Another Exhaust Thread

[DrewPeacock76]

All good. Found em

 

[RevNev]

" exhausts make more power because they are less restrictive overall at WOT.

Yes, a 3" will make more power than a 2.5" if the engine can use it. I wouldn't consider a 3" on an LS3 unless the engine was making around 380kw on the dyno, then a 3" is worth a try.

I'm also not a fan of stainless headers, or exhausts, unless they are 321
I find that I don't like the "tone" that cheap 304 stainless exhaust makes

I don't like the sound of thin walled 304 or 409, mild steel I think always sounds best! You don't need to back purge mild steel with Argo when TIG welding it either and particularly with unleaded fuel, mild steel doesn't corrode and burn out prematurely, painted with VHT, a mild steel exhaust looks good and lasts for years.

 

[panhead]

The loss of output from a 3 inch on a minor modded car over a 2.5 inch is minimal at best and for a street driven car it's something that you'll never legally get to experience or ever tell from seat of the pants driving.

A 3 inch over a 2.5 inch for a street car comes down to what you prefer sound wise and of course there are many other factors that play a part as well like cats, mufflers, stainless vs mild steel, header choice and and exhaust design.

I like the sound of a 3 inch and can easily live with the loss of power that I don't even notice.




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[Skylarking]

Guess 3” or 2” on a road car is like a saxophone or trumpet… same lungs, different sound

 

[RevNev]

The loss of output from a 3 inch on a minor modded car over a 2.5 inch is minimal at best and for a street driven car it's something that you'll never legally get to experience or ever tell from seat of the pants driving.

A 3 inch over a 2.5 inch for a street car comes down to what you prefer sound wise and of course there are many other factors that play a part as well like cats, mufflers, stainless vs mild steel, header choice and and exhaust design.

I like the sound of a 3 inch and can easily live with the loss of power that I don't even notice.

Years of trying to make circuit race cars win races with a birds eye view of exhaust effects on performance and lap times that don't lie, it's hard to recommend a road car exhaust that you know from experience performance wise isn't optimised. A few years ago, we took an 1 7/8" 4 into 1 header and 3" exhaust off a VE 6 litre Improved Production race car and fitted an 1 3/4" Tri-y and 2.5" exhaust. The car was 3 tenths faster around Mallala and picked up 8 kmph of terminal speed at the end of the back straight. Mallala is a tight track with a few low RPM corner exits and the smaller exhaust made the car rev quicker off the corners with better cylinder scavenging that can't be seen on a dyno. Someone reported something similar over the 1/4 mile in WA with a modified VF1 SS going back from 1 7/8" to 1 3/4" headers and the car was a 10th faster over the quarter with the smaller header, and that makes sense!

You're right on a road car I agree, it's 2 tenths of nothing if an exhaust isn't optimised, most aren't with cats anyway. 2.5" exhausts hang down enough under a VE/VF and 3" visually and ground clearance wise makes it worse particularly in the absence of a performance gain.

 

[Not_An_Abba_Fan]

Back in 1988 when Ravenswood Raceway was the place to race, I had an XW 351C and for some fun I went to see how quick it was. Can't remember the exact times, but it was low 13s. Tuned 4-1's into a twin 2" system running the old Lukey 0099's. Then I dropped the exhaust off the headers and tied them up out of the way and it was something like 2/10's quicker and about 15mph faster.

 

[PeteSS]

The loss of output from a 3 inch on a minor modded car over a 2.5 inch is minimal at best and for a street driven car it's something that you'll never legally get to experience or ever tell from seat of the pants driving.

A 3 inch over a 2.5 inch for a street car comes down to what you prefer sound wise and of course there are many other factors that play a part as well like cats, mufflers, stainless vs mild steel, header choice and and exhaust design.

I like the sound of a 3 inch and can easily live with the loss of power that I don't even notice.




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Correct.

When we bought my Redline it had a full 3 inch Pacemaker system. Was way too loud, so I changed it out to 2.5 inch Hurricane, with single outlet mufflers . Also changed out the 100cel cats to 200cel. It still has the Pacemaker 1 7/8 headers it came with.

The tuner reckons it made no difference to power. I certainly can't feel a difference

 

[PeteSS]

There used to be killer exhaust shop in Sydney called Lambros in Darlinghurst, they did a set of custom headers for us years ago with show quality TIG welding, awesome fabrication work!

Still around. I think they call themselves Hi Tech Mufflers now.

 

[RevNev]

Correct.

When we bought my Redline it had a full 3 inch Pacemaker system. Was way too loud, so I changed it out to 2.5 inch Hurricane, with single outlet mufflers . Also changed out the 100cel cats to 200cel. It still has the Pacemaker 1 7/8 headers it came with.

The tuner reckons it made no difference to power. I certainly can't feel a difference

The smaller exhaust will make a difference in lap times on a race track, it'll be a couple of tenths faster! People just don't believe how smaller headers and exhaust can improve lap times until they see it. V8 Supercars primarily run 1 7/8" headers and twin 3" exhausts to make 630hp in a narrow RPM band. When someone thinks a stock or cammed LS3 road car needs the same sizing, emphasises what they don't know about exhausts. If catless was legal, 1 3/4" tri-y's and twin 2.5" exhaust works best across the RPM band of an LS3 road car. Cats mess this up and often, the better cats on a 3" exhaust is responsible for the power increase seen on a dyno, not the pipe sizing.

Someone in WA posted detailed drag racing results with header sizing on a cammed automatic VF SS with a hi-stall converter over the 1/4 mile and discovered that an 1 3/4" header was the fastest and optimum size and made a lot sense!

 

[panhead]

The smaller exhaust will make a difference in lap times on a race track, it'll be a couple of tenths faster! People just don't believe how smaller headers and exhaust can improve lap times until they see it. V8 Supercars primarily run 1 7/8" headers and twin 3" exhausts to make 630hp in a narrow RPM band. When someone thinks a stock or cammed LS3 road car needs the same sizing, emphasises what they don't know about exhausts. If catless was legal, 1 3/4" tri-y's and twin 2.5" exhaust works best across the RPM band of an LS3 road car. Cats mess this up and often, the better cats on a 3" exhaust is responsible for the power increase seen on a dyno, not the pipe sizing.

Someone in WA posted detailed drag racing results with header sizing on a cammed automatic VF SS with a hi-stall converter over the 1/4 mile and discovered that an 1 3/4" header was the fastest and optimum size and made a lot sense!

I can definitely understand the principle behind what you say, I just don't believe it has any relevance to a street driven car and therefore I go for what sounds good to my ears which I realise may not sound good to the next person and especially one of my neighbours from years back.

It's like big brakes on a street car, they look great but their real advantage over the usual smaller stock braking systems fitted to most cars is being able to make multiple hard stops before starting to fade.

Where a smaller stock setup will fade after one emergency stop but if you need more than that on a street driven car then you probably should change your driving style.







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