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Discussion Starter #1
I'm replacing my exhaust in my '74 Spider. Great sound is important as is longevity.

I am considering the Magnaflow SS system.

Also looking at Vick's SS header at $299 with either a custom SS system or the mild steel stock system.

Those that have headers: Performance increase worth the cost?
 

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With a stock motor headers are unlikely to make much difference, especially if you have the factory 2 piece manifold. Good headers make a difference to a motor which has other performance modifications such as racing cams, race ported head, Webers, etc. Not all of the headers are good and some may reduce performance because they are not well matched to the exhaust ports.
The downside of almost any headers is they will dump extra heat under the hood.
 
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Way back when John Shankle was selling Alfa performance items, he told me that the stock 1971-1974 Alfs exhaust manifold flowed just as good as his tube header. That said, there are better header designs now and even products like the Burns Collector that replaces the collector at the end of the generic tube headers currently sold (as recomended by Wes Ingram).

I'm replacing my exhaust in my '74 Spider. Great sound is important as is longevity.

I am considering the Magnaflow SS system.

Also looking at Vick's SS header at $299 with either a custom SS system or the mild steel stock system.

Those that have headers: Performance increase worth the cost?
 

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Way back when John Shankle was selling Alfa performance items, he told me that the stock 1971-1974 Alfs exhaust manifold flowed just as good as his tube header.
And Shankle headers are better than most!
 
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Discussion Starter #6
Way back when John Shankle was selling Alfa performance items, he told me that the stock 1971-1974 Alfs exhaust manifold flowed just as good as his tube header. That said, there are better header designs now and even products like the Burns Collector that replaces the collector at the end of the generic tube headers currently sold (as recomended by Wes Ingram).
This looks like a cost effective upgrade, think I'll add this.
I'll report back with my butt Dyno!
 

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So you think that Vick's headers are better than Shankle's?
 

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The Burns collector is an addition to headers. I know a couple of knowledgeable racers who have been unable to get any extra power using them, but even if they are effective you need good headers to go with them. Check out Performatek - Performatek - Online Catalog. They do headers with a Burns collector. But I still say that you are wasting your money putting them on a stock motor. I have Shankles on my street motor that makes 180 HP.
 

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Here is a private email to me when I was designing my exhaust system. It is from a national Champion -

by the way... these header guys spend a lot of time pushing these " merge
" collectors and they are expensive.... and are useless in any real sense.

i manufactured and raced cars called sports 2000's . 1100 lb sports prototypes powered by 2l ford motors that were , essentially stock but with
small mods allowed. an average one made 138 hp most made 142 to 145 and
the best one in history was 150. in racing , hp equals downforce and
downforce is what wins you the races. so... people would kill their
mothers for 2 hp. and exhaust systems were the first magic bean that
everyone worked on. lola manufactured cars for this category which
started in 1978 and ended last year . their cars arrived with a 4 into 1
header with the 1.625 primaries , 32" long into a 2.25 pipe that was roughly 40 " long . ... this is 1978 ...

in 1980 when i really started building these cars in mass, i did a dyno
study on the exhaust on my own dyno. two motors , 5 days , hundreds
and hundreds of pulls, scientific methodology. i made 4 sets of headers
using 4 different primary diameters , segments that allowed me to change
the primary lengths an inch at a time and create stepped designs. 4
different sized exhaust pipes and the ability to change those lengths.

i started on day one with motor #1 with the box stock lola exhaust system and established the baseline curves...

