Garrett G Series

[waxracing]

2 minutes ago, GTSBoy said:

It's a 3L block so he might have a little more vertical clearance to help with the engine mount, but I'd still worry about the space to the side of the engine bay.

The problem is you have 2x small flaps instead of 1x large one. For the space available and taken up by the 2x small flaps, you can't get anywhere near as much flow area as you can in a single scroll setup. So there's not really any such thing as a "modern internal wastegate" where they description is expressing some hope that they've managed to improve the design of something that has almost no improvement available.

I know the efr is using an internal wastegate with only one flap. I was looking at one of those but they have a huge supply issue at the moment.

I do not want to look argumaneitve towards what you are saying. I do really appreciate your input 

[waxracing]

17 minutes ago, r32-25t said:

Did you read the rest of my post? Do it properly and use external gates, there’s no such thing as a modern internal gate and they don’t work well anyway 

Yes I did read your post, Did you read where I asked what is wrong with a modern internal gate. I find it strange that efr "engineered for race" and Garret would make such a bad internal gate for a performance turbo ??. Im am genuinely interested in knowing what's wrong with an internal gate as they have them now with the blend into the rear housing they have gone for instead of a 90 degree entry. Please explain it to me 

[waxracing]

23 minutes ago, r32-25t said:

Did you read the rest of my post? Do it properly and use external gates, there’s no such thing as a modern internal gate and they don’t work well anyway 

 

[GTSBoy]

1 minute ago, waxracing said:

Garret would make such a bad internal gate for a performance turbo

Well, that's just it. Garrett don't even bother with internal gate twin scroll housings.

BW have them for the same market segment, but it doesn't mean that they're actually a good way to control boost. You'd be far better off utilising an external gate.

And here's the kicker. You have a manifold already set up to just do exactly that. So.....just put an ATP housing a G30 or use the Pulsar per @Lithium, and throw an external gate on the manifold and it will all be great.

[waxracing]

2 minutes ago, GTSBoy said:

Well, that's just it. Garrett don't even bother with internal gate twin scroll housings.

BW have them for the same market segment, but it doesn't mean that they're actually a good way to control boost. You'd be far better off utilising an external gate.

And here's the kicker. You have a manifold already set up to just do exactly that. So.....just put an ATP housing a G30 or use the Pulsar per @Lithium, and throw an external gate on the manifold and it will all be great.

Yeah I get it. Its one way to do it. I would have preferred to blank off the external wastegate and gone for the nice and easy way of an internal. Less piping to crack 

[r32-25t]

7 minutes ago, waxracing said:

Yes I did read your post, Did you read where I asked what is wrong with a modern internal gate. I find it strange that efr "engineered for race" and Garret would make such a bad internal gate for a performance turbo ??. Im am genuinely interested in knowing what's wrong with an internal gate as they have them now with the blend into the rear housing they have gone for instead of a 90 degree entry. Please explain it to me 

we have seen results on here of efr turbos internal vs external gates and the internal didn’t work. It’s why no body else makes them 

[waxracing]

Just now, r32-25t said:

we have seen results on here of efr turbos internal vs external gates and the internal didn’t work. It’s why no body else makes them 

OK thank you 

[Duncan]

I totally get that you are coming from an "internal gate is easier to install" point, but fundamentally a single wastegate for a 6 cylinder is not very effective due to the conflicting exhaust pulses.

It only really works well for smaller turbos in a proper setup, like the factory twins, where the separate exhaust pulses don't clash and the level of airflow that the wastegate needs to bypass is smaller.

External gates are more painful to install but perform much better for big turbos, and twin wastegates on twin scroll for a single turbo on a 6 cylinder at the most effective; for most people modifying their car it is worth the effort.

[waxracing]

10 minutes ago, Duncan said:

I totally get that you are coming from an "internal gate is easier to install" point, but fundamentally a single wastegate for a 6 cylinder is not very effective due to the conflicting exhaust pulses.

It only really works well for smaller turbos in a proper setup, like the factory twins, where the separate exhaust pulses don't clash and the level of airflow that the wastegate needs to bypass is smaller.

External gates are more painful to install but perform much better for big turbos, and twin wastegates on twin scroll for a single turbo on a 6 cylinder at the most effective; for most people modifying their car it is worth the effort.

That's a well written explanation, thanks for that 

[Lithium]

This isn't to beat a dead horse or have a go or anything, just basically adding a +1 to the other comments about internal wastegates on "big turbo" RBs and add some further reason to it so it doesn't feel like you've just hit a trigger point that people are going to hate on because it's trendy to.   For what it's worth, I've not yet seen a situation where someone has gone that way initially and not ended up regretting it, and potentially changing at significant expense.

The stuff you see in regards to the design itself is perfectly right, aerodynamically the Borg Warner internal wastegate setup is very nice - no issues with boost creep and they also don't appear to negatively impact turbine efficiency.   If you can keep the gate closed when it needs to be then you won't have issues with performance, and when target boost is achieved the wastegate path allows the drive pressure to be managed nicely.   Borg Warner are not being misleading about this at all, in my opinion.

The issue however is the actual control of the gate flapper itself.   The significance of exhaust pressure on boost control is often massively underestimated, when you see wg spring pressures that really effectively is making a big assumption about what exhaust manifold pressure will be doing at that point and how whatever drive pressure management being used actually responds.   Flapper style wastegates seem only too keen to crack open a little bit under any amount of pressure which can immediately start reducing the effectiveness of the turbine, and it only gets worse as exhaust pressure increases.   A stiffer wastegate actuator can HELP, and often the solution seems to be using a stiff enough spring to be able to achieve the "high boost" target pretty much by itself - and then additional electronic boost control input to maintain the target boost.

