H pipe ??
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Melting Slicks
Joined: Jul 2010
Posts: 2,762
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
H pipe ??
We had my '77 on the lift this morning to do rear O-ring calipers
and we lowered it an inch w/ the 8" bolts that I bought last fall. While it was up there my mechanic who does excellent custom pipe work was scoping it out to see if I should buy the true dual conversion kit or just custom bend a 2 1/2" system. He said not to waste my money on the kit as it would be an easy custom build and that he wants to run about a 2" H pipe for better scavenging and thinks it will also have better sound. This setup makes perfect sense to me, what do the Experienced forum experts think?
PS The motor is basically stock w/ a rebuilt carb and rebuilt, re-curved distributer per Lars and Gorlich Accelerators mufflers, the cat has been gone for a while!
and we lowered it an inch w/ the 8" bolts that I bought last fall. While it was up there my mechanic who does excellent custom pipe work was scoping it out to see if I should buy the true dual conversion kit or just custom bend a 2 1/2" system. He said not to waste my money on the kit as it would be an easy custom build and that he wants to run about a 2" H pipe for better scavenging and thinks it will also have better sound. This setup makes perfect sense to me, what do the Experienced forum experts think?
PS The motor is basically stock w/ a rebuilt carb and rebuilt, re-curved distributer per Lars and Gorlich Accelerators mufflers, the cat has been gone for a while!
Melting Slicks
Joined: Dec 2009
Posts: 3,233
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From: Thunder Bay
I think he hasn't actually bent up a system for a Corvette before. The kit from Corvette Central duplicates the factory system in every way, including all the little tweaks and crimps for clearance. There is no chance whatsoever that your guy will be able to do as well with a custom system, especially if you have lowered your car. Even with the kit, you are going to be challenged for ground clearance.
As for the H-pipe it will tone down the exhaust note - much more mellow. I'm not convinced it will make any difference in terms of performance.
As for the H-pipe it will tone down the exhaust note - much more mellow. I'm not convinced it will make any difference in terms of performance.
Burning Brakes
Joined: Sep 2006
Posts: 1,071
Likes: 86
From: Rotonda FL
True dual exhausts pepped up my stock 77 L48 (this was a LONG time ago). Headers helped more. (I now have an L-31 with a bigger cam plus a hot rodded TPI and a 700R4. The duals and headers remain.)
The H-pipe (which I installed after the headers & duals) evened out the exhaust and gave the impression it was more quiet.
The H-pipe (which I installed after the headers & duals) evened out the exhaust and gave the impression it was more quiet.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
An H pipe reduces the sound a bunch at higher RPM's. Not so much around town. I had to slightly richen the idle mix screws (1/8 turn out) after I had mine installed.
Last edited by gcusmano74; Apr 7, 2013 at 06:23 PM.
Thread Starter
Melting Slicks
Joined: Jul 2010
Posts: 2,762
Likes: 820
From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
I think he hasn't actually bent up a system for a Corvette before. The kit from Corvette Central duplicates the factory system in every way, including all the little tweaks and crimps for clearance. There is no chance whatsoever that your guy will be able to do as well with a custom system, especially if you have lowered your car. Even with the kit, you are going to be challenged for ground clearance.
As for the H-pipe it will tone down the exhaust note - much more mellow. I'm not convinced it will make any difference in terms of performance.
As for the H-pipe it will tone down the exhaust note - much more mellow. I'm not convinced it will make any difference in terms of performance.
Last edited by BPHORSEGUY; Apr 6, 2013 at 04:47 PM.
Thread Starter
Melting Slicks
Joined: Jul 2010
Posts: 2,762
Likes: 820
From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
True dual exhausts pepped up my stock 77 L48 (this was a LONG time ago). Headers helped more. (I now have an L-31 with a bigger cam plus a hot rodded TPI and a 700R4. The duals and headers remain.)
The H-pipe (which I installed after the headers & duals) evened out the exhaust and gave the impression it was more quiet.
