Has anybody done any custom exhausts?

My RRC has a few annoying little leaks, and the muffler sits close to the body and puts a lot of heat in the car

I'm curious if anyone has set up one of these rigs with a two into one and single cat?

I'm contemplating using a single high flow cat and a good muffler and building a custom set of pipes to get from manifolds to the cat.

Or just find and weld up the leaks and call it good. At least it's not all rusty

 

re: Or just find and weld up the leaks and call it good.

Best idea IMHO.

Might also look at summer time bypass of heater core if there is no on/off valve. Many Rovers have hot coolant in the core at all times.

Being a member of the Beluga Black tribe, I'm glad a previous owner had windows tinted.

 

Heater core is bypassed already!

The floor just behind the driver seat gets so hot on long freeway drives that it will just about melt a plastic baggy..The muffler is almost touching (heat shield is in place).

I have a local muffler shop that has done a lot of work for me in the past. He will build me a comlete new exhaust system for under $500 using a big high flow cat and a free flowing but not obnoxious muffler.

He will also weld up existing for ~$150ish..

I just feel like this little motor has a cork up its ****..

 

While it may improve the heat, as would some extra insulation, like http://www.summitracing.com/parts/th...FVCf4AodgkAAVw

as for performance increase, not so much. Too much metal, never enough power. Wish it could be 5 mpg increase, 0-60 in 3.2 (wait is that gallons or seconds?).

 

i cut out my cats and have it straight piped. i am about to build true dual exhaust on mine just waiting on ne manifold gaskets and o2 sensors. after i cut my cat out i did have a decrease in engine running temp(about 30-40F) Also gained uphill power. It use to slow down and sometimes downshift on long hills but now i can accelerate going uphill without the truck downshifting.

At the very least with a good exhaust it will sound good!!!!!!!!!!!!

 

I have contemplated removing my cats. Just gotta figure out what to do with the downstream O2s and I really don't want it to be too loud with the flow master muffler.

 

Having experienced other "corked" motors in the past, I can tell my little 3.9 feels throttled, it labors to breath up about 3500rpm. I believe it is restricted beyond just the small ports and valves..the intake is PUNY, and the exhasut is really restrictive.

I'm in the process of preparing a bigger motor for it, that one alone will help justify a more open and free-flowing exhaust.

for off-road, no matter, it works great, but when I get up to highway speeds, it just flattens out like its plugged (the cats may be plugged anyway). could also be a worn cam, a worn out timing set, etc..not to mention over geared, but the gearing shouldnt cause it to flatten out like it does (it flattens when I try to redline it in lower gears as well)

 

anyone know what thread/size defowlers are needed?

 

The exhaust isn't the problem, it's the ports on the head, and the intake design. That's why the bosch engines switched to a more efficient intake design, and hotrodders enlarge the head ports. Good luck with that though.

 

I agree with EricTyrrell that it is mostly the motor but i had the same symptoms on mine sluggish at hills, slow throttle response and just no highway power. after i cut my cat and resinator it made a huge difference!!! now i can maintain speed and accelerate uphill at highway speeds without the truck even downshifting. If you have cats that are older than 10 yrs they need to be removed and replaced or just deleted all together. As far as noise goes, as long as you have a good muffler it will sound good.

Intake and exhaust are the biggest things that restrict a motor no matter what the make or model. cold air intake and a good exhaust system you WILL notice a difference.