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Discussion Starter · #1 ·
I've got an '89 MX-6 Turbo, the engine has just been reconditioned (3000kms ago) with a new turbo on board. I'm just about to undergo my first mod, starting with the exhaust. I can't afford much so I'm modifying from the cat to the tail pipe. My main question is, what size pipe should I increase to? I've been advised either 2.5 or 2.25, is there any difference? What's better? Am I going to lose power before I hit the turbo if I get a bigger pipe? I need help, I'm only a novice!!!

I have also got a problem with a leaking standard factory fitted sunroof. I know it's the rear drains, because it is only a problem when I park facing up a hill and it rains. Is there any easy way to unblock it without pulling down all the interior?
 

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I cant help you with the sunroof problem because my 1991 GT does not have one (I have been told that this is rare for a GT).

As far as the exhaust goes, get the 2.5 inch exhaust. You dont have to worry about back pressure on a turbo. That only goes for a natural aspirated engine where if you have too little back presure you could have a problem with the engine.

A turbo is a completely different beast. The first mods to do a turbo is free up the intake and the exhaust. The freer the exhaust the faster the spool up time and that spells more power.

I have a HKS cat back. I love it. However they are expensive. Hopefully some other members can tell you about some inexpense cat backs that are worth it.

Good Luck.
 

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I suggest a 2.5 exhaust. The only decrease in power you may notice is a slight loss in low-rpm torque. It should be very minimal. The benefits will definitely outweigh the costs in this case. Although I havent upgraded my exhaust yet, from what I've heard it makes a very big difference by reducing turbo lag and increases power throughout the boosted rev range. As far as your sunroof is concerned, all you need to do is blow compressed air through the drainage tubes at the bottom of the car. There should be two plastic tubes coming out underneath your bumper right behind the rear wheels. Blowing these out should fix the problem. I had the same problem as you and this totally cured it.
 
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Discussion Starter · #4 ·
Thanks guys, you've sold me on the 2.5!!!!

And extra thanks Anarchyx for the sunroof info, it's going to save me a lot of bucks and unwanted cold showers!!
 
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