does 1/8" make a difference with headers? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

MyCamaroSS · 11-28-2010, 11:37 AM

why are SLP's long-tube headers 1-3/4", while ARH, Dynatech and StainlessWorks are 1-7/8"? are the factory headers 1-7/8"? trying to decide what to go with, thanks

danhr · 11-28-2010, 11:51 AM

yes

go with 1 7/8

/thread

xxlbeerz · 11-28-2010, 12:04 PM

http://www.camaro5.com/forums/showthread.php?t=63640

SLP headers are way over-priced. If you go 1-3/4" just get BBK.

Apex Motorsports · 11-28-2010, 12:11 PM

Yes, 1/8 inch does make a difference. With each progressive size up in diameter you will make a little more power (the more power a car is already making the more this is true) and the peak power numbers move further up the RPM range. For these cars, I like going with 1 7/8 headers for naturally aspirated street applications. For race or forced induction applications then I like 2 inch. Here is a good article that explains this and several other factors in selecting headers.

Slowhawk · 11-29-2010, 05:14 AM

It seems like the SLP header cars alway make less hp/tq than the cars fitted with ARH 17/8's on my dyno.

tjbusa · 11-29-2010, 08:19 AM

Maybe power robbing factory manifolds are 1 3/4" but they aren't long tubes into 3" collectors. I bought a complete SLP system for its unique sound which makes this driver happy. A couple of horsepower is the difference at high RPM in 1 3/4 vs 1 7/8.
Also the right CAI selection will show some difference on the dyno.

2010 SS RS · 11-29-2010, 08:49 AM

Its all about how a header scavenges the gasses away. Conventional headers it is best to go to the size you need to scavenge the gasses you create. Most semi stock or mild power adder equiped cars are fine with 1 7/8...High HP 700 RWHP up can benefit from 2 inch exhaust. However, in my case I actually went with 1 3/4 Doug Thorley Tri Y headers. The way they scavenge is unique in that they clear the gases out of opposing firing cylinders thus clearing the tube for the next one that fires. The net result is a collector that is not constricted to 3in but is equivilent to a 4 1/2 inch collector. Just food for thought.
Stock is fine with 1 3/4
mild is fine with 1 7/8
wild is fine with 2

Apex Motorsports · 11-29-2010, 09:07 AM

Quote:

Originally Posted by Slowhawk

It seems like the SLP header cars alway make less hp/tq than the cars fitted with ARH 17/8's on my dyno.

Quote:

Originally Posted by tjbusa

Maybe power robbing factory manifolds are 1 3/4" but they aren't long tubes into 3" collectors. I bought a complete SLP system for its unique sound which makes this driver happy. A couple of horsepower is the difference at high RPM in 1 3/4 vs 1 7/8.
Also the right CAI selection will show some difference on the dyno.

On a typical bolt on street car application you will pick up about 5-10 horsepower and 5 lb.-ft between 1 3/4 and 1 7/8.

tjbusa · 11-29-2010, 05:05 PM

Quote:

Originally Posted by Apex Chase

On a typical bolt on street car application you will pick up about 5-10 horsepower and 5 lb.-ft between 1 3/4 and 1 7/8.

The SLP System and a CAI gave me enough pull till I get a cam. I won't do a cam till my main warranty is over. I don't race mine, so it suites me.

xx_ED_xx · 11-29-2010, 05:12 PM

1 3/4 - na
1 7/8 mild FI
2 inch if you are going bigger then stock and a big blower etc

You will notice if you actually get one car and swap all these out where you gain and lose power. Unless you drag race it only, power in the midrange and torque is more important then the 10 hp at 7000 rpm

bowtienick · 11-29-2010, 06:13 PM

I went with 2" primaries. My car with full exhaust and cai and 2" primaries sw headers dyno'd 434 rwhp. Engine pulled 429 before tuning. Mine's an ls3 and everything else is stock.

axis · 11-30-2010, 06:20 AM

Quote:

Originally Posted by xx_ED_xx

1 3/4 - na
1 7/8 mild FI
2 inch if you are going bigger then stock and a big blower etc

You will notice if you actually get one car and swap all these out where you gain and lose power. Unless you drag race it only, power in the midrange and torque is more important then the 10 hp at 7000 rpm

It's been shown that each size bigger gave bigger gains while not compromising any lowend.

walhan_qtr · 12-02-2010, 02:17 AM

Quote:

Originally Posted by bowtienick

I went with 2" primaries. My car with full exhaust and cai and 2" primaries sw headers dyno'd 434 rwhp. Engine pulled 429 before tuning. Mine's an ls3 and everything else is stock.

wow is that SAE numbers? this is probably the highest exhaust/CAI/tune car ive ever seen!

Ivan @ Southwest Speed · 12-02-2010, 08:00 AM

I'd been a traditional "Bigger is Better" sorta guy when it comes to primary sizing...but there are exceptions to about every rule. This is the only 1 3/4" Header verses 1 7/8" header Dyno that I've seen where a 1 3/4"design (DT Try-Y) could come close to a 1 7/8"......and in this case it actually made more power. It's hard for us to reccommend a product to a customer that costs more and doesn't make as much power when it comes to these.

