3.6 Conversion - Exhaust Considerations

[ahendy]

Originally Posted by Bill Verburg

The absolute best street sounding 3.6 exhaust, this side of a real 993 dual can setup, that i have ever heard is Fabspeed RSR, I can actually hear the cooling fan again as the engine revs and all the high frequency clatter and resonance is gone, Just a real nice basso rumble especially w/ RS cams

Do you have any videos of it? Are you using it with the sport cats or without?

[blucille]

Originally Posted by ahendy

Curious if anyone else has thoughts on this? Still struggling with it a bit.

M&K is very backed up and I don't expect I'd be able to get anything out of them for quite a while. Also still not convinced that it's the answer anyway for quiet.

you should call Brian at M&K, I had him custom make a set of headers and a muffler for me. He said it was done a month ago, but with the delays I went a different direction. He said if he can sell them soon, he will refund my rather large deposit. Otherwise, at some point I will complete the purchase and resell them.

It was designed for a 3.6 964 motor going into an SC, to be used with an M&K or any other 2-in muffler.

[BrewsterBear]

I see Brian hasn’t changed much since I ordered from him 3 years ago and they failed to keep their promises. Many times.

I’m currently getting the Bursch 1 3/4” GT3 system fitted to mine. It’s not cheap but it’s sized correctly for a 3.6 Varioram and it looks pretty sweet. I’m looking forward to driving it and hearing it next week.

[Bill Verburg]

Originally Posted by BrewsterBear

I see Brian hasn’t changed much since I ordered from him 3 years ago and they failed to keep their promises. Many times.

I’m currently getting the Bursch 1 3/4” GT3 system fitted to mine. It’s not cheap but it’s sized correctly for a 3.6 Varioram and it looks pretty sweet. I’m looking forward to driving it and hearing it next week.

Looks like a nice setup

The GT3 mufflers sound great too, I almost went that route

[ahendy]

Well as with all things, this appears to be a rabbit hole, as many of the exhaust options require backdating to the 911 crossbar and single crankshaft pulley. Seems like there's not a ton that will fit without doing this...

And the saga continues..

[blucille]

Originally Posted by ahendy

Well as with all things, this appears to be a rabbit hole, as many of the exhaust options require backdating to the 911 crossbar and single crankshaft pulley. Seems like there's not a ton that will fit without doing this...

And the saga continues..

Of all the steps towards doing the 3.6 conversion, the cross bar and Lilly seem pretty minor. I might even have those parts for you.

[ahendy]

Originally Posted by blucille

Of all the steps towards doing the 3.6 conversion, the cross bar and Lilly seem pretty minor. I might even have those parts for you.

Sure, not a huge effort to replace, but was hoping to avoid needing to drop the engine to do any of this work..

[BrewsterBear]

If you support the engine on a jack it should be possible to remove the hanger bar and pulley, plus removing the AC compressor plinth without dropping the engine. This makes it easy to install the earlier bar. The biggest expense is the RS single pulley.

[rothaus]

Originally Posted by BrewsterBear

I see Brian hasn’t changed much since I ordered from him 3 years ago and they failed to keep their promises. Many times.

I’m currently getting the Bursch 1 3/4” GT3 system fitted to mine. It’s not cheap but it’s sized correctly for a 3.6 Varioram and it looks pretty sweet. I’m looking forward to driving it and hearing it next week.

Looks like your car is a longhood. How will the middle part of the rear bumper fit. I planned to use a GT3 muffler, but there is no way it will fit under the bumper.

Here is a picture, I would need to cut out the middle section of the rear bumber to make it work. I have also removed the heating cross over pipe. The engine was temporarely installed in a 84 911.

[BrewsterBear]

It looks like you still have the AC plinth and 993 engine hanger. I removed the plinth and used an SC hanger which, with the crossover pipe removed, gives some more space.

My mechanic has fitted the exhaust but I can't collect it until next week. Here's a still from a video he sent of it idling. My rear panel is a separate steel section and although it's tight on space it looks like it's just about fitted over the silencer.

[ahendy]

Alright. I've been trading emails with James @ Patrick over the last few days, and have spoken to a few other folks as well (including Timmins) and this is the conclusion I've come to:

Nearly any great quiet(er) option is going to require me to replace the 993 console, crossmember, and pulley with a 911 console, crossmember, and single pulley. There's just not enough room in the bumper to do anything meaningful without doing this. So I think I'll bite the bullet and tackle that.

The other conclusion I've come to is that the 993 headers are quite limited as well, and most options require moving to a different header system. Fine.

James suggested that if I want stock quiet (or nearly so), the new 41mm SSIs that they sell could be a good starting place — then I could bolt up whatever I want to those, including a 911 style banana single outlet muffler. They aren't cheap but this combo may be the most simple path to a stock sounding car.

Next step: gather parts to backdate the console/crossmember/pulley... and find a new place to put my coil packs too (they're currently welded to the 993 cross member).

[blucille]

it's worth mentioning, to me at least, that if anyone is interested in a rarlyl8/m&k header and exhaust for a 3.6 into an F or G body car, Brian has one ready to ship, I'm told.

[BrewsterBear]

Originally Posted by ahendy

Alright. I've been trading emails with James @ Patrick over the last few days, and have spoken to a few other folks as well (including Timmins) and this is the conclusion I've come to:

Nearly any great quiet(er) option is going to require me to replace the 993 console, crossmember, and pulley with a 911 console, crossmember, and single pulley. There's just not enough room in the bumper to do anything meaningful without doing this. So I think I'll bite the bullet and tackle that.

