Do U lose low end Torque with 1 7/8 Headers?
10-03-2010, 10:20 AM
#1
Drifting
Thread Starter
Do U lose low end Torque with 1 7/8 Headers?
As a daily driver car would this happen compared to 1 3/4? Is it minimal though. I plan to do more mods in the future but will have just the headers on for a while?
10-03-2010, 11:50 AM
#4
In my opinion you do loose low end power with 1 7/8. My friend has an 06 z51 man. with 1 7/8 american racing headers high flow cats and corsa extreme exhaust w/tune and it is noticeably down on power under the curve (below 2000 rpm) compared to my 07 non z51 manual car.
Even tho his has the lower gears compared to mine, we both agree mine has more pickup from idle to maybe 2000-2500 or so. but after that his is noticeably faster. I would assume that the lack of backpressure has this effect.
Even tho his has the lower gears compared to mine, we both agree mine has more pickup from idle to maybe 2000-2500 or so. but after that his is noticeably faster. I would assume that the lack of backpressure has this effect.
10-03-2010, 07:14 PM
#5
Race Director
Going from stock exhaust manifolds to 1 7/8" headers you gain torque at every point on a dyno graph. More of an increase at higher PM but gains everywhere.
10-03-2010, 09:25 PM
#6
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St. Jude Donor '09
The best documented comparison I know of was done by PowerLabs.
http://forums.corvetteforum.com/c6-t...p-results.html
San
http://forums.corvetteforum.com/c6-t...p-results.html
San
10-03-2010, 10:03 PM
#7
Le Mans Master
i just bought a set of breathless performance headers (made by kooks)that step from 1 3/4 to 1 7/8...how will this affect my vette?
10-03-2010, 10:36 PM
#8
Burning Brakes
I didn't want to start a "pissing match" between those who bought the right ones for their car and those who try to defend their uninformed choice....
I've had many modified LSx cars over the years and just went through this SAME EXACT question last week on my new 2010 LS3 vette. It bothered me soo bad, I drove 200 miles (1 way), all the way to LG Motorsports in Dallas from Austin, just to have a 1 on 1 talk with them as to recommended header sizes for cars, since they are the ones who designed/contract the manufacturing through Borla/and sell some of the highest quality header systems around w/ the highest HP and TQ curves!
After talking to the people at LG in person, THEY STRONGLY RECOMMENDED the 1 3/4" headers for any street driven LS1/LS2/LS3 and EVEN the 427ci LS7 motor as long as its factory or mildly modified with just cam or heads/cam!!!!! They mentioned the 1 7/8" headers gain about 5HP above 5,000 RPM's but at the expense of about 15TQ in the mid range! So unless you drive your car around town most of the time above 5K RPM's....it not worth the loss overall under the curve! They mentioned, 1 7/8" makes more sense when going with big cube stroker motors or FORCED INDUCTION.
REMEMBER...their claims/data/recommendations are with their own LG headers that have 32" long primaries (tuned length for LS based motors). Other brands of headers are designed cheaper,use shorter primaries, and DO NOT HAVE TRUE RACE COLLECTORS. The situation may change when comparing against other brands. The longer tubes are what promotes TQ, which is why a larger header may seem to make more power when they don't have the longer primaries.
Also, the only problem I see with that dyno comparison is that both headers tested where using the cheaper/shorter length primary design....I wonder what the dyno graph overlay would have shown if the smaller diameter 1 3/4" headers would have had a longer primary like the LG version of 32"? One would assume there would be a noticeable difference in mid range, but out of those two brands KOOKS AND AMERICAN RACING....they seem equal on what ever you choose.
LINK TO DYNO CHARTS...
http://forums.corvetteforum.com/c6-t...e-headers.html
I've had many modified LSx cars over the years and just went through this SAME EXACT question last week on my new 2010 LS3 vette. It bothered me soo bad, I drove 200 miles (1 way), all the way to LG Motorsports in Dallas from Austin, just to have a 1 on 1 talk with them as to recommended header sizes for cars, since they are the ones who designed/contract the manufacturing through Borla/and sell some of the highest quality header systems around w/ the highest HP and TQ curves!
