I'm not an expert on this, but I can tell you what I have seen. With the Borla there was less back pressure than the straightpipes (less boost). I'm pretty sure this had to do with the bends (not mandrel).

These measurements are from the outside of the pipes(approx).

stock

in 20.5 cm
out 20.5 cm
bends 19 cm
thickness is 2mm

Borla

in 18.5 cm
out 18.5 cm
bends 18.5 cm
thickness 1mm

I would be surprised if the Borla gave more HP than the stock system. It sounds a little bit better and doesn't have that annoying 90 mph vibration.

 

I gained approx. 1.5 mpg over stock in mixed traffic driving with the Borla. It must have some advantage over stock. 240 miles per tank to 275 with the same amount of fuel added.

 

This may have been posted before, but i could not find information about the Magnaflow having a built in X-pipe. Anyone know abour this? I ordered the 12468 for 90 bucks. I hope the performance is worth the expense and all...

Thank's

 

Everyone her has 2 cents worth of advice and here is my 2 cents worth of experience. Pure stock my 2000 Lightning ran the Ford posted numbers like clock work 14.5 sec. quarter mile. I made 3 mods the next week and went back to Silver Dollar Raceway and ran 13.4 consistantly at 104 MPH. I could not floor it coming off the line due to the track on the stock tires. Anyway, 1.1 sec decrease in e.t. was from PSP chip and filter plus 2 FLowMaster Delta 50s. Convince me these are restrictive mufflers and burn up tail pipes....... have over 30K miles on the Flow Masters and with my econmy program in my chip I get 19.9 mpg on trips to Ohio or Florida.... lock the cruise at 77mph. No dobbt I will try something else later, but some people here are giving FlowMasters a bad rap with only hear say and no data. I am not a spring chicken and because someone said does not mean it is so...... show me the data. See I gave you data on my gas mileage but it is skewed. I now have the Nitto 315 55 18s dropping my gear ratio to about a 3:23. That means 2000 rpm is about 77 mph. Still great gas mileage.

Dan you took a hit now let's see what happens with my post.

 

Masterloggie,

I brought this topic up to see what the tuners thought about it. I'm thinking that, since FM is a supporting brand name here, I may be wasting my time if I'm expecting a straight answer. The longer the thread goes on the more difficult it will be for one of them to figure out what it is I'm asking anyway.I'm not picking on FM specifically, but chambered mufflers in general. And for the L "only". I don't think I can proove anything to you but since you seem to be challenging me to try, I'll take a swing.

I mentioned in an earlier post some of the virtues of the Flowmasters. Torque building is one of them. This will help at the drag strip. How much of your improvement at the track was due to them over the chip and filter combo, the weather conditions, and the track conditions I don't care to "guess".

Your fuel economy, I'll wager, has more to do with the economy program on your chip and the 3:23 gear ratio than the flowmasters. It would definately be better with a freer flowing exhaust. (Dynomax, Magnaflow, Borla, etc.....)

As long as you don't dog your truck with the flowmasters on, (Extended periods of high speed driving) you probably won't have any problems with them. If you do ride it hard, I think you're asking for trouble.

You want proof of restriction..... I've posted this once before, But here we go again. Dyno chart for 2001 L w/ Diablosport chip claiming 385 rwhp, drop in K&N filter, and dual FM delta series 40s: At 335 rwhp, I dynoed 20-30 hp less than most stock Ls but made 450 lbs. ft. of torque at a little over 3600 rpm. That's more torque than some trucks are making w/ aftermaket pulleys. When I had the mufflers replaced, the shop that installed them gave me a credit line on labor equal to the amount paid for the Flowmaster setup in the first place. They did this because the FMs were ashey and brittle from the heat that had been generated. I had not taken the vehicle over 90 mph on more than 4-5 occasions, and never for more than a hand full of seconds.

 

The shop that installed my muffler was a dealer for Dynomax,Flow Master and Magnaflow.The owner is a one man operation.I questioned him about the 3 brands.He recommended the Magnaflow in particular due to straight through design with a built in crossover.He was also very critical of the Flow Masters.He had cut-a- ways of the two brands of mufflers from different vehicles he had taken them off of,as well as new cut-a-ways.After seeing these examples I would find it hard to disagree with him that the Flow Masters are not restrictive.He also showed that the Flow Master trapped water in the chamber causing a frying effect that made the muffler brittle.I asked why he sold that brand if he knew it to be a problem design.He said because many people insist on them no matter what he recommended.As he pointed out that he was there to make a living,not change the world.

I don't profess to know anything at all about mufflers or exhaust,but I was offered free advice from a man that has intalled exhaust systems everyday for 27 years.What little experience that he shared with me,I felt confident in.I only offer this as another mans opinion that you may want to consider in your attemt to form a conclusion.

 

Odin's Wrath

I think you answered part of your theory when you answered my post. So.... what was the temp, barometic pressure and relative humidity on the day you tested the FM versus any other muffler.

Keep the playing field level as you did with the mods. I do not doubt yor reasoning in a non-chambered muffler will help this truck because of the supercharger and now with pullies even more air to expell. I do worry about the amount of HP gain you said without providing the environment specifications for each run.
Think about it.... if your theory was true JDM could only say the headers he is selling are only worth 10HP if we use your 30HP gian on just a muffler.

I plan on putting a maganaflow on with the headers. In a heart beat if I believed the headers were only worht 10HP I would not waste my money. Just my 2 cents and no tuner has even touched your questions and many others have given there comments.

Ron

 

Masterloggie,
I learned the hard way that running dual pipes to the back of the truck is NOT a good idea. Heck it did not even have a good sound!! We are gunna install the 12468 real soon anticipating great results.

Thank you,

 

Masterloggie,

Having read your reply thru 4 times now, the only reply I can come up with is.......WTF? The only thing I'm sure of, is that I didn't convince you of anything. As i mentioned before, I wasn't expecting to. I guess we'll just have to agree to disagree.

Roger

 

Analytical data with a standard reference point is good way to start and not this day I did this and this day I did that. Each day has a different humidity, barometric pressure and temperature. I do not argue the fact that freeflow mufflers will give more HP. Only question is how much and at what rpm?

xjmd44
"running dual pipes to the back of the truck" Where did you dream this up? I never said that. My exhaust exit in the stock location


I plan on getting the Maganaflows and headers. This is over the top now and I will bow out.