Jump to content
SAU Community

Recommended Posts

Hello. I am in the finishing stages of a 3.2L gtr build and was settled on using g a G42-1450 but the more I read about the 9280, the more I'm starting to sway. It won't give me the same peak power but might make it a faster car due to better responce and torque while still netting a 4 digit dyno sheet. Im thinking 1.45 twin scroll rear housing. What do you guys think?

The power target would be helpful with this discussion

Generally speaking, most people I know who have tried the EFR9280 have not been particularly blown away so far, exhaust back pressure seems to be a thing - especially on bigger engines... if you're going to do it then the 1.45a/r hotside is the only option I'd consider.  The G42 1450 is definitely going to flow better but also most definitely comes at an impact to response, in fact one of the guys I know went to a G42 1200 from an EFR9280 and that delivers power in the higher rpm better but even that turbo added reasonable lag over the EFR.

 

  • Like 1
7 minutes ago, Lithium said:

The power target would be helpful with this discussion

Generally speaking, most people I know who have tried the EFR9280 have not been particularly blown away so far, exhaust back pressure seems to be a thing - especially on bigger engines... if you're going to do it then the 1.45a/r hotside is the only option I'd consider.  The G42 1450 is definitely going to flow better but also most definitely comes at an impact to response, in fact one of the guys I know went to a G42 1200 from an EFR9280 and that delivers power in the higher rpm better but even that turbo added reasonable lag over the EFR.

 

Interesting that everyone is saying back pressure is a thing  - I assume that is only once you starting pressing out 900+hp?

Here is my 8474 using 1.05A/R on 3.2L Nitto.  about 750hp at hubs.     eMAP/MAP is rarely over 1.2:1  as you can see here 1.17:1 @7515rpm     

Yes circuit car, not Drag car - but I guess I this would be around 800-820hp at the engine - at what point does exahsut pressure become a problem - ?   Or do you think I already have a problem...?

 

Screenshot 2021-04-16 124204.png

1 minute ago, R32 TT said:

Interesting that everyone is saying back pressure is a thing  - I assume that is only once you starting pressing out 900+hp?

Here is my 8474 using 1.05A/R on 3.2L Nitto.  about 750hp at hubs.     eMAP/MAP is rarely over 1.2:1  as you can see here 1.17:1 @7515rpm     

Yes circuit car, not Drag car - but I guess I this would be around 800-820hp at the engine - at what point does exahsut pressure become a problem - ?   Or do you think I already have a problem...?

 

Screenshot 2021-04-16 124204.png

Nice!  Awesome to finally see some data on the EFR8474 looks really solid in terms of what the data is saying about it - I'd be happy with that EMAP at that power.  What is odd though, and seems to be a bit of a trend...  where your IMAP is, and where your turbine speed is lines up with 90lb/min of compressor flow.   Do you reckon you're making the power you'd expect when your compressor speed and boost level suggest you are pushing at least 90lb/min of air?  This is part of what I've been told from people who have tried black series EFRs, they aren't getting the numbers they were expecting before they run out of compressor speed but perhaps the expectations need to be adjusted?

And yeah, the back pressure comment was about people looking at making use of the >100lb/min rated compressor flow of an EFR9280 - so closer to the 1000hp @ hubs territory, unfortunately I don't have first hand data so much as just going from people who I'm spoken to who have used them.  

  • Like 1

back pressure not relevant to compressor flow. (in the context of the operating point on a compressor map. yes, it affects VE)

but remember that 2.6 bar gauge inlet pressure will end up being more like 3.7 absolute PR (Possibly higher) once you factor in the inlet filter and intercooler pressure drops, which crosses closer to low 80s flow point at that wheel speed.

i'd be happy with 750hp at the hubs at this operating point. 900 at the hubs through diffs and gearbox flowing ~85lb/min is asking a bit much isn't it?

the Motec will have a logged VE calculated airflow. if your injector data is good and you lambda=target the Motec calculated airflow will be accurate if you wanted to verify.

Edited by burn4005
  • Like 1

Sorry what I meant was, in answer to this question - "Do you reckon you're making the power you'd expect when your compressor speed and boost level suggest you are pushing at least 90lb/min of air?"    -  I'd say 'I think so',  given the restriction to overall flow caused by eMAP.       

Would that be correct?  Or am I misunderstanding?

 

 

13 minutes ago, R32 TT said:

Or am I misunderstanding?

Probably misunderstanding. The compressor map should be viewed as a statement of fact. If the shaft speed is Z and the PR is Y, then the flow on the X axis that corresponds to that operating point is what the turbo is flowing. That flow is happening regardless of the restriction caused by the EMAP. If the EMAP were some different value and your turbo was operating at that same point, the flow would still be the same value. Make sense?

I think the element of surprise exhibited by other posters above is that the operating point you describe sounds like you shoudl be making more power than you think you are, which starts to throw some doubt on the factiness of the compressor map (or perhaps the measurements you have to put the operating point on the map).

  • Like 2

The trick is there seems to be a trend of this from the few black series EFRs I've seen results in, at least one tuner I've spoken to has decided it's a back pressure issue but this data doesn't suggest that to me.  The trick is I don't know where to go with it beyond the possibility that the compressor map or something about the data is not accurate which I'm not going to leap to concluding.

