Extractor Size

[hfcmad]

I'm looking to buy a set of extractors for my 5.7

I'm thinking of getting Tri Y's because I was told Tri Y's are better for low-mid range &
4 into 1's are for top end performance

Whats better 2.25" or 2.5" outlet
Is there a notable difference ??



Cheers

[Reaper]

Depends on how fast you want to spin your motor. If you have a cam/tune and regularly run at the top end of the rev range then go the larger dia. If you are just going for a mild tune/zorst upgrade or zorst only then go the smaller dia as gas velocity will be higher and you will get more of a scavenging effect (ie they will work better )

If it's a street car then I'd go tri-y 95% of the time.

Reaper

[hfcmad]

If it's a street car then I'd go tri-y 95% of the time.

I have a mafless tune & 2.5" exhaust & it's 100% street no track

[undar8ed1]

2.5 tri-y`s into twin 2.5 exhaust is more than enough for a standard gen 3 even with otr, maffless and cam upgrades, 4 into 1s are for big power and usaually have 3 inch outlets turbo, blown and bombed N/A V8`s benifit from 3" outlets.
I`m going through the exhaust route for my gen 3 I`ve got (sitting in my shed) pacemaker tri ys with 2.5" inch outlets 2.5" 200 cell cats and considering twin 2.5 inch or 2.5 inch into single 3" for the cat back this is gonig to replace the crappy exhaust set up on there now cosisting of HSV 2 1/4" headers and 2 1/4" cats into a twin 3" system that really lets the car down low (like steping on a bucket of water) people who put twin 3 inch exhausts on stock motors are dumbass`s.

[Vt_vic]

i went from 4-1 from pacemaker 1 5/8 to tri y and there wasnt much difference im gonna get pacie 1 3/4 4-1 asap

[Not_An_Abba_Fan]

Totally up to what you want and how you drive. As already said, 4-1's have a higher powerband than tri y's. 4-1's sound better in a lot of peoples opinions.

A lot of people also believe that the bigger the exhaust and the least restrictive it is, the better, but this is not the case on 99% of cars. Back pressure is another misconception. Back pressure in any form is bad, exhaust velocity is good. Tri y's can maintain velocity lower in the rev range and keep low end torque, where as 4-1's don't start working until the engine gets revving higher.

So to summarize, tri y's for street driven performance, 4-1's and a big exhaust for dyno results or lots of noise. Also, having the wrong exhaust behind the extractors can have a negative effect.

[hfcmad]

So to summarize, tri y's for street driven performance, 4-1's and a big exhaust for dyno results or lots of noise. Also, having the wrong exhaust behind the extractors can have a negative effect.

2.25" or 2.5" will there be much difference ??

[hfcmad]

Also, having the wrong exhaust behind the extractors can have a negative effect.

I have an Xforce 2.5" catback & the exhaust shop did such a shitty job I'm not going back for the extractors

How about this set up

HM 2.25" Tri Y's
2.5" 100 cpsi cats ( 4" Body )
Xforce 2.5" CatBack

[Not_An_Abba_Fan]

2 1/4" or 2 1/2" won't make that much difference, but I would go with 2 1/2" as that mates up with the rest of the exhaust.

As far as cats go, apart from 100 cpsi being illegal, they are over kill. 200 cpsi are fine, and the Magna Flow ones meet all the EPA emissions requirements.

[hfcmad]

Thanks for your help

[Not_An_Abba_Fan]

Never mind, I read the other thread.....

[Vt_vic]

ive got some pacemaker 1 5/8 tri y 2.5 collector i think that im gonna sell when i get some new ones in if anyone is interested??

[Reaper]

How much do you want for them?

Reaper

[Vt_vic]

400 or there abouts

[undar8ed1]

Thats cheap.

[danz_ss]

give steve a call from s&s racing in sunshine he fitted my full twin system on my vu ss b4 xmas and he done a awesome job he is a str8 up kinda guy wont bs u like alot of shops