17/8, 117/8 stepped, 2" ????
12-12-2009, 03:43 PM
#1
17/8, 117/8 stepped, 2" ???? LS3.4 (417) 11.0 to 1, Tony M. Ported 205's, Vengence ported 92/NW92 and 238/246 at .603/.606 115+4.
I have 13/4 now. So going to 17/8 would mean I could use existing ORY. Stepped 17/8 or 2" have 31/2" collectors, so thats another $400.00
Any thoughts.
This is a daily driver set up to be strong on the bottom.
I have 13/4 now. So going to 17/8 would mean I could use existing ORY. Stepped 17/8 or 2" have 31/2" collectors, so thats another $400.00
Any thoughts.
This is a daily driver set up to be strong on the bottom.
12-14-2009, 07:28 AM
#2
The only way stepped header really show their stuff is when there's no back pressure behind them. The stepped change is cross section is designed to enhance velocity through the exhaust. This is somewhat negated when you add a closed exhaust. My advice, if you're after big numbers, go with the larger headers and the larger collectors, then neck them down to 3" duals as soon as you can. You should be able to adapt them to your current y-pipe with minimal cutting. Hopefully, your current mid-pipe is dual 3" already and has a 4" y-collector and 4" cutout. If not, you're not going to see much of the gains of the larger headers due to the downstream restrictions.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
12-14-2009, 03:44 PM
#3
Ron at Vengence wrote this PM
"Good to hear from you sir.
My suggestion is 1 7/8 with your current 3" Exhaust. Anymore primary size is overkill for your combination.
Let me know if we can help you out."
Still looking for opinions! the more the better!
Ed
Ron
"Good to hear from you sir.
My suggestion is 1 7/8 with your current 3" Exhaust. Anymore primary size is overkill for your combination.
Let me know if we can help you out."
Still looking for opinions! the more the better!
Ed
Ron
12-14-2009, 06:10 PM
#4
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I have 1 7/8 stepped headers on my motor. I know of another almost identical motor that made almost the same power (slightly higher) with 1 7/8. I'd take Ron's advice unless you have plas for FI or a lot of spray.
12-15-2009, 07:11 PM
#5
PM reply I post these here in so maybe they can help others Ed,
In testing in the past I haven't seen huge differences between 1 7/8" and 1 7/8"-2" stepped headers on an exhaust with mufflers and long extentions. Basically, the point is that the step can move your torque curve and SOMETIMES give you a broader power band, however it is highly application dependent based on cam, cubic inches, downstream exhaust, etc.
In other words there is no 'right' answer other than testing for your particular combo.....
I think either pipe size will work fine for your needs.
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Geoff Skinner
Engine Power Systems, Advanced EFI Engine Innovation
Custom LSX Valvetrain Components, EFI Dyno Tuning Solutions, EFI Live, LS1/LT1 Edit, Tuner Cat, HP Tuners.
225-751-8500
In testing in the past I haven't seen huge differences between 1 7/8" and 1 7/8"-2" stepped headers on an exhaust with mufflers and long extentions. Basically, the point is that the step can move your torque curve and SOMETIMES give you a broader power band, however it is highly application dependent based on cam, cubic inches, downstream exhaust, etc.
In other words there is no 'right' answer other than testing for your particular combo.....
I think either pipe size will work fine for your needs.
__________________
Geoff Skinner
Engine Power Systems, Advanced EFI Engine Innovation
Custom LSX Valvetrain Components, EFI Dyno Tuning Solutions, EFI Live, LS1/LT1 Edit, Tuner Cat, HP Tuners.
225-751-8500
