Jump to content
SAU Community

3.5 Inch To Big?

ClutchBurndout-:(
 Share

Recommended Posts

ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
Posted

hey all, this is more a "just curious" topic, but i purchased a car (havnt picked it up yet) and the car has a 3.5 inch zorst with a stock turbo, now in the past ive had a 3 inch zorst on the same system and found it enough, but will 3.5 inch be worse for the performance of the car? to me it seems like there wouldnt be enough back pressure.

Anyway, i guess the MAIN question is, how much of a drop in perfomance will there be with this exhaust? should i invest in a 3inch?

stock PSI to BTW

cheers

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/
Share on other sites
ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
  • Author
Posted
It will not hinder performance.

EPA issues however are most likely.

sound or pollution?

An exhaust CAN'T be 'to big' UNLESS you are going to give the exhaust 'to Big Al, your mate'.

Otherwise it is 'too big'.

But in this case, it isn't.

:P

i dont get it

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306028
Share on other sites
gwilkinson34 Collaborator

gwilkinson34

Posted
Posted
sound or pollution?

i dont get it

Lol. 'to' and 'too' - two (hehe) different words.

The problem will be with volume, but I wouldn't worry about it (unless you get defected).

The size shouldn't make any difference to emissions as long as there is still a cat.

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306048
Share on other sites
ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
  • Author
Posted
Lol. 'to' and 'too' - two (hehe) different words.

The problem will be with volume, but I wouldn't worry about it (unless you get defected).

The size shouldn't make any difference to emissions as long as there is still a cat.

no i don want to take the cat out, srsly, i dont want the extra 500rwkw from taking the cat out, its just to fast for me, so ill leave it in.

i was under the impression that you need some sort of back pressure, but iono

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306058
Share on other sites
gwilkinson34 Collaborator

gwilkinson34

Posted
Posted
no i don want to take the cat out, srsly, i dont want the extra 500rwkw from taking the cat out, its just to fast for me, so ill leave it in.

i was under the impression that you need some sort of back pressure, but iono

I believe the extra 500rwkw will make it too fast for you.

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306088
Share on other sites
ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
  • Author
Posted
turbo engines are rather different to natro engines when it comes to exhaust requirements. as has been said, you won't notice any difference between a 3" and 3.5" system. if it was on a NA car, then it would be a totally different story

ok, good thanks! :P

i dont realy care about the size, i just didnt want it to be any worse than a 3 inch, which i beleive is optimal for a stock turbo.

I believe the extra 500rwkw will make it too fast for you.

is that all you picked up? lol what about - don, srsly or iono, but its good to see u picked up a missing "o"

cheers mate :angry:

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306102
Share on other sites
gwilkinson34 Collaborator

gwilkinson34

Posted
Posted

As far as I'm concerned any of those 'made up' internet slang words mean you are speaking another language.

But mix up your 'to, too, two' or 'you're, your' etc while attempting English and it's just plain slack. :P

But srsly, your exhaust is fine.

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306173
Share on other sites
ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
  • Author
Posted
As far as I'm concerned any of those 'made up' internet slang words mean you are speaking another language.

But mix up your 'to, too, two' or 'you're, your' etc while attempting English and it's just plain slack. :P

But srsly, your exhaust is fine.

hehe ok cheers mate

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306181
Share on other sites
slo_sprint Apprentice

slo_sprint

Posted
Posted

It won't decrease performance, on engines with forced induction the less exhaust restriction the better.

My 33 had a 3.5" system with a stock turbo and very few mods and it was pretty damn loud (didn't have a cat or any mufflers bar the cannon though), did sound mint but.

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5306751
Share on other sites
discopotato03 Grand Master

discopotato03

Posted
Posted

Provided you have control of the fueling and timing it shouldn't be a problem , noise and cops aside .

The theory is that the best exhaust is no exhaust behind a turbocharger which obviously isn't going to cut it in a road car .

The turbo rally people like to start out big behind the turbo and step down in stages on the way to the back . What this is said to do is maintain gas speed in the exhaust system as the gas cools and contracts so to speak .

Its a way of having a large volume behind the systems chief restriction , all gasses are channelled and accelerated into the turbine housing , so the red hot gasses have room to expand into . The way to drive the turbine is to have hot gas at speed on one side and a large volume to spread out into on the other side .

As the gas cools it wants to slow down if the exhaust tract is the same all the way to the back , if it slows down too much you can have reversion issues if say the turbo/exhaust manifold/ports/valves/cams are sized to make high rev grunt .

So , the way to keep it moving is to step the tube size down in stages so that the gasses maintain some momentum and velocity .

My old dinosaur Subaru RX Turbo (1.8L 2 valve tiny port flat four GT2554R turbo) has a 3" tube from the turbo to the back of the gearbox and 2 1/2 from there . Its surprisingly quiet but both mufflers are in the 2 1/2 section behind the 3" cat .

