JRE 4" exhaust

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I finally had the opportunity to have a 4" exhaust system for my 99 24v installed this morning. The system is from Ted Jannetty and JRE. Here are some initial impressions.

Its going to take a while getting used to the extra noise, especially the drone around 2100 rpm. Its not that it is very loud, but it is certainly a different sound. Exhaust noise from hard acceleration is very noticable.

Turbo whistle is much more evident. Turbo spool up comes much easier ... in 2nd gear, 3000+ rpm comes up very quickly now.

The inlet/outlet of the muffler was bigger, perhaps too big, for the 4" pipes. There seemed to be too much play when the two were connected. Even with the clamps on tight, I am a little concerned about exhaust escaping here.

As for hp/mpg gains, only time will tell. My primary reason for going with the 4" is too allow me egt room to add additional performance features. I feel more comforatable now w/ adding the 275 hp injectors and an add on computer, and won't worry so much about the egts.

The stock exhaust system came out very easily. In fact, it came out in two peices - the down pipe, and the rest. So now what I am going to do with a complete exhaust system?

Craig

[This message has been edited by CCollar (edited 11-03-1999). ]

 

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CCollar, is your truck totally stock except for the exhaust and gauges? What about your air filter? When I go 4" (2nd planned mod on my truck after gauges) I will probably throw the resonator on too. I operate my truck in the 2100 rpm range frequently and maybe the resonator that JRE offers will help cut the drone.

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Vaughn MacKenzie

1998 3/4T QC 4x4 Longbed, 24-valve 5-spd, White over Driftwood, Leather & Loaded, foglights, airdam, DeeZee Running Boards. 50,245 miles (11/02/99)

Member of KISS aspiring to BOM

 

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I've got a KN air filter in the stock air box. I've been thinking about adding the resonator too, but I'm going to wait awhile to see if I get used to the new sound.

Craig

 

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CCollar, you can find some non threaded round stock at Orchard Supply hardware to create the hanger you lack. They can be purchased in 3 foot sections. If you go to a welding shop to purchase the round stock, you could have them heat the metal to create any bends needed to attach to the body. Bar stock would be overkill I think.

Can I still claim most obnoxious Ram Runner or should I get the sawzall out?

Good to hear the surgery was successful!

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3/4 ton, 5 sp, lsd, 2wd, qcab, guages, Scotty sys. Rhino liner, Blue Box hp enhancement

 

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CCollar,
What is the resonator? What is it supposed to do? I also have a 4" exhaust and in my opinion the "drone" at 2100 rpm is also too loud for me. Definitely can't hear the engine over the drone. Is the resonator tuned to attenuate some sort of frequency?

 

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Fitz,

The resonator is a pre-muffler canister that does pretty much exactly what you describe. I believe it re-tunes the exhaust system to another frequency, or attenuates certain frequencies. How it actually works, I am not sure.

I have been listening to the system pretty closely, and it sure sounds like the drone originates farther back in the system then where the resonator goes.

If the problem is resonance, particularly in the long straight piece of pipe running from the down pipe to the muffler, there should be a simpler fix than adding the resonator. A fellow sent me an email a few days ago and said he routed his 4" straight back after clearing the rear axle, and now there is no more drone.

Anybody else with any novel ideas?

Craig