are 1 7/8 headers overkill on mild cam only
Sounds like we have some strong opinions here about not using 1 7/8 headers on a stock motor. Take a look at this stock engine dyno test numbers. They dropped 1 ft lb of torque but that torque number came 600rpm lower rpm than the 1 3/4. That says the 1 7/8 have more lowend torque. Let the numbers speak for themselves. Someone is going to all mad about this. I can see it now. Look for yourself.
http://www.carcraft.com/techarticles...o_numbers.html
http://www.carcraft.com/techarticles...o_numbers.html
Originally Posted by 2002_z28_m6
Sounds like we have some strong opinions here about not using 1 7/8 headers on a stock motor. Take a look at this stock engine dyno test numbers. They dropped 1 ft lb of torque but that torque number came 600rpm lower rpm than the 1 3/4. That says the 1 7/8 have more lowend torque. Let the numbers speak for themselves. Someone is going to all mad about this. I can see it now. Look for yourself.
http://www.carcraft.com/techarticles...o_numbers.html
http://www.carcraft.com/techarticles...o_numbers.html
Beside my posted above tests results. If they are AR headers they have the high velocity merge collector so they should really give you excellent results. These headers are top notch. Im not saying that they are better than every other header. Just that they are a very nice piece. I have 1 7/8 American racing headers and catted AR Y pipe. They truely do nice work.
I have the Super Comp headers along with the rest of my exhaust, ran the times in my sig without a tune or a lid. So no, they are not too big. Didnt feel like I lost anything down low at all, in fact I picked up .1 in the 60'. I also have 3.42's in the back.
I think you'll be ok with the 1 7/8 set up. If you decide to do a bigger engine the 1 7/8 will be very nice.
While the data provided was good, it really best to have the actual dyno charts to overlay.
While the data provided was good, it really best to have the actual dyno charts to overlay.
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Damn, just concede the point: you'll loose low end power. Since all races are won from idle to 2500rpms, that 5rwhp/5rwtq you're sacrificing will really set you back. 
Forget racing your mom in her Town and Country to the grocery store, she'll be the king of the streets...
Forget racing your mom in her Town and Country to the grocery store, she'll be the king of the streets...
Originally Posted by BigDaddyBry
Damn, just concede the point: you'll loose low end power....
Originally Posted by SSpdDmon
If bigger were always better, then funny cars would be running sewer drains for headers.
Seriously though, there is a point of diminishing returns. Will you see more power over stock manifolds? Of course. Will you see more power with a 1 7/8 inch header over a 1 3/4 inch header on a stock cubed motor? Highly unlikely. I've read about and watched tests performed on engine dynos proving it.
If I were you, I'd either take the headers, try to sell & make a profit on them, and buy something good OR I wouldn't even waste my time and go straight to buying something good.
In the end, it's his car and he can do whatever he wants. No skin off my back. But, you ask for my opinion and I'll gladly give it.
Yahoo!: http://www.crankshaftcoalition.com/wiki/Header_design
AND http://www.superchevy.com/technical/...t/0505phr_exh/
Seriously though, there is a point of diminishing returns. Will you see more power over stock manifolds? Of course. Will you see more power with a 1 7/8 inch header over a 1 3/4 inch header on a stock cubed motor? Highly unlikely. I've read about and watched tests performed on engine dynos proving it.
If I were you, I'd either take the headers, try to sell & make a profit on them, and buy something good OR I wouldn't even waste my time and go straight to buying something good.
In the end, it's his car and he can do whatever he wants. No skin off my back. But, you ask for my opinion and I'll gladly give it.
Yahoo!: http://www.crankshaftcoalition.com/wiki/Header_design
AND http://www.superchevy.com/technical/...t/0505phr_exh/
Originally Posted by LS1rulz
There's no reason that they'd make you lose anything. Nobody has yet shown that LS motors benefit from "backpressure".
i can see the post above showing the increase but just want to play devils advocate:
Im not sure about anything Im about to type but here it is. I thought the best benefit of a long tube header was scavenging, in that each exhaust pulse helps to "suck" the exhaust out of the next cylinder. If this is the case then running a larger pipe would slow the velocity and compromise scavenging.
Does that make sense? I wouldnt be surprised if thats were the whole idea of "1 7/8's is too big" came from. I mean obvisously thats not the case, but maybe thats why people think you should only use 1 3/4 headers.
Originally Posted by 68chevypu
i can see the post above showing the increase but just want to play devils advocate:
Im not sure about anything Im about to type but here it is. I thought the best benefit of a long tube header was scavenging, in that each exhaust pulse helps to "suck" the exhaust out of the next cylinder. If this is the case then running a larger pipe would slow the velocity and compromise scavenging.
Does that make sense? I wouldnt be surprised if thats were the whole idea of "1 7/8's is too big" came from. I mean obvisously thats not the case, but maybe thats why people think you should only use 1 3/4 headers.
Im not sure about anything Im about to type but here it is. I thought the best benefit of a long tube header was scavenging, in that each exhaust pulse helps to "suck" the exhaust out of the next cylinder. If this is the case then running a larger pipe would slow the velocity and compromise scavenging.
Does that make sense? I wouldnt be surprised if thats were the whole idea of "1 7/8's is too big" came from. I mean obvisously thats not the case, but maybe thats why people think you should only use 1 3/4 headers.
Originally Posted by Asmodeus
Well then why not just run a 2 inch header?
Originally Posted by WS6NIGHTMARE
Im not going to concede it. Like I said I picked up .1 in my 60', so I apparently didnt lose any bottom end.
Originally Posted by BigDaddyBry
Drop the stick, and pull up your pants. It was a joke man, that's what these things are for:
