Exhaust manifold vs headers

[alfacat]

First of all, I checked prior threads before asking this question and have read all that were available regarding the cracked manifold which is my problem. Small crack currently. I have an 85 Spider and thought I might just go with new headers for a little performance increase. The question is can I do so on the Bosch injected Spider and what retuning will be necessary. I thought I saw headers at IAP which included sensors. Any input will be appreciated.

[JoeCab]

AlfaCat,

Centerline also had headers that are designed to work with late spiders and allow you to use a Catalytic Converter. They also have a fitting for your o2 sensor. It is part # PH118.

You shouldn't have to do any tuning to make your car work with headers, although you will see the biggest performance gains with performance camshafts and a big valve head. But, you can always add those later.

Joe

[bill_bain]

Another option is to use the manifold and downpipe/cat from an S4 Spider. The stock S3 system isn't real good and headers do offer some improvemnt, but if you live in a state which has visual inspections, it might be easier to go with something that looks like stock. The S4 system is just about as efficient as headers.

[desert spider]

I have an '84 Spider with Bosch injection. I replaced my cracked exhaust manifold with Centerline Headers which I assume are the same or similar to the ones sold by IAP. No retuning was necessary. There was a noticable performance increase along with slight improvement in fuel mileage. There will be a slight increase in under the hood noise level but it is not objectionable. I'd say go for it.
Jim
Deser Spider '84