Replace SSI with Headers for 83 sc
 

I have SSI in pace but dont use the heat at all...unfortunately even after rebuilding the flappers I still get some heat leak to the floor vent (toasty feet in 90 degree weather). I am considering removing the enter heat system and replacing with headers to the exhaust

what do i need to take into consideration when planning this?
is there a risk with the bolts when removing the SSIs
I assume headers connect direct to 2 in 1 out muffler?
while i need to retune the car as a result of going to headers
any other caveats?

thanks

bob

it's a plug and play conversion.
maybe block off plates for the heater duct entry ports where the flap regulator sits.
and yes maybe a little re-tune.

I learned not to heat-tape the headers as you don't want extra heat to crawl back into the engine on a halt.

Thanks Flo

can anyone comment on suggested headers to consider? I m not racing the car, so just functional effective headers (none of that Fabspeed crap)

I ditched the heat for headers. I certainly don't need heat where I live.

http://forums.pelicanparts.com/uploa...1605015051.jpg

AG..what make are those?

Those are RarlyL8 Motorsports

bob -- as I understand it, SSI headers are properly sized for a stock(ish) 3.0 (they're a bit small for a 3.2). Thus, not sure what you'd gain, performance-wise, replacing them with a new set of headers that lacks heater boxes.

If the problem you're looking to solve is hot air leaking past the flapper boxes, why not simply disconnect/remove the hoses running from your SSIs to the flapper boxes and leave the SSIs in place?

Because instead of fixing the problem correctly.......

Bob - darrin has the same question I have. SSIs are a nice improvement over stock headers. You can fairly easily block off where the flexible hose from the SSIs connects to the air valve part (flappers). To go a bit farther, you could then remove the wires which control the flappers, and seal the opening. A lot simpler and less expensive than going to racing headers. The reasonably priced racing headers are basically like what the SSIs are, just without the surrounding sheet metal to do the heat exchanging. Nobody makes a non-heat exchanger header whose sole difference from stock (or at least the SSI 3 into one configuration) is to get rid of the heat exchanger part. They are all designed to get more performance out of the engine - which isn't needed at all for street driving.

Why not simply repair, adjust, or replace the flapper boxes that close off the heater ducts?

once you want headers, you get headers ;-)

but yes, somehow the rebuilt went wrong. fix that.

easiest would be to delete the hot-air pipe from the flap to the SSI.
then rethink the plan

I ve decided to keep the SSIs and fix the flappers..in fact I am not sure where the isssue lies since the flappers appear to be closed but yet I still am getting some heat...i backdated the engine and removed the fan to drive additional blown heat...i will like have to tear into the vent system as well this winter to see if those flaps are working correctly..i dont think they are...should be a lot of fun in an unheated garage!

Those poor flapper boxes lead a very hard life. It's not unusual to get a good deal of leakage past the internal flap when corrosion will no longer allow it to fully close. Fortunately, new ones are relatively cheap, and even available in stainless. From our host, no less. About $140 each for the SSI made ones.

Unfortunately, the bolts holding them on lead an equally hard life. The biggest challenge in replacing the boxes is getting those buggers loose. They are invariably absolutely rusted in place.

I did pull the flappers, redid them both, ruined one stud while doing, covered in dirty grease...lets just say i did not enjoy the task. New cables and guides done too. Told by experts that just blocking SSI outlets (where flappers fit) is bad idea as SSIs retain heat which heats the engine bay...better off figuring how to block flapper box and let excess heat escape out of open flapper vents. So this winter..I will check flappers again, possibly just replace with new ones to be 100% sure since I dont want to do this job any more times then called for..and then tackle getting all the frunk vents working properly

crap...i am really not looking forward to this without a lift...

Might cheat and get my trusted garage to install flappers for me and save all the aggrivation, then tackle the vents

Since you got the flapper units off once, just take them off again. Make aluminum plates to fit over the holes. If your flapper adventures were like mine, you snapped off at least one of the studs. But two studs/nuts, plus putting caulk under the new plates, will be more than adequate to keep the plates doing their job.

Did you disable the footwell blowers? Easy enough to disconnect their wiring.

