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Discussion Starter #1
I need to replace the exhaust system in my 86 Spider. My question is.. Is ther much of a performance increace going with headers and just a center muffler. If so, what headers do you recommend, IAP or Centerline's? I was also thinking of disconnecting the A/C compressor. In my Alfa, it seems like any increase in power will help blending into the flow of traffic, going onto the highway. :)
 

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Any gain you'll get from a header would be more toward the top end rather than bottom end.

AFA going with just a center muffler, there would be a slight increase there too as there would be less restriction, however some states require a catylitic converter on cars of X year and newer. EG: New York requires them on 74 and newer)

On the flip side, even if you don't have to have a converter, an expansion chamber in that location (just an empty can, no baffles or the like) takes advantage of a harmonic pulse which gives a tiny boost also within a certain rpm range.

As to the rear can, without it you'll pic up at the top a little bit, but with it you'll have a little more low end torque due to the back pressure it creates.

Regardless, changing or tinkering all of the above isn't going to get you a whole lot of power in the grander scheme of things. Somewhere around the 5-12hp range depending on RPM, free-ness of flow and a few other variables. (in other words you might notice a gain, you might not, and in some instances you could potentially lose a few bhp at certain RPMs as everything is a trade off for something else)

Taking the belt off the AC compressor is worth a couple hp itself due to less parastic drag, but the weight of the thing (along with the rest of the AC system) kinda offsets any gain you'd get from doing so.

As in yes, you'll pick up a little, but it wouldn't equal what a non-AC equipped car would produce from a horsepower to weight ratio.

Truth be told, if you want a little more snot when accelerating, and due to the way the L-jet system works or accepts alterations, you'd likely be better off trying to find a 4.36:1 differential gear setup (likely not going to happen due to stateside rarity) or, you could go with a slightly smaller tire diameter/rollout which would effectively change the final drive ratio to something quicker than the 4.1:1 gearing you have now. (changing final drive or tire diameter would of course cost you a bit of top end though due to that trade off aspect of things)
 

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nh,
IMHO you will get a noticeable improvement in performance and better gas mileage (with reduction in oil consuption) if you send out your fuel injectors for Ultrasonic/Solvent cleaning.
Though I had no specific complaints, I sent mine to "Cruzin" and found that the pattern was "poor" on 3 and the 4th was "fail". The "Fail: injector was passing only 40% flow.
After service the overall flow was 10% higher than as sent and the bad one flow was restored. I went further and got more "used" injectors as donors and subbed a couple to get them more matched.
Rather than a headers, try to get a pre 74 or an S4 2 piece exhaust manifold.. and incorporate a Magnaflow 74004 cat...you'll get the performance with a lot less hassle.
My 2 lire's worth Elio
 

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Discussion Starter #4
Thanks for the replies and some very good advise. The reason I wanted to go to a header as apposed to a pre-74 manifold was I don't want the hassle of welding a bunge on it for the o2 sensor. I would replace the cat but not at the prices IAP charges and here I really don't need one. An S-4 manifold might work, if I could find one. I'm not trying for a race car or to drag race it, just for more power merging into traffic. Over the winter I will take the injectors our for servicing. I just hate being slower then a Prius! :)
 

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I need to replace the exhaust system in my 86 Spider. My question is.. Is ther much of a performance increace going with headers and just a center muffler. If so, what headers do you recommend, IAP or Centerline's? I was also thinking of disconnecting the A/C compressor. In my Alfa, it seems like any increase in power will help blending into the flow of traffic, going onto the highway. :)
The first performance upgrade I ever did to my 1984 Spider (I bought it new) was to swap out the manifold for headers and then replace the stock cat for a free-flow type. In both instances, I noticed the improvement right away, and I got a gas mileage improvement from stock.

When the headers were installed, I noticed that my Spider could handle the long interstate inclines much better. It used to seem to me that it was just not possible to accelerate when going uphill, and the headers certainly gave it a bit more "oomph". Another power gain was also noticeable when the cat was replaced. I never dynoed the car, but I after both mods, I did see the mpg increase from mid-20s to upper-20s.