Basically the result OFTEN (but not always) seems to end up being pretty poor flexibility in terms of boost control, and often a lot of messing around to get what would often be seen as the bare minimum with an external wastegate setup.   I would argue that if there was a good electronic wastegate actuator option (so it can keep the gate properly shut until it's meant to be open) that was compatible with the EFR IWG range then a lot of the criticism would be completely negated, buuuut a .92 IWG housing is still probably on the smaller side for a RB30 unless you're going with an 80-series turbine wheel.

That's at least my limited experience and opinion on the situation, there could be other things I've not seen or considered.

 

Edited February 9, 2023 by Lithium

[mr_rbman]

17 hours ago, waxracing said:

Great reading here.

I am just in the process of buying a new turbo for my 26/30.

Im only after about 500 whp with killer response max rpm about 7000-7500

I was lucky enough to pick up an old hks split pulse manifold ( low mount with top mounted wastegate)

Cant make up my mind between a g30-770 or a g30-900 with a .85 divided manifold . Im really open to what every one thinks, im looking for and would appreciate help . I did look at the efr but its impossible to get them at the moment. 

 

I think you posted this same thing on the FB page for RB25/26 etc. or whatever it is and i did respond (if this wasn't you i do apologise)

but I told you the G30-770 and 900 were both too small... IMO

I am speaking from personal experience here...

I have a Garrett G30-900 (1.01) with a 45mm external gate on an Artec Manifold making 433rwkws on 21 psi using E85 (standard stroke RB26) it makes from memory 378rwkws on gate pressure (~16-17psi) on 98RON

It is getting close already to being too small of a turbo, we haven't been able to add anymore boost as I'm getting voltage drop (suspect that the standard alternator isn't keeping up) but my tuner says he feels it probably only has a little left before it chokes so add another near on half a litre of displacement and it'll be well and truly choking even earlier..

 

Just my 2c

[waxracing]

3 minutes ago, mr_rbman said:

I think you posted this same thing on the FB page for RB25/26 etc. or whatever it is and i did respond (if this wasn't you i do apologise)

but I told you the G30-770 and 900 were both too small... IMO

I am speaking from personal experience here...

I have a Garrett G30-900 (1.01) with a 45mm external gate on an Artec Manifold making 433rwkws on 21 psi using E85 (standard stroke RB26) it makes from memory 378rwkws on gate pressure (~16-17psi) on 98RON

It is getting close already to being too small of a turbo, we haven't been able to add anymore boost as I'm getting voltage drop (suspect that the standard alternator isn't keeping up) but my tuner says he feels it probably only has a little left before it chokes so add another near on half a litre of displacement and it'll be well and truly choking even earlier..

 

Just my 2c

Thanks Mate.  Yes that’s me.   Much appreciated, I’m starting to think the g35 900 with the .8 housing may be the go based on what you saying.   Being that the g35 will have a bigger rear wheel.  

[mr_rbman]

1 minute ago, waxracing said:

Thanks Mate.  Yes that’s me.   Much appreciated, I’m starting to think the g35 900 with the .8 housing may be the go based on what you saying.   Being that the g35 will have a bigger rear wheel.  

I know a guy running a G35-900 (0.84) rear on a standard stroke RB26 and he's having issues too...

RB's love big exhaust sides, I'd personally go the 1.01 rear at a minimum if it were me...

You'll see a heap of examples on this site alone where guys have kept the same turbo but gone up a size in the rear and lost virtually no response...

[vito_96]

7 hours ago, mr_rbman said:

I know a guy running a G35-900 (0.84) rear on a standard stroke RB26 and he's having issues too...

RB's love big exhaust sides, I'd personally go the 1.01 rear at a minimum if it were me...

You'll see a heap of examples on this site alone where guys have kept the same turbo but gone up a size in the rear and lost virtually no response...

Hey. 

 

I just picked up a g35-1050 t4 twin scroll with a/r of 1.06, for my rb26/30. 

Don't sell your self short Garrett turbos make about 100 less hp than advertised. Also with a rb30/26 it's move more air than rb26, don't go with a smaller A/R anything lower than 1 you will choke it at higher rpm.  My car currently has a T04Z with a/r of .86 and it made 577hp and 435tq but when we added more boost (22+) we just saw more heat and not much more power.

Im hoping this new turbo will give me 7-800whp

 

 

[waxracing]

[waxracing]

Thanks Mate, Yes I will be going for a 1 ar on my turbo. Above is the style of manifold I have.

[vito_96]

1 hour ago, waxracing said:

Thanks Mate, Yes I will be going for a 1 ar on my turbo. Above is the style of manifold I have.

Is that a bottom mount or top mount. 

I'm running a 6boost, save the cash and get a good flowing manifold you will see great gains. 

I know waiting such my build took my 8 years. 

 

 

[waxracing]

13 minutes ago, vito_96 said:

Is that a bottom mount or top mount. 

I'm running a 6boost, save the cash and get a good flowing manifold you will see great gains. 

I know waiting such my build took my 8 years. 

 

 

It’s a split pulse manifold low mount made by hks.  They are good for about 600 whp. Way more than I am after 

Edited February 9, 2023 by waxracing

[Duncan]

that is a very interesting manifold design. 

I know you've got it so you want to use it, but you should also consider selling it to someone who wants genuine, period correct parts for a gazillion dollars and then buy something more modern and top mounted that has more space for a turbo and a more efficient design

[Duncan]

just to add....keep in mind "600hp" is about 300kw at the wheels, which is not a lot these days (every second gtst seems to be making 1,127hp).

You can get there with the standard manifolds on an RB26 and probably a 25 too (not sure what car or engine you are talking about because it doesn't say on your profile)