It still has its AM radio tech computer and suffers no reversion crap/no pops spits OR drones anywhere .

I suggest that if you have to do something to reduce noise start at the back , its the cheapest easiest way that gives the least restriction in an exhaust system . Car manufacturers having been doing precisely this for some years now .

A .

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5307360
Share on other sites
ClutchBurndout-:( Grand Master

ClutchBurndout-:(

Posted
  • Author
Posted
Provided you have control of the fueling and timing it shouldn't be a problem , noise and cops aside .

The theory is that the best exhaust is no exhaust behind a turbocharger which obviously isn't going to cut it in a road car .

The turbo rally people like to start out big behind the turbo and step down in stages on the way to the back . What this is said to do is maintain gas speed in the exhaust system as the gas cools and contracts so to speak .

Its a way of having a large volume behind the systems chief restriction , all gasses are channelled and accelerated into the turbine housing , so the red hot gasses have room to expand into . The way to drive the turbine is to have hot gas at speed on one side and a large volume to spread out into on the other side .

As the gas cools it wants to slow down if the exhaust tract is the same all the way to the back , if it slows down too much you can have reversion issues if say the turbo/exhaust manifold/ports/valves/cams are sized to make high rev grunt .

So , the way to keep it moving is to step the tube size down in stages so that the gasses maintain some momentum and velocity .

My old dinosaur Subaru RX Turbo (1.8L 2 valve tiny port flat four GT2554R turbo) has a 3" tube from the turbo to the back of the gearbox and 2 1/2 from there . Its surprisingly quiet but both mufflers are in the 2 1/2 section behind the 3" cat .

It still has its AM radio tech computer and suffers no reversion crap/no pops spits OR drones anywhere .

I suggest that if you have to do something to reduce noise start at the back , its the cheapest easiest way that gives the least restriction in an exhaust system . Car manufacturers having been doing precisely this for some years now .

A .

thanks for the info, very helpful, so with the 3.5 system in there with stock dump and front pipe, its not helping it i assume haha, but i will invest in a 3 inch bellmouth for the dump/front.

i dont have an issue with sound at all, its quite quiet actualy...

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5307384
Share on other sites
mad082 Grand Master

mad082

Posted
Posted
so ive heard

What im wondering will a 3 inch dump/front pipe into 2 3/4 catback be aiight..is there any real point buying a whole system for 1/4 of an inch?

Or will i be captain sloooow.........

the only place you may lose some power is high up in the revs. general driving around and even just reving up to around 5000rpm probably won't make a scrap of difference. anything above that i think you would have to put it on a dyno to see the difference in power. don't think you'd notice the power when driving it. if you were aiming for 250kw+ then it might be worth going 3" though.

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5307439
Share on other sites
75coupe Grand Master

75coupe

Posted
Posted

so if you were after more responsive midrange power the 3.5" exhaust is too large, is that what people are saying?

I was told by a tuner that a 2.5" custom made exhaust would be better than my 3.5" hks, this is what I was told when I told him I wanted to get a tune done for a HKS2835 with supporting mods...

I did say I was after good midrange response, and that I was not interested in ultimate peak power.

I didnt know wheather to trust him or not?

this is on a 33gtst

Link to comment
https://www.sau.com.au/forums/topic/325866-35-inch-to-big/#findComment-5308677
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kapr
      ECU sees many times the speed than speedo does (R34 swap)

      By Kapr · Posted

      The car/ECU will have all the sensor that it needs and expect to have. I think i do not have to explain to you how the Link is way better specialy if you have swapped engine   I just do not want to deal with any "problems" cuz i have only Nistune which i learned is not that great and in my case cant even deal with that speed problem (Link can) And of course it will be way more easier to tune and diagnose and safe. And for the ECU/speed problem...i dont know.
    • wizlb
      Who has a Infiniti Q60, Q50 (V37)?

