105 Headers Comparison/shootout! - Page 8 - Alfa Romeo Bulletin Board & Forums
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post #106 of 126 (permalink) Old 02-25-2019, 04:13 PM
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According to the table for exhaust systems at 5000 rpm a '76 made 109 HP and a 77 made 118 HP. The exhaust manifold was the same. Where did the extra 9 HP come from?
What is interesting is that the 76 had cam LC's of 114. 114 and the 77 had 102, 102. My guess is the difference is cam timing and not exhaust system.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #107 of 126 (permalink) Old 02-25-2019, 04:42 PM
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Quote:
Originally Posted by Tom Frasca View Post
At the end of the day.... when god judges you, to tell the truth ....can you really differentiate the difference in a street drive?
Tom, I’m not the best person to ask that...in the past I’ve lost my license twice ��

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Originally Posted by PocketAce View Post
How about that removal of the engine fan?
Lol... now you know why the Gta and gtams had the stubby fan option.

Disappointed with the test gains... Shankle gained 7hp on his catalogues I recall since he wanted to sell more electric ones :-)

Last edited by davbert; 02-26-2019 at 02:44 AM.
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post #108 of 126 (permalink) Old 02-25-2019, 05:13 PM
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The no fan HP gain is about 10HP at 7000 rpm.
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Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #109 of 126 (permalink) Old 02-25-2019, 05:32 PM
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Truth be told it takes a real pro to translate 8-10 HP in competition performance. The trick here is anyone can spend money ...but to spend it wisely takes talent and a little experience. So speaking as a fool who did all this nonsense, 5,10,15 even 20 HP on your street car means squat, seek life elsewhere. I now put money into drivability, tuning suspensions, lightning flywheels that were designed for a family sedan, synchronizing first gears, lightening the gearbox rotating masses, better braking, well-done cosmetic enhancement...ah it's just an old near 70 guy thinking out loud..

The older I get.. the faster I was....
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post #110 of 126 (permalink) Old 02-25-2019, 06:16 PM
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My experience is that the best improvements come from the loose nut on the end of the steering wheel. And the track time and training that takes is a lot of fun as well. When I was racing, I always noted that my last few laps were always faster than the first ones, on any track.

Robert
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post #111 of 126 (permalink) Old 02-25-2019, 07:58 PM
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Quote:
Originally Posted by Tom Frasca View Post
Truth be told it takes a real pro to translate 8-10 HP in competition performance. The trick here is anyone can spend money ...but to spend it wisely takes talent and a little experience. So speaking as a fool who did all this nonsense, 5,10,15 even 20 HP on your street car means squat, seek life elsewhere. I now put money into drivability, tuning suspensions, lightning flywheels that were designed for a family sedan, synchronizing first gears, lightening the gearbox rotating masses, better braking, well-done cosmetic enhancement...ah it's just an old near 70 guy thinking out loud..
This "old" 1960s guy is with you.
But in a 101 Spider the mechanical fan robbed HP and worse--was noisy.
Unless you have a show car, get rid of them.
The aluminium ones look good, mount one on the wall of your shop, or den.
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post #112 of 126 (permalink) Old 02-25-2019, 08:39 PM
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Hi Jim,

Have you measured top to bottom or side to side?

I have twos sets not mounted on the car and another one mounted that I can't measure. To me it looks like the inside diameter of the tubing is about 38mm. However, there is some crude porting done that is very visible on my NOS set ... and indeed 1 and 2 have the 40mm dimension top to bottom on both sets. the side to side dimension on the used set is consistently 38mm and varies from 37 to 38mm on the other set. My money is that the apparently different size primaries are attributable to the porting of the flanges rather than due to differnt pipe diameters.

IMO 38mm works better on the street than 40mm or above and it may significantly lower the rpm when max torque comes in.

Re: some of the comments on drivability ... putting 1600 GTA headers with a 2 1/4" GTA exhaust on an otherwise very stock Giulia Super made a huge difference in bottom-end torque and drivability ... right up there with with close ratio box, lightweight flywheel and good shocks ...

Shankle/Centerline headers (38mm) - not the replica GTA type which is 40mm - work great on a 2-liter, especially when combined with an improved merge collector and a good exhaust with 2 1/4 or 2 1/2 diameter. However a ready made Alfaholics set-up may be a lot easier ...

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Here are the primary diameters of my GTA headers. This might explain why Classic Alfa offered "big tube" 40mm headers (presumably from CSC). When I get a chance I'll measure my Alfaholics headers for comparison.

