dfw

**BLK2012GT** · 10-10-2012, 02:37 PM

Is there a difference as far as performance goes between the two sizes of headers?

**Grandpa** · 10-10-2012, 03:37 PM

Depends on the amount of air being flowed.

**Phuck Phace** · 10-10-2012, 03:39 PM

Go 1-7/8.

**Grandpa** · 10-10-2012, 03:40 PM

Originally Posted by Phuck Phace

Go 1-7/8.

That makes sense for a boosted car, not so much for N/A. On motor his car might be a little lazy until he hits the panic button.

**Midnight11** · 10-10-2012, 03:46 PM

hes got nawsssss though lol

**Phuck Phace** · 10-10-2012, 03:55 PM

Originally Posted by Steve

That makes sense for a boosted car, not so much for N/A. On motor his car might be a little lazy until he hits the panic button.

Futureproofing, better to put them in now than to change them out later.

**BLK2012GT** · 10-10-2012, 04:03 PM

Just got off the phone with Tim and he explained everything.

**Midnight11** · 10-10-2012, 04:04 PM

explain what he said lol

**Phuck Phace** · 10-10-2012, 04:09 PM

Check this...
http://www.svtperformance.com/forums...8-headers.html

**Grandpa** · 10-10-2012, 04:11 PM

Originally Posted by BLK2012GT

Just got off the phone with Tim and he explained everything.

Oh lord... lol.

**TrueStreetTim** · 10-10-2012, 04:53 PM

Originally Posted by Steve

Oh lord... lol.

As we know; any engine will make its best overall power when treated as a complete system. Let me nerd out for a moment....

As engine speed increases, so does flow rate. As restrictions (collector, converter, muffler, bends etc) increase, velocity reduces power accordingly. Smaller diameter pipes flow less volume than larger ones, but the exhaust in the smaller pipe flows faster. Until you reach the RPM where the sheer volume of exhaust gases require bigger primary tubes. This is the basis for the OP's question.

Essentially; Each header size creates a certain "torque boost". The size of the header determines at what RPM. If you plan to drive the car around all day at say, 3-4.5 RPM, a 1" 5/8 header is your man! Any bigger and you'll lose a noticeable amount of low end torque. 1" 7/8 header lives above 5k where most of you have your fun. Not to mention the Coyote's spin to the 7's. There is no reason not to go for the 1" 7/8 with the Coyote in our opinion....no matter the combo.

**Grandpa** · 10-10-2012, 04:59 PM

Originally Posted by Steve

Depends on the amount of air being flowed.

Originally Posted by Steve

That makes sense for a boosted car, not so much for N/A. On motor his car might be a little lazy until he hits the panic button.

Originally Posted by TrueStreetTim

As we know; any engine will make its best overall power when treated as a complete system. Let me nerd out for a moment....

As engine speed increases, so does flow rate. As restrictions (collector, converter, muffler, bends etc) increase, velocity reduces power accordingly. Smaller diameter pipes flow less volume than larger ones, but the exhaust in the smaller pipe flows faster. Until you reach the RPM where the sheer volume of exhaust gases require bigger primary tubes. This is the basis for the OP's question.

Essentially; Each header size creates a certain "torque boost". The size of the header determines at what RPM. If you plan to drive the car around all day at say, 3-4.5 RPM, a 1" 5/8 header is your man! Any bigger and you'll lose a noticeable amount of low end torque. 1" 7/8 header lives above 5k where most of you have your fun. Not to mention the Coyote's spin to the 7's. There is no reason not to go for the 1" 7/8 with the Coyote in our opinion....no matter the combo.

That's what I said. lol.

**BLK2012GT** · 10-10-2012, 05:01 PM

Originally Posted by Steve

That's what I said. lol.

Is not

**Courtesy Flush** · 10-10-2012, 05:31 PM

The pypes headers are what i wish i went with, even with all their bad rep with fitment and quality. Seen quite a few guys running em and making good power. Stepped header design 1 5/8ths stepped to 1 7/8th into a 3 inch collector.

Best of both worlds? could be.

Wouldn't know as i went with the 1 7/8th SW setup personally, very exotic sound with these headers when you creep into the top of the rpm band.

**TrueStreetTim** · 10-10-2012, 06:51 PM

Check this...
http://www.svtperformance.com/forums...8-headers.html

Nice, yo. I like how they concluded that no TQ was lost which is to be expected. Shorty's to LT's would show a loss but, again, only up to its volumetric efficiency.

Originally Posted by Courtesy Flush

The pypes headers are what i wish i went with, even with all their bad rep with fitment and quality. Seen quite a few guys running em and making good power. Stepped header design 1 5/8ths stepped to 1 7/8th into a 3 inch collector.

If it were a carbureted, open header car 110% yes. The smaller diameter section on a stepped design helps to scavenge the gases out of the motor making the cylinder more efficient. Non-carbureted cars, and especially the Coyote, we are able to tune each cylinder individually (bonus)! Once you bolt on an exhaust (with its added restrictions), no matter the platform, the design fails and negates all advantages. Feel good about your purchase, man!