM

i used a 75mm

By-Tor · 02-05-2010, 08:13 AM

Thanks for the replies guys!! The box is brand new so I can shave the opening for any size spacer. I am expecting to lose some bottom end grunt so I am hoping the 3.73's will still keep things fun from a dead stop. Has anyone here run a similar setup? Any comments about how it was?

N8Miller · 02-05-2010, 08:31 AM

i wouldnt use less than a 75mm...

SlowGT · 02-05-2010, 01:01 PM

here's a little something from Accufab for reference:

ACCUFAB 65MM
TESTED @ 5" - 280 CFM
CORR @ 20" - 560 CFM
CORR @ 25" - 627 CFM
CORR @ 28" - 664 CFM

ACCUFAB 70MM
TESTED @ 5" - 332 CFM
CORR @ 20" - 664 CFM
CORR @ 25" - 744 CFM
CORR @ 28" - 787 CFM

ACCUFAB 75MM
TESTED @ 5" - 390 CFM
CORR @ 20" - 780 CFM
CORR @ 25" - 874 CFM
CORR @ 28" - 924 CFM

figure out how much air is required to make the amount of power you're looking for and go from there. remember to compensate for the appropriate amount of boost. and keep in mind these are numbers from Accufab throttle bodes...known to be the best flowing in the business.

By-Tor · 02-06-2010, 09:12 AM

Thank you!! That is a big help.

02-04-2010, 07:52 AM	#1
By-Tor Member Location: Shillington, PA Posts: 53 Trader Rating: 1 View Garage Join Date: Jun 2006 Credits: 274 Cash: $ 500	What size TB and EGR for S-trim? I am looking to run a S-Trim into a Comp-Poly intake. 306ci,GT-40p heads, B cam. What size TB and EGR should I look to run? Thanks!! __________________ 1985 Mustang Road Racer,SCCA American Sedan #30 1988 Mustang GT, Vortec S-Trim supercharged \"My Drinking Team Has A Racing Problem\"

02-04-2010, 08:11 PM	#2
SlowGT Name: Jared Location: Columbia Co, PA Posts: 1,846 Trader Rating: 8 Year: 1995 Model: R, GT & GT Vert View Garage Join Date: Oct 2007 Credits: 6,600 Cash: $ 600	what size is the opening on the box? ideally you'd like to maintain good air velocity through the TB and on into the intake runners but with the box you lose some of that velocity as the air expands trying to fill it up. however, maybe not so bad with boost. a B-cam 306 with an S-trim will work fine with a 65mm. i'd use a 73-75mm air meter. don't expect to see a lot of bottom end with such short intake runners. but it should come on nice in the 3800 neighborhood with the blower. __________________ 95 GT - 428w...coming soon to a redlight near you 95 Cobra R - #73...stock, 6128 miles 95 GT vert - stock...Numidia Friday Night Street Legals Champion...Jun 22, 2007

02-04-2010, 09:48 PM	#3
xr4ti85 Name: Tom Faus Location: orangeville Posts: 3,237 Trader Rating: 7 Year: 1987 Model: Xr4ti View Garage Join Date: Dec 2006 Credits: 25,128 Cash: $ 500	i used a 75mm __________________ 1987 Merkur Xr4ti custom 3"exhaust,255 lph pump, ihi 6.5 turbo,external wastegate

02-05-2010, 08:13 AM	#4
By-Tor Member Location: Shillington, PA Posts: 53 Trader Rating: 1 View Garage Join Date: Jun 2006 Credits: 274 Cash: $ 500	Thanks for the replies guys!! The box is brand new so I can shave the opening for any size spacer. I am expecting to lose some bottom end grunt so I am hoping the 3.73's will still keep things fun from a dead stop. Has anyone here run a similar setup? Any comments about how it was? __________________ 1985 Mustang Road Racer,SCCA American Sedan #30 1988 Mustang GT, Vortec S-Trim supercharged \"My Drinking Team Has A Racing Problem\"

02-05-2010, 08:31 AM	#5
N8Miller Mr. 331: The jbower86 killer Name: Nathan Location: Kingston pa Posts: 3,152 Trader Rating: 2 Year: 1986 Model: Mustang GT View Garage Join Date: Oct 2006 Credits: 879 Cash: $ 400	i wouldnt use less than a 75mm... __________________ 1986 GT:331, Edelbrock Vic Jr heads, Jay Allen custom cam, TFS R intake, etc etc Power of a low 12 second car, Traction of a high 14 second car!

02-05-2010, 01:01 PM	#6
SlowGT Name: Jared Location: Columbia Co, PA Posts: 1,846 Trader Rating: 8 Year: 1995 Model: R, GT & GT Vert View Garage Join Date: Oct 2007 Credits: 6,600 Cash: $ 600	here's a little something from Accufab for reference: ACCUFAB 65MM TESTED @ 5" - 280 CFM CORR @ 20" - 560 CFM CORR @ 25" - 627 CFM CORR @ 28" - 664 CFM ACCUFAB 70MM TESTED @ 5" - 332 CFM CORR @ 20" - 664 CFM CORR @ 25" - 744 CFM CORR @ 28" - 787 CFM ACCUFAB 75MM TESTED @ 5" - 390 CFM CORR @ 20" - 780 CFM CORR @ 25" - 874 CFM CORR @ 28" - 924 CFM figure out how much air is required to make the amount of power you're looking for and go from there. remember to compensate for the appropriate amount of boost. and keep in mind these are numbers from Accufab throttle bodes...known to be the best flowing in the business. __________________ 95 GT - 428w...coming soon to a redlight near you 95 Cobra R - #73...stock, 6128 miles 95 GT vert - stock...Numidia Friday Night Street Legals Champion...Jun 22, 2007

02-06-2010, 09:12 AM	#7
By-Tor Member Location: Shillington, PA Posts: 53 Trader Rating: 1 View Garage Join Date: Jun 2006 Credits: 274 Cash: $ 500	Thank you!! That is a big help. __________________ 1985 Mustang Road Racer,SCCA American Sedan #30 1988 Mustang GT, Vortec S-Trim supercharged \"My Drinking Team Has A Racing Problem\"

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