Twin Scroll T04z On A 25/30

[Lukas 33]

I drive a built 32 gtr with a T04z on the circuit and i dont think the car will be any fun at all with a 7k redline. Honestly your power ban and redline will come together like cousins at a tasmanian family reunion!

You need to be able to rev it til at least 8000-8500 to really make it somewhat responsive!

HAHAHA Yeh well true. Is your 32 gtr a 26 or 26/30? What is your redline? What rear housing do you have on the turbo?

[Duncan1]

HAHAHA Yeh well true. Is your 32 gtr a 26 or 26/30? What is your redline? What rear housing do you have on the turbo?

Its just a forged 26, The 32 is my best mates and was only recently acquired from another

friend who invested the big dollars into the car. I shift at about 8k on the circuit [which is hard in the lower gears], im not sure what the redline cutout is. I have seen the car spin nearly 9k without the revlimiter cut-out so i imagine it is @9k. from memory the rear housing is .84. not 100% though

will find out.

It might be a completely different application to yours, but i think that 7k will still prove to be too low in the lower gears.

[discopotato03]

These are just my thoughts for what they're worth .

A good friend used to tell me that a given result was "adequate" , and there doesn't necessarily have to be a number on it .

At a guess a street driven Skyline doesn't need 420 Kw to feel good and be more than adequate .

Trying to be realistic I think something in the 260-300 RwKw area is good performance provided it pulls reasonably and has a wide useful rev range .

I think aiming for a number like 420 Kw means the state of tune would have to be high even with three liters and maybe not so nice when driven like a std street car around the burbs .

Twin scroll single turbos can be great things but the munjaras to get everything working just so is a big stack of notes . Most people want an Rb30 bottom end to have more torque off boost and to spin bigish dryers up reasonably easily .

I would not be a great fan of GT3582R's but they have their place and some like them on RB30 twin cam engines . There obviously comes a time when the std manifold becomes a limitation and if it didn't the "t3" sized flange would .

Really the T04Z's need a turbine housing with the larger T4 International sized mounting flange because they have larger inlet passages as would an exhaust manifold with that sized flange . HKS uses the T4 sized flange and arguably their housings work better than Garretts Diesel spec ones on that cartridge - for a petrol application .

For me I'd use a GT3076R with the largest 1.06 A/R wastegated turbine housing on a steet car , wouldn't get 460 Kw but with a bit of engine work and the right CR I think 320 is achievable . Most won't go with that 1.06 housing because they think it makes GT3582R's feel laggy , why I don't know because it wouldn't have the GT35 turbine or GT40 compressor and as a plus a GT30 turbine housing is a match for a GT30 turbine . Different story with a GT35 turbine in a bored out GT30 turbine housing - maps show why .

Big turbine housings usually don't have creep issues because the gas speed is lower so more likely to take the exit stage left turn out throught the gate when it opens .

Just my two street cents spent , cheers A .

[Lukas 33]

Its just a forged 26, The 32 is my best mates and was only recently acquired from another

friend who invested the big dollars into the car. I shift at about 8k on the circuit [which is hard in the lower gears], im not sure what the redline cutout is. I have seen the car spin nearly 9k without the revlimiter cut-out so i imagine it is @9k. from memory the rear housing is .84. not 100% though

will find out.

It might be a completely different application to yours, but i think that 7k will still prove to be too low in the lower gears.

AH ok yeh 26 are fine for rev's compared to the 30. Yeh if you could please find out that would be lovely.

Disco - I had a 3076r 0.82 for the car when it was to be a 25 but changed up to the 3582r 0.82 when i decided it would be a 25/30. Thought the 3076r would be a little too small and too lightswitch for the 30. I was told the 3582 on a 30 would be like a 3076 on a 25. Hoping so anyways. How would you rate the difference in spool time, etc etc (mainly everything you personally can think of) between the T3 1.06 gt35r and the T4 0.84 TS t04z

[discopotato03]

Well the whole idea of the 1.06 A/R turbine housing is to raise the boost threshold so it wouldn't be "too snappy" .

