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968 3.0 16v turbo. Anybody got any experience with a Garrett gtx 3076

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968 3.0 16v turbo. Anybody got any experience with a Garrett gtx 3076

Old 10-27-2018, 02:11 PM
  #31  
gruhsy
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Because you are in the middle of building the intake read this article. I posted the thread the other day. The bell mouths for your intake.

http://www.profblairandassociates.co...mouth_Sept.pdf

https://rennlist.com/forums/944-turbo-and-turbo-s-forum/1105221-intake-bellmouth-design-read-i-found.html
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Old 10-27-2018, 06:02 PM
  #32  
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Old 10-28-2018, 08:51 AM
  #33  
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Originally Posted by Paulyy View Post
I would still suggest going with a GTX3576R with a twin scroll if your going for the TS approach.
Note that im not saying a GTX3582R but a GTX3576R which is a GTX3076R with a bigger turbine wheel more suited for the compressor wheel and also more suited for a 3L motor.

IMO a GTX3582R is the perfect size for a 3L build. the GTX3576R is a step down.

Also some side info. People had discovered after modifying the turbos by swapping wheels around that the gtx3576r configuration even though being a bigger framed turbo, it out performed the gt3067r in every way... That's when garrett started offering that size turbo.
and also Ford Australia used that size configuration on their 4L engines.
Yes I agree it was actually a typo in my last post I meant gtx3576R after yours and others recommendations. Your preferred choice would be the 82R. What would be the real life difference between the two at what point would you expect full boost in the Rev range. I put a large turbo on my 951 some years ago and it was very laggy and only made power late in the Rev range it was quickly changed. We are running 9:1 compression on this 968 engine and standalone ecu. The ecu on my 951 is made by a British company called DTA but I think we will use a more upto date ecu for this car. I think the boost was also mapped to the throttle position which seemed to work well. I donít want to put a spanner in the works at this stage as I need to purchase the turbo ASAP, but where does the new G series turbo fit in relation to these gtx turbos do they make a twin scroll version. Garrett seem to be marketing them as the new chapter in turbo development.
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Old 10-28-2018, 08:52 AM
  #34  
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Originally Posted by Humboldtgrin View Post
Does this design have a specific function or is it just increased plenum capacity.
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Old 10-28-2018, 09:00 AM
  #35  
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Originally Posted by Northern porker View Post
Is the motor 16v. Like the car looks a bit like my 951


Thanks for the info a bit of light reading for the weekend. In summary am I right in thinking that the trumpet with the largest radius flute and angled sides flows the greatest amount of air ie is more beneficial to performance design.
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Old 10-28-2018, 09:03 AM
  #36  
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Originally Posted by Northern porker View Post
Does this design have a specific function or is it just increased plenum capacity.
Sorry posted response to wrong person please see above.
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Old 10-28-2018, 11:14 AM
  #37  
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A dual plenum accualy has a purpose. https://www.bufkinengineering.com/in...0manifolds.htm
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Old 10-28-2018, 01:39 PM
  #38  
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Originally Posted by Northern porker View Post
Yes I agree it was actually a typo in my last post I meant gtx3576R after yours and others recommendations. Your preferred choice would be the 82R. What would be the real life difference between the two at what point would you expect full boost in the Rev range. I put a large turbo on my 951 some years ago and it was very laggy and only made power late in the Rev range it was quickly changed. We are running 9:1 compression on this 968 engine and standalone ecu. The ecu on my 951 is made by a British company called DTA but I think we will use a more upto date ecu for this car. I think the boost was also mapped to the throttle position which seemed to work well. I donít want to put a spanner in the works at this stage as I need to purchase the turbo ASAP, but where does the new G series turbo fit in relation to these gtx turbos do they make a twin scroll version. Garrett seem to be marketing them as the new chapter in turbo development.
2-3 hundred rpm spool difference i would guess. depending on boost levels you should be full boost 3200-3800 rpm.

The G series turbos are they new flagship series. unfortunately they only have 2 variants and there's no twin scroll option. I had spoken to Garrett about a twin scroll housings for these and they said due to the design and such small frame, there's no real world benefit.
It's hard getting numbers of such a new turbo, but there's a skyline that produced 1200 rwhp on 2 G25-660 turbos. so the claimed 660hp is plausible.

I probably wouldn't put a G25-660 on a 3L i think it may be a little small unless it's a full on street car setup then maybe i'd consider it. You'd want to put the .92 housing on it as that's slightly smaller than the .82 on the GTX35 frame.
I would imagine that would be spooling up at 2500 rpm. probably sing to 6krpm. just don't know how restrictive the housing would be for a 3L
That would be a shot in the dark though.
I would think that would be close to a "what would porsche put on a 3L in today's world" type of situation.