If you follow the compressor map the line where 116,000rpm sits hovers over 90lb/min until about PR3.2 which I would be surprised if it is reaching that high, but never know. 

Fwiw Gen2 GTX3582Rs fall fairly short of 90lb/min on the compressor maps and cars have made more power at the hubs than this on E85.  Not hating at all, I would prefer an 8474 over a GTX3582 but there are things I still have some question marks about

Yes all good - the only way for me to know is swap to a GTX3582 or 6466, perhaps 6870 to compare.  A fair bit of money just to experiment though,  and then - will I miss how it drives...?     that said the 8474 is noticeably lazy compared to the 8374 for just an inducer change.  Its not the "same down low but more up top" the internet seems to suggest.  

Edited by R32 TT

You know Elon Muskrat has won a contract with the Lebanese space agency to make a special Uranus probe lander mission using emotionaltron ECU and GTST body shell with special hiflow fitted with EFR black series internals using all the hypothesis off this forum, he was saying the key is the independent staged drive by wire and keeping the turbo on the small side cause when you do a hektik launch everyone knows that its area under the curve that is important when going to Uranus

  • Haha 1
On 4/16/2021 at 5:28 PM, R32 TT said:

Yes all good - the only way for me to know is swap to a GTX3582 or 6466, perhaps 6870 to compare.  A fair bit of money just to experiment though,  and then - will I miss how it drives...?     that said the 8474 is noticeably lazy compared to the 8374 for just an inducer change.  Its not the "same down low but more up top" the internet seems to suggest.  

Yes, yes... Come to the dark side

  • Like 1
  • Haha 2
15 hours ago, SimonR32 said:

Yes, yes... Come to the dark side

Run an OPR and an oil filter and they will last, at least they won't shit out turbine wheels if you accidentally over speed them :)

2 minutes ago, Dose Pipe Sutututu said:

Run an OPR and an oil filter and they will last, at least they won't shit out turbine wheels if you accidentally over speed them :)

Have been over speeding my 8374 by a few 1000 rpm since the day it was put on 2017. Was pulled off a few weeks ago in perfect condition. No shaft play, no missing turbine wheel. 🤷‍♂️

  • Like 2

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • A 180SX has a much better look than a FD. The roofline is far superior being a fastback. It's popups look better. In a world where we all subconsciously add a little bit of low, and wheels of our preference, it's just more handsome than the FD is. The FD just looks 'bubbly' in comparison. It can come down to preference, sure. But "The FD is the BEST looking (on appearances alone) 90's JDM car without question?" Nah. Plenty of questions lol. I could think of 8 cars I think look fundamentally better, and probably a handful of ones that look about on par with a FD. (like say a SW20 MR2) I feel people like/overrate the FD because of it's mythicality/rarity, its rotary and it's unpredictable nature. It probably drives great, you can stuff a ton of tyre under there, has a unique sound, light as hell. I feel that people reading this thinking "YOU CANT RATE A 180 ABOVE A FD BECAUSE A 180 IS A CHEAP DRIFT BUCKET" prove the point about bias as to what the car represents, moreso than how it actually looks.. And this thread is purely about looks :p
    • A red or yellow S15 wins my vote, Ack that it just scraps in with the 90's cars theme, but they are great looking little sports car Next would be a A80 Supra (pre face lift), whilst the A80 has its own issues, I feel is the best looking larger GT car As for the FD, "I" feel that the reason it triggers me in a non-positve way when looking at one, is like looking at a high maintenance pretty girl who you know is mentally unstable and likely to explode for no apparent reason
    • Yes, it's because it has hips and bulges on the top/front surface, a tiny cockpit and roof, and the skin looks like it is stretched over muscle. The proportions are....perfect. Long nose, short rear, short roof. What's not to like? It continues the theme started with the S1, that peaked with the FC, being "looking like a front engined Porsche", while gaining a little more of the 60's Mustang coupe profile and stretching the skin more tightly over the understructure. The FD is definitely colour sensitive though. Like all Mazdas. There are plenty of details on it that changed over the years that were either better or worse, could have been done better the first time and/or never changed for the worse. But...the same can be said for the NSX. In fact, that's probably even more true for the NSX. I've also just worked out that part of the reason I don't like the rear of the NSX is that the integrated wing is too similar to that shitful R33 rear wing.  
    • I wonder if people like the FD because it reminds them of old 60's roadsters and such. It just gives me such a 'roadster/soft cruising' vibe as opposed to anything more hard-edged and purposeful. That, mixed with 90's melted soap bar styling. It's hardly ugly, but it's kinda oddly proportioned to me, relative to about 10 other cars I had a think about based on this thread. 
    • Well, unless you are prepared to do it yourself, or to pay someone for a lot of labour, you don't want to move the rear camber around much at all. Close to stock length on the rear upper arms (both the RUCAs and the tension arms) will minimise the addition of bump steer. That means you should probably be satisifed with whatever neg camber you end up with as a result of it being lowered, and not try to dial too much of it out. Dialling it out by making big changes to the RUCA length will require effort put into tuning the length of the tension arms. And, apart from front caster and toe at both ends.....that's all there is to talk about. So, yes, toe settings, pretty much.
×
×
  • Create New...