3inch Or 3.5inch Exhaust

[alwaysdreaming]

GT30R would be my pick for 300rwkw. It's the smallest turbo that will make the power, but will still be a little laggy on an RB25.

If you are serious about drifting, consider the HKS GTRS kit. I made 270rwkw: Head porting, Tomei cams, std manifold, std plenum. Had a great power band, great package to drive.

I have since cracked a piston, at a track day, so have upgraded to an rb30det, using the same 25 head, but with ETM manifold, GReddy plenum, and a few other upgrades. The GTRS was going to restrict the flow of the rb30 so i upgraded to a GT30R; smallest turbo recommended by a few "experts". Once the build is complete i should see about 300-330rwkw, with better response than a std high-flow on an rb25

o ok, i am hoping for more than 300 so will have to go bigger than the gtrs kit.

that sounds like a serious machine!

do drift or are you more circuit?

RB30-power

i was looking at the 3076 pro s from hks i think but that is a really pricey turbo and thought there would something else. wats the 3540 rated at?

is the A/R wats going to affect spool?

thanks guys

gezza

[Al]

I intend on doing a few motorkahna, hill climbs and track days, so response was my biggest priority.

Am i correct in saying: a Garrett GT30R is the same as a Garrett GT3076.

Mind you a HKS equivalent will always be a little better.

[alwaysdreaming]

I intend on doing a few motorkahna, hill climbs and track days, so response was my biggest priority.

Am i correct in saying: a Garrett GT30R is the same as a Garrett GT3076.

Mind you a HKS equivalent will always be a little better.

o ok sweet, are you in a racing club?

gt30r is the same as 3076r i belive yeah.

did u ever try drifting b4 cracking your piston?

[alwaysdreaming]

I intend on doing a few motorkahna, hill climbs and track days, so response was my biggest priority.

Am i correct in saying: a Garrett GT30R is the same as a Garrett GT3076.

Mind you a HKS equivalent will always be a little better.

o ok sweet, are you in a racing club?

gt30r is the same as 3076r i belive yeah.

did u ever try drifting b4 cracking your piston?

[R31Nismoid]

if you go 3040, you would be better off with the 3540, that way you don't have the restrictive hot side and can make full use of the large gt40 compressor wheel, even if you went with a smaller ar housing, it would still be more efficient.

people are really beginning to realise what a mismatch the 3040 turbo was, especially when tuning on pump fuel.

The 3040 is ok in the 500/550 HP configurations.

Its only when you get the 600hp that the issues are noticeable, mainly low rpm surging which slows the boost build up.

I had that issue

Its ok on fuel though, just not PULP

[alwaysdreaming]

o that reminds me if i put a big turbo such as the gt30r would it not run properly if i kept it at like 10psi for street use?

thanks heaps

[Al]

o ok sweet, are you in a racing club?

gt30r is the same as 3076r i belive yeah.

did u ever try drifting b4 cracking your piston?

No racing club, just SAU VIC and CAMS license.

Did a drift training day on a huge skid pan (DECA), but that's about it. Never bothered to try at Calder Park, as i wish to keep my panels straight .

[Al]

o that reminds me if i put a big turbo such as the gt30r would it not run properly if i kept it at like 10psi for street use?

thanks heaps

Should be ok, but will make jack all power, as it's well below it's efficiency range. I intend to use 12psi for street and 20psi for other applications

[FineLine]

Re your original question hers my take on it. We started with a 3 inch then went to a 3.5. Noteworthy is the fact that the car made the same power on 3 lb less boost. Less restriction equals win win for turbo engines.

[Al]

Re your original question hers my take on it. We started with a 3 inch then went to a 3.5. Noteworthy is the fact that the car made the same power on 3 lb less boost. Less restriction equals win win for turbo engines.

How much power?

[FATAZZ]

i have a 80mm centre - centre straight through muffler for sale $100. if you were interested.

im also going through replacing my cat-back 80mm exhaust with a 3" hence the newly purchased muffler for sale.

but i want the exhaust to follow the standard route,up high with alot of bends.

will the excessive amount of bends in the exhaust be sufficientin flow & sound deadining if i loose the muffler between the cat and the rear cannon in 3" mild steel.

will it still flow good enough for upto 200rwkw and not be over the 90db limit?

[FineLine]

How much power?

492 hp at the rears.

[Al]

will it still flow good enough for upto 200rwkw and not be over the 90db limit?

Flow should be sufficient, but doubt you'll be under 90db, without at least one muffler between your cat and rear muffler/canon.

[Al]

492 hp at the rears.

That has made my mind up, i'll be going 3.5" on my set-up, thanks.

Looking at 300-330rwkw, maybe a little more, but don't want it to be restrictive.

[alwaysdreaming]

i have a 80mm centre - centre straight through muffler for sale $100. if you were interested.

im also going through replacing my cat-back 80mm exhaust with a 3" hence the newly purchased muffler for sale.

but i want the exhaust to follow the standard route,up high with alot of bends.

will the excessive amount of bends in the exhaust be sufficientin flow & sound deadining if i loose the muffler between the cat and the rear cannon in 3" mild steel.

will it still flow good enough for upto 200rwkw and not be over the 90db limit?

thanks for the offer mate, but ill just leave it to what the guy doing the custom decides with.

with the 90db, were do they take the reading from and at wat rpm?

i am looking into the exhaust valve that alows you to select wether it opens half or full depending on wat your doing/how loud u want it, it sounds like a good idea to me .

Gezza

[alwaysdreaming]

492 hp at the rears.

thats a insane figure

i am definatley going for a 3.5 aswell haha.

wat other mods have you got to make that kinda power?

cheers

gezza

[FineLine]

thats a insane figure

i am definatley going for a 3.5 aswell haha.

wat other mods have you got to make that kinda power?

cheers

gezza

Its a fully built top to bottom 25 with no stone unturned, It should make more and we are currently making changes to find the missing fat.

basics are......the obligatory forged bottom end with all the neccesary fruit, Massive headwork, solid cams, bigger valves and springs etc, garret 35/40 on highmount. power fc pro. Etc, etc, etc,.

Had an overheating issue and slightly warped the head. surfacing 8 thou we reassembled and lost 40 hp due to higher compression and the timing we had to take out to prevent knock.

The head is coming off again next month for bigger cams and a thicker head gasket. I am hoping we can reach the build target of 550 plus ponys. Time will tell.

[alwaysdreaming]

Its a fully built top to bottom 25 with no stone unturned, It should make more and we are currently making changes to find the missing fat.

basics are......the obligatory forged bottom end with all the neccesary fruit, Massive headwork, solid cams, bigger valves and springs etc, garret 35/40 on highmount. power fc pro. Etc, etc, etc,.

Had an overheating issue and slightly warped the head. surfacing 8 thou we reassembled and lost 40 hp due to higher compression and the timing we had to take out to prevent knock.

The head is coming off again next month for bigger cams and a thicker head gasket. I am hoping we can reach the build target of 550 plus ponys. Time will tell.

thats a hell of alot of work, do you work in a work shop?

well good luck mate, hope you can get it making 550 wit out to much hassels.

let me know how it goes.

Gezza