I will say that for some reason my 1984 always felt more "restricted" than my 1987 Spider. Since yours is a 1986, I don't know if you will notice as much difference as I did, but IMHO, if you are going to spend money on the exhaust, then it is smart to spend a bit more and go with headers and a free-flow catalytic converter. This won't really make you car fast off the line, but it will perform better under load, and I think that is pretty much in line with what Tifosi mentioned. Also, I do think that Elio is on to something with his advice. (Part of my winter plan is to send my injectors to Cruzin'.)

I have never used the IAP headers, but have been very pleased with the two Centerline sets that I ordered and installed, as well as the ones I had from AR Ricambi. (The last were the original set I installed first, made by Shankle Engineering.) I would also strongly suggest having the headers Jet-Hot coated. (Their web site is JETHOT The Hottest Header Coatings! Jet-Hot, jet coat, hot jet, headers, coatings, sterling,Header coating, Ceramic coating, corrosion protection, Metallic Ceramic Coatings, MCCI, metallic ceramic, exhaust coating, performance coating, temperature re.) It's not inexpensive to do all this (headers, Jet-Hot, free flow cat), but as I mentioned before, this would be the most cost effective time to do it, and I think you will be pleased with the results. Furthermore, you'll be ready to build on these mods, should you decide to continue your quest for additional power.

I would not disconnect the A/C, just like I would not run a car without the cat. I simply don't think there is good reason for this, as I doubt it will make much difference in the overall power band. I think the A/C increases the versatility and comfort of the car tremendously, and I'm sure you will appreciate it if caught in a summer downpour and when your significant other doesn't want to arrive to her destination "glowing" and with a new wind-styled 'do. With modern cats, I don't think you need to risk being out of compliance with Federal regs, or making your Spider environmentally unfriendly.

Last, but equally important... Doing upgrades when work is already going to be performed is smart, but in your quest for power, be aware that the most significant upgrade you can make is in improving the skills of he who is behind the wheel. After doing that "improvement" myself, I can drive my stock '87 onto the interstate ramp and join in on traffic faster than I ever could as a "non-improved" driver in my heavily modifed '84 Spider...

Best regards,
 

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Great stuff from Enrique as usual!

Wanted to add that if you locate pre 74 headers, the Centerline downpipes and muffler (not CAT) will fit up real well! OE405 and OE437 or the IAP one piece 63004.

TTFN Elio
 

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Hi Ra;ph,

Not sure what' going on with your 86, but my 86 is slow off the start but cranks it after I get over 40 mph. from 50+ it just wants to run. Might want to go low buck and send the injectors out first. Personall, I had the center muffler cut out. Not sure about increased perfomance but it sure does sound like it should now.
 

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I just went this route on my 85 graduate, got the headers from Centerline, and had a high flow cat installed. Muffler guy had a hard time installing headers, had to cut and reweld, but the install turned out nice. A slight gain in top end, come on nice at low RPM too. I get a slight hesitation if it idles in traffic too long (maybe not enough pressure from headers??) but comes on OK. Quite a bit louder too. I think maybe it's time to get my injectors cleaned etc. , time to check out Cruzin'.
 

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... Muffler guy had a hard time installing headers, had to cut and reweld, ...
You are not saying he cut a portion of the headers, are you? (He would have to cut and re-weld to install the free flow cat...)

Best regards,
 

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...it seems like any increase in power will help blending into the flow of traffic, going onto the highway.

I'm not trying for a race car or to drag race it, just for more power merging into traffic.
Just a thought, but perhaps the throttle linkage &/or pedal stop is not adjusted correctly and preventing the throttle from opening 100% ?

There is (or should be) a pedal stop on the floor under the throttle pedal. That stop can be screwed in or out (then its position fixed with a locking nut). It should be adjusted so that when the pedal is 'floored', the throttle plate is fully open. Remove the hard plastic intake duct on top of th eengine and you can see the action of the throttle plate.

Also the throttle rod under the plenum can be adjusted for total length. If it is mis-adjusted the throttle may not open all the way. While checking & adjusting these items, also make sure the throttle does not go past wide open (if that is physically possible).

Have a peek at this thread: double your HP


...for some reason my 1984 always felt more "restricted" than my 1987 Spider.
Are you comparing centrifugal VVT vs solenoid VVT?
 

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Are you comparing centrifugal VVT vs solenoid VVT?
No... My sense, and that of other '84 and '85 Spider owners that I know (or knew back in the day) is that the catalytic converters of the later cars flowed better...