It's really all about what you want to achieve with the car. And also note that where you'll be driving it if it's a street car. Here in melbourne, having a laggy car isn't bad, we dont have small roads ect so having big turbos is fine for us here.
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Old 10-28-2018, 08:03 PM
  #39  
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Originally Posted by Humboldtgrin View Post
A dual plenum accualy has a purpose. https://www.bufkinengineering.com/in...0manifolds.htm
I noticed that there was a 90 or 180 degree turn after the TB before entering the plenum, I am assuming for flow characteristics. With the 180 the throttle body appears fairly removed, what happens to the throttle response? On your version are you having the air enter the front or the back of the plenum?
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Old 10-28-2018, 11:00 PM
  #40  
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I'd go the next size up on the turbine housing if it is twin scroll, the 83 is too small.
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Old 10-29-2018, 08:03 AM
  #41  
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Originally Posted by Paulyy View Post
2-3 hundred rpm spool difference i would guess. depending on boost levels you should be full boost 3200-3800 rpm.

The G series turbos are they new flagship series. unfortunately they only have 2 variants and there's no twin scroll option. I had spoken to Garrett about a twin scroll housings for these and they said due to the design and such small frame, there's no real world benefit.
It's hard getting numbers of such a new turbo, but there's a skyline that produced 1200 rwhp on 2 G25-660 turbos. so the claimed 660hp is plausible.

I probably wouldn't put a G25-660 on a 3L i think it may be a little small unless it's a full on street car setup then maybe i'd consider it. You'd want to put the .92 housing on it as that's slightly smaller than the .82 on the GTX35 frame.
I would imagine that would be spooling up at 2500 rpm. probably sing to 6krpm. just don't know how restrictive the housing would be for a 3L
That would be a shot in the dark though.
I would think that would be close to a "what would porsche put on a 3L in today's world" type of situation.

It's really all about what you want to achieve with the car. And also note that where you'll be driving it if it's a street car. Here in melbourne, having a laggy car isn't bad, we dont have small roads ect so having big turbos is fine for us here.
Thanks useful information. We have a lot of tight roads in England and Mallorca particularly Mallorca where the car will be staying for the next couple of years and a lot of our race tracks are quite technical and tight. For this reason quicker spool and throttle response would be more important than outright power. I know a lot of people are chasing big power for street and certain race applications and that 500 bhp is old hat for these engines, But I want an engine l can really drive and push as I am certainly no pro driver so I think the slightly smaller GTX35 would be the better choice for me. I also think that past this power level I would have to seriously look at the chassis and drivetrain and reliability is very important to me as I am no mechanic. This info is a great help.
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Old 10-29-2018, 08:04 AM
  #42  
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Originally Posted by thingo View Post
I'd go the next size up on the turbine housing if it is twin scroll, the 83 is too small.
What is the next size up and what effect does it have on the turbo.
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Old 10-29-2018, 08:30 AM
  #43  
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Follow Rod's advice. He's built a few of these and speaks from experience.
These 3lt 16v turbos breathe very well and the extra capacity will take care of lag. You don't want to compromise flow in the upper rpms with too small a housing. It will just go into choke and potentially cause other problems with egts.

If you want to reply to multiple people just click 'Multi Quote' at the bottom rh side of their posts. Click on each one you wish to reply to and then hit reply at the bottom of the page. You can then answer everyone in a single post. Good luck with the build.
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Old 10-29-2018, 09:00 AM
  #44  
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On my 3L 8V I tested GTX3076R 0.82 -> GTX3076R 1.06 -> GTX3576R 0.82, all with Tial housings.
The GTX3576R 0.82 has been the best configuration for my particular engine and I strongly doubt that a GT30 frame turbo would suit a 16V engine.
If you stick to standard 968 camshafts I would imagine that a GT35 0.82 housing would still be large enough.

I would not spend the extra for any of the Gen 2 GTX turbo. They seem a lot more pricey than their Gen 1 counterparts and the compressor maps suggest less efficiency.
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Old 10-29-2018, 10:00 AM
  #45  
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Originally Posted by Northern porker View Post
What is the next size up and what effect does it have on the turbo.
use the 1.01 like this, and use a Garrett housing

https://gcg.com.au/petrol-performanc...1-01a-r-detail


there is also a v band twin scroll available. Because itís divided you can go up a size in a/r

Dont go too big on the crossover pipes. The 16V is a great engine.

Thatís a Brey Krause brace in the pic, Iím not sure if they are still available but there are other types around. I think they help.
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