Question on Headers and Cats..

[lmoengnr]

As Hama stated, the tri y, versus 4-1 argument doesn't really apply to large capacity engines, with their big flat, fat torque curves.

I'm talking pushrod, 2 valve engines..........

It does apply to high revving, multi valve, OHC(s) with way oversquare bore/stroke ratio engines that really need high revs to make decent power. Different intake/exhaust configurations can make large differences in torque delivery to these types of engines.

 

[Turtle2388]

I thought the same thing but after a good discussion with NAAF, he explained that the 6ltr has more than enough torque to cope with 4-1's if your goal is streetable low-mid range power. Tri-y's would sound crap compared to 4-1's and wouldn't yield as good driveability all round as 4-1's.

Well said.

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[RoaringSky]

Mate, I have a 2.5" mild steel cat back, 3" stainless high flow cats, and 1 3/4" mild steel 4 into 1 extractors. All Xforce.

When I just had the cat back alone, the noise was just a little more audible compare to stock and bit more rumble to it. No drone for sure, especially under 1500 rpm.

Now with all those mods and a VCM OTR, above 2000rpm, the in cabin noise is about 50% more than just with the cat back. However at or under 1500rpm the noise level is just a tiny bit louder if not the same, and definitely no drone.

I too use my car as a family car on the weekends and I am a big hater on cabin drones and I am currently very happy with the noise level vs. V8 rumble that I have:

- idling and cruising at 1500rpm, little bit engine noise and a gentle rumble but not loud at all and no drone for sure.
- down change a gear or two to get above 2000 rpm u get the noise up and the engine jumps into roaring angry mode.
- put the foot down and rev it out, mate, it is just an acoustic orgasm!

 

[Turtle2388]

If it's auto it will drone. Xforce sounds good but will drone with an auto.

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[Not_An_Abba_Fan]

The tri Y Vs 4-1 argument is moot on EFI. Older carby engines, yes, they made a difference, with EFI, the PCM controls timing and fuel delivery and will optimise the trims to suit what the extractors do. Even more so after a tune.

There was a performance shop over east that did back to back runs on the same car with different brand tri Y's and 4-1's, there was about 5kW in it between them all, but the biggest difference was torque delivery. But even then, there wasn't a lot in it, maybe 20NM between the best and the worst. This was on an LS1.

Personaly, I'd fit 4-1's over tri y's every day of the week on an EFI car. Sound better, go better, look better, and theres the pub too, "what extractors you run?" "1 7/8" 4-1's"...."cool"....

4-1's tend to reduce drone more too.

 

[PIR4TE]

I thought V8 SuperCars, NASCAR and Formula One cars were all EFI?
Seems like a huge market opportunity for 4-1s in racing and then, maybe suggest it to engineers at AMG too!

 

[DLFHUB666]

One of the reasons I went tri-ys over 4into1's is that they sit higher, my tri-y's atm are only 85-90mm off the ground! I would hate to see where 4into1's would sit *Scrape*

 

[Not_An_Abba_Fan]

NASCAR are carby.

Formula 1 pretty much all use the same header design, tuned length 4-1. Interestingly, the outlet of the collector is the same size as the primary pipe.

V8 Supercars use 4-1.

Without Googling too much, the 2012 AMG Roadster uses 4-1.

 

[PIR4TE]

OK NASCAR are carbs, use Tri-Ys, you are the professional here, but Google does say different statistically re use of Tri-Ys in other than drag racing and the whys.
On the DiFilippo site there is an interview between Darren and a bit of skepticism from Street Machine magazine. Seems there is nothing better than 4-1 for everyone?! Personally I balance that view with GM High Tech Performance Magazine, and the debate to date with Performance and LS1 Tech guys.
Both work fine apparently, was my 2¢ for the OP... there are other options to achieve his goal in a family wagon.

 

[anarklov3r]

I'm no expert, but from what i've found and learnt over the years is that:
Tri-Ys are better for low down
4-1's better for top end

BUT, the Tri-Ys beat the 4-1s in LOW DOWN by such an insignificant margin (1-1.5%) that its not worth giving up the extra top end power.

If you want more power, but not alot more noise, go for some HSV headers and cats. The cats are the same as regular holden ones, however the headers are a mild steel tri-y system, can be bought almost new on ebay for under $300 (for headers and cats!) from people who have taken them off their cars.

I put some from an e3 maloo onto my 07 WM caprice, straight bolt up, sounds nice and looks factory (because well, it is.. i guess..) Shouldn't cause issues with the fuzz or insurance either.

To put it into perspective, i have 195rwkw stock, bumped to 209 with HSV headers, cats and a 2.5" HM Perry S/S exhaust without a tune.

I then got a 219/224 cam (only a baby cam) OTR and tune and got 280rwkw.

I think id be up around 295-300 with some big honken (and expensive) 4-1 headers and cats but for a <$300 upgrade done in my drive way in like 2 hours, totally worth it!