Muffler

[Dennyjr74]

I need a new muffler on my stock 93 Typhoon. What do you guys recommend? I'm also doing the cat. Delete since it wont need to go through the emission tests anymore.

[Aeroking]

For a turbo engine you are looking for the least amount of backpressure in the exhaust system. That means a straight-through style exhaust with no baffles. Some of the popular ones are the Magnaflow perforated tube style. Also the Borla XR-1 is really good. Steer clear of the Flowmasters.

One key thing to remember when deleting the cat converter is overboost. The cat converter and the baffled muffler create backpressure in the exhaust system. Typically back pressure is a bad thing, but in the case of a stock turbo'd truck, it helps the stock wastegate control boost. When you delete the cat and upgrade to a free flowing exhaust, you run the risk of overpowering the wastegate and overboosting the engine. Just my 2 cents.

[Dennyjr74]

Thanks for the info Brandon, what can I do to keep from overboosting? I'm having a problem getting midrange boost now. It's good to about 5 pounds and then it falls and struggles getting to 10 pounds. I was thinking maybe the cat was half plugged up and I know the muffler is bad, you can hear the baffles in it. I been having trouble getting it to run right since the rebuild and I pretty much put it back to stock. It's just bored .030 over and light gasket match porting. It ran 13:50 in the 1/4 before the rebuild and now I doubt it will get in the 15:00's

[Aeroking]

Your problem of slow spooling can be a number of things, including a plugged exhaust system. Are you using an aftermarket boost gauge, or are you reading the dashboard gauge?

To avoid overboosting you can also adjust the wastegate rod to open the flap sooner to catch overboosting before it happens. Make sure the wastegate lever swings freely. Also check your boost hoses around the turbo port, solenoid ports, wastegate ports. You can port the wastegate hole, or upgrade to a Forge actuator from Sportmachines. Overboosting on a stock truck is fairly common, there are a number of different solutions depending on your part combinations and how far you want to take it.

[Captain Morgan]

The setup I prefer to run is a 3" high flow (insert favorite brand here) cat and no muffler if you're looking for a louder exhaust.

I've also done 3" cat w/ muffler (ATR, Borla, etc) and installed an electric cutout at the bottom of the downpipe, so you can have the best of both worlds at the flip of a switch.

[Dennyjr74]

I'm using stock gauge but I can also feel the boost lag between 5-10 pounds. The exhaust is all stock and the Typhoon sat for about 12 years after i blew the motor. I'm pretty sure the cat is probably atleast half plugged with crap. When I first got it back up and running and would have it running in the garage it would leave little piles of rust on the floor where it came out of the exhaust pipe. I dont necessarily want a louder exhaust I just want a good free flowing. And want it to sound good too.

[Aeroking]

The absolute first thing i would suggest is getting an aftermarket boost gauge. The stock gauge is horribly inaccurate. You could actually be a lot higher in boost than the gauge is showing. You need to add a new gauge before anything else.

[Dennyjr74]

I'm planning on getting a new boost gauge, but I honestly doubt its overboosting. My Typhoon is probably the slowest stock one out there right now. I know it dont have the boost or power it had before the rebuild and it should have more.