Best regards,
 

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Rather than a headers, try to get a pre 74 or an S4 2 piece exhaust manifold.. and incorporate a Magnaflow 74004 cat...you'll get the performance with a lot less hassle.
Good recommendation. Depending where you live you may want to drop the cat alltogether and install a stock early Euro non-cat exhaust.

While I am a firm believer in headers on Alfas - yes they do increase bottom end too - the hassle to do it properly with regard to set-up, custom exhaust fabrication and brackets, heat management, noise is not worth it for most people.
 

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You are not saying he cut a portion of the headers, are you? (He would have to cut and re-weld to install the free flow cat...)

Best regards,

Zunige, No, he had to cut at the branch and reweld. Layed a straight edge across the header flange and they were'nt even flat. Used a spare head to do reweld, couldn'y get in there to tack in place.
 

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That's not quality. He should've sent them back...On this BB I've heard less than glowing reports of low end aftermarket headers. Can't go wrong with the early S2 2-piece manifolds.

To the OP, compared to fitting headers there is much LESS hassle having a shop weld in a O2 bung--takes <15 minutes and cost me $15. OTOH, Headers that don't fit is a HUGE hassle.
 

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Zunige, No, he had to cut at the branch and reweld. Layed a straight edge across the header flange and they were'nt even flat. Used a spare head to do reweld, couldn'y get in there to tack in place.
Wow! I would have sent those back... Like I said, I've bought two sets, one in 2006 and another in 2007, and they went in fine. In fact, the Centerline fit is absolutely great, and the "Y" connector is just perfect to bolt up to a free flow cat. They are a bit tricky to install, because you do have two long independent pieces that bolt up to the head, and there isn't a lot of room there... But it is also that design that is better than the manifolds...

One thing to note is that much of what one sees as performance products offered by aftermarket vendors are duplicates of what was offered in the Alfa Performance catalogs of the period. It's interesting to look at one of those and then an aftermarket catalog. The headers, and their design, were actually developed a long time ago. Of course, pre-1975 cars could use these performance headers without issue, but for the cars that followed, these were for "off-road use only".

Best regards,
 

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Of course, pre-1975 cars could use these performance headers without issue, but for the cars that followed, these were for "off-road use only"
That's really not a problem though:

Unless all 4 wheels come off at the same time and the chassis pancakes down to the pavement, the headers are indeed used 'off road' for 100% of thier service life. ;)
 

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Discussion Starter #17
I decided to go the Centerline headers and cat. The rear pipe f my cat is rusted through also. Centerline headers, cat and center muffler should work out pretty good. I do all my own work, even exhaust work. I did check out the throttle linkage adjustment and it is fine.
So far it looks like the biggest problem is removing the four nuts from the manifold to downpipe. Not enough room down there. Since the Cat is bad anyways, I'll just cut off the downpipe about 6 inches from the manifold connection. It seems that there is never enough room to work, on a Spider! :) Thanks to all for the great suggestions and advise.
 

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Discussion Starter #18
Just an aside. As I was under the Alfa looking at the exhaust I noticed my engine mounts could also use replacement. Looks like a new exhaust sytem, sending injectors out for cleaning and new motor mounts should make a good winter project. Maybe I should just pull the engine and tranny and go through everything. Ahh, the life of an Alfa owner.:)
 

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Most often when you (sanely) modify an engine you are spending money for very little noticeable effect. IMHO a set of freer flowing headers is the biggest performance bang for the buck you can get on an Alfa spider. I have a set of Shankle headers and I remember being impressed with the noticeable performance gain they gave.

I also had the AC compressor bypassed, it can't hurt and if you want to re-attach it it is just a matter of re-attaching the belt.
 

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Discussion Starter #20
Most often when you (sanely) modify an engine you are spending money for very little noticeable effect. IMHO a set of freer flowing headers is the biggest performance bang for the buck you can get on an Alfa spider. I have a set of Shankle headers and I remember being impressed with the noticeable performance gain they gave.

I also had the AC compressor bypassed, it can't hurt and if you want to re-attach it it is just a matter of re-attaching the belt.
I agree. Headers make a big difference on my Vettes. The A/C unit places a load on the engine so I am going to remove the belt and free up about 2 or 3 horses. I hardly ever use the A/C.
 
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