Another one. Exhausted

I must say I love an exhaust question. Always so many things to work out.
Just to break it up I found this a semi scientific test on headers.
Yes its from USA but if you can watch until around the 4 min mark it gets interesting.
There is also other episodes on exhausts including x-pipe vs h-pipe this was interesting as some are after a deeper sound.

 

Advance headers in SA do a 4 to 1 tuned lengthy and a 4 to 2 to 1 try y, unsure if it will clear oil cooler. I used them on my VS 5L in 98 so been around for ages

 

I’m a subscriber to Motor Trend, watch these buffoons prat on weekly. Suffice it to say an engine tune doesn’t adapt to changes in volumetric flow through optimisation by itself, was fairly crap initially, ie. motor detuned.
Consider all the ooh wow, old-school aftermarket unicorn brand-listing special treatment, and the tune gets... 85 hp/litre. For perspective that's a poofteenth better than a stock LS3 tune with log headers, original airbox, legal emissions tune with twin inline cats, etc.
I suspect custom 400 ci race block with those mods, reasonable tuned output should be close to 100 hp/litre.
Point is that measuring CFM / HP at WOT without VE tuning will produce same shit result with same shit tune.
All the video does show is how the tune of the 'hot' old small block popular 30 or 40 years ago, was not optimised for the exhaust (or vice versa shows those straight 4-1 headers were crap in first place).

 

A race engine is not a street engine. Quoting performance results in race applications can't compare to how a header performs on a street car. If you want 4-2-1's you will have to get them custom made to suit the rpm range you want to keep the engine in. That's how they work, yes, you will probably have better throttle response across a broader rpm range with off the shelf tri Y's but I still say the difference between them and 4-1's is negligible. True performance is matching primary pipe to rpm, cam and compression. And having no exhaust after the headers. Once you bolt on the legal requirements (cats and exhaust) anything you gain in "tuning" tri Y's is well and truly lost.

 

Oh, and in my opinion, Advance headers are rubbish. Made to fit, not to perform. They are cheap for a reason.

 

I had a look at the AH website after seeing the post and it looks like the secondary pipe is press bent?

I am still liking the idea of the Tri-Y on a Daily Driver where more usable low down torque is going to be there at the sacrifice of a bit of high end HP.

I'd like to have a look at these internally though and see how much overlap there is on the slip joints, although that may work and as an anti reversion lip too?!!?

I know on my 550hp 383 Holden the 1-3/4" Primaries Tri-Y's were good when I fitted a 3" collector and I even had a set made with 1-3/4" primary to 2-1/4 secondaries and 3-1/2 collector to suit the COME alloy 427 at the time.

In comparison to the 10,500rpm Tri-Y headers on my race car, the primaries look at little longer and the secondaries are much longer. That must be for the lower tuned RPM?

The Pacemakers look good.

 

I don't usually post links, but I did find this write up particularly interesting.

http://garage.grumpysperformance.com/index.php?threads/calculating-header-design.185/

 

Yes cheaper but still good basic design and excellent when fitted with a tuned secondary, comes with HFCs for less than a grand. So not really you get what you pay for, these are great value on a budget, $600 less than PH5387. I think Pacemaker's second brand like Wildcats is to Genie.

Many of the technical answers to the ideal spec for base LS3 are in detail in this post.
Many of the critical dimensions of the tri-y spec for base LS3 are discussed and pictured in this thread. It's worth reading (coz gist gets repeated every couple of days in new threads of same substance ad infinitum), hots up around Post 33.
If you make it to the end of thread, yes I'm still looking into it

 

Thanks Monstar, you know I like a little bit of R&D.

 

Cuda unless you’re going to race me on the street you’ll never know if you’re the length of a bee’s dick quicker to the next set of traffic lights or not.

The tech involved in setting up the perfect exhaust is tricky, well documented and argued on the net but doesn’t really relate to street driving and even more so in today’s environment where the penalties for using your poofteenth extra low down available power are severe.

I’ve run both and haven’t been able to really feel a seat of the pants different between the tri-y and 4-1 but I do notice the sound and I’m a person who enjoys the mechanical symphony of an engine so a set of 4-1’s with high flow cats is my preferred choice.

If you don’t isolate just the exhaust and add to the equation the skill of your tuner, choice of rubber, trans, suspension, driving skills it all starts to become muddy as to which is the quicker option.

If you’re not going to be dragging your guts along the ground which I doubt you’d do to your MSE then clearance shouldn’t be a factor.

I like to percolate along listening to what I believe is a nice sounding exhaust and when it comes to sound I understand others may think differently, I don’t like driving full throttle on the street where I risk losing my car.

It’s 4-1’s for my money.

