Garrett G Series

[morboost]

which 3" exhaust do you have?

[Tillis3]

 

18 hours ago, morboost said:

which 3" exhaust do you have?

It’s a fabbed 3in downpipe to a 3in ISR (cheap) catback. It’s all straight pipe and 1 can at the rear. 
 

I have found several examples of the same turbo making more power on less boost with 98 RON or similar (non ethanol) fuels. But, maybe I am wrong or getting bad info. 19 psi seems like a lot for that power. 

[Dose Pipe Sutututu]

1 hour ago, Tillis3 said:

 

It’s a fabbed 3in downpipe to a 3in ISR (cheap) catback. It’s all straight pipe and 1 can at the rear. 
 

I have found several examples of the same turbo making more power on less boost with 98 RON or similar (non ethanol) fuels. But, maybe I am wrong or getting bad info. 19 psi seems like a lot for that power. 

Pull off your front timing cover and see if the intake & exhaust cam is in the right spot vs. the crank pulley

Easy check

[Tillis3]

On 4/2/2024 at 10:31 PM, Dose Pipe Sutututu said:

Pull off your front timing cover and see if the intake & exhaust cam is in the right spot vs. the crank pulley

Easy check

I will do this next week and report back but timing does not seem off.

[TurboTapin]

On 3/31/2024 at 11:08 PM, Kinkstaah said:

Also yeah, that is a reasonably good result for petrol at 19psi. I'd say this is working as one would expect. If you dialled in 25psi into it it may be interesting to see what it'd do, but because you're on 93 (hello USA) the answer is probably knock.

Almost all of the results you read here are on E85, which makes dramatic differences.

98RON (EU) = 93AKI (NA). We also have 94AKI in Canada which is 101.5RON. In the US. they have E85 unlike us in Canada. 

[Kinkstaah]

Sorry yea - I know 93 = 98 = Premium, I only said Hello USA because that's how people use the term, nobody down under refers to anything 93

But I was wrong, and it was Canada, aye. So hello, better USA.

[morboost]

19 hours ago, TurboTapin said:

98RON (EU) = 93AKI (NA). We also have 94AKI in Canada which is 101.5RON. In the US. they have E85 unlike us in Canada. 

damn no e85, the only reason Australia has it GM (holden) did a deal with caltex (a fuel company) to supply a e85 for a flex fuel domestic model car. The car was a dud as owners where using 30% more fuel in a non performance application and just started filling the car with regular unleaded. The car company went broke and the fuel company stopped selling it. Thankfully another fuel company started selling e85 as the performance benefits had been realised in boosted application its ozzy 98ron with 15% ethanol, loves boost and timing.

[r32-25t]

E85 was around in Sydney before Holden built the e85 cars 

[TurboTapin]

1 hour ago, morboost said:

damn no e85, the only reason Australia has it GM (holden) did a deal with caltex (a fuel company) to supply a e85 for a flex fuel domestic model car. The car was a dud as owners where using 30% more fuel in a non performance application and just started filling the car with regular unleaded. The car company went broke and the fuel company stopped selling it. Thankfully another fuel company started selling e85 as the performance benefits had been realised in boosted application its ozzy 98ron with 15% ethanol, loves boost and timing.

We don't have E85 at the pump due to our winters. It wouldn't be pretty. But most of our petrol is an E15 mix. 

[BiZbAiRd]

Hi all,

I have done a lot of reading but still just as confused as when I started!!

RB25det (neo)
Forged internals, all the other good stuff.
Haltech ECU.
Plazmaman plenum with factor runners, DBW 68mm throttle body.
98 pump gas
Should be capable of revving to 9k.

Going to be used for mostly road/odd track day, 500WHP target. Looking at a Artec manifold with G30-770 but with the reading I have done, a lot of people recommend twin scroll. Not a lot of options with the G series when going to twin scroll. Garrett say not to worry about twin scroll?

With response being important for drivability on the road, not top-end HP (while still important), what do people recommend for turbo? I like how easy the V-band g-series look and am keen on a g-series but not 100% sold.

Also, recommendations for an intercooler. Historically I've always run cheap large ones but looking for something smaller and more efficient, capable of flowing the 500WHP.

Thanks

[Dose Pipe Sutututu]

On 23/06/2024 at 1:19 PM, BiZbAiRd said:

Garrett say not to worry about twin scroll?

odd thing for a turbo manufacturer to say, the proof if there, twin scroll always performs better, sure non twin scroll and twin scroll you'll end up at the same overall peak power, however a street car/track car needs a wide powerband unlike a drag car.

In terms of intercooler, a good one goes a long way. For reference (I've posted it somewhere here the data) I had an older HDi Core (pre dates the GT2 style cores, they seem decent!) and my runs were peaking over 60 degrees Celsius, went to a Plazmaman Pro Series 76mm core and temps dropped down to the mid 30s. Similar ambient temp, similar motor build, same turbo setup, same exhaust system, mostly same IC pipework.

[Lithium]

On 23/06/2024 at 3:19 PM, BiZbAiRd said:

Not a lot of options with the G series when going to twin scroll. Garrett say not to worry about twin scroll?

I've never seen Garrett say not to worry about twin scroll - they have twin scroll options for all their G and GT series turbines from the 30 series up.  

What kind of dyno are you expecting to be making 500whp on?  So far it sounds more or less like you're doing a G30-770 kind of setup, and realistically an open housing will be good response etc

[BiZbAiRd]

Hi Lithium,

I have heard a couple people say, Garrett say with the smaller G-series twin scroll is not require and I have assumed this is the case, based on the lack of twin scroll availability. Garrett only do a T4 twin scroll 1.06a/r, which I feel is too big for an RB25 for my use case? Yes, I was certainly thinking the G30-770 but was concerned about the lack of twin scroll.

The 500whp isn't the critical part, it's a 'build for this power' and hopefully get there. More important are drivability and response.

Regards

[Full-Race Geoff]

18 hours ago, BiZbAiRd said:

Garrett only do a T4 twin scroll 1.06a/r, which I feel is too big for an RB25 for my use case? Yes, I was certainly thinking the G30-770 but was concerned about the lack of twin scroll

G30-770 with their 1.06 a/r twinscroll housing is an awesome combination.  Will be over the moon with that on a properly configured RB25

[BiZbAiRd]

Would you expect to see 500whp from the g30-770 1.06a/r twin scroll T4? I  feel like it's to big for a primarily street application?

[waxracing]

17 minutes ago, BiZbAiRd said:

Would you expect to see 500whp from the g30-770 1.06a/r twin scroll T4? I  feel like it's to big for a primarily street application?

Its just big enough for what you are trying. I would not go any smaller. your compressor map is right in the middle. I have a g35-900 for my 30/25 build and looking to get 550-600 with out going above 1.5 bar 

[BiZbAiRd]

What a/r and rear housing/flange?

[waxracing]

10 hours ago, BiZbAiRd said:

What a/r and rear housing/flange?

t4 split

1.06

v-band outlet

[BiZbAiRd]

Thanks @waxracing

Turns out G30-770 T4 twin scroll 1.06a/r isn't available for reverse rotation. So really, the only real question is, will the G30-770 v-band .83a/r produce 500whp on pump gas? If it's unlikely, should I go to G30-770 1.01a/r, G30-900 .83a/r or G35-900 .83a/r? Or any other combination...

[waxracing]

Well if you look at the compressor map I would say that the g35-900 will do it alot easier and be in a better efficiency range. In regard to throttle response and boost threshold, I doubt you would feel the difference but obviously there will be one.