Author Topic: Header chrome performance query  (Read 671 times)

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Offline exponent

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Header chrome performance query
« on: April 02, 2023, 03:08:43 PM »
I had a curious question and maybe someone knew an answer. Does the chrome plating on 550/750 headers affect performance? Does it mitigate or help control heat? I've no ideas I don't know the chemistry or thermodynamics of chrome.

Wondering this partly because I wire brushed some of the chrome off my headers on accident and have been thinking of getting them redone.
'78 550K 2106630

Offline Don R

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Re: Header chrome performance query
« Reply #1 on: April 02, 2023, 03:38:28 PM »
 These days re-chroming usually costs more than new headers. I think chrome is usually more for aesthetics than performance. My new pipes get coated with eastwood interior header coatings, mostly for corrosion control but I think it protects the chrome as well. 
 I'd take a look at Stainless steel headers if yours begin to look worse than you want.
No matter how many times you paint over a shadow, it's still there.
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Online newday777

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Re: Header chrome performance query
« Reply #2 on: April 02, 2023, 04:06:44 PM »
Most chrome platers won't rechrome pipes because of the oils in side the pipes from exhaust deposits which will contaminate the batch.

Chrome is for looks.
The Honda stock headers came double walled to help prevent blued pipes.
Most aftermarket pipes are single wall pipes.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline Tracksnblades1

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Re: Header chrome performance query
« Reply #3 on: April 02, 2023, 08:23:09 PM »
I had a curious question and maybe someone knew an answer. Does the chrome plating on 550/750 headers affect performance? Does it mitigate or help control heat? I've no ideas I don't know the chemistry or thermodynamics of chrome.

Wondering this partly because I wire brushed some of the chrome off my headers on accident and have been thinking of getting them redone.

Good question,

The engineering hand book shows chominum has a heat coefficient of 70-80 dependent on temperature 71.3@ 991*
and 80@ 621*.  Where as carbon steel has a heat coefficient of 54 and they don’t show any different coefficients for temperature changes.. Copper having a heat coefficient of 383 @ 621*, and aluminum has a heat coefficient of 232 @ 621*,
for some examples of some metals that can really conduct heat always..

Looks like chrome helps conduct heat faster than just plain carbon steel..  cast iron has a coefficient of 54.7@ 621*….

Like others have said…. May not see any big HP with either type Dyno you use…
Age Quod Agis

Offline exponent

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Re: Header chrome performance query
« Reply #4 on: April 03, 2023, 09:38:35 AM »
I had a curious question and maybe someone knew an answer. Does the chrome plating on 550/750 headers affect performance? Does it mitigate or help control heat? I've no ideas I don't know the chemistry or thermodynamics of chrome.

Wondering this partly because I wire brushed some of the chrome off my headers on accident and have been thinking of getting them redone.

Good question,

The engineering hand book shows chominum has a heat coefficient of 70-80 dependent on temperature 71.3@ 991*
and 80@ 621*.  Where as carbon steel has a heat coefficient of 54 and they don’t show any different coefficients for temperature changes.. Copper having a heat coefficient of 383 @ 621*, and aluminum has a heat coefficient of 232 @ 621*,
for some examples of some metals that can really conduct heat always..

Looks like chrome helps conduct heat faster than just plain carbon steel..  cast iron has a coefficient of 54.7@ 621*….

Like others have said…. May not see any big HP with either type Dyno you use…

Thanks this is interesting! Guessing I'll leave them as is
'78 550K 2106630

Offline C317414

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Re: Header chrome performance query
« Reply #5 on: April 03, 2023, 11:16:58 AM »
I had a curious question and maybe someone knew an answer. Does the chrome plating on 550/750 headers affect performance? Does it mitigate or help control heat? I've no ideas I don't know the chemistry or thermodynamics of chrome.

Wondering this partly because I wire brushed some of the chrome off my headers on accident and have been thinking of getting them redone.

Good question,

The engineering hand book shows chominum has a heat coefficient of 70-80 dependent on temperature 71.3@ 991*
and 80@ 621*.  Where as carbon steel has a heat coefficient of 54 and they don’t show any different coefficients for temperature changes.. Copper having a heat coefficient of 383 @ 621*, and aluminum has a heat coefficient of 232 @ 621*,
for some examples of some metals that can really conduct heat always..

Looks like chrome helps conduct heat faster than just plain carbon steel..  cast iron has a coefficient of 54.7@ 621*….

Like others have said…. May not see any big HP with either type Dyno you use…

Thanks this is interesting! Guessing I'll leave them as is

Decorative chrome usually has three layers over the original metal substrate: copper, nickel, and chromium.  The thicknesses are so small, that the effect on heat transfer is insignificant. 

Offline Flyin900

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Re: Header chrome performance query
« Reply #6 on: April 03, 2023, 02:04:57 PM »
I have had a variety of old exhaust systems rechromed on high level builds and the shop I use will chrome used pipes. As previously noted the pipes will contaminate the tanks if left exposed. The plater I use designs plugs to seal the system to prevent that happening.

