Exhaust upgrade for turbo'd LLT

[Can't_C_Me]

So I'm about to finally look into upgrading my piping to 2.5" or 3" from the stock 2.25" I have now. I'm running the MRT V1 exhaust out the back. So I read up on the pros and cons of both pipe sizes, but non were related to turbo equipped Camaro's or FI period. So I'm asking the community on their thoughts before I pull the trigger. I am leaning towards 3" because of the high volume of exhaust that exits the car under boost. But then you have Derrick running almost 700rwhp with 2.5" lol. I get some boost leak and Derrick in a conversation with him said the same. So maybe 3" could be the best bet, SOOOO what does everyone have to say? I'm also debating on going without any mufflers.

[sneakypete]

The turbos do a great job at muffling the sound as is.

[Lil' Nasty]

I would normally say 2.5 but in your case cisco, I would test out the 3"...With the V1's. But Im biased about the mufflers

[The_Blur]

Even the boosted V8s don't need 3 inches. I'd go with 2.5" to avoid the buzzing sounds usually associated with overly large exhausts on smaller displacement engines. Power differences will be negligible, especially considering forced induction. You'll be fast either way.

[GretchenGotGrowl]

The drop off in boost is fairly small (1-2 psi at 20+ psi) so I would stick with 2.5". I would worry you may not have enough back pressure if you go too big, but that's just a guess on my part having not tried it.

[menendez1293]

My vote goes to the 2.5" with exhaust. If you go 3" I would be concerned about the fact that you might not only loose back pressure but also the flow velocity in which the gasses travel through the pipes. My reason for keeping the V1s is because a V6 without mufflers generally doesn't sound very good in my opinion.

[Can't_C_Me]

Thx for the input so far everyone. When I get above 5k RPM the car is moving mighty fast, but sounds terrible lol. Also seems at times like the gases are straining to exit. So far 2.5" seems to be winning. Will start to look for a set of LS3 take off pipes. It's so hard to find a C5 around here in Atlanta thats been junked. Will see who in the club may have some. I may also venture into the 3" after 2 -3 months of testing what works best.

[GretchenGotGrowl]

Have you thought about cut outs a couple of feet behind the turbos?

[Can't_C_Me]

Originally Posted by GretchenGotGrowl

Have you thought about cut outs a couple of feet behind the turbos?

That aint a bad idea Derrick, never thought of that. Going to see if I can find a set on the for sale threads.

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[sycraft]

I went for the 3". but 2.5 should be great. I did say add mufflers to the 3" for the back pressure needed. 2.5" with a dump may be cool too.

[Can't_C_Me]

Ok another curve ball, should I go with straight pipe or x pipe. Tomorrow I'm getting estimates to see if it's cheaper to get custom or buy already bent pipes like the BBK 2.5 with the x pipe bent into it. Or LS3 take off.

[JDP Sales]

With a turbo setup, take everything you know about back pressure and scavenging and throw it out the window. Larger piping will allow more room for exhaust gasses to flow before before creating any back pressure and this will allow for the quickest spool. You can also consider no mufflers as the turbos will do a good job muffling as is.

Also, No X pipe. Go strait pipe.

Best regards,

Tyler
888-308-6007

[Can't_C_Me]

$250 for custom 3" straight pipes to the mufflers. Then later will add cutouts.

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[hunterv6]

Add cut outs first would be my opinion. I agree with jdp but with cutout after your turbos no need to up size the exhaust just open them up when needed.

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