The other conclusion I've come to is that the 993 headers are quite limited as well, and most options require moving to a different header system. Fine.

James suggested that if I want stock quiet (or nearly so), the new 41mm SSIs that they sell could be a good starting place — then I could bolt up whatever I want to those, including a 911 style banana single outlet muffler. They aren't cheap but this combo may be the most simple path to a stock sounding car.

Next step: gather parts to backdate the console/crossmember/pulley... and find a new place to put my coil packs too (they're currently welded to the 993 cross member).

I bought a set of 41mm SSIs, only to find that they didn’t clear the 993 chain cases. They would have needed modifying to fit which defeated the purpose.

SSI also make a set they advertise as intended for a 3.6 conversion but they have 39mm primaries which would choke the Varioram. For some unknown reason they don’t make a 3.6 conversion set in 41mm, or at least they didn’t unless that’s changed recently.

Exhaust solutions for this have been my biggest headache on the conversion. I bought a set of 41mm SSI and a also a set of 41mm Eisenmann which I don’t think they make any more. Neither were a straight fit for the 3.6 and would have needed a fair bit of modification to go on so the SSI were returned. The Eisenmann UK distributor refused to accept returns to I ended up selling them myself.

I tried ordering a muffler to mount to the 993 headers from RarelyL8 and they kept pushing back their promised delivery date which was seriously delaying my bodyshop guy so had to cancel that order too. I ended up getting my old 2in muffler modified to fit to the 993 headers as per the photo and have been running that for the last 3 years but it wasn’t an ideal solution, hence biting the bullet and going with the expensive Bursch system now.

As for the coil packs, mine were bolted to the old crossmember and I just bolted them to the replacement SC one. I’ve seen others mount them where the rear electrical pack goes and it looks pretty enough.

[ahendy]

It would appear that SSI does make their 41mm headers specifically for 3.6L conversions now (at least that's what I was told by James Patrick).. so my gut is that's the right way for me to go. He's preparing a proposal for me at the moment and then I'll decide how to proceed.

I do agree though — exhaust does seem to be the single biggest hangup when it comes to 3.6L conversions in early cars. There's no slam dunk, and while a bunch of folks have come up with a lot of great solutions, there's no obvious clear choice.

Excited to hear how you like the Bursch/GT3 setup. It sure is beautiful. Curiously though.. I spoke to Sierra Madre Collection yesterday and they said the headers wouldn't clear something if put on a 3.6L and would require some modification to make fit. Was there any modification required to get yours to fit?

[BrewsterBear]

If that’s now the case then SSI would be the way to go I think. I did ask about a 41mm 3.6 set less than a year ago and was told they had no plans to make them. Just be mindful that a 2 in silencer intended for a 3.0-3.2 might not flow enough for a 3.6. It’ll probably give you the best balance for heat, sound and performance though.

My mechanic said the Bursch was a pig to fit and has modded the rearmost tinware to get clearance for the GT3 silencer, but the headers and exhaust didn’t require any mods. I’m looking forward to driving it next week. The biggest difference I’m expecting is in noise, but if I gain a bit of performance too I won’t complain. It’ll certainly be less restrictive than what I had. It’ll also be interesting to see what difference the loud and quiet modes make.

[Bill Verburg]

Besides fit and flow, most of us also care about heat and to a degree sound

There are several different ways to get heat, easiest is to leave the heat components above the tin stock(maybe w/ an RS heat tube

like this


below the tine there are optional ways to go

easiest is a 964 heat cross over tune connected to the stock heat down tube

like this


B&B headers w/ oval 964 heat inlets and 911 heat outlets, 964 crossover



or you can fab a splitter where the heat emerges from the tin and then route 2 separate tubes

Here is an early trial setup w/ SSI



The bigger the muffler the better the sound attenuation, quietest and best sounding that I've has were an early B&B muffler w/ cat tips and the current Fabspeed RSR setup.

The FLowmaster I uses foe a few decades was great sounding to me,but not track legal9most tracks anyway) and if neighbors are a concern they will hate it.

lastly some headers will run close and parallel to the oil line, some heat insulation is warranted in that case



Fabspeed RSR is nice because besides great fit, finish and sound they provide a nice heat solution that connects to the 3.6 tin, the heat lines to the chassis can be easily disconnected to fget to the engine mounted oil filter

[sgroer]

I had this incredible exhaust fabricated using the triad as a core. The sound is insane, loud but not droney. The triad was far too quiet. I cannot believe the sound

[ahendy]

Ah I'm envious.. Honestly the Triad would be exactly what I'm looking for... tragic that Dave passed..

If anyone has one they'd sell to me, let me know!!

[rothaus]

Originally Posted by BrewsterBear

It looks like you still have the AC plinth and 993 engine hanger. I removed the plinth and used an SC hanger which, with the crossover pipe removed, gives some more space.

My mechanic has fitted the exhaust but I can't collect it until next week. Here's a still from a video he sent of it idling. My rear panel is a separate steel section and although it's tight on space it looks like it's just about fitted over the silencer.

Do you have a picture straight from the back ? I'm in the process to do the same setup with the SC engine suspension, and it looks like the muffler is sitting to low.

Thanks
Engelbert

[BrewsterBear]

Hope that helps.