cheap horsepower

I know it was a while ago, but i saw the post where someone was making reference to our 3.9L as a "mod motor". Well, I have to make the correction; the 3.9L is not in the modular family, it has entirely it's own architecture. The 3.9L is BASED off the 4.0L Jag engine, however they share almost no commonality what so ever.

Mod motor V8's are limited to the 4.6, 5.4 and the VERY RARE and expensive 5.0 "cammer" which is a FMS parts crate engine. Then there is the 6.8L V10. That's it as far as the mod motor family goes.

And on a side note... a lack of back pressure will not damage your engine in and of itself. As was stated, back pressure builds lower end torque. Inversely, lack of back pressure creates high RPM torque. You can have one, but not both. If you pay attention, most racing engines run very very simple, virtually back-pressure free exhausts; these engines also live a life of constant high RPMs and will only see numbers below 3000-4000RPM when they idle.
 
Exactly, paid 15k for my 2000 ls sport, and you know what the dealership paid 32k in warranty covered repairs ( 50 thousand mile curse) and I see em going for a lot less than 10k even with the premium 75k powertrain warranty like I have. Every 19 year old gangsta now owns one anyways for that reason as well, so ghetto realy should have no deffinition here considering there is not alot of aftermarket selections for this car. So then again, is it realy ghetto cause you made it for under 500 bucks and didnt pay over a grand for elegance that lasted 10 thousand miles like mine. I wish I would have just got the pipes from some barn yard machine shop and used my own mufflers. It sure isnt ghetto to all the hotroders that ripped the cats off and sent a straight pipe out the side as soon as they get the car cause they like it loud. Dude configure the pipes yourself, thats your perogative and I realy think it kinda sounds more like blowing up rice with an american car.
 
Sorry this was supposed to follow loudisgood666 post just above a few. OOOOOPS.
 
What do you think about those universal filters with the metal shield around the cone and not shaped like a box
 
Why cant you just get rid of your mufflers completely on an LS? Or can you? Wouldnt running no mufflers at all be louder and more powerful than running mufflers? What are the positives and negatives to doing this? Any responses are greatly appreciated
 
Quik LS said:
nope - if you go too big with the exhaust (like cut-outs or 4" piping) you will end up moving the torque curve up the rpm scale because you have lost soo much backpressure.

so you need some backpressure to have the torgue down in the lower rpms for a good launch - but too much will build at the higher rpms and hurt the performance there.

so like anything else - it's a trade.
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Why cant you just get rid of your mufflers completely on an LS? Or can you? Wouldnt running no mufflers at all be louder and more powerful than running mufflers? If you did this you could keep all your stock tubing to. What are the positives and negatives to doing this? Any responses are greatly appreciated
 
How can it be march and no answer to that?
I actually did try that.I took my 02 off the hoist after cutting the muffs off and took it for a ride...As soon as we started it , it sounded like an old 5L...Quite nice actually. However , hard hitting out on the road , and it was wayyyyyyyy too loud for a luxury sport , and did crackle/pop on throttle lift.
Great at an idle tho!
 
5 months with no further data on running muflerless... hmmm... has anyone else tried? I'm more looking for dyno results, not just seat of the pants... also, what would I need to have torrie change with my xCal profiles to take advantage of the lower backpresure? Thanx in advance for any solid info...
 
ive actually been running straight 2 1/2 inch pipe to a magnaflow x-pipe and straight back with no cats or mufflers for about 6 or 7 months now... and i get compliments all the time about how good it sounds.. but i also get people who complain about how its to loud.... but who cares i love it..... as for backpressure, i have felt no loss in torque but a huge gain in high rpm horsepower ..but when u loose backpressure its allways a good idea to open up the intake side (intake, ported TB & Upper Intake Plenum) .....and to add a bit more fuel to keep from runing to lean.. .i have also had a custom tune made by torrie which does help alot.... but before the tune, it did run great without the mufflers and cats for a about 2 months. i hope i helped
 
i just recently removed the back half of my exhaust running no resonators or mufflers and it was too loud for me. i did feel a difference in the high rpms tho but cops are too quick to pull over anyone in my area with an exhaust that loud. i only kept it like that for that night.
 
hi i have a 1992 lincoln town car with the modular 4.6l and im trying to make it fast but i used to have the exhaust detached from the downpipe back so about the equivalent of long tube headers with a little extra length but it sounded freakin awesome and a slight increase in performance but recently i gutted the cats and wit the exhaust how i used to hve it i lost a tone of low end power from the lack of back pressure wich was provided by my cats before and plus it leaves that big chamber where the gases start to rotate in and causes less power so now i put pieces of metal in between where the down pipe and mid pipe connect and then tightened the bolts on to it to leave about a 1/4" gap doesnt sound very good because u can here the air ruching around the corners but did see improved power and plan on eventually putting 2.5" mustang manifolds with 2.5" x-pipe and maybe hook the rest of the exhuast all the way up and btw i have 12" glasspacks so what gases to keep flowing trough go through those and when its all bolted up it sounds nice but too much of a 4 cylinder sound and not loud enough for me but theres some info for u if u can replace ur catted downpipes with straight pipes and since its pot 96 use o2 eliminaters and u should see some power and if u want leave it open like i have mine or get some flowmast single chambers
 
Dyno tuned no mufflers 3 inch 2 foot long SS tips been like that for 3 months loud at times but i have bridgestone potenza's on the car so im not relly going shooting for quite!! Old people say you arent supose to hear a luxary car all the car buffs Drule when they hear it, ive had a few cops and a state patrol compliment my exhaust.The first thing everyone needs to do is get a SCT and have the throttle open delay turned off and the shift firmness maxed.
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Just wanted to let yall know that I've put 12" glass packs on my '01 Ls and I know your probably think'n idiot but it actually has a nice tone though, I get compliments on it all the time people think its actually bigger than what it is most people think that it is a 4.6 out of a mustang, kinda sounds like one..that was the sound I was going for so it works for me, dont know if I lost any or gained any last time @ the strip I was a little slower but I did have a half a tank of gas, new tranny, and exhaust, not to make excuses.:D
 
i am now running straiht pipes sounds GREAT and its not too loud either im guessing the way the tailpipes are it cuts back on the sound but i like it
 
About the original question, ls steve. Have you ever considered lake-pipes or cutouts? That would be exactly what you need. Loud when you want, quiet when you dont.:D
 
I have 05 LS v6. I had 2.5 with an x-pipe from the resonators back to 2 Magnaflows installed. These are 18" 4x9 and yes I lost some low-end, but at about 3000 rpm and above this really made a big difference. I have KKM CAI installed with my own engine block-off installed. The exhaust makes a nice euro sound when I start her up and nice tone as I accelerate. I am very pleased with the outcome and all of my car buff friends like the way it sounds also.
 
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