Food for thought.
Ivan @ Southwest Speed

11-28-2010, 11:37 AM	#1
MyCamaroSS Drives: 2011 2SS/RS Blue/Silver Stripe Join Date: Nov 2010 Location: Niantic CT Posts: 16	does 1/8" make a difference with headers? why are SLP's long-tube headers 1-3/4", while ARH, Dynatech and StainlessWorks are 1-7/8"? are the factory headers 1-7/8"? trying to decide what to go with, thanks

11-28-2010, 11:51 AM	#2
danhr BAMF SS Drives: 2016 Camaro 1SS A8 Join Date: Mar 2010 Location: Ford City, PA Posts: 3,023	yes go with 1 7/8 /thread __________________ 2016 1SS A8: FBO + Circle D + P1X + Meth + Tuned by Pray Performance Stock Longblock 800 SAE rwhp. 9.4 @ 145 mph.

11-29-2010, 08:19 AM	#6
tjbusa Serious Sleeper Drives: 2010 CGM 2SS/RS M6 Join Date: Nov 2008 Location: Lexington,SC Posts: 3,129	Maybe power robbing factory manifolds are 1 3/4" but they aren't long tubes into 3" collectors. I bought a complete SLP system for its unique sound which makes this driver happy. A couple of horsepower is the difference at high RPM in 1 3/4 vs 1 7/8. Also the right CAI selection will show some difference on the dyno. __________________ ************************************* Drive-by Fact of Life: After Monday and Tuesday even the calendar reads... W T F *************************************

11-29-2010, 08:49 AM	#7
2010 SS RS Drives: 2010 2SS/RS IBM Black Polished Join Date: Feb 2009 Location: Colorado Posts: 2,108	Its all about how a header scavenges the gasses away. Conventional headers it is best to go to the size you need to scavenge the gasses you create. Most semi stock or mild power adder equiped cars are fine with 1 7/8...High HP 700 RWHP up can benefit from 2 inch exhaust. However, in my case I actually went with 1 3/4 Doug Thorley Tri Y headers. The way they scavenge is unique in that they clear the gases out of opposing firing cylinders thus clearing the tube for the next one that fires. The net result is a collector that is not constricted to 3in but is equivilent to a 4 1/2 inch collector. Just food for thought. Stock is fine with 1 3/4 mild is fine with 1 7/8 wild is fine with 2 __________________ 418 Stroker, 621RWHP 648 lbs TORQUE Built by Laramie GM Auto Center Tuned by Nick at Mac Autosport. EForce SC, 2 3/4pulley,LPE dual fuel pump, JRE Twin fuel rail upgrade, posi clutch kit, RX oilcatch can and breather, Callies Compstar crankshaft and rods, Racing bearings, CP -13.8 race pistons, steel rings, Comp Cams X6 blower cam, Springs, HD timing chain and tensioner, Doug Thorley Tri Y LT headers, 89.7lb injectors, RPM rollbar, DSS1400 shafts, Simpson 5 pt harness, BMR Toe rods and trailing arms, led lights, RPM input and output shafts

12-02-2010, 08:00 AM	#14
Ivan @ Southwest Speed Drives: '15 Z06, '01 NBM SS, '97 SS Join Date: May 2009 Location: Rio Rancho, NM Posts: 12,170	Doug Thorley Long Tube Headers vs 1 7/8"... I'd been a traditional "Bigger is Better" sorta guy when it comes to primary sizing...but there are exceptions to about every rule. This is the only 1 3/4" Header verses 1 7/8" header Dyno that I've seen where a 1 3/4"design (DT Try-Y) could come close to a 1 7/8"......and in this case it actually made more power. It's hard for us to reccommend a product to a customer that costs more and doesn't make as much power when it comes to these. Food for thought. Ivan @ Southwest Speed Attached Images

11-28-2010, 12:04 PM	#3
xxlbeerz Drives: 2010 Black on Black Join Date: Oct 2010 Location: Houston, TX Posts: 533	http://www.camaro5.com/forums/showthread.php?t=63640 SLP headers are way over-priced. If you go 1-3/4" just get BBK.

11-28-2010, 12:11 PM	#4
Apex Motorsports Drives: 2000 Camaro SS Join Date: Feb 2010 Location: Louisville, Ky. Posts: 25,179	Yes, 1/8 inch does make a difference. With each progressive size up in diameter you will make a little more power (the more power a car is already making the more this is true) and the peak power numbers move further up the RPM range. For these cars, I like going with 1 7/8 headers for naturally aspirated street applications. For race or forced induction applications then I like 2 inch. Here is a good article that explains this and several other factors in selecting headers.

11-29-2010, 05:14 AM	#5
Slowhawk Drives: 1999 Trans Am Join Date: Jul 2009 Location: Bridgewater,Ma Posts: 2,017	It seems like the SLP header cars alway make less hp/tq than the cars fitted with ARH 17/8's on my dyno.

11-29-2010, 05:12 PM	#10
xx_ED_xx Drives: 04 Silverado Join Date: Jun 2010 Location: Floriduh! Posts: 1,113	1 3/4 - na 1 7/8 mild FI 2 inch if you are going bigger then stock and a big blower etc You will notice if you actually get one car and swap all these out where you gain and lose power. Unless you drag race it only, power in the midrange and torque is more important then the 10 hp at 7000 rpm

11-29-2010, 06:13 PM	#11
bowtienick Drives: 2010 ss m6 Join Date: Dec 2009 Location: houston Posts: 117 View My Garage	I went with 2" primaries. My car with full exhaust and cai and 2" primaries sw headers dyno'd 434 rwhp. Engine pulled 429 before tuning. Mine's an ls3 and everything else is stock.

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