Exhaust Experts

[DanWA]

Chasing some advice from people in the know

I need exact part numbers for cats/mufflers/xpipe preferably Magnaflow or similar that i can get from Summit or similar priced

Engineering/Rego needs to be kept in mind as the car will need to pass emissions etc here in W.A and be under the legal W.A DB limit (96db?)

The custom headers have 3" collectors so twin 3" all the way is the plan

The engineer has been useless for help, so i am open to change on that front to!

[Tocchi]

cats - http://www.jegs.com/webapp/wcs/stores/servlet/KeywordSearchCmd?Ne=1%2b2%2b3%2b13%2b1147708%2b114 7708&Ntt=magnaflow&langId=-1&Ntk=all&storeId=10001&catalogId=10002&N=4294965540&Nty=0

mufflers - http://www.jegs.com/webapp/wcs/stores/servlet/KeywordSearchCmd?Ne=1%2b2%2b3%2b13%2b1147708%2b114 7708&Ntt=magnaflow&langId=-1&Ntk=all&storeId=10001&catalogId=10002&N=4294965590&Nty=0

part numbers are common throughout the online stores, so what they are on Jegs/summit etc is the same for every american online store

[DanWA]

Cool Cheers

My other major question is, is there actually a purpose for having twin 3"? Would a single not be enough? Got asked the question and couldn't really answer why. My custom extractors have 3" collectors so i thought why not

Its a comp cams cam 238/240 with 605 lift, cnc ported performance wholesale heads, yt roller rockers, aftermarket springs/pushrods.

[RELEASE]

if this is the same engine you bought from tony, then a single 3" will be too restrictive.

[DanWA]

Yeah its Rob Corica's engine (Tony's mate)

So would twin 3" be too much?

Even the engine builder (Tim Slako - West Racing) hasn't been able to definitively tell me what i need

[RELEASE]

twin 3" wont be too much with that cam and from what i remember rather worked aftermarket heads.

if youre worried about it being too big or losing too much low down torque then get cats that are 3" in and 2.5" out and run a dual 2.5"

[AGIT8D]

Cool Cheers

My other major question is, is there actually a purpose for having twin 3"? Would a single not be enough? Got asked the question and couldn't really answer why. My custom extractors have 3" collectors so i thought why not

Its a comp cams cam 238/240 with 605 lift, cnc ported performance wholesale heads, yt roller rockers, aftermarket springs/pushrods.

I would be looking at a single 3.5". Slightly less flow capacity but superior flow characteristics.. Should provide you with ample back pressure.

I believe twin 3" is too big for my engine, personally, and would go as far as saying the primaries are probably too big as well. When it's N/A, it doesn't need unrestricted flow, as you'd know.

You can reduce your noise by getting offset mufflers as well, so have a look at those.

[DanWA]

There is absolutely no way i would get 3.5" over the diff, i think 3" is going to be super tough enough already but cheers for the muffler suggestion Dan :)

I do plan on some FI down the track so might just stick with the twin 3" after all the above comments.

[mattyj]

i assume this is an exhaust for an ls1? give john a call at SQP. What he doesn't know about these motors isn't worth knowing.

[sprint347]

Twin 3" is huge.

From the little details given I'd say twin 2.5" should be enough. What size collectors are you running?

No point having a massive exhaust if it'll be restricted at the cat.

[DanWA]

3" collectors

[AGIT8D]

If forced induction is an option later then twin 3" will suffice. Take a look at Balistic low profile cats for maximum clearance and good flow properties. Then just scan through Jegs until you find the right magnaflow mufflers. I think they do make low profile mufflers as well, which would be worthwhile where clearance is an issue.

Make sure everything is stainless steel!

[DanWA]

Yeah definately making sure everything is stainless

Still tossing up where to take the car for the rest of the exhaust to

[AGIT8D]

I'm not sure who you've considered yet or what your time frame is but I would be talking to Josh otherwise Norm from Butler Built.

[DanWA]

Josh told me he wasn't doing exhaust back in Jan when i started sorting the fuel system out with him

The Extractors guy has offered to do it, but i had to do the cat/muffler research as hes not an engineer, sounds like time to chew Josh's ear off on the phone.

Norm farms alot of work out to this other bloke anyway

[Turbo2.6L]

Dom @ prestige for exhaust work.

[AGIT8D]

Josh told me he wasn't doing exhaust back in Jan when i started sorting the fuel system out with him

The Extractors guy has offered to do it, but i had to do the cat/muffler research as hes not an engineer, sounds like time to chew Josh's ear off on the phone.

Norm farms alot of work out to this other bloke anyway

Ahh okay well that bloke might be worth talking to. Regarding engineering for the exhaust it really is going to be tricky, different mufflers are packed with different gear and you'd probably have to crunch your head flow specs etc etc to do it accurately. A muffler on each pipe and a big one at the ass end should keep it relatively quiet, however, and of course you have the option to run a varex on the ass to really shut it up.

As for Josh doing exhausts, he still isn't, but might have the shop setup to do them soon. That doesn't change the fact he's booked up for work into the new year already lol.

[SSICK]

Nick @ Perth exhaust centre. Next door to XFT.....don't let that put you off tho. Excellent work.