Lextreme

Lee,

Where did you get this job done at? Looks like we are at the same muffler shop.

azari

make sure you'll post the clips. We are all eager to hear your car. It's very interesting for the first time to hear a "loud" lexus. Because all I've heard/experienced in my life is about how quiet these cars are, lol.

JBrady

Lee, you are risking damage to your cats and exhaust manifolds. The system is not supported properly and WILL cause something to break. I ran my car very briefly with only the Y-pipe and resonator (like yours but stock parts) and it was LOUD also. This is due to many things not the least of which is resonance between the road and the floorpan of the car. While I test drove mine I used a piece of wire to hold the system up and it still streched the wire from bouncing. I only drove it 10 miles.

Anyway, from what you say your goal is I highly recommend you take off the glass pack, re-attach the front and rear sections and just run straight pipes or glass packs instead of rear mufflers. Understand this is NOT what I would normally do, just trying to keep it within you low cost goals. Also, post of pic of the Y pipe area if it is not stock.

Lvangundy

I'm taking in what you guys are telling me, but I don't really have any option right now to change it. If I go back and change the glasspack I just lost $45. If it gets to the point of risk thousand plus damage then I'll just put everything back to stock which is putting the 3 resonators back in. I'm positive my rear mufflers and resonators are clogged or blown because the outside of the can is busted open by like 1/8".

Where does the damage come from and why doesn't this damage occur on old american cars with glasspacks and short exhausts?

Why doesn't the car support it?

JBrady

Lee, just have them weld the glass pack to the rear Y-pipe. This will extend your pipes and tie the front and rear together and prevent the front section from bouncing up and down. It is this impact bouncing and the leverage of the length and weight of the system that is your problem. Frankly, I am shocked the shop didn't warn you about this. If the stock mufflers are clogged... cut them off. At least have short extension pipes welded or clamped in place of the muffs. This will also quiet down the system. Again, this is not ideal but better.

Regarding older cars with glass packs dangling off of the headers... this DID result in cracks and damage. However, the problem is worse with the heat in the cats and the length of you lever arm vs any support, not to mention the cost diff.

Lvangundy

Ok. So the risk is more of a physical issue. Not a chemical problem or something?

First off - Based on Dynomax's Powertech index, is it OK (good for performance/bad) to go with a higher CFM than what you need? Baed off their calculation of my 175HP in a dual system (or is it single due to the centor resonator? it's a mix, what is it? ) I'd need a CFM of about 200. The dynomax SS is 'rated' at 1000CFM.
The flowmaster is around 300CFM according to dynomax in their test. Does CFM work in a similar matter as back pressure and flow velocity? As in, Too big = No good? Where do I find a reffereence for how big the pipes should be? How do we know what the optimal flow velocity is ? Stock piping is perfect? Too big, too small?

I'd reading more and more about glasspacks actually being bad for flow and quality. At the same time I'm referring to Peter Scott's site about his exhaust testing. What is the stock measurement on the exhaust piping? It differs at each section correct? I'm thinking of going with 2.5" piping throughout the rear end (if stock is less than 2.5" otherwise 2.75") of the sytem after the center resonator. I'll remove the glasspack (unless someone can offer a counter argument on why to keep it) and connect back to the piping going to the rear mufflers.

My concern on just removing the rear mufflers is that visually this would look very odd because normally the mufflers and tips are obvious from the rear. This is different on the 95+ models as the bumber covers it. Like I mentioned I'm pretty positive the rear mufflers are dead/clogged/blown and need replacing but dynomax mufflers are about $100 each installed. So I'm looking at like $225+ with the center piping. I'll take a picture again to show how many bends there are before the rear mufflers. Wondering if I should ask them make new straight pipes to keep flow.

Input? anyone?


Here's an interesting article on backpressure.
http://www.hondalife.com/articles/backpressure.htm

Here is a quote from this site about Transam tuning -
http://www.angelfire.com/ct/transam/howto.html

"Mufflers

Mufflers are a good place to start when speeding up your car. With all the types available, 2/3 chamber, 2-out, glasspacks, race, disc, and many others, it's easy to choose the wrong one. Plain and simple, high flow and good sound are are a must. Most companies will tell you CFM ratings, but the sound is a trial-and-error kind of thing. In a John Lingenfelter (Mr. Smallblock) lab test, Borla is the highest flow, yet it is close to the most pricey. Just stay away fro m glasspacks and open pipes, these are the two worst options, due to too much and not enough backpressure. H.P. = Dyno's by HotRod Magazine show 11 for a Borla muffler. Cost = $20 to $300 Options = Stainless steel, 2 or 3 chambers, glasspacked, multi-outlet, lightweight "