5 days later after every permutation of design and configuration including
4 2 1 designs that showed any promise at all which was probably about 100 or more different types and sets as some were just garbage immediately so
the were investigated no further , the results were crystal clear. the
box stock, plain jane absolutely ordinary lola design using the same math
and theory that had driven header design from the 50's was the best.

other designs would move the power around some ... gain one or two at 7000
lose 4 or 5 at 5000 sort of thing but the simple fact was that the area
under the curve of the std set was always the best. every single time.

now... fast forward to 2003 when i won my last championship. i build that
car and while im doing it i get calls from header guys with all the new
magic ****. and they send it all to me for testing... LOTS of magic
merge collectors... i was retired by then and the dyno was gone so we
just took them to the track and ran them with full instrumentation...
none could get within a 1/2 second of the std lola set at mid ohio no
matter what tuning exercise they tried. i started on pole and won that
race by 15 seconds with headers and exhaust that were designed in 1978.

i don't figure that these 2l alfa motors are meaningfully different in any
way. same power. same torque, same rev range , the only thing different
is the fact that the head is al and cools a bit better and is less prone to detonation so you can run a couple more degrees of timing if you want ...

i would keep it as simple as possible.
 

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Here is what I did:
I kept the Shankle headers and I had an exhaust shop custom build everything back. The stock exhaust is 2". He cut off the merge at 2.25" and kept that diameter all the way to the tail pipe. Got rid of the stock boxes and replaced it with a single Borla Straight through muffler. The total cost was about $360. Do a search on me and Borla and you will find the details and also a video with a sound track.
 

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FWIW, I installed a complete GTA system - headers and 2 1/4" exhaust - on a close to stock Giulia Super many years ago. As compared to the stock system I got much better low down torque, I got slightly leaner fuel mixture and better fuel consumption. Top end power was improved as well. For me that is enough to tell me that at least a GTA header with exhaust works better than the stock system on an almost stock motor (cam timing tweaked and jetting slightly changed).

I have run both stock exhaust and headers without the resonator after the collector. With that set-up top end power appears to be unchanged but the torque curve falls on its face when driving in city traffic. To my pleasant surprise using a Burns collector with Shankle headers seems to completely avoid that low down bog when not running a front resonator.

Regarding collectors I would say that the stock as well as Shankle supplied collector are definitely inferior to both GTA and Burns. I would consider the Burns set-up superior to GTA as it at the very least drops the weight of an additional resonator. The GTA side pipe does away with the resonator but is very sensitive to even slight changes in configuration and I wouldn't choose it for low down torque - nor noise for that matter. YMMV
 

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When I bought my '88 Grad it had the stock single piece exhaust manifold.

I replaced that manifold with a set of IAP headers and noticed a significant increase in performance from about 4K rpm on up.

However, a year or so after that I test drove an '87 I saw on a dealers lot. It had the single piece cast manifold, and to be honest I couldn't tell much difference between my car and that one as far as performance was concerned.

I don't know what that means in the big picture, but passing on some data points.
 

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My 30mph to 70mph times in 3rd gear measured with a data logger improved by 0.5 second when I dumped the 2" resonator and final muffler and replaced them with the 2.5" Borla but the Borla is in about the same place as the resonator was. I will eventually get the car back on the dyno and I will be able to compare the torque curves but the other changes include cams and bigger Webers so it may not be completely clear. But I have logged AFR curves and hence acceleration times after each modification.
 

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I replaced that manifold with a set of IAP headers and noticed a significant increase in performance from about 4K rpm on up.

However, a year or so after that I test drove an '87 I saw on a dealers lot. It had the single piece cast manifold, and to be honest I couldn't tell much difference between my car and that one as far as performance was concerned.
I don't know if they have improved but the IAP headers that I know about shroud the exhaust ports.
 

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I don't know if they have improved but the IAP headers that I know about shroud the exhaust ports.
Interesting, so do you feel that the single piece cast manifold is well designed ?

I held on to it thinking that I might want to switch back to it someday.

Just curious !!
 

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The one piece manifold is inferior to the two piece which is well designed.

The late Russ Neely wrote on the Alfa Digest about his experiences with IAP headers. The good news is that they took them back and gave him a refund.
 

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Who knows what the correct answer is. My Burns collector is the same as on the 190+ HP regular gas Berlina Wes built for the Mexican Road race. Back when Jack Beck had his shop, he sold "anti-reversion" tube headers for around $1,500.

The one piece manifold is inferior to the two piece which is well designed.

The late Russ Neely wrote on the Alfa Digest about his experiences with IAP headers. The good news is that they took them back and gave him a refund.
 
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