Boat tail exhaust stink

[Trav]

I have read several threads regarding exhaust gas getting into spiders cockpits. They all seem to say a curved down (ie Stock) tail pipe is the solution. I kind of like my straight pipe.

I was wondering if a chin spoiler or small air dam might change the air flow enough to eliminate the problem. It might also help the front end from lifting at speed.

My 86 had one (and a rear flip) and it had no smell problems.

I found a black plastic front spoiler someone had scraped off their car on a curb that is about the right size. I'm thinking about experimenting with it.

Before I go to the effort does anyone out there have any experience they can pass on?
Since this will block air flow to the oil sump will temps rise?

Thanks TD

[gprocket]

Hmm,

I have the same problem (1750 Spider) which I've always blamed on a (too rich) worn SPICA. Interesting that the tailpipe might be the culprit.

Perhaps you could rig the airdam temporarily to see if eliminates the problem. I'm sure you could finish the experiment long before overheating becomes an issue (which I don't think is a problem anyway).

Personally, I would choose the funky tailpipe over a funky airdam...

- Rich D.

[Roadtrip]

The tailpipe is turned down for very good reason. Alfa was not willy-nilly in it's engineering. There are definate reasons why things on the car are as they are. Many things that owners do to "improve" upon the Alfa engineers actually wind up hurting performance and utility.

[JoeCab]

I have found that an angled pipe that sticks out at least a few inches past the bumper works the best for the Duetto/1750 Spiders.

The downturned tip was NOT original/stock on these cars, only on later square-tail Spiders. The trick is getting an tailpipe that points outward (i.e away from the center of the car) and extends further out thant the bumper.

On square-tails, a down turned tip or a straight pipe that sticks out far enough will work fine. What will cause fumes on either car is the ANSA twin tip rear sections, which are actually angled upwards.

One other thing to check if you have bad fumes - the integrity of your tail light and trunk gaskets/seals!

Joe

[gprocket]

I rushed home to look at the tailpipe and found that I indeed have a straight, left-angled pipe. In looking through one of my spider books it is seems that the pipe should come just under the bumper, not past it.

Again, looking at the pictures, I there is a very early Kamm back with a straight pipe but thereafter all kamms up through the mid 80's (I'm guessing based on these pictures) had the down curved pipe. Two observations:

1) A Kamm is over 5" shorter that a boat (rear axle to bumper: 1065mm vs. 935mm) and presumably the tailpipe is reduced accordingly.

2) The Kamm tailpipe appears to be tucked up tighter against the bottom and has a cutout at the rear valance for clearance. The down curve brings the mouth of the pipe down to the height of the boat tail tailpipe.

It could be that the straight pipe was a problem all along and the engineers didn't find a fix until '71. Anybody have a boat tail that doesn't pull fumes (that is in stock trim)?

As far as the trunk seals are concerned, I am going to stuff the trunk with the car cover and what ever else I can find to fill it up. If the fumes go away then it's clear that it more of a seal problem. Really I can't see the trunk being a big contributer with the top down. Perhaps with the top up...


- Rich D.

[turbolarespider]

Quote:

Originally Posted by Roadtrip The tailpipe is turned down for very good reason. Alfa was not willy-nilly in it's engineering. There are definate reasons why things on the car are as they are. Many things that owners do to "improve" upon the Alfa engineers actually wind up hurting performance and utility.

[wesley55]

Use the OEM exhaust. I had the same problem with that stupid ANSA twin tubed exhaust in the 70's, and black all over my license plate area. OEM solves the problem.