TSP Duals vs Y Pipe/Catback for H/C/I 150 shot
 

So a few years ago I picked up a set of TSP 1 7/8's and their rumbler duals. They were intended for another car that they never went on.

So now I'm building this car and still have them sitting there.

That said, the duals will present a few issues for me. I'm going to be lowered on strano's/koni yellow's, so ground clearance with the duals will suffer compared to a y setup.

The other issue is drone, the duals can suck in an automatic (which this car is).

The other "possible" issue is smell. I do have the option to run cats with the y pipe setup to cut down on the odor if I so choose.

If not for the potential power loss, I'd absolutely go with the y pipe setup.

So, in regards to the power being given up between the two, what are we realistically talking here? Both H/C/I and with the 150 shot?

Maybe a 4" catback would be the best route. Maybe tsp with cutouts at the headers?

one guy just saw big gains from true duals out the back.

Everything is a sacrifice.

Check out Mavn's build thread on the gen 3 page. Picked up YUUUGEEE gains with the speed engineering duals over the stocker y pipe stuff

Cant compare dual to stockish y pipe setup. A good merge with a 4" outlet is gonna sound the same and perform better in my opinion. My heads/cam car is trapping 99MPH in the 1/8th and sounds damn good.

I didn't know it was gonna be a pro tree so I left at too low of an rpm. Otherwise I would have left around 6,000

I've learned that if you want to run a Y pipe and get the most out of it you will need a y pipe merge of 3inches into 4 inches and then a cutout.
A Flowmater merge is the best bang for the buck that I've read.
Here are some pics of what I mean.
https://cimg2.ibsrv.net/gimg/ls1tech...e9158926d1.jpg
https://cimg8.ibsrv.net/gimg/ls1tech...27544dd93a.jpg
https://cimg9.ibsrv.net/gimg/ls1tech...9d54b09404.jpg

Damn that looks pretty!!
What are all the parts you used and how did you get it one color?

I wonder what brand cut outs are those? I don't recognize them.

They look like any standard cutout available at Summit or Jegs, plain jane 3 bolt flange setup, just custom trimmed by installer to align properly with the Y-pipe.

My vote will always be running an x pipe over y ive just seen too many times where a y pipe holds a combo back and imo these things sound wayyyy better with a dumped x i have it set up like that and dont seem to have a droning issue

This is what I did. I'm H/C/I on a 150 shot.

https://ls1tech.com/forums/generatio...e-cutouts.html

Problem is a Y-pipe/cutout combo is much easier to live with vs. true duals. I had Kooks TDs for 6 years. It was miserable. Absolutely fucking miserable. Inside the car was 95db when the stall was slipping in traffic. 95! With second skin damplifier throughout for noise suppression. Cruising was 80-85. Idle was 77-78. Again, that's inside the car. Louder than my damn Harley. I had my brother stand outside with my SPL meter. I was over 130db WOT driving away.

With the TSP catback, it's more like 75 now inside. But it doesn't drone... the low frequency resonance isn't there. Cutout picks up about 15HP over the catback. Duals are worth a good 20HP at least. More torque in the midrange and more power after peak. I may eventually swap mufflers out on the duals (like Corsa 3" RSCs) and go back to them. But eh.

Whoa man that thing moves out. What's your suspension setup?

I would never bother with the extra weight of a dual setup. Good 3" Y into a 3.5 or 4" merge and then pick how you want to finish it. I've been running a catted ARH 3.5" Y for two years now with a single Coastfab muffler dumped before the axle. Lightest setup you will find and keeps the car at ~98dB at 50ft under WOT. If you don't like the noise in the cabin just run it all the way out the back.

https://scontent-ort2-1.xx.fbcdn.net...6f&oe=5CE3469A
https://scontent-ort2-1.xx.fbcdn.net...86&oe=5CE2C85C

That's definitely good information about the dB levels with Kook's True Dual Exhaust vs TSP Catback with Y pipe.

Downloaded Sound Meter dB app for my cellphone and checked the following. I'm sure that's not quite as accurate as a dB meter.

02 Z28 - stock
Idle in the car 45-50 dB
Idle outside the car, 20 inches from exhaust phone at exhaust level 45 degree angle - 55-58 dB
​​​​​​2,000 rpm cruise - 60-63 dB

99 Trans Am - 416, Kook's LT's headers, no cats, Hooker Blackheart 2.5 inch True Dual exhaust with x-pipe.
Idle in the car - 60-65 dB
Idle outside of the car, 20 inches away at exhaust level, 45 degree angle - 78-82 dB
2000 rpm to 2500 rpm- County road - 73-76 dB
2500 rpm - interstate - 70-73 dB

​​​​​​​The BlackHeart is close to my limit of being able to tolerate and daily drive or do a long trip. Can't imagine what the Kook's True Duals would be like.

This is what I have. I got it from Mufflex. I have the 1 cut out after the merge on 4" pipe. The flowmaster merge creates good flow. Gain was 5mph in the 1/8. 98.38mph. 6.9 et.

Those Flowmaster merges pay for themselves...

Gained 5mph over using WHAT?
What did that replace? 5mph gain is a LOT.
I'm curious what you had prior to Mufflex/Flowmaster merge.

I have a mild 6.0 with just a set of 1-3/4" BBK longtubes and their included Y.
Turbo spec'd cam that it had, showed zero gain between full closed exhaust (Jeg's) and 3" cutout open, mounted in the "I" pipe under passenger side rear seat.
Now with better cam, there's an obvious power difference between the two.
Just trying to figure if I should "start over" exhaust wise?