Half Exhuast

[red_dog007]

Ok, so I am thinking 3.2.1 exhaust. Not really sure if I should do 6.1 exhaust.

Though this is my idea.

Buy the manifold and then have a custom pipe made. What I was thinking was having the exhaust cut of shortly after the transmission and have it point downwards. Somewhere between the end of the exhaust and manifold put in a cherry bomb or something to help with noise. Or even a slim jim muffler.

Now, my concern is would this be too loud? I want quiet when around town with maybe a little throaty noise, but when I get on it I want it to sound good and loud, but not Honda loud.

Then my second concern is if I have the exhaust cut off after the transmission pointing downwardish, am I going to have to worry about catching the road on fire or anything? I wouldn't have the end at a 90 degree angle, maybe something more like 45 to 60 degrees so exhaust won't be blowing directly on the street.

[John Coffey]

What I was thinking was having the exhaust cut of shortly after the transmission and have it point downwards. Somewhere between the end of the exhaust and manifold put in a cherry bomb or something to help with noise.

Dumb idea. it will be loud and stinky inside the car. I've had racers ask me to build exhausts just like this and every one has come back and at least had me run the exhaust out the back of the car or to the side just in front of the rear wheel.

[Oiluj]

On my 1972 240Z, the previous owner put a 2-1/2" single exhaust with a small, (10" long, 3" dia), cherry-bomb style resonator midway back. At the tail end it has an open split over/under angled tip at the back. (no muffler).

The car sounded like a race car, but was unpleasantly load and attracted lots of attention. The first thing I plan to do when I get the car back together is to change the exhaust before a cop hears it and gives me a ticket!

[red_dog007]

Yeah, that is what I figured. Would be too loud and stink up the cabin.

Guess I will get full exhaust. Need to find some exhaust clips of the 3.2.1 and the 6.1 to see which I like better.

[peterc]

FWIW, on my '83, I have a 3.2.1 header stock to the CAT, then just pipe out to the rear of the car. Didn't plan it that way, but when the old muffler tore off after getting caught on a curb (don't ask) I just added a strraight piece of exhaust pipe until such time as I replace the muffler.

Im now having second thoughts about replacing the muffler at all. As it is now, at idle and low rpms, it sounds throaty, but not loud or harsh, and under hard acceleration it sounds ferrari-like, especially at the upper rpms. No bark, no resonance. When the time comes I think I'll run one piece of custom-bent stainless form the CAT back.

[e_racer1999]

I have some vid clips of my 6-1 with no exhaust. Youtube user corndogbatter

[red_dog007]

So you have the 6-1 manifold and that is it? Nothing else on the exhaust? That sounds freaking awesome! That is what I want right there! Maybe a touch quieter.

Stock my engine sounds like that but much quieter. Maybe I will just get a manifold, and then get a shop to fit me up a pipe. If I fell like I need a muffler, I can just always go back to get one put on.

[FHPTOM]

I definitely agree with John Coffey. I had another racer talk me into cutting my exhaust back to the transmission for extra HP and save weight.

It is really too loud which makes it hard to hear what the rest of the car is doing on the track.

Now I need to get it redone taking it back out to the rear. $100 - $150 that could be spent elsewhere.

Tom

[geezer]

I have some vid clips of my 6-1 with no exhaust. Youtube user corndogbatter

Jason, I noticed the safety shut off switch is working. Won't it shut off with the ignition switch?

That's OK if you like it loud, but your neighbors might appreciate a token pre-muffler to cancel out some of the resonance. Guess it depends, how you plan to use the car and the tolerance level of the local constabulary.

Edited August 12, 2008 by geezer

[m4xwellmurd3r]

I ran my Z with only the resonator on it for a few days for testing. under cruise it was really mellow. not too loud, and very deep, but step on the gas and it really opened up. I really didn't get exhaust fumes too badly, but maybe I've somehow been desensitized to them.

[Walter Moore]

FWIW, on my '83, I have a 3.2.1 header stock to the CAT, then just pipe out to the rear of the car. Didn't plan it that way, but when the old muffler tore off after getting caught on a curb (don't ask) I just added a strraight piece of exhaust pipe until such time as I replace the muffler.

Im now having second thoughts about replacing the muffler at all. As it is now, at idle and low rpms, it sounds throaty, but not loud or harsh, and under hard acceleration it sounds ferrari-like, especially at the upper rpms. No bark, no resonance. When the time comes I think I'll run one piece of custom-bent stainless form the CAT back.

Actually, I have had several older GM products where the exhaust fell off just after the converter, and in most cases I was able to just drive them that way for years. The older converters did a pretty good job of silencing the exhaust noise without a muffler. Some newer converters however will be objectionably loud without a muffler. (The car companies must have made them less restrictive over the years...)

But in my opinion you still need enough pipe to get the exhaust behind the passenger compartment, which on a Z means out the back.

[e_racer1999]

Jason, I noticed the safety shut off switch is working. Won't it shut off with the ignition switch?

That's OK if you like it loud, but your neighbors might appreciate a token pre-muffler to cancel out some of the resonance. Guess it depends, how you plan to use the car and the tolerance level of the local constabulary.

Well, that was the first time staring it after 12 months of not running. I had relocated the batt to the back and did the IR alternator conversion. Messed up with the diode so it didn't shut off, hence the cutoff switch.

I only ran it for a day without the full exhaust system (MSA 2.5" aluminized). The exhaust system through and through is the tits (6-1 w/ MSA 2.5")