Custom exhaust suggestions/help needed

[DirtyDisco]

Since there aren't a lot of affordable performance things you can do with the 4.0 engine, I was thinking of squeezing 5 ponies or so out of a custom exhaust. I'm wondering what you think would be the best way to go...

I'm thinking of cutting the middle muffler off right before it bolts to the catalytic pipes. That way I can still unbolt the y-pipes when I need to. Should I put a flowmaster type muffer in place of that one and use the same exhaust tubing and just remove the rear muffler... or... should I have the exhaust shop do custom piping and install a stainless steel "tuner" style muffer where the rear muffler is?

I'm leaning towards the tuner muffler with custom pipe, because I don't particularily like the flowmaster sound and I did this once to my old honda with good results, but I'm just wondering what to do.

 

[joey]

Either way will sound good, but it will do little for performance.

 

[DirtyDisco]

Oh alright. I'm still debating whether to even change the exhaust at all. It's hard enough to hear my stereo as it is.

 

[Stupidjeep]

I bought a DynoMax UltraFlow muffler at Advance Auto for $40-something. Got it welded on at a local shop for $50-I know I got ripped off for install, but whatever. The rear muffler/resonator/thing is still in place. I'm not sure what it has done for power, it feels faster off the line, but its probably in my head. The sound is perfect, it isn't very loud, but what do can hear is beautiful!

I think I am going to look for a performance chip soon. I think that is the ticket for cheap power.

Chris--D1, CB lift and MT/Rs

 

[healey1006]

First thing you should do is rechip your computer because it's constantly monitoring and making adjustments to ignition and fuel to keep everything within the stock program parameters. This works against any intake or exhaust mods you make.

 

[Stupidjeep]

I thought the computer could learn new parameters if it was reset, as in pulling the battery and reattaching after a moment. Let it idle for a few minutes and it will rev up/ down a little. I thought it did this to moniter and make adjustments to an extent. The "chip" is an adjustment itself, I believe, that changes the fuel/ignition points for performance. Does this sound close?

Chris--CB lift and MT/Rs

 

[joey]

The Land Rover ECU will not learn anything, it just resets back to the factory setting, the Transmission on the newer Land Rovers will learn how you drive and will shift as it has learned, but the engine ECU is another matter all together.

 

[healey1006]

Joey has it right. The ECU won't "learn" anything. You would need to re-chip...and by the way there are two chips involved here, one for fuel and one for ignition. There's only one place I know of that sells BOTH and that is RPI of England. Hold onto your wallet 'cause it aint cheap! But, these guys know what there doing.

 

[beemer]

Under 7/100K warranty back in 2002 with the dealer screwing up the 95 3.9 I had them install a 4.6 that came without cam, lifters and timimg set. I gave them a RPI cam, lifters and Edelbrock's Buick V-6 timing set while I had a speed shop modify the heads and correct Rover's crap valve problems. I port matched intake and exhaust ports, again big gain. After break in I installed RPI's Tornado chip, that woke it up big time, cost $250 USD. Went to a Borla cat back after opening up the iron manifolds and down pipes plus high flow cats. This changed the motor again plus the chip relearned and all is well. Pulls hard to 5,800 without the problems of the factory chip, this is a 5 speed.
Just don't have brake lights since last night.

 

[Stupidjeep]

Damn, beemer! nice equipment.. Was that RPI's ignition or fuel chip?

Chris--D1, CB lift and MT/Rs