I have a question. I have a set of Magnaflow mufflers and will be getting some high flow cats, etc. My question is since I know someone who welds so we are gonna just weld in everything using the existing 2.25" piping for now with reducers to go up to 2.5" which is what the components will be. Will I even notice that much of a difference if I stick with the 2.25" as compared to later when I switch out all the piping to 2.5"? Is that .25" really gonna make that much of a difference in sound, power etc?? Any thoughts, opinions, evidence??

 

Excellent question Vance, I'm glad you asked. I did a lot of research on this topic to make my final decision to stay with the stock piping at 2.25 all the way through. I never noticed any loss of low end torque as a few have stated like Bfs. My conclusion is that b/c of those guys increasing the stock pipping to 2.5 instead of using what was stock 2.25 caused the low end torque loss. Final analyses, staying with .25 will not affect the sound, but performance might be questionable due to using 2.5 pipping causing slight loss at low torque end.

Hope I could help out brother, and good luck on the welds, I have some pics of my Hi flow cats somewhere in older posts of mine, take a look at how I placed the 02 sensors if you have any doubts.

****Update: link to pics of CAts installed! https://www.jaguarforums.com/forum/s...ad.php?t=43505
Peace!

 

Yea the welding should be good cause by we will be welding I really meant he will be welding and I'll be giving him the ata boys. LOL. I have never welded and he has been welding since he was little.
Depending on the output of this topic I may just stick with the stock size and not go up in the future. But I may still stick with 2.5 with reducers at the components just so I have the option.

 

No problems amigo, let me know how you like the outcome of it . I'm sure you will be turning heads on campus with that sound

 

Forgot to ask what size tips are you going to go with? 4" maybe???

 

Yes you are correct. I will more then likely have the same tips as you. Wish I could find a pic of the 4" tips on an 05+ body style since the rear valance is a little different. Not sure if the openings are the same size as the stock size seems to fill them quite well. I dont want to have to cut the openings bigger.
Anyone with an 05+ got pics of some 4" tips on?

 

Awesome! Your STR is going to be one bad *** Jag!

If my memory serves me correct one of the members here "Stypernut" has 4" tips on his 05' STR, take a look here https://www.jaguarforums.com/forum/s...t=40926&page=4
You could ask him more about the valence for the rear on the 05's.

 

+1 With that stay with the 2.25 stock pipe, keep the low end torque, It is all good quality stainless steel will last forever.

 

Hi vance
i got mine with a 4"inch tail pipe. (and mine is 05 STR)
i did my muffler with set of magnaflows i do believe it was 2.5in, as i remember the muffler store i went recommended a step up when reaching towards the end (muffler, if you step down, there will be a bottle neck... something like that)

i love the sound on the magnaflows.. not too loud.. just nice...

http://www.youtube.com/watch?v=Zg8570NvlPM (this is before the magnaflows)

 

I wonder what this guy put on his jaguar STR over in the UK, it sounds fckn' crazy . Take a look.........

http://www.youtube.com/watch?v=mo3nd...eature=related

 

Dudes. Before useing 2 1/2" pipe for my full exhaust mod, I mentioned in threads that I felt the stock 2 1/4" was adequate and would maintain low end trq. up to 475 hp. I succumbed to 2 1/2" because others felt the opposite was true if high level of mods were to be added to attain power beyond 475 hp...500+ hp. Though I cont. to feel that 2 1/4" pipe is adequate to support up to 475 hp, 2 1/2" can be used when coupled with muffler components that slow down escaping gases. This is one of the reasons I discarded the Magnaflow's in favor of a pair of 12" Walker glass packed tube resonators leading to a pair of Dynomax Super Turbos'. Aside from a quieter yet still aggressive exhaust note, my butt-dyno feels the return of low end trq. You'll observe both the new n/a and s/c 5 litre Jags use 2 1/2" pipe with glass packed pre-mufflers and glass packed chambered mufflers (similar design as the Dynomax Super Turbo's). The reason for this is not soley due to increased displacement but to freer flowing incoming air intake charges, etc. This is what's happening with our STR's as we mod em. Example: K&N a/f to 4" free flowing air intake elbows, to ported/polished blowers with smaller pulley's spinning them faster (what about the massive amount of air churned by a future twin screw?), ECU tunes that increase ignition lead and fuel curves, hi-flow cats allowing spent exhaust gases to escape faster which in turn cause more complete scavenging of cylinders...this process requires more air to be pulled in from the intake-down= larger diameter pipe. By the way, 2 1/4" pipe makes for a louder exhaust than 2 1/2" pipe due to the freer flowing (less air friction) characteristics of 2 1/2" versus 2 1/4". The Magnaflows are quieter than the Super Turbo's at light throttle during cruise, but much louder than the Super Turbos' when dipping further into the pedal at a stop or cruise. I wrote a thread a while back: "Don't lose too much back pressure". Hope this helps guys.

 

A muffler that I have been looking at is the new Dynomax VT series. It is more of a straight-through design, but has a valve that closes at part throttle (highway cruising) to help eliminate some of the noise.

http://www.dynomax.com/mufflers.php?muffler=vt

 

Thanks Mike. The Dynomax VT muffler may be the "Missing link" for having the best of both worlds?

 

After getting my Magnaflows installed awhile back I had Second thoughts; I took a gamble with the Magnaflows over the Dynomax VT at the time. I still love the Magnaflows but I should have went with the Dynomax VT's instead after reading a thread on the test results of people who actually tried them out and giving their opinions about it. http://forums.evolutionm.net/evo-eng...y-muffler.html

Down the line, I might change over to the Dynomax VT to cancel out the drone. It isn't too bad with the Magnaflows, but it would be better if the drone sound was a lot less than what it is now. Anyhow thanks for mentioning about the Dyno Vt' mufflers Mike! Let us know how they are after you get them installed. I have been following that thread for a very long time and people are giving mix reviews about it, it has its pros and cons just like any product.

Cheers!

 

Vettes sound quiet till they are opened up due to this technology.