Thread: worth every penny! dynomax VT $90!

^I'll look into it.

Which one for turbo 3"?

Brent

I've been told the fluttering, buzzing noise on the under 4.0L model was fixed. If that is the case, then the under 4.0L model should be used for N/A but the over 4.0L model should still be used for turbo.

Basically, do you make more power than a stock 4.0L Jeep engine? If yes, and most of our mild turbo builds do, then get the over 4.0L model.

Dynomax Performance Exhaust | Mufflers | Dynomax VT Muffler

^Link here.

Part# 17949 for 3" center with offset to the right look.

Part# 17962 for 3" center to center look.



^So you think the over 4.0L model will/would hold back power on fully bolted stock ve at WOT?

I'd be worried the valve wouldn't open soon enough, causing the loss of some mid range power (and low range) on an N/A engine. I can't say for sure one way or the other though, since I've not tested them.

Basically the valves open at a certain HP level (air flow volume). I'd guess the under 4.0L muffler probably opens somewhere between 100 and 200 WHP. The over 4.0L valve probably opens somewhere between 175-275 WHP.

- Hmmmm, I'm going to go ahead and call one of their techs like the other guy suggested.

so the valve opens based on the ammount of air volume that the engine is exhausting, is this correct? theres no mechanical parts but more or less just the air pushing and opening the valve?

I'm worried too about exhaust restriction on a turbo at low RPMs. Do you think this would have any negative effect?
The NA engines may like some back pressure, but I always thought that with any turbo the least restriction the better.

Correct. The valve is sort of like a flapper valve. The outgoing air pushes it open. The spring in each model holds it closed. The mufflers meant for higher horse power engines have stronger springs holding the flapper closed.

While the valve is closed or partially open you'll see quite a bit of back pressure which will harm performance. To what degree, is open for debate.

N/A engines do not like back pressure ever. The back pressure is detrimental to both N/A and turbo engines alike.

^Just got off the phone with a tech, I hope he is right. He says I would be better off with the 4.0L and under muffler. He said that the 4.0L and over would not open on a car making 190whp. I just gave him a ball park average of a fully bolted stock VE. Looks like I'll be getting the part# 17156.


^I hope you are right and they fixed the design. Where did you read/hear this? I asked about air flow volume results and he said they don't have them yet. Makes me wonder how he would know that about the 4.0L and above muffler.