As far as I remember SSI's are really just stainless headers with a heater box surround. Take a close look, they are individual tubes. You are not going to get any noticeable extra power.
Please enlighten me if I am mistaken.

SSI's are headers.....

Walt
it was suggested that that block off approach leads to extra heat in the engine bay because the hot air in the SSI collector has no where to go versus when the air is exiting the flapper pr being directed to the cabin. If one were to use a block off plate...it might be an option to put some vents in it (somehow designed to stop water getting in) or leave as is and block at the exit of the flapper (going to cabin)

Likely i will bite the bullet and pull them to check integrity of closure seals and just replace them, selling the old one on PP to partially fund (only after I check to see why seal is not working..it was when i rebuilt them). The real issue comes with the ventilation system up front and why air is not following the path it should and whay hot air is getting in if hot air lever is set to closed (or is it always open regardless of slider position..ie should i suspect one of the vent flappers as my culprit?)

Porsche got their engines right but lord, the design of that vent system is a nightmare

If anyone has an article on re-jigging the vent system I would love a copy (ie..is there one in the porsche service manual since most reference books dont go into much detail on those systems)

thanks all

well, you have to pull the ducting front and rear fron the collector. that's OK,

Thats easy enough but still leaves the SSI outlet open to water/debris which would eventual gunk up the ssi or cause internal damage?

They are Stainless Steel so what could possibly happen to them? The heater box surround are not completely sealed up so they still get water and dirt in the surrounds.

Think about it this way:
a) with the heat off, water and stuff could get into the system through the flappers (which are closed to the cabin, but open to the heat exchangers and the atmosphere. And the SSIs are stainless, and water is going to boil off pronto anyway. This isn't an issue.
b) As to blocking off the exit from the heat exchangers causing the exhaust manifold to overheat, 1) don't block it off there. 2) Without the heater fan, very little air is blown through the heat exchangers, although some from the engine cooling fan does get through, and it will continue to do so - it will just exit at a different place. And 3) technically, headers work best when hottest (which is why you often see racing headers with an insulating wrap) because that raises the speed of sound in them, which changes their acoustic properties in a good way, promoting scavenging and cylinder filling. So being hot isn't necessarily a bad thing. There can be issues with wraps and localized overheating and weld cracking, but those supposedly are due to header construction issues.

This doesn't seem to be a common issue. I suggest you simply remove the flexible hoses, disable the power to the footwell blowers, and see if you still have hot air (hotter than ambient, anyway) blowing into the cockpit. If it is, remove the flapper boxes and plate over the opening. Or replace the flapper boxes. The air surrounding the transmission is apt to be hotter than ambient in any event.

when deleting the heat system anyway e.g. by closing the flappers and disconnecting the heat tubing from SSI, you can cut open the SSI-collector and take it off... tadaaa headers.

when you cut in such a way that you can weld the collector shut again, your good

Flo

I dont think marring these pieces of art is the best way to fix this...my goal if I want to remove heat) is to block at outlet of flapper instead and have flapper wide open (maybe remove the open/close wheel which is only a 1 minute job...well after removing the damned flappers which is more like 1 hour each side on your back looking up into pieces of dirt that tend to fall right onto face every time)

IIts getting colder up here inn Canada so maybe in a couple of weeks I will start at the frunk vent system and so what a poor engineering marvel can be corrected for air flow direction..ie flappers in main boxes and checking cables for correct run

I wish there were a simple diagram showing which cable goes where and flapper position for each...that could be part of the issue but not all since flapper should be blocking heat 100% from getting to cabin and it isnt

lord ..should have left old flappers alone and lived with it as it was..then i wouldnt have buggered up the frunk vent system

I did wonder why a denizen of the frozen north would want to disable completely the cabin heat system.

My only experience is with the manual cable/lever system. That is relatively easy to adjust so that lever all the way down means valve closed.

Does yours involve the automatic/thermostatic system? That might have more ways of not working just right?

Manual

replaced cables/guides
pulled flappers , cleaned and rebuilt

had front vent system apart to fix air controls and i am sure something isnt correct..so that what i will tackle next along with pulling flappers again to confirm 100% closure

i ll just plug away til its right