      By wizlb · Posted

      Per Mark Roberts of Sonictune: Mark Robert Author At this time, no. No ETA either 2016-17 models. You will be able to purchase and install a 2018.5+ TCU though   TCU purchasing and pricing info! As we near the release of TCU tuning, I am going to answer some questions I get asked often.   What do I need for TCU tuning? At this time, you will need a 2018.5+ TCU to be able to tune. If you have a 2016-to early 2018, you will need to replace your TCU with the newer version. One good way to know if your TCU is good is if you have auto upshift in manual mode in 1st gear around 6500 rpms. If your manual 1st gear goes to 7k rpm and will hit the rev limiter unless you shift, you have the older TCU.   Why do I need to buy another ecu license/phone flash if I already have it on my ECU tune? The TCU is its own computer module. It is completely separate from the ECU. Because of this, you will be required to purchase a TCU license and, if your tuner has it, the phone flash license required to tune it via phone/bluetooth.   Do I need TCU tuning? TCU tuning is NOT required. However, the faster your setup, the more it will assist in track and dragy time consistency.   If I’m ECU tuned by (tuner A) can I get my TCU tuned by (Tuner ? Yes, since it’s a different module and a completely separate flash, you can have two different tuners. However, it is highly recommend that you have both tuned by the same tuner. For me, my TCU tuning will directly complement my ECU tuning style and features and running my ECU and another TCU or vice versa MIGHT cause some issues. At this time and for the foreseeable future, I will only be tuning my current ECU tuned customers TCUs.     I have a SYVECS AWD controller. Do I still need it? Yes! The AWD controllers main job is to control your AWD system. However, with TCU tuning, you will no longer need the auto-shift function as that will be done through the TCU. The AWD controller will still be very beneficial for racers looking to maximize traction on the launch.     Shift schedule changes: holding gears longer at lower pedal input as well as max shift rpm changes. Please note, the new ECU race rom coming out will address 90% of the shitty drivability issues these cars have through custom maps from myself and Racebox—as well as others I am sure.   Increase shift speeds: as seen in the videos I’ve been posting, the TCU shifts much faster once tuned.   Increased shift pressures: as also seen in the videos, much firmer full throttle shifts.      
    • wizlb
      Who has a Infiniti Q60, Q50 (V37)?

      By wizlb · Posted

      Per Mark Roberts of Sonictune:     Mark Robert Author At this time, no. No ETA either 2016-17 models. You will be able to purchase and install a 2018.5+ TCU though   TCU purchasing and pricing info! As we near the release of TCU tuning, I am going to answer some questions I get asked often.   What do I need for TCU tuning? At this time, you will need a 2018.5+ TCU to be able to tune. If you have a 2016-to early 2018, you will need to replace your TCU with the newer version. One good way to know if your TCU is good is if you have auto upshift in manual mode in 1st gear around 6500 rpms. If your manual 1st gear goes to 7k rpm and will hit the rev limiter unless you shift, you have the older TCU.   Why do I need to buy another ecu license/phone flash if I already have it on my ECU tune? The TCU is its own computer module. It is completely separate from the ECU. Because of this, you will be required to purchase a TCU license and, if your tuner has it, the phone flash license required to tune it via phone/bluetooth.   Do I need TCU tuning? TCU tuning is NOT required. However, the faster your setup, the more it will assist in track and dragy time consistency.   If I’m ECU tuned by (tuner A) can I get my TCU tuned by (Tuner ? Yes, since it’s a different module and a completely separate flash, you can have two different tuners. However, it is highly recommend that you have both tuned by the same tuner. For me, my TCU tuning will directly complement my ECU tuning style and features and running my ECU and another TCU or vice versa MIGHT cause some issues. At this time and for the foreseeable future, I will only be tuning my current ECU tuned customers TCUs.     I have a SYVECS AWD controller. Do I still need it? Yes! The AWD controllers main job is to control your AWD system. However, with TCU tuning, you will no longer need the auto-shift function as that will be done through the TCU. The AWD controller will still be very beneficial for racers looking to maximize traction on the launch.     Shift schedule changes: holding gears longer at lower pedal input as well as max shift rpm changes. Please note, the new ECU race rom coming out will address 90% of the shitty drivability issues these cars have through custom maps from myself and Racebox—as well as others I am sure.   Increase shift speeds: as seen in the videos I’ve been posting, the TCU shifts much faster once tuned.   Increased shift pressures: as also seen in the videos, much firmer full throttle shifts.      
    • The Bogan
      NC MX5

      By The Bogan · Posted

      The fancy pants red shock tower brace is finally incoming from MX5 Mania, getting it shipped from 'Merica has been a long and problematic process, and GWR, the 'Merican supplier will not ship directly to consumers outside of the US, Mania basically had to order a heap of them, the colour choice was silver, or red, and we all know anything red adds 5 killerwasps of dynotorques..... Whilst it does fit over a 2.5, and I've seen a few photos and videos of it being installed and fitting, google also says it might get real close to the FAB9 intake front runner, people in the US says it does fit with the FAB9 intake, except for one person who said it slightly touched.......so there is that.....LOL..... As it seems that I am the first in AU to have this combination of parts there's no local knowledge about fitment, so I'm just a willing guinea pig in this endeavour, I'll cross my fingers and toes and hope for the best In other news, I ordered stuff from China  on the same day I ordered the 23° silicone bend from Victoria, the stuff from China arrived a day ago, the 23° silicone bend is still travelling around Australia thanks to Australia Post, and "may" be here next week
    • Duncan
      Who has a Infiniti Q60, Q50 (V37)?

      By Duncan · Posted

      Very good news...I contacted Racebox about it last night. My car is a 2016 so remains to be seen if it is compatible, requires a TCU swap, or is impossible.
×
×
  • Create New...