The H-pipe (which I installed after the headers & duals) evened out the exhaust and gave the impression it was more quiet.
Last edited by BPHORSEGUY; Apr 6, 2013 at 04:58 PM.
Thread Starter
Melting Slicks
Joined: Jul 2010
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
[QUOTE=drwet;1583566167] Even with the kit, you are going to be challenged for ground clearance.
Okay, I have crawled under the car and realize the low point isn't near the crossmember. The Y pipe just before the tire carrier is only just less then 5" above the ground with the tire carrier being about a half inch higher then that. The pipes where they will go through the crossmember have more then 8" and of course are protected by the crossmember. These measurement are with the car lowered 1". I still think my guy should be able to do this and maybe even improve on this! If I am still missing something please educate me! I could always buy the kit later if this doesn't turn out as well as we think it will !
Okay, I have crawled under the car and realize the low point isn't near the crossmember. The Y pipe just before the tire carrier is only just less then 5" above the ground with the tire carrier being about a half inch higher then that. The pipes where they will go through the crossmember have more then 8" and of course are protected by the crossmember. These measurement are with the car lowered 1". I still think my guy should be able to do this and maybe even improve on this! If I am still missing something please educate me! I could always buy the kit later if this doesn't turn out as well as we think it will !
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Race Director
Joined: Dec 1999
Posts: 11,096
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From: Sierra Foothills CA
The H pipe evens out exhaust pulses and should give you a small bump in power. If your mechanic is used to building custom exhaust he'll have no problem taking care of you.
Team Owner
Joined: Oct 2004
Posts: 81,241
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From: altered state
St. Jude Donor '05
about a 2" H pipe for better scavenging and thinks it will also have better sound.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
As an engineer I'm more inclined to believe (fellow engineer) Vizard's claims than other people's claims to the contrary.
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Vizard has a different opinion about that than you do. He says it's a 100% probability of reduced noise, a 60% probability of increased horsepower, and 0% probability of reduced performance .
As an engineer I'm more inclined to believe (fellow engineer) Vizard's claims than other people's claims to the contrary.
As an engineer I'm more inclined to believe (fellow engineer) Vizard's claims than other people's claims to the contrary.
There are plenty of other sources who agree with him. I've been too busy to engage in a debate over it, so I decided not to respond.
Le Mans Master
Joined: Oct 2007
Posts: 7,455
Likes: 977
From: RI, Now Franklin/Nashville TN
H and X pipes absolutely will sweeten the tone and help the HP. H pipes have been used for a kazillion years by hot rodder s going back to the 70's and just about every car manufacturer today that utilizes true duals utilizes an H/X pipe of some sort-It's NOT for show! My 94 Mustang GT Convertible had an H pipe from the factory and I replaced the H pipe and cats with a magna flow X pipe with high flow cats and boy does it sound sweet at high RPM. The L-82 has 2.5 duals with McJacks shorty headers with no H pipe simply since the kit did not include one.
Le Mans Master
Joined: Oct 2010
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From: melbourne florida
2023 C3 of the Year Finalist - Modified
actually , Chrysler engineers working on the max wedge program determined it was worth horsepower. that obviously applies to cars with full exhaust. oh yes that was about 1961 or 62
Thread Starter
Melting Slicks
Joined: Jul 2010
Posts: 2,762
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Race Director
Joined: Dec 1999
Posts: 11,096
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From: Sierra Foothills CA
Burning Brakes
Joined: Jun 2009
Posts: 840
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From: Syracuse IN
Summit has a great "narrow" X pipe, Check out this link
http://www.summitracing.com/parts/sum-643125
http://www.summitracing.com/parts/sum-643125
Thread Starter
Melting Slicks
Joined: Jul 2010
Posts: 2,762
Likes: 820
From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Thread Starter
Melting Slicks
Joined: Jul 2010
Posts: 2,762
Likes: 820
From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Summit has a great "narrow" X pipe, Check out this link
http://www.summitracing.com/parts/sum-643125
http://www.summitracing.com/parts/sum-643125