ch@0s

I like the way the flowmaster sounded great but they were too loud on the highway where I spend most of my time. You have too hear it in person the Magnaflow are more throaty yet mellow.

BTW: I have Flowmasters and Y for sale.

RC000E

You gonna cut me a deal? Make some parallel lines on the pipe, chop in the middle of the lines, cut the Y in 3 pieces...easy to ship. I'll TIG it back together and use the sharpie lines as witness marks....bada bing.

ch@0s

I talked to my tuner about the popping.
He said its unburnt gas in the exhaust.
The car was running lean and I'm waiting for a new tune.
I turned up the FPR to make it a little rich.
He also suggested I get Copper gaskets for the headers.

RetiredSFC 97

I like it!!!

Damn, now I you got me thinking!

joesgulfstream

Cart before the horse ?

ch@0s

that's exactly what we were talking about in PM.

RC000E

Yeah, I just wanted to talk to him about it and see what kind of numbers we were talking. Inevitably though, I need to see what is on the car, and then proceed but that I was interested if the car was stockie.

dogfish246

Interesting! Thanks for the follow-up! Your new magnaflows sound GREAT! Any resonance? How about on the highway? Looks great too! I wonder if the tune will stop the popping; it will definately be interesting to find out!
Oh... What would copper gaskets do compared to your current gaskets?

mnstrlt1

Just to give you the heads up, the 92' and newer c4's didn't use the "old school" y-pipe configuration. You'll essentially end up using "only" the mufflers and tips. in which case most guys end up getting generic (center in/out) 40 series mufflers and welding them into the existing place of the stock mufflers. This is what was on my vette when I purchased it. they DO sound good, much louder than the existing magnaflows that I have now.

to the OP, cool thread!

the significant other looks about as enthusiastic to help you out as my
"old lady", when I get her involved in anything car related...

RC000E

Yeah, I'd discussed with him cutting off the mufflers only. Seems like everyone is predicting our conversation here...lol.

I truly intend on doing a full aluminum exhaust v-band'd. I've done it on other cars, and it acts as a tremendous weight reducer, and is a ton more durable than you'd think. It's not very common to most people, but I've built several and the first one I did has over 10k on it. The catch is, your TIG welds have to be SOLID...no craters, full penetration and full backpurge...but I got that handled. Ever hold an entire catback with your index finger?

Need to cut some weight off these things...lol....get'er down to 3k.

ch@0s

I never answered the drone question. The exhaust sounds great,, my son and I went on a 150 mile trip and there was so little resonance I didn't even think about it. On the way back it hit me .. no more resonance!!

mcm95403

That's great to know! Having worked at Flowmaster for 2.5 years, I'm prejudiced towards them, but you had universal mufflers, not the ones designed for the car so I'm not surprised you had noise issues.

On the other hand, I like the look of the Magnaflows and their tips much better than the "correct" Flowmasters.

Curious what rear gears you're running......and which converter you bought.

dogfish246

Thats awesome! Im glad it worked out for ya! No resonance and a great sounding exhaust is almost every C4 owners dream!

Phantom_Vette1

Hey looks great!
So these aren't as long as "long tubes" right?
Just wondering if you have lost any low down torque! seeing as 4 into 1's are usually for top end power! but yours look shorter?
I would really like some tri y's headers! 4 2 1 configuration! but don't know if they are available anymore?
i want torque, not interested in top end! but these hedmans look good!

ch@0s

No torque loss .. did a dyno run recently, I put down 312 to the wheels that's almost 400 foot pounds at the crank and the run was aborted because of a downshift ..
They are long tubes and IMO the best bang for buck mod for a L98.

Phantom_Vette1

Thanks! Great effort on the dyno!
Well if no torque loss i am very interested!
you still have y pipe into cat then y out correct?

I wonder if going dual's would loose back pressure?
I've been told that long tube 4 into 1's with bullet cats, balance pipe and mufflers would loose torque!
And that i need 4 2 1 pipes to keep the backpressure for the torque! I don't know, so many different stories

Anyway thanks for the reply!

ch@0s

Still running 2.59 i have a 3.07 i bought from fc-soldier so we will know soon.. keep you posted... I also still have the stock converter it is going to be replaced as well.

ch@0s

I don't know that that is true.. compared to stock? and how much of a diff we talking 8-10 foot pounds *shrug*

mcm95403

It's NOT true, it's an oversimplification that has been around forever. An engine does not "need backpressure to make torque", it needs a correctly sized exhuast system that is matched to the power output of the engine. You wouldn't put an 1150 cfm Holley Dominator on a stock 305, right? You also wouldn't set it up with a dual 4.5" exhuast system either. Both of those are too big/mismatched. The stock system on the TPI cars (which were factory rated around 240hp and didn't rev past 5500) was a non-mandrel bent 2 1/4" system merged into a single 3" converter then back out to 2 1/4". This can efficiently support about 300-325 hp depending on the RPM range of the engine. The big limit there is the 3" converter. You can go to dual 2 1/2" mandrel bent pipes and that will support upwards of 425 hp, but that single 3" converter will be your restriction.

That's not to say that you won't make more than 325 hp with that 3" cat in place, only that you would make more power (if the engine is capable of it) with a larger diameter converter there. Of course, you can't get a larger diameter converter, which is why the LTx cars went to true duals.

To pre-empt the next question, a dual 3" system would be good for an engine making a peak of 600-650 hp, but would NOT work well on a stock type engine making maybe 250 - that's where that old myth comes from. Too big is always too big and that goes for carbs/efi, cams, heads, headers and exhuast systems.

This subject could certainly be a thread of it's own, so I won't hijack it any further.

ch@0s

Thanks for the info .. I always thought that was a myth but have never hear otherwise. I can tell you I have built a lot of cars with duals and turn downs.
I figured it was bull.