New Exhaust This Week!

[GTS4dood]

Im buying a new exhaust this week. Now im unsure of wheather to go for a 3" turbo back or 3 1/4" turbo back. most people seem to have the 3". Is there going to be much difference.The only other thing i have done to the car is the air filter. i have an intercooler on the way, and im running stock boost til xmas,then up to 12psi. not looking to do much more for a while after that besides more interior. Is there going to be enough performance difference between the two to worry?

[Evil]

i have a 3" turbo back and difference it made over the stock system was sensational... i don't know if the extra 1/2" will make a huge difference...

[GTS4dood]

well i have a mate with a 4" system on his 33,loud as hell! but he runs E-boost at about 11psi and has a cooler and a few other little mods. i always thought that he'd be losing compression and power with it that big? would that be the case.

[Driver]

4" with mild mods is overkill

[RellikZephyr]

with a turbo car its as simple as the bigger the better

RellikZephyr

[GTS4dood]

with a turbo car its as simple as the bigger the better

so then why does everyone talk about compression loss with bigger exhausts. or does that not apply to turbos?

[RellikZephyr]

the compression loss your talking about is Back Pressure it is needed an NA cars which is why NA dont go with the bigger the better thing

but with a turbo the turbo itself provides the necessary back pressure required for the engine (even with no exhaust the gases still hit the turbo and restrict the flow providing back pressure) understand? hard trying to find the words to explain

once the gases are through the turbo you want them out of there as soon as possible so the biger the better

RellikZephyr

Edited November 22, 2005 by RellikZephyr

[GTS4dood]

Yeah makes sense. Having second thoughts about the 3" might go for 4" but i dont want it to be stupidly loud. Cheers for the replys. B)

[MacGuyver]

Yeah I always thought that when it came to turbo cars that bigger is better also, but not the case with NA cars. I've got a 3" system and noticed a massive difference over the stock system also. Not sure if this applies to Skylines but my brother was recently told that having a 3" dump pipe on his 95 Supra was too big as the stock waste gate needs a little back pressure to control the boost properly.

"There's very little meat in these gym mats!"

[RellikZephyr]

not sure about that thing with the supra but could be right because the supra is a sequential setup

but ive got 3" dump pipes and full 3" straight thru exhaust on my GTR and its great even without a boost controller (will be installing on very soon) it has given me 1 bar off boost and obviously that has given me quite a large increase in power

RellikZephyr

[GTS4dood]

not sure about that thing with the supra    but could be right because the supra is a sequential setup

but ive got 3" dump pipes and full 3" straight thru exhaust on my GTR  and its great  even without a boost controller (will be installing on very soon) it has given me 1 bar off boost  and obviously that has given me quite a large increase in power

RellikZephyr

<{POST_SNAPBACK}>

Thats what i'll be getting. 3" straight through from turbo back. No boost controller til xmas i dont understand how its given you 1 bar of boost? does it increase boost just from giving it much better flow?

[RellikZephyr]

yes the better flow has resulted in an increase in boost because the whole system can breathe better

when i initially got the car it had a silencer plug in the muffler and i was running about 0.8bar of boost and just from taking out the plug it increased to 1.0bar and got a WHOLE lot louder (no longer legal) so ill be fitting a new muffler or resonator soon so the boys in blue dont bother me

and if anyone wants to attempt to gain boost by removing silencer plug from exhaust dont be alarmed when your boost starts playing up and not holding properly (sort of) at the beginning its just the ECU remapping to the new setup (had me worried for a bit )

also most likely got something to do with giving the boost restrictor the flick

but really as for your choice of exhaust size it depends on your plans for later on if your going much further get the 4" now if its only mild modding 3" is plenty

RellikZephyr

Edited November 23, 2005 by RellikZephyr

[FATAZZ]

would having a 3 1/2" catback exhaust on a 3" dump & front pipe cause any problems?

[RellikZephyr]

no not really because the cat itself is the most restrictive part of the exhaust

3" dump pipes would give you heaps of flow (unless you going HUGE power, in which case the cat would a problem)

RellikZephyr

[Links]

Out of interest how much would it cost approx. for a full through 3" exhaust system..

I may look into getting this changed at some stage..

[silva33]

there is no need to go for a 3 1/4 exhaust unless your chasing some serious power, my car made 211rwkw with the silencer still in it!! so if your going for mild mods then just get a 2 muffler system and it will be very quiet!

[GTS4dood]

Out of interest how much would it cost approx. for a full through 3" exhaust system..

I may look into getting this changed at some stage..

<{POST_SNAPBACK}>

I was quoted bullsh1t prices all over the place. for a 3"stainless, turbo back, Hi-Flow cat, resonator and cannon the prices ranged from $1390-$1890 from memory. I ended up finiding a guy through a mate that had been doin exhausts all his life and is only charging me $1150. i was damn happy. pick it up tmoz morn!

its done now, but i have to wait for tmoz to get my licence back in the morn after a very long 6 mnth wait.

Also my exhaust guy said that he didnt know of many companys that make the 3 1/4 in aust. it would most likely have to be shipped in.

[RellikZephyr]

yeah i think cheapest and best way for exhausts nowadays is to get a custom built one is generally cheaper than japanese brands and if the size is ok is just as good

RellikZephyr

[tuleo99]

I just bought the full system muffler 3' stainless today. Just finish install, it is a second hand Apexi, it cost me $530, and $20 for polish scream, after 1 hour polishing, it looks new, price is very cheap, isn't it? If anyone want to buy one in future, i will give you phone number, so you can contact him. I just join in this forum yesterday, so i want to share with you the good cheap things.

[wal]

I have a 3" madrel bent stainless and it is damm loud. If you want performance and not to worried about going deaf. Get one!!