One of the things that makes Garrett's GT30 and GT35 turbines laggy in some peoples opinions is the big trim size - 84T . The point I'm making is that going big in A/R with a big trim turbine makes a big difference in gas speed through the housing . Usually when this topic is discussed I suggest people look at the turbine map for the GT30 turbine . The difference in the gas flow lines on Garretts graph is vast , greater than the difference between their 0.63 and 0.82 A/R GT30 housings . I also suggest they look at the GT3582R's turbine map and note the gentle curve towards the right for all three A/R housings with that GT35 turbine .

The only T series turbo , T04Z is a BB T series unit , I knew about on a SOHC RB30ET was a bush bearing T04S which had a 1.00 A/R turbine housaing and P trim T04 turbine . From memory the compressor was a T04 60-1 in a 0.70 A/R comp housing and the report was that it tore up the tarmack on 10 lbs of boost .

IMO is is an urban myth that mid sized twin scroll turbine housings improve "spool" . Twin scroll systems are not about gas speed they are about reducing manifold pressure and taking advantage of the pulse energy available .

A .

[Lukas 33]

Well the whole idea of the 1.06 A/R turbine housing is to raise the boost threshold so it wouldn't be "too snappy" .

One of the things that makes Garrett's GT30 and GT35 turbines laggy in some peoples opinions is the big trim size - 84T . The point I'm making is that going big in A/R with a big trim turbine makes a big difference in gas speed through the housing . Usually when this topic is discussed I suggest people look at the turbine map for the GT30 turbine . The difference in the gas flow lines on Garretts graph is vast , greater than the difference between their 0.63 and 0.82 A/R GT30 housings . I also suggest they look at the GT3582R's turbine map and note the gentle curve towards the right for all three A/R housings with that GT35 turbine .

The only T series turbo , T04Z is a BB T series unit , I knew about on a SOHC RB30ET was a bush bearing T04S which had a 1.00 A/R turbine housaing and P trim T04 turbine . From memory the compressor was a T04 60-1 in a 0.70 A/R comp housing and the report was that it tore up the tarmack on 10 lbs of boost .

IMO is is an urban myth that mid sized twin scroll turbine housings improve "spool" . Twin scroll systems are not about gas speed they are about reducing manifold pressure and taking advantage of the pulse energy available .

A .

Yeh well that makes me think a little differently now I guess. If there is minimal difference noticeable in twin scroll then meh. From what I was reading is it was wonderful Im still yet to see what my 3582 with 0.82 rear maxes out on. Cheers for the wise words

[sneakey pete]

You're right I should pull out the motor and rebuild it all again? Is it so bad that I don't want to rev the f**k out of the motor? It is all balanced etc I just don't really want to rev the f**k out of it. Ive never even seen the rev limit in my car EVER. I will see how the car goes rev wise with this tune. Maybe I will put the limit at 7500. I was just thinking 7000 as I don't want to have to wait so god damn long if I had to rebuild again. I just kind of wanted this motor to last longer than 4 weeks. A build takes quite a while being a pov ass uni student. Is the extra 500rpm that big of a difference? It only a street car. It has never seen a race track or a drag strip ever.

Haha, don't get me wrong, i only own a Suzuki serrai, I don't think i've even ever touched a skyline. However, logically, you can pretty easily determine that if your engine goes, its either going to be because of some catastrophic failure (eg, oil pump), or from general wear. Ask the guy who built the engine how high it should be reved, get a good oil pump if your worried about that shitting itself, and set your rev limit accordingly. Remember, redline at 7000 or 8000rpm isn't going to be a huge difference in wear, especially if its not a full time track care and will be seeing a lot of time putting around the suburbs at 3000rpm anyway.

