lsxTAlemy

iTrader: (2)

ok guys like the tittles says. im looking to see if this is holding me back. i have a 6.0 lq9, victor jr efi, ms3 cam, 241 ported polished milled heads, full bolt on's and i have an off road y i think tsp with a 3' magnaflow system. i would like to know what u guys think if this y pipe magnaflow set up is holding my motor back. i love that the car is so quiet now. had true duals and loved it! till i gutted the car sounds too loud for me every thing shakes and u cant even hear the radio.

redtan

iTrader: (5)

A different y pipe (still catless) might net you a handful of hp (~5) so no it's not really holding anything back.

A 2.5"+ true dual with an x pipe might be worth a few more hp over that.

lsxTAlemy

iTrader: (2)

thanks for the reply

i had a true dual 3'' mandrel bend h-pipe with magnaflow bullets. but the drone was killing me. also they told me that the set up i have will give me back pressure and will net more hp at the end. is this true i was thinking about doing the 4''. im guessing sense its so quiet now my mind might be playing tricks on me lol

im also thinking a big shot of nitrous in the near future. but ill ad a 3 in cutout out at the 4'' y to compensate and add more exhaust flow...

VandykeT/A

I went from a single Hooker catback to dumped 3 duals and I could feel alot of low and midrange. Never had it on the dyno but I definately felt a difference. That was a heads/cam stock bottom end. I don't really think a 3" single system would give you more power than a 3 dual set up. Back pressure is bad. Why not run the duals under the axle?

sbf

What numbers did you put down. What trans and who port the heads

lsxTAlemy

iTrader: (2)

yea i know it wont give me more power. im saying if feels like its holding me back but not sure if its the noise or if it really is. under the axle doesn't look good u can see the pipes from the back of the car.

i haven't dynoed the car. i street tuned it and that was it. the heads were ported by a friend of mine that says he's the **** porting the combo before was 5.7 ls1 with same heads and same cam true duals and now everything the same on a 6.0 lq9 with y pipe but feels slower...

with the 5.7 i went 7.1 at the 1/8 at 90 mph. im taking it to the track this Friday to see what it runs...

lsxTAlemy

iTrader: (2)

don't know what it is but i ran a 7.6 last night hit the trans brake at 4000 1.7 1.8 6.0s dont know if its the exhaust or the converter

low2001gmc

iTrader: (148)

i would put the dual 3 back on with a flowmaster y merge (dual 3 into single 3.5 or 4). how long were the bullets? the flowmaster y merge has a smoother transition and really helps get rid of drone. the hooker maxflow straight flowing 14 inch case muffler is nice muffler to add. magnaflow oval case 14 case would also be good.

with car gutted, hard to get quiet. i would put some dynamat extreme sound deadner. adds weight but it is not in the front so not bad.

but definitely you need dual 3s exiting from headers with an lq9 6.0 and big cam. no doubt. i oughta know....

lsxTAlemy

iTrader: (2)

i think the bullets were 14 or 16 in not sure. i just got tired of everyone saying my car is not a dd or a street friendly car. so i quiet it down but i see and feel that is held back. i didn't know if it was the exhaust or the converter. *** now i have a way tighter converter.... i have the magna flow case right now

lsxTAlemy

iTrader: (2)

thanks for the help so far. would like some more info some more people shim in.

lsxTAlemy

iTrader: (2)

anyone

lsxTAlemy

iTrader: (2)

well went open header to the track and picked back up what i had los os im guessing it was the exhaust only things changed were exhaust and plugs

JakeFusion

iTrader: (7)

Unless you are running a very high quality 4" merge into an open cutout, the true duals will pick up peak power and a lot of area under the curve to any F-Body catback once you're over 400rwhp and especially once you hit 450rwhp.

A 3" open pipe can't support that sort of HP without pretty big losses. At 450+ the duals pick up a lot of torque compared to just a 3" cutout - but you change your A/F running open vs closed. Which is why I advocate running one or the other. Of course, the duals will always be louder than something like a Magnaflow, but you could run the duals out the back and use Flowmaster 44s or something and get the noise down.

Alvin@PCMofNC

We had a magnaflow setup on a 2000 F-body literally pick up nothing by opening up the cut out. I think you make the most by optimizing the Y. I do think true duals will make a touch more power.

We also had a 99 twin turbo formula with a magnaflow catback. That car picked up 55 rwhp by opening up the cutout. A turbo car is a whole different animal though and any exhaust restriction will kill them quick.

lsxTAlemy

iTrader: (2)

im going back to true dual x pipe with 4 bullet dyno max mufflers and see how it goes. im going to run them out to the back under the diff see how it works out. i don't know how much power im putting down never dynoed the car always street tune. but by my mph it should be 440 wheel hp

i know turbo anything after the down pipe is a waist but in n/a nitrous def felt the difference tho. the car went from 89 mph to 94 so either exhaust or plugs made big difference...

by the mph it went from 380 hp to 440

99Bluz28

iTrader: (35)

Change out the Y-pipe merger for either a Flowmaster, or Vibrant with a 4" exit, then run it into a 4" cut-out followed by a 4" to 3" reducer and back into the magnaflow cat back.

lsxTAlemy

iTrader: (2)

im gonna go with true dual 3' x with 4 3' in dyno max mufflers 2 before and 2 after the diff call it a day