Arm yourself with what you want to achieve sound wise and go to your preferred shop and see if they can put it into reality for you and don’t get caught up with bench racing is the approach I’d take, after all it's just a street car not a racer and its looks alone already has you on a winner.




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SO to summarise, the 4-1 are not actually much use in racing cross-plane NA V8s, least not competitive in NASCAR, V8 Supercar, LS drag racing, Moto GP... even though their sole purpose is that they are designed for crazy high RPM peak HP.
There is no argument in favour of basic 4-1 being more effective within normal driving RPM, not as versatile or flexible for the street or highway.
BUT... there's blub blub blub old school which, like those who dig a badly tuned cam at idle, fits a certain sound profile of the older muscle cars, before EFI.
Thing is you can tune any car with a flat torque curve to come on strong up high, not vice versa. To my mind driving around blub blub blub like a 50's rocker with the cross sectional equivalent of a firehose strapped to a garden tap coz noise seems retarded and ridiculously wasteful. Yet that seems to be where the profit is in the aftermarket, so for the mass majority the exorbitant price for eight straight pipes gathered together in two bundles each side of the motor before the cats fits the bill as one-size-fits-all performance solution.
Opportunity sold out for love of blub

 

Ground clearance can be a bit of an issue with Pacemaker 4 into 1's. mines lowered 1 1/2 inches, and they scrape on even the mildest speed hump.

They also don't have the best of clearance when it comes to fit either

 

Totally different applications. Competition engines are not the mass produced LS shit boxes found Commodores. Competition engines are built to work in a specific RPM range. Competition Tri Y's are tuned to work in a specific RPM range. The Tri Y's bolted to a NASCAR/Moto GP bike or a V8 Supercar are far removed from your off the shelf generic Tri Y that is built to fit the engine bay. Bolt a set of Try Y Pacemakers to a NASCAR and see how badly they perform. Also, bolt a set of NASCAR 4-2-1's to a Commodore and see the bugger all difference in performance between them and any other bolt on header.

Yes, we all know the benefits of a "proper tuned set of Tri Y's" but it makes no difference to a street car. You can't tune them to suit street applications. The loads and RPM changes that a street car is subject to makes tuning Tri Y's impossible. All you can hope to do is move your 20-30 usable NM of torque up and down a few hundred RPM. As Panhead says, will that allow you to make the next set of lights ahead of the numpty beside you? Will the next set of lights see him grab traction because you have parked on a bit of spilled oil? Tuning is about consistency. A racecar is tuned in every aspect of it's build to pull consistent lap times. A street car is tuned to impress your mates at the pub. (Or on a forum)

 

Seat of the Pants Dyno - 100-160 no blub just my bum on your lips (KMA).

Dyno Log - went straight to the pool room.

Shout Sheet

Sound - idle and zero load blip, full load WOT mid to top blast.

Clearance - 4" HFCs do the Lipton (teabag) sometimes.

Lipton Cats

Bottom End Torque - Rips up asphalt vs Bogs Down from idle.

 

GenIV GM V8 is a high performance engine, and doesn't need to stay a shitbox if you fit a set of decent pipes to pump it. Rather than turn it into a muse to reminisce about misspent youth.

Yeah, so is the GenIV.

Of course, but that range is far wider than with a peaky 4-1.

You clearly didn't see the analysis of R07.2 race headers and Pfadt 4-2-1 above. There is bugger all difference.

Well you should watch the video I posted of the world's fastest NA GenIV in a Zeta body, because it has the Pfadt NASCAR spec, puts paid to the nonsense.

To answer briefly I believe you are mistaken. Versus straight pipes gathered in a cone, 4-2-1 capitalises on several orders of the engine's peak harmonic. Established header and exhaust devices which optimise exhaust scavenging over four defined levels. Conceptually the approach is more like join the dots vs shoot for Uranus or bust.

Yeah true, all about the bragging rights when you have a winning combo in every sense, choice is there, whatever floats your boat... blub blub blub

 

You guys have all seen my video featuring DPE 4-1s and high flow cats. The sound is amazing. Even though I rate the quality of the sound system in my MSE as pretty good I never use it because I just want to lower my windows and listen to my exhaust every time. Given my setup fits as standard and sounds great it has to be high on the list as an option Cuda.

 

I've only ever had Pacemaker Tri-y's so I can't comment on their 4 into 1's.

This is a front and rear view of a Hurricane system with 4 into 1's, 200 cell cats and a 2.5 inch catback.

The car is moderately lowered 1.5 inches and I never had any clearance problems with it.

The cats were the lowest point and only by just a little bit.



View from the front



View from the rear





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Mine seems to hit at the flange at the back of the headers. Mainly the right one.

100kg sitting in the drivers seat doesn't help Not the best photo, though this is my set up

 

Is that a 3 inch system?



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