Engine sound/upgrade question

calling911 · 03-05-2010, 06:15 AM

Hi yall..

I had an early porsche 2.0l with weber carbs in it I sold. What I want to do is upgrade my 76 to more HP but I want that classic early porsche sound. I can only assume this low end rumble came from the webers (correct?).

That being said.. whats a good route for me to go keeping a tight budget in mind.. I assume the best bang for the buck would be to sell my motor (which appears to be totally stock including tensioners and crappy exhaust) right out of the car.. its relatively quick, no smoke can only assume its gonna have good compression based on performance, lack of smoke and idle characteristics).. Probably1500- $2k in this economy??

But then what route do I go to get that awesome sound?

I assume btw that my motor would require cams to go to carbs which would be really expensive to do?

Also, note my car does not require inspection in this state as of next year.. she turns 30 which is the cut off point.

Third gear needs finesse in my 915 trans.. can be shifted with no crunch but requires careful upshifts which includes either a double clutch or a careful match-rev.

This is getting more expensive as I think about it lol..

I just miss that classic sound and want it back in my life.

Regards.

javadog · 03-05-2010, 06:48 AM

You'd get more of "that sound" by changing the muffler. Get a pair of SSI heat exchangers and an early muffler. It's a much cheaper option than swapping the engine, which won't necessarily do anything to change the sound. Fitting the engine with carbs will change the intake sound but that isn't what you are after.

JR

calling911 · 03-05-2010, 07:36 AM

Quote:

Originally Posted by javadog

You'd get more of "that sound" by changing the muffler. Get a pair of SSI heat exchangers and an early muffler. It's a much cheaper option than swapping the engine, which won't necessarily do anything to change the sound. Fitting the engine with carbs will change the intake sound but that isn't what you are after.

JR

So, my assumption is dead wrong then.. it was NOT the webers but the exhaust?? Hell if thats the case Im all over an exhaust swap since mine is nothing but a motor baker anyway... (thermal reactors are still in place).

You sure about this? I thought for sure it was the intake that was letting me hear that low end rumble.. it also had those small K&N's on it fwiw..

If thats the case I'll throw some nice early heat exchangers on it and I guess if the muffler was part of the sound then I'll look for a new muffler.. I dont see a need to do SSI's here in the south..

javadog · 03-05-2010, 07:48 AM

Early 911 mufflers were a lot louder than the ones that followed. Anti-noise legislation progressively got more restrictive, to the point that most modern cars make almost no exhaust noise, other than a characterless hissing sound.

Webers will make more intake noise than CIS, but that's not the sound you hear when a 911 drives by. I suggested SSI's because they offer the same benefits as the early heat exchangers and they are contructed better. If you can find some early heat exchangers that are in good shape (not rusty) then go ahead and use them. I'd bet that route will be harder than finding a good used set of SSI's. Note that the muffler is the main goal here and not all two-in single outlet mufflers will sound the same. If you want a lot of noise, a two-in, two-out muffler will give it to you...

Have fun,
JR

calling911 · 03-05-2010, 08:30 AM

Quote:

Originally Posted by javadog

Early 911 mufflers were a lot louder than the ones that followed. Anti-noise legislation progressively got more restrictive, to the point that most modern cars make almost no exhaust noise, other than a characterless hissing sound.

Webers will make more intake noise than CIS, but that's not the sound you hear when a 911 drives by. I suggested SSI's because they offer the same benefits as the early heat exchangers and they are contructed better. If you can find some early heat exchangers that are in good shape (not rusty) then go ahead and use them. I'd bet that route will be harder than finding a good used set of SSI's. Note that the muffler is the main goal here and not all two-in single outlet mufflers will sound the same. If you want a lot of noise, a two-in, two-out muffler will give it to you...

Have fun,
JR

Thanks for the help.. Im not looking for noise.. in fact I HATE the droning sound at freeway speeds some "sport" mufflers can make. I am about as far from a ricer as you can get when it comes to my sound tastes.. My 69t had a low end rumble that was not annoying as hell.. THAT is the sound I like..

Im glad I posted this as I think I was gonna go down the wrong road..

I need to take care of my thermal reactors before summer anyway... and I hear that early exchangers will buy me a few ponies in the process.. so it makes good sense all around..

I did some looking in the classifieds.. not a ton out there but patience will pay off..

Wonder what the difference in design in between my 2in 76 muffler and an early 2 in muffler like the one that was on my early car.. hmmm things that make you go hmmmmm

Maybe there is a loop inside the newer designs..

Im tempted to pick up an early muffler and just throw it on so I'll know.. would take about 15 minutes to install one I bet.

javadog · 03-05-2010, 08:43 AM

Quote:

Originally Posted by calling911

Wonder what the difference in design in between my 2in 76 muffler and an early 2 in muffler like the one that was on my early car.. .

I can't answer that question directly but there had to be quite a difference. If you listen to an early car, it is much louder than a '76. In fact, I find the '65-67 cars to sound vastly different to the later long-nose cars.

As you say, it wouldn't take long to find out... the challenge would be to find an early muffler in good condition, as opposed to an aftermarket replacement muffler.

