Would Modifying Exhaust Effect Tune?

[Thunderstruck95]

My car has kooks headers, 2 1/2” into a Magniflow resonator with a single 3” outlet, then a Y with two generic turbo style mufflers. It also has cams, converter, gears, and other basic good stuff. It was dyno tuned by Dave Dalke and the whole package runs well. If I were to change my exhaust setup to get rid of the resonator, have an x pipe, use same mufflers, and essentially dump before the diff; would my tune be notably effected?

 

[Grog6]

It will breathe a little better; so it could add a couple of hp. If you go thru the dyno tune process, You could improve things 5-10%, depending on whether the airflow is perfectly tuned. Depending on cost, it might be better. You already are flowing about as good as it gets. I doubt you will see a larger inprovement than that. But the better it flows, the better small tweaks help.
The shm throttle body adds 10hp, to a 350hp engine. It wont add that to a stocker.Dalke s a great tuner, so I doubt it will change a lot. I'd ask him; He's probably tuned about every variation by now. Don had said wbw that he had a canned tune for about everything you can do to a 4.6l engine. I'd bet the rest of the guys that have been in it this long.

 

[XR7-4.6]

Downstream exhaust tweaks shouldnt have any effect on the tune

 

[theterminator93]

No tune changes needed.

If you were to mess with the setup between the engine and the O2s, then possibly. But it doesn't sound like that's on your list.

 

[Grog6]

I stand corrected.

 

[Grog6]

BTW, what did you do with the "Sand Machine Mad Max Mark VIII" you built? That was an awesome idea; But ground clearance is a serious problem. We only have mud here; it's worse than sand imho, lol.

 

[Thunderstruck95]

I removed the rear end and sold the rest to a guy who wanted the engine, trans, ECU and harness for an old ford pickup project. I possibly would have taken that project farther but didn’t have the money at that time.

I took it to the dunes twice. The first time was magic. I drove anywhere. I went back 6 weeks later (and it hadn’t rained since the last trip) and the car buried itself on flat ground. I had to have people drag me past the entrance and then through the park area all the way to the exit. With the sand that much drier the car couldn’t go anywhere.

My next move would have been getting bigger sand tires for the rear but I wasn’t sure it would be a full fix and I couldn’t put any more money into it at the time.

Biggest personal takeaway from that project was the benefit of weight reduction. The car felt crazy light on the street. The handling was night and day different with 500-600 ish pounds removed.

 

[Grog6]

I've raced a dirt bike on sand. Which surface you get all depends on rain, lol. I'd almost want more over less, but That's actually worse.