After talking to the people at LG in person, THEY STRONGLY RECOMMENDED the 1 3/4" headers for any street driven LS1/LS2/LS3 and EVEN the 427ci LS7 motor as long as its factory or mildly modified with just cam or heads/cam!!!!! They mentioned the 1 7/8" headers gain about 5HP above 5,000 RPM's but at the expense of about 15TQ in the mid range! So unless you drive your car around town most of the time above 5K RPM's....it not worth the loss overall under the curve! They mentioned, 1 7/8" makes more sense when going with big cube stroker motors or FORCED INDUCTION.
REMEMBER...their claims/data/recommendations are with their own LG headers that have 32" long primaries (tuned length for LS based motors). Other brands of headers are designed cheaper,use shorter primaries, and DO NOT HAVE TRUE RACE COLLECTORS. The situation may change when comparing against other brands. The longer tubes are what promotes TQ, which is why a larger header may seem to make more power when they don't have the longer primaries.
Also, the only problem I see with that dyno comparison is that both headers tested where using the cheaper/shorter length primary design....I wonder what the dyno graph overlay would have shown if the smaller diameter 1 3/4" headers would have had a longer primary like the LG version of 32"? One would assume there would be a noticeable difference in mid range, but out of those two brands KOOKS AND AMERICAN RACING....they seem equal on what ever you choose.
LINK TO DYNO CHARTS...
http://forums.corvetteforum.com/c6-t...e-headers.html
Last edited by C6-LS2-MN6; 10-04-2010 at 04:20 AM.
10-03-2010, 10:45 PM
#9
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St. Jude Donor '09
That said you really can't go wrong with any of the popular header makers. The OP asked about 1 3/4 versus 1 7/8. Contrary to popular belief, the 1 7/8 don't seem to have any downsides.
San
10-03-2010, 10:56 PM
#10
Burning Brakes
If that is directed towards me because I posted up a fairly reasonable post that compared 1 3/4 to 1 7/8 headers I guess you'll be disappointed to know I have 1 3/4 LG longtubes on my C6.
That said you really can't go wrong with any of the popular header makers. The OP asked about 1 3/4 versus 1 7/8. Contrary to popular belief, the 1 7/8 don't seem to have any downsides.
San
That said you really can't go wrong with any of the popular header makers. The OP asked about 1 3/4 versus 1 7/8. Contrary to popular belief, the 1 7/8 don't seem to have any downsides.
San
NO, I'm sorry...it wasn't towards anybody
06-11-2014, 09:20 PM
#14
Melting Slicks
maybe you did as I immediately noticed a increase in torque (untuned) when I installed my slp 1 3/4. don't think the airaid gonna get it back tho.
Last edited by tennblkc6; 06-12-2014 at 08:09 AM. Reason: spelling
06-12-2014, 07:34 AM
#16
Racer
I also had a discussion with LG and I was told the same thing, if you don't plan on making above 525whp or going FI or big cubes the 1 3/4 are the best option. I was also told to get the street series over their pro series there is not a big difference take the money I saved there and get my intake and throttle body ported.
06-12-2014, 08:46 AM
#17
Instructor
Take it for what it is worth. But I now have 1 7/8 lg headers and not one time not one time have I ever said damn I wish I had more torque. Stock gearing still.
06-12-2014, 11:13 AM
#18
Race Director
Answer is still the same as above. 1 7/8" or 1 3/4" you will gain TQ at all RPM over stock manifolds. 1 7/8" will breathe a little better at higher RPM.
06-12-2014, 11:26 AM
#19
Race Director
Here is the difference between 1 3/4 1 7/8
06-12-2014, 03:08 PM
#20
Tech Contributor
Dennis what is this comparative dyno chart telling us?
Which headers were run on 4/16/13 and which ones were run on 4/17/13?
OP one thing to keep in mind, if you do your own wrenching, the ball and socket collector connection like American Racing has is terrific for removing headers if you do things like swap heads or clutch or otherwise need to remove your headers or mid pipes. The strap connection used by other brands sticks the headers to the mid pipes and makes disconnecting either a tough job. Plus the ball and socket provides a leak free joint.
Which headers were run on 4/16/13 and which ones were run on 4/17/13?
OP one thing to keep in mind, if you do your own wrenching, the ball and socket collector connection like American Racing has is terrific for removing headers if you do things like swap heads or clutch or otherwise need to remove your headers or mid pipes. The strap connection used by other brands sticks the headers to the mid pipes and makes disconnecting either a tough job. Plus the ball and socket provides a leak free joint.