JR

sean m · sean m's Garage

JP,
Let me know how it goes on removing the heat exchangers. I've got the same issue, but after reading posts of what a pain it is to remove them I chickened out.

calling911 · 03-05-2010, 09:07 AM

Quote:

Originally Posted by javadog

I can't answer that question directly but there had to be quite a difference. If you listen to an early car, it is much louder than a '76. In fact, I find the '65-67 cars to sound vastly different to the later long-nose cars.

As you say, it wouldn't take long to find out... the challenge would be to find an early muffler in good condition, as opposed to an aftermarket replacement muffler.

JR

Thanks.. I'll do some looking around..

In regards to the exchanger swap.. I'll let you know how it goes.. I have a lift in my garage which will make it easier but Im not looking forward to removing the rusted nuts.. My initial thought is to use a air tool to cut a piece off of each nut effectively damaging a very small area of the threads in each stud... be a hell of a lot better off than breaking one off... I need to do some searching and see what others have done.. I have replacements for the thermal reactors that just bolt up to the existing heat exchangers but without the additional HP upgrade id get from SSI's or early exchangers my motivation has been very low....

88-diamondblue · 03-05-2010, 11:53 AM

To get the nuts off use heat as in get them "cherry red" with a torch. I tried getting mine off using Kroil and went right to the torch. All came off easily with the heat. New nuts and use copper anti-seize when you put the new ones on.

calling911 · 03-05-2010, 12:22 PM

Quote:

Originally Posted by 88-diamondblue

To get the nuts off use heat as in get them "cherry red" with a torch. I tried getting mine off using Kroil and went right to the torch. All came off easily with the heat. New nuts and use copper anti-seize when you put the new ones on.

Glad I invested in acetylene.

I'll try that first.. I've done this enough time to know a simple penetrating oil is a practice in futility.

WIL84911 · WIL84911's Garage

How about trying a pre-muffler / Bursch exhaust combination before you remove your exchangers? It's a cheap route and you might like it.

calling911 · 03-05-2010, 05:01 PM

Quote:

Originally Posted by WIL84911

How about trying a pre-muffler / Bursch exhaust combination before you remove your exchangers? It's a cheap route and you might like it.

I dont know what you mean... besides the exchangers pretty much have to go because the ones with the reactors (which I have) supposedly cooks the 2.7l..

But Im curious as to what you are refering to here...

javadog · 03-05-2010, 05:02 PM

He's referring to a later style exhaust configuration. Not what you have, or want.

JR

calling911 · 03-05-2010, 05:19 PM

Quote:

Originally Posted by javadog

He's referring to a later style exhaust configuration. Not what you have, or want.

JR

BTW.. it appears as though an early muffler will bolt up but the tip will be at the wrong angle.. I suppose nothing a little cutting and welding wouldnt fix but still.. not a direct fit... if someone knows different chime in.

WIL84911 · WIL84911's Garage

OK please ignore my suggestion. After re-reading your post it seems 'droning' will be a major issue. But it does sound good. That's what's on my car when I got it. Good luck!

javadog · 03-06-2010, 03:39 AM

Quote:

Originally Posted by WIL84911

OK please ignore my suggestion. After re-reading your post it seems 'droning' will be a major issue. But it does sound good. That's what's on my car when I got it. Good luck!

The thing is, his car has a different exhaust setup than yours. His system doesn't gather the exhaust from both sides at a common point on the left side of the engine. To do the a system like what you suggest, he would first have to add the heat exchangers that an SC or Carrera has as stock, plus the crossover piping for the right side. If he changes the heat exchangers, he's better off using the early style.

JR

calling911 · 03-06-2010, 08:22 AM

So after some scraping and grinding and so on.. my muffler seems to say:

Bischoff 911 025 00 (and it looks like the 2nd 0 in 00 was replaced with a 2 or visa versa at one point) / 74

So 911 025 00(2) / 74

Trying to find info on it but coming up with very little so far.

WIL84911 · WIL84911's Garage

JR, thanks for clarifying... did not know 76's are like that.

ClickClickBoom · ClickClickBoom's Garage

Hey,
I removed my thermal destroyers and replaced them with a set of "headers", they bolted right up to the rest of the OEM exhaust system. It was a good intermediate swap until I found some used SSIs. I also installed a Leistritz(sp?) muffler with a 3" single outlet, no cutting of sheet metal required. The sound is awesome, and the power is way up!
My exhaust system came off with out much drama.
eric

calling911 · 03-07-2010, 06:31 AM

Quote:

Originally Posted by ClickClickBoom

Hey,
I removed my thermal destroyers and replaced them with a set of "headers", they bolted right up to the rest of the OEM exhaust system. It was a good intermediate swap until I found some used SSIs. I also installed a Leistritz(sp?) muffler with a 3" single outlet, no cutting of sheet metal required. The sound is awesome, and the power is way up!
My exhaust system came off with out much drama.
eric

Thermal destroyers.. I like that..

I noticed something last night with my setup.. It actually sounds nice at idle (dont really give a crap about that) but when you get on it.. nothing.. its a non-event.. so its the opposite of what I want.. when I got on my 69T she rumbled like a v8. Real LOW tones...