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Discussion Starter #1
ok, first of all i know that most of you guyz have upgraded to 2.5" im planning on getting 2.5" piping for my car soon. but almost every shop i have gone to ask for prices they tell me 2.5" piping is way too big. Then friends and famaly that know about cars also told me that 2.5" piping for my mk2 is way too big

now here is my question why do people keep telling me that 2.5" piping for the mk2 is way too big for it?
 

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All I know is that on my 6M 2.5" piping isn't way too big. That is with a thorley header and a 2.25" cat with 2.5" Brullen exhaust. I think it is just right. I don't think you will have any problems and will probably like the 2.5" piping just fine. Are your friends/family use to 4 cyl cars??
 

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Discussion Starter #3
my friends and family have big V8's. they say that 2.5 is too big for a 6cyl engine :roll:
 

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I'm getting 2.5 in a couple of days and no one had any probs with it. Tell the shop your money is all the same with you getting 2.5 or 2.25. I don't think 2.5 is too big. 3" is too big on a NON turbo supra IMO.
 

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When I had my first exhaust done, I asked for 2.25"....to pass smog and inspection...lolz..the guy at the muffler shop said WTF? why would yoo want such a small exhaust??? He then proceeded to show me something I never knew...the outlet of the stock downpipe is roughly 2.5" =) Which makes me wonder why the DT headers exit so small. hmmm...... well either way, 2.5" is the way to go for a NA 5/6M.
 

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I know the Thorley goes from a 2.5" at the collector to a 2.25" at the cat. Why exactly I don't know. I would like to change that to 2.5" all the way. Wouldn't be that hard, the pipe isn't very long but has some slight bends.

I'll have to check my stock 5M downpipe, but I believe it was smaller than 2". Eitherway the Thorley made a big difference.

Yea, two 1 5/8" pipes to a single 2" outlet at the cat on the stock downpipe.
 

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BAAAAAHHH :bad-word: :silly:

Me thinks these guys don't know any better....

I'm also currently running the 2.5" Brullen Cat-Back exhaust on my 5MGE & it's perfectly fine. More than likely, they were concerned about the lack of backpressure, or the loss of low end power, when the tach is below the powerband (below 3K rpms). For my car, I've noticed that it's breathing just slightly easier (I previously had the HKS 60mm cat-back exhaust, which is 2 1/3" inches (so EXPLAIN THAT to your muffler guys, a Japanese performance company used 2 1/3" piping on our cars!!!!), and I really don't have much of a "loss of power below 3K rpms" because I have the 4.30 rear ratio, which helps the motor spin up faster.

So yes, I upgraded from 2 1/3" piping, to 2 1/2" piping & my car is perfectly fine... :shock:

Also tell them that a exhaust company up in Canada (Brullen), tested this out, and THEY say it's fine. Otherwise, some of us would not have bought this exhaust!!!!! :!:
 

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Okay, I just got my head out of my ass, and I have to correct my earlier statement. The 2.5" outlet was from the CAT...not the downpipe. I'll double check it tomorrow to make sure I'm not still dreaming. Eitherway...2.5" is the way to go.
 

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zankone said:
my friends and family have big V8's. they say that 2.5 is too big for a 6cyl engine :roll:
On their big V8s (350/351?) would they consider 2.5" duals too big?? Afaik a 2.5" dual system is mandatory on a performance street prepped V8 in the 350 cu.in. range winding 6k RPM.

Explain that the Supra 6cyl is roughly half that size (2.8L X 2 = 5.6L) so a single 2.5" is just as necessary on the 5M and just a tad small for a 6M!! After all, RPM is a factor too and ours are capable of 6500 more easily than theirs!
Jamie <-- got talked out of a 2.5" the first time too,... Never again!
 

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Sounds like you are on the right track, Jamie. I bet they think you have a V6....
 

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they just don't want him to have 2.5 inch or he may generate excess "kill" stories............
Have to keep those v8s out front one way or another
 

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Well, I'll give my $0.02 this one too... Back in '99 (before the 7mgte) I upgraded from 2.25" piping to 3" mandrel bent and noticed a nice increase in topend power. From about 4300rpms to redline, the power curve was much stronger and thats where these M-motors need it, IMHO. I did; however, notice a slight loss in power under 2000rpms, mostly while letting the clutch out.

My recomendaton would be to upgrade to 3" piping if it's the same price as the 2.5". This will come in handy if you so decide on a turbo upgrade.:)
 

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Discussion Starter #13
:shock: 3" now that seems abit big for a 6M. maybe ill just go with the 2.5"
 

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82Spearco said:
Sounds like you are on the right track, Jamie. I bet they think you have a V6....
A v-6 will produce the same volume of exhaust as an inline six, just it doesn't come together until the Y-pipe... however the dual exhaust for a V-8 arguement sounds good too...

Tho the argruement I like the best is simply, "Its my Car, my Money. I'll do as I please." :wink: And then go and listen to the people who have firsthand knowledge of the situation... Then when its done.. take them for a ride and make em sorry the doubted ya ;)
 

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Definately go with the 2.5. I, just today, got my exhaust done with 2.5 from the Thorley through a 2.5" cat to the 3" inlet Magnaflow; nothing is smaller than 2.5 inches. I've had this stupid grin on my face all day! I didn't know the 5M could sound like this! Can't wait for the 6M!

So yeah, 2.5 is worth every penny!

Nick
 

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The guys at both muffler shops here said the same thing to me when I had mine put on. That 2.5 was too big for a 6cyl car and that I should go with 2.25. I figured why would 2.5 be too big for a 168 cu/in car when my uncles SMALL (considering it was one of the smallest V8's that were put on back then) 302 cu/in 69' ford fairlane has dual 2.5 short piping with no cat. That's 2.5 for each 151 cu/in per side. That makes no sense coming from a muffler guy.

The guys at my muffler shop changed thier tone just as much as my supra did after the 2.5 was put on.
Just say to put the 2.5 on and you'll see how you like it, cause basically what it comes down to is what YOU want.
 

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Discussion Starter #17
does any one have any idea how much it would cost to get 2.5"pipping+ 2.5" cat + muffler?

i might be needing it soon for my white supra.
 

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Mine was 350 installed + $62 for a cat from Summit. That included everything.

Nick
 

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I had a mandrel bent heavy gauge stainless steel 2.5" system built for $500.00. I most likely paid too much, but choices on the East Coast are limited.
 

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Im taking mine in on Monday to have 2.5" put on Ill let you know.
 
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