OK, some of my club guys and I have been discussing this:

Right now, I have a stock L98. I already have the SLP 1.75" headers, and I'm looking at getting the Mufflex 3.5" with the Spintech muffler. Yes, I do have engine mods planned too, but let's keep this debate on simply adding the exhaust system to the stock L98.

The question is whether or not the 3.5" is too big. Now let's not start the backpressure debate. Some of the guys said that the 3.5" is too big to scavenge/pull intake charge on a stock L98. I suppose I'd agree with that, but my logic is that it's still a thousand times better than all the restriction of the stock system.

Here's how I see it. I'm not seeing any scavenging now. No one can tell me that the OEM exhaust is not restrictive, so I figure ANYHTHING less restrictive will help, even if it is a little big to scavenge.

...and down the road, when the engine buildup starts...

 

3.5" is big for a stock L98. I'm not going to say that it's too big ... I'm just saying that it is big and you don't need something that big. The restriction isn't the 3" diameter on a stock L98. It's the cat(s) and the muffler. IMHO, you're better off putting that $500+ into mods that will really make a difference in performance. I've run 11.6's @ 117mph through a single 3" exhaust.

Tim

 

Yeah, I see where you're comin' from.

I wasn't as much sold on the 3.5" as much as EVERYONE seems to love the mufflex/spintech set-up, performance wise, and sound wise. I don't think they sell a 3"...but now that I think about it, I could just get any 3" I pipe.....

Thanks for the reply....

 

I saw a performance increase going from a Hooker 3" to a Mufflex 4" (I plan on a head swap in a few months). I don't have an L98/B2L, but I don't see why that would make a big difference.

Tim: That's pretty good going through a single 3". But at 117MPH N/A there is power to be gained with a larger exhaust. I've seen you complain about the SLP headers having small collectors at just under 2.5" ID, which is one of the reasons why you swapped to Hooker's LT's. So if you complain about the collectors being small, and the larger 3" collector being better, why put a single 3" exhaust on a system with 2 3" collectors?

Have you at least considered it?

 

Marc,

You are absolutely correct with regard to my complaint of the SLP headers. The collectors were 2.2" ... which still supplies more volume than a 3" pipe (since there are two 2.2" pipes going into a single 3"). I had no right to complain Point taken. However, I didn't go with the Hooker LTs because of the SLP collector. I went with them because I had 1-5/8" headers and I needed to step up to a 1-3/4" header. The LTs offered more performance and room to grow than the SLP 1-3/4" headers. That's why I went with the long tubes.

In any case - I cannot say that I wouldn't see a gain by stepping up to a bigger exhaust. I'm just showing that you can definitely run fast with a 3" exhaust. Problem is - most people are using a 3" muffler that really limits them (IMHO). Most mufflers like the flowmaster and spintech have nice walls on the inside that impede flow and reduce the overall flow rating. That's why the fourthgen guys with their wide open Borlas run so well at the track with a 3" setup - because basically there is no muffler. I rectified this by using a straight through 3" muffler that according to dynomax comes "with a 1500 cfm rate. In a single system it can handle 682 hp". I also need an exhaust that will give me substantial velocity to work with my cam in helping to pull the new intake charge into the motor. A 3" gives me that. So, maybe I would run faster with a bigger exhaust. But, I've talked to others who have run high 11's to low 12's who have ran a wide open 3" exhaust and then converted to a 4" mufflex .... and they gained no more than a tenth. Keep in mind that this is a WIDE OPEN 3" with no cats as compared to a 4" with a spintech or flowmaster. Also, another thing to keep in mind is that the mufflex is a very heavy exhaust system.

Right now everything is working and working well on my setup so I am not messing with it. I have bigger fish to fry besides a bigger catback.

Tim

 

I've got your movie file saved on my computer from the LT install sticky. I could have sworn you had a Flowmaster 3" single in/out. Didn't know you went to a Bullet...

And I'll agree on the Mufflex being heavy. The original Mufflex system I bought was the Spintech dual out. It weighed a good 25lbs more than my Hooker system. However, when I changed over to the Flowmaster 4" single in/out it weighed less than my Hooker.

2.2" collector for the 1 5/8" primary SLPs? I always thought the 1 3/4" and 1 5/8" had the same collector. Mine measures out to 2.4" ID. Regardless I'll be modifying them for a larger Y-pipe when I do the heads.

Also I didn't realize that you don't plan on taking the car much further. You've already had impressive results, but you WILL eventually tire of the setup and want more. Everybody says they don't but eventually give in

 

I didn't install a bullet. I installed a Dynomax straight through ultraflo welded muffler. I have new sound clips posted as well as pics of the muffler.

Look at everything that I posted here...
https://www.thirdgen.org/techbb2/sho...hreadid=209782

Tim