That said a few systems ago one of my exhausts let go of the plug in his tank and destroyed the tank chemicals with contanimates. With the eye watering prices he charges I'm sure all was good.

It's hard now to find anyone who replates for cheap anymore, because of the environmental laws etc.
Common sense.....isn't so common!

1966 CL77 - 305cc - Gentleman's Scrambler
1967 CL175K0 - Scrambler #802 engine
1972 CB350F - Candy Bacchus Olive - Super Sport
1973 CB350F - Flake Matador Red - Super Sport
1975 CB400F - Parakeet Yellow - Super Sport
1976 CB400F - Varnish Blue - Super Sport
1976 GL1000 - Goldwing Standard
1978 CB550K - Super Sport
1981 GL1100 - Goldwing Standard
1982 CM450A - Hondamatic
1982 CB900C - Custom
1983 CX650E - Eurosport
1983 CB1000C - Custom X 2 Bikes now - both restored
1983 CB1100F - Super Sport - Pristine example
1984 GL1200 - Goldwing Standard

Offline Stev-o

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Re: Header chrome performance query
« Reply #7 on: April 03, 2023, 02:35:28 PM »
Most chrome platers won't rechrome pipes...

I've had exhaust re-chomed, was not cheap or quick. Chrome wont get you home!
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Online newday777

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Re: Header chrome performance query
« Reply #8 on: April 03, 2023, 03:12:37 PM »
Most chrome platers won't rechrome pipes...

I've had exhaust re-chomed, was not cheap or quick. !
How recently? What shop and where?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline MauiK3

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Re: Header chrome performance query
« Reply #9 on: April 03, 2023, 03:49:05 PM »
There is a chrome shop in SoCal, if you need the contact I’ll look it up.
Expensive but very nice work.
1973 CB 750 K3
10/72 build Z1 Kawasaki

Offline Tracksnblades1

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Re: Header chrome performance query
« Reply #10 on: April 03, 2023, 08:34:12 PM »
I had a curious question and maybe someone knew an answer. Does the chrome plating on 550/750 headers affect performance? Does it mitigate or help control heat? I've no ideas I don't know the chemistry or thermodynamics of chrome.

Wondering this partly because I wire brushed some of the chrome off my headers on accident and have been thinking of getting them redone.

Good question,

The engineering hand book shows chominum has a heat coefficient of 70-80 dependent on temperature 71.3@ 991*
and 80@ 621*.  Where as carbon steel has a heat coefficient of 54 and they don’t show any different coefficients for temperature changes.. Copper having a heat coefficient of 383 @ 621*, and aluminum has a heat coefficient of 232 @ 621*,
for some examples of some metals that can really conduct heat always..

Looks like chrome helps conduct heat faster than just plain carbon steel..  cast iron has a coefficient of 54.7@ 621*….

Like others have said…. May not see any big HP with either type Dyno you use…

Thanks this is interesting! Guessing I'll leave them as is

Decorative chrome usually has three layers over the original metal substrate: copper, nickel, and chromium.  The thicknesses are so small, that the effect on heat transfer is insignificant.

I’m glad you included the last sentence in my post… 😁

Carry on….😁    You must…😁
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Offline MRieck

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Re: Header chrome performance query
« Reply #11 on: April 03, 2023, 08:50:03 PM »
Jet Hot silver.
Owner of the "Million Dollar CB"

Online PeWe

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Re: Header chrome performance query
« Reply #12 on: April 03, 2023, 11:38:53 PM »
Jet Hot silver.
I could not resist to search.
Lots of hits and nice photos.

www.jet-hot.com
Look good! ;D
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Stev-o

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Re: Header chrome performance query
« Reply #13 on: April 04, 2023, 12:52:17 PM »
Most chrome platers won't rechrome pipes...

I've had exhaust re-chomed, was not cheap or quick. !
How recently? What shop and where?

Two years ago, Kawasaki pipes [3].  Cen Tex Plating in Austin...David is the owner.

https://centexplating.com/

'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline MRieck

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Re: Header chrome performance query
« Reply #14 on: April 04, 2023, 01:34:55 PM »
Jet Hot silver.
I could not resist to search.
Lots of hits and nice photos.

www.jet-hot.com
Look good! ;D
You can coat the outside and inside. Pipes cool down very quickly.....nice if you have to work on the engine after running it.
Owner of the "Million Dollar CB"

Online newday777

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Re: Header chrome performance query
« Reply #15 on: April 04, 2023, 03:35:42 PM »
Jet Hot silver.
I could not resist to search.
Lots of hits and nice photos.

www.jet-hot.com
Look good! ;D
You can coat the outside and inside. Pipes cool down very quickly.....nice if you have to work on the engine after running it.
Is that a do it yourself product or do you send the exhaust to their shop?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A