Exhaust mods for a 7mge

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suprasteveo

New Member
Jun 25, 2015
16
0
0
Ridgefield, WA
Alright, so I'm a noob to the site and new to the magnificent mk3 Toyota supra. (If this is posted in the wrong section, please ignore the stupidity, It comes naturally in this one :icon_bigg ). I had some questions about the exhaust. I'm sure all the "elder supra wisdom holders" on here are rolling their eyes and in total disappointment that another person is asking about the simplest things like exhaust. But I just had some basic questions I need cleared up. (My car is an 87' 7MGE with the a340e auto trans for those who are wondering) Firstly, should I change to a new exhaust system? Or would I be best to stick with what I have? There's nothing necessarily wrong with my exhaust, I would just like to free up some power and sound. Next question, this car is my DD so would it be stupid to fit a test pipe and cut out the cat? I don't mind the smell of exhaust on me especially cause I'm working as a technician at a dealership, but would it be too overwhelming of a scent? Thirdly, If I went with a new full system what size should I go with? I've done some bare minimum research on this and people seem to get the best results with 2.5" exhausts systems, is this true? Or should I just say POWERRR and go with a full 3" exhaust system? I'm aware that that may cause not enough flow in the system, cause back pressure and be detrimental to the engines power, but I would still like to get some opinions. Last question is... Should I go to a exhaust shop and get it done or should I buy it online? Or does it even matter? I'm sure buying it online would be my cost effective, but having a custom exhaust from a shop is pretty cool too. I also live in the US, in Washington, and wont need to do emissions testing (thanks 25 year rule :icon_bigg ). Anyway, that's It for now! I thank you in advance for the responses!:biglaugh:

-Suprasteveo
 
Roger UK

Roger UK

Member
Jun 20, 2010
67
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6
Newcastle
I presume you just have ONE Cat (like on UK Cars), after the twin downpipes?

Here in the UK there is no legal requirement to have a Cat, as long as the car still meets the Emissions Spec (which the 7M EASILY does!) And having no Cat does not cause any kind of exhaust smell !

HOWEVER . . . simply removing the Cat on the N/A engine means it's not receiving the correct backpressure. What you then notice is a lack of low to mid range power.

BUT Toyota made a Non-Cat exhaust front section for the earlier Mk3s that didn't have a Cat. Basically the two front downpipes combine and then go into a front box. This box isn't restrictive, but provides the correct back-pressure that the engine is expecting.

So after I removed my Cat (about 12 years ago) and noticed the power loss, I bought one of these and it was much better. The same stock (or aftermarket) cat-back exhaust bolts onto the back of this front box. With no Cats (but with this front section) the engine certainly produces more power than with the Cat fitted!

Here is a picture of the Non-Cat Front Section for the 7M-GE (top one - lower is one I had modified to fit my new 2JZ-GE engine)

exhaust3.jpg
 
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Silver MK3

Silver MK3

New Member
Jan 24, 2011
1,517
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Madison, AL
Keep your cat, don't do a test pipe in my opinion. If you aren't planning on going Turbo then 3" is way overkill, I went with 2.25" on mine. I get a lot of compliments on how it sounds. I put a lot of research into it too though to make sure I was getting exactly what I wanted. Here's my thread on it, there should be some video clips of the exhaust in there too.

http://www.supramania.com/forums/showthread.php?193652-Exhaust-Suggestions
 
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