#1 40.08 mm
#2 40.11 mm
#3 37.00 mm
#4 37.00 mm
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post #113 of 126 (permalink) Old 02-25-2019, 11:17 PM
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[quote]
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I have twos sets not mounted on the car and another one mounted that I can't measure. To me it looks like the inside diameter of the tubing is about 38mm. However, there is some crude porting done that is very visible on my NOS set ... and indeed 1 and 2 have the 40mm dimension top to bottom on both sets. the side to side dimension on the used set is consistently 38mm and varies from 37 to 38mm on the other set. My money is that the apparently different size primaries are attributable to the porting of the flanges rather than due to differnt pipe diameters.
I measured the .o.d. of the primaries about 5in down from the curve. I'll be happy to do some more measuring if you want. BTW: I imported these headers about '73 or '74. The guy I bought them from was pretty well connected with Alfa so I think he maybe was buying direct, although at the time Alfa stil had stocking part numbers for the headers along with most other GTA and even TI Super specific stufff that could just be ordered at any dealer.

Quote:
IMO 38mm works better on the street than 40mm or above and it may significantly lower the rpm when max torque comes in.

Re: some of the comments on drivability ... putting 1600 GTA headers with a 2 1/4" GTA exhaust on an otherwise very stock Giulia Super made a huge difference in bottom-end torque and drivability ... right up there with with close ratio box, lightweight flywheel and good shocks
Coming from someone who won his class in a TI Super against some respectablly fast competition in the '08 Carrera, I'd say this is a pretty solid observation. Your secret sauce works.

Sadly the GTA headers require some modification to fit a 2 liter Alfa motor. Nonetheless, they are such a good design that I've wondered why none of the vendors haven't convinced their supplier to make authentic vintage-style GTA headers that will fit a 2 liter's taller block. I bought the Alfaholics exhaust for my Super because it was stainless and the headers were GTA style and the exhaust dia was 2 1/4" or 2 1/2". I'm very happy with the way it works with my version of John Trevey's "in the style of" version of your Rally motor.

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series

Last edited by 180OUT; 02-25-2019 at 11:24 PM.
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post #114 of 126 (permalink) Old 02-26-2019, 02:53 AM
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Originally Posted by Subtle View Post
This "old" 1960s guy is with you.
But in a 101 Spider the mechanical fan robbed HP and worse--was noisy.
Unless you have a show car, get rid of them.
The aluminium ones look good, mount one on the wall of your shop, or den.
removing the fan might be ok in balmy BC summers but not so well in socal 405 traffic jam...

ive notice just removing the fan shroud will affect the cooling in rush hour traffic on a mod motor with more heat generated.

what next? electric water pump and axle driven alternator so it can read higher on dyno? lol

Last edited by davbert; 02-26-2019 at 02:59 AM.
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post #115 of 126 (permalink) Old 02-26-2019, 06:16 AM
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Mechanical fans move little air when you need them most - when the motor is turning slowly. They move lots of air when the motor is turning fast but then you normally have high air speed. A good electric fan will move lots of air when the car is stuck in hot traffic and it will turn off when you are moving quickly and when you can the extra HP.
It should surprise no one that modern cars use electric fans.
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Ed Prytherch
79 Spider
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76 Suzuki GT500
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A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #116 of 126 (permalink) Old 02-26-2019, 06:40 AM
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I overlooked mentioning the Spal puller fans with the paddle blade.
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post #117 of 126 (permalink) Old 02-26-2019, 07:54 AM
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Talking about primary tube diameters, look at Giulietta Veloce headers, they are absolutely tiny, does smaller diameter add a performance gain in 1300 cc engines. Most suppliers claim their headers fit, 1300, 1600 1750 and 2000cc engines, and no doubt they fit, but is a larger bore primary overkill on a small displacement engine? I know in race engines a smaller engine might benefit from bigger diameter primaries, I suspect, at least at the time Alfa knew what they were doing with veloce headers. Just wondering.

Cars ruined my life! 😱
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post #118 of 126 (permalink) Old 02-26-2019, 08:19 AM
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Got it. This is likely attributable to their construction being sand bent tubing then ...

[quote=180OUT;8380744]
Quote:

I measured the .o.d. of the primaries about 5in down from the curve. I'll be happy to do some more measuring if you want.
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post #119 of 126 (permalink) Old 03-01-2019, 06:23 PM Thread Starter
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Just as a side note for the original question regarding engine note.

I finally broke in my new borla muffler and the car sounds a lot better! Especially in 3rd gear!

I highly recommend people allow 300-500 break in miles on a new muffler before making any decisions regarding further modifications.
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post #120 of 126 (permalink) Old 03-01-2019, 07:42 PM
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Thai Made Shankle?

Anyone ordered these?

https://www.ebay.com/itm/Alfa-Romeo-...SfEz:rk:1:pf:0
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