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View Full Version : Full three inch exhaust on L body.



jeff1234
01-14-2020, 03:24 PM
Has anyone noticed clearance or installation problems with the Turbos unleased three inch system?

contraption22
01-14-2020, 05:26 PM
It's very tight but it fits. Big pipe, tiny car. Had to hammer the seamed edge of the fuel tank a bit for a little extra clearance.

supercrackerbox
01-14-2020, 05:37 PM
Like Mike said, it's really tight but it's a very nice system. One thing I did change on my Charger was to take a couple of 22° scrap bends I got from work and made an offset to give a little more clearance around the shifter, but beyond that it's a pretty straight-forward installation.

jeff1234
01-14-2020, 05:53 PM
It's very tight but it fits. Big pipe, tiny car. Had to hammer the seamed edge of the fuel tank a bit for a little extra clearance.
I am mostly concerned about the area where the tube crosses between the tank and the body above the axle. I have 2.5 right now and it rubs on the body occasionally. I probably didn't get it installed just right. Is there a significant change in power? I have a Turbonetics T4B '69 16 MM and I wonder if the change over results in power increase or faster spool up.

contraption22
01-14-2020, 05:56 PM
I am mostly concerned about the area where the tube crosses between the tank and the body above the axle. I have 2.5 right now and it rubs on the body occasionally. I probably didn't get it installed just right. Is there a significant change in power? I have a Turbonetics T4B '69 16 MM and I wonder if the change over results in power increase or faster spool up.

Bigger is always better. It’s tight but it fits.


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supercrackerbox
01-14-2020, 06:14 PM
I am mostly concerned about the area where the tube crosses between the tank and the body above the axle. I have 2.5 right now and it rubs on the body occasionally. I probably didn't get it installed just right. Is there a significant change in power? I have a Turbonetics T4B '69 16 MM and I wonder if the change over results in power increase or faster spool up.

I can't speak for having a bigger turbo, but I can say that the spool up was noticeably better on my Charger with a full-length 3" with muffler vs. my CSX-T which had a 2.5" side dump and no muffler. My best advice for clearance is to get it roughed in with the rear axle hanging, and then put jack stands under the rear axle so the weight is on the suspension and adjust as needed. Try to get it as close up into the body channel as you can without touching and as high above the axle as you can. Luckily you don't have to work around the panhard bar mount like on the K-based cars.

4 l-bodies
01-14-2020, 06:20 PM
Jeff,
IMO, on a modest HP car, you may not see much of a performance difference. If you have a true 3" swingvalve, ie; Rob (shadow), TU, or ATP v-band, running a 3" downpipe will be a noticeable gain. On the downside, you will also gain DB's. It is tough quieting down any 3" exhaust with straight through muffler with no catalytic converter. That is very subjective though. I really don't care for super loud cars, I never have. On one of my GLHT's, I have full 3" exhaust until it goes over the trailing axle, where I use a gentle 3" to 2.5 Flowmaster coned reducer, so I can run a 2.5" muffler. Much quieter than others that run 3" mufflers. Also made it out of 304 stainless so that quiets it down too and never deteriorates. Wished the vendors still offered 304 stainless. As a result I usually make all my own cat back L-body exhaust with 2-90's and 2-45's. Fit is very good in either 2.5" or 3".
Todd

jeff1234
01-14-2020, 07:00 PM
I have three inch swing and down pipe. I too don't like a loud car and these engines already have a drone to them. Food for thought in these posts, thank you. :-)

contraption22
01-14-2020, 08:15 PM
I have three inch swing and down pipe. I too don't like a loud car and these engines already have a drone to them. Food for thought in these posts, thank you. :-)

I used a magnaflow 6” round muffler. Made sure the tip extended past the body. Sounded great. Had zero drone. And I have no sound deadening.


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jeff1234
01-16-2020, 08:16 AM
I have the same muffler and discovered, as you did, that the tip needs to be beyond the lower edge of the rear body panel. Made a significant difference.

Dr. Johny Dodge
01-19-2020, 10:46 PM
keep the heat shielding in the tunnel
the carpet backing stinks when it melts and it really never goes away ..

trannybuster
07-10-2020, 11:43 PM
I used a Borla...nice snd, but went beyond panels as stated.!

stargazer7467
07-14-2020, 08:51 AM
I have the full 3" system on my GLH with a Dynomax Ultraflow mufler, does well. Sometimes i hear a rattle at the back axle but nothing intense.