F41eatsFords

OK, I have an 84 with a stock LG4. When I bought it, it had all factory exhaust (2.25" pipe all the way). I replaced the rusted out muffler with a flowmaster, and a few months later cut out the cat and welded in a pipe at the school shop.

A couple years ago I bought a 2.5" mandrel bent dynomax cat-back and bolted it in(old pipe finally rusted out), and had to use the dynomax muffler since it was late at night and I didn't have anything to modify the flowmaster to work (too short). I ran a pipe where the cat would be. It was quiet (stock sound, too quiet for me).

Long story short, one of the joints was loose and leaking most of that time and I didn't find out 'til last weekend. I found out when the exhaust finally fell apart and I had to drive home with a straight pipe (love that sound!). when I resecured it, it was back to quiet, and not the quiet I've come to love, if you know what I mean.

I've come up with a way to make my own dual exhaust (what I've always wanted anyways) for cheap using two 2.25 stock pipes and some extra bend pieces to the manifolds.

My main question is: will going from a stock 2.25 y-pipe with 2.5 mandrel cat-back to true dual crush bent 2.25" straight pipe system affect the performance of the stock LG4 significantly? Both will have stock manifolds, since it's more for show than go (until the motor dies; then everything gets redone). I'm planning on remaining stock for a while, so no concerns with future upgrades.

I'm planning on installing comp engineering bolt-in (eventually welding them) SFCs in the near future, so rerouting the exhaust is necessary anyways for clearance.

Hopefully I've provided the info to clear up any questions. Again, with stock manifolds, is the performance of true dual 2.25" crush bent pipe going to have much different performance than my current stock y-pipe, 2.5 mandrel system? I'm not looking to go all-out on the best system, or for replies that the idea's not worth it, etc. I just want a cheap true dual system that won't really compromise the current performance as it stands. I figure stock was one 2.25" crush, two should be just as good as current, but I wanted to hear back from you guys first. Thanks!

deadbird

You can't hurt what you don't have...

F41eatsFords

Let's put it this way, even if I have a 2.5" exhaust, it's still really only a 2.25 exhaust due to the y-pipe. I know it still flows a bit better, but I just want to make sure my theory's not off. Thanks.

deadbird

The LG4 isn't a performance motor.
The exhaust manifolds are even more puss than the motor.
Single or dual exhaust won't make a bit of difference, sorry.

Build your exhaust to whatever motor you want to put in there. The LG4 will be weak no matter what you do. I owned one... the lg4 305 sucks.

F41eatsFords

Thanks for the input. I figured the manifolds were gonna be what holds it back over the y-pipe, but I had to double check. No time or money to install headers, a full exhaust, AND do all the other necessary stuff included in that, unfortunately. But i would like to reiterate my original post, just to avoid confusion, and possible heated discussion from others who might get the wrong idea from the original post.

-I understand it isn't a performance motor, I just wanted to make sure that this idea (crush bent 2.25 duals) WOULDN"T MAKE IT WORSE than it is as it sits (with the dynomax cat-back). I'm not trying to get more power necessarily, just give it a sound more to my liking without compromising what little I already have.

-I plan on keeping the motor for a while yet, just because it's been really reliable for me and the gas mileage is really decent for a carbed V8 (25-27 hwy). This exhaust system will likely need replaced by the time I get around to putting a new engine in anyways, and the expense will be minimal, so that's not a huge concern to me. I'm content with my little LG4 for a while until I can get something bigger. Other things taking more priority for the time being.

-Though I know frowned upon by some, it's still a V8, and IN MY OPINION, there's still nothing that sounds better than a V8 true dual exhaust rumble, be the engine big or small. Hence why I'm looking to go with duals. Again, JUST MY OPINION; I know others differ and I respect that.

Hope I've cleared up any confusion and haven't upset anyone.

deadbird

Don't get me wrong.. I have no problems with a 305 or dual exhaust...

F41eatsFords

Very nice setup; out of curiosity, are the fuel lines still running along the stock route? I always thought there was need for concern running the exhaust that close to them. Or maybe the exhaust is just further from them than I think? Just wondering.

deadbird

Fuel lines routed stock.
Gasoline doesn't burn very well enclosed in a tube and in liquid form so, the fuel lines could be welded to the exhaust and still not be a fire hazard.
If it was a real worry, I'd be more concerned about the exhaust heat burning the brake fluid.

F41eatsFords

Good to know; but an FYI to any novice, if you have older or original fuel lines, you might want to replace them before running duals like deadbird did. if they rust out (I had that happen), then you'd likely be spraying gasoline directly on the hot exhaust pipe.

deadbird

One would hope if you're under the car for that long making exhaust... you'd notice.

F41eatsFords

I agree, but sometimes they can "look OK" and they're actually not. Especially with someone fairly new to the game who's in denial that there could be anything wrong with their new (to them) Thirdgen. I had that happen with my brake lines on the axle; a month after I bought the car, the pedal went right to the floor. Thankfully, I was pulling it into the school shop when it happened, and not when I was blasting down the expressway. I just know when I first bought mine I was on here quite a bit to get advice about how to do things. It's always good to put the thought in someone's head before hand than for them to find out what they should have done as prevention after the fact (especially when it involves fuel and heat).

WickedCrazy

It might not cause the fuel to ignite but you still need to have decent space. If its to close to the exhaust pipe you can start to boil your gas and then you can get bubbles in your lines and fuel pump. If you feel like its going to be close and dont want to relocate the fuel lines just build a heat shield to protect them

88 Z-ROC

iTrader: (1)

@ deadbird.. Outta curiosity, what kinda mufflers do you have..

deadbird

I don't disagree, I was using that as an extreme example.
I have roughly 1.5" space. Since the fuel is constantly recirculating while the pump runs, it's not something I've personally worried about.

88-Z-ROC - I made them.

DBLTKE

iTrader: (1)

Two words: Vapor Lock.