[JonnoHR31]

8000rpm puts about 1.3 times the relative stress on the motor that 7000rpm does, fair bit for only 1000rpm

[Lukas 33]

Haha, don't get me wrong, i only own a Suzuki serrai, I don't think i've even ever touched a skyline. However, logically, you can pretty easily determine that if your engine goes, its either going to be because of some catastrophic failure (eg, oil pump), or from general wear. Ask the guy who built the engine how high it should be reved, get a good oil pump if your worried about that shitting itself, and set your rev limit accordingly. Remember, redline at 7000 or 8000rpm isn't going to be a huge difference in wear, especially if its not a full time track care and will be seeing a lot of time putting around the suburbs at 3000rpm anyway.

Yeh I think Im not going to touch the 8000rpm limit. putting around the burbs haha just sounds so silly. Yeh well I dont want to risk oil pump failure. Maybe if the engine does a naughty broken thing I will just put in the better oil pump that time. Yeh like JonnoHR31 said I thought there was a fairly big difference between stress from 7000 to 8000.

I just never thought it was common practise to take the twin cam 30 to 8k. I will definately update this thread depending on what tuner says etc etc and how my 35r 0.82 goes on the 25/30 Which reminds me it is once again time to phone the mechanics to see what they have to say with progress etc

Edited December 17, 2009 by Lukas 33

[TiTAN]

AH ok yeh 26 are fine for rev's compared to the 30. Yeh if you could please find out that would be lovely.

the RB30 engine has no issues with revs

my 30 is currently limited to 7500rpm as i only have the stock ballancer

AL's 30 is limited to 8000rpm with an aftermarket ballancer

both engines are forged and all the internals well balanced.

or there is the rips engine massive power and stock internals (with some prep work) and occasionally hits 10000rpm

[Lukas 33]

the RB30 engine has no issues with revs

my 30 is currently limited to 7500rpm as i only have the stock ballancer

AL's 30 is limited to 8000rpm with an aftermarket ballancer

both engines are forged and all the internals well balanced.

or there is the rips engine massive power and stock internals (with some prep work) and occasionally hits 10000rpm

Yeh my internals are balanced but only has a stock balancer. You have to admit rob is an exception when it comes to rb30. Just because he can rev to 10000rpm and hit 1000hp doesn't mean I have a chance in hell haha

[fatz]

my old gtr motor 9k at the track built

2530 7.2k at the track not built

both went as quick as each other

[PM-R33]

my old gtr motor 9k at the track built

2530 7.2k at the track not built

both went as quick as each other

Ouch!

[Lukas 33]

my old gtr motor 9k at the track built

2530 7.2k at the track not built

both went as quick as each other

Thats a little disappointing Use the 2530's both times?

[TiTAN]

he means an RB30 with a 25 head.

[Lukas 33]

he means an RB30 with a 25 head.

OH right well that makes a little more sense then :S now im a douche

[bubba]

Good balancing and a good balancer, there is no reason why you can't spin the 30 to 9k.

My mates 30 has the rev limit at 8k and I'll probably set mine the same unless power drops off earlier.

[Lukas 33]

Good balancing and a good balancer, there is no reason why you can't spin the 30 to 9k.

My mates 30 has the rev limit at 8k and I'll probably set mine the same unless power drops off earlier.

Even without a good oil pump?

[Lukas 33]

OH FFS!!!!!!!!!! The mechanics havent done a single thing to my car and it has been in there for two weeks. Also they just told me they close from 24th dec to 19th jan. FARK

[SirRacer]

For information sake, my seat of the pants o meter seems to think there isnt really a huge deal between the .82 and 1.06 housing lag wise on a rb30/25.

I changed from the .82 to the 1.06 housing and while boost didnt spool as early, it was annoying undrivable. I actually prefer the fact it kicks in a bit more.

I would love to give you some comparible dyno numbers but unfortunately my engine lost all oil pressure while i was getting the 1.06 turbo tuned. When its fixed, ill post up some comparisons

Edited December 18, 2009 by SirRacer