header install.... Do I need these hoses???

[Sporttracguy]

I have a 1970 911E 2.2Lwith MFI and i am removing the swiss cheese heat exchangers and replacing them with SS headers. I've never used the heat in this car (because I knew the condition of the heat exchangers) so I'm not going to miss it.

I was able to remove all of the bolts and remove the heat exchangers but here are my questions:

here are several hoses coming from the exchangers that return back to the engine, Do these need to be hooked up to anything for the engine to run properly or can I just remove all of these hoses and leave the ports open? I feel like they are there for a reason, as long as that reason is just for the heater then I'm ok.

First Photo: There is a hose that runs from the exchanger up to the air intake that seems to be using a siphon action to pull hot air into the engine? Can this be deleted? I've seen several cars where the intake is cut short and that hose is no where to be found.



Second Photo:

This very thick rubber hose connects to the exchanger and runs up through the engine bay....This seems like an overkill hose, What is its purpose? Can I delete this?



Photo #3

Hose #3 connects to hose #2 from below and goes into the engine through a port that is unknown to me. It all looks important to me but I feel like it is all heater related. can any of this be deleted? How should these hoses be routed since they don't have a connection now that I only have headers?



thanks in advance for all your help, I know there are a lot of knowledgeable people on there that will have an answer.

STG

[bkreigsr]

The waffled plastic hose to the thermostat (what's this?) should have an foil insulated hose inside of it. You need these to be hooked up to the heat exchanger and plumbed to the thermostat for the correct mixture at colder tempertures.
Hose #1 could be removed without effecting performance.
MFI PUMP

My post should get things going as the experts start to chime in.

Also, for the hot air to get pumped to the thermostat, the big hoses from the fan shroud need to be installed - at least on the left side.
Bill K

[Jack Stands]

You will lose some cold weather drivability with the hose to the MFI thermostat hose disconnected, but I don't know where you'd get warm air to the thermostat without the heat exchangers.

The large hoses that come off both sides of the fan and connected to the heat exchangers just provide air flow to the heat exchangers. There are block off plates that can close off these outlets (also clean up the engine compartment), and that should also help provide a bit more cooling for the engine.

[Sporttracguy]

When you say "Cold Weather Drive ability" What are we talking about? Snow driving or below 50*?

So far it's looking like I can remove hose #1 from the air intake, install two black off plates for the blower hoses (left and right), but I need to find a way to get hot air to the thermostat. I know I'm not the first to remove the heat exchangers on a MFI engine, there must be someone who can chime in...

Thanks for your replies so far

[HawgRyder]

You don't need to get hot air to the MFI thermo...you can remove it...and put a push type lever on it with a Borden cable to the driver's compartment.
This will give you and effective mixture control. (which is what the heat going to the thermo does).
Bob

[Sporttracguy]

Originally Posted by HawgRyder

You don't need to get hot air to the MFI thermo...you can remove it...and put a push type lever on it with a Borden cable to the driver's compartment.
This will give you and effective mixture control. (which is what the heat going to the thermo does).
Bob

Can you expand on this setup?

Thanks

[bkreigsr]

Originally Posted by Sporttracguy

Can you expand on this setup?
Thanks

I don't mean to sound harsh, but you really should do some homework. Plenty of resources right here. For instance - MFI Check Measure Adjust - click for high resolution

Putting a hand lever in to control the rack spacing like the first generation RSR's, is more of a pain than keeping a good set up with heat-exchangers and forced hot air. Given the pain vs gain - you should stay with the stock design. - (my opinion - as in - been there, done that)
Bill K