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Guys for the 680hp forged OEM capacity rb26 8374 ar.91 is the best way to go with fastest spool and lowest lagg with that power level? Or better option is 6266 DBB with smaller ar.84 divided?

 

Which fuel?  I tend to have a strong preference for the externally gated housings btw, the 1.05 would be fine on a 2.6 I reckon -especially if you are aiming for that kind of power area.

98 octane, well it will be external wastegate i have Tial already on my twin scroll manifold. Just wanna ar.91 for the lower lagg than 1.05

Im a little scared of 1.05 ar with ~2.6l for the street car.

 

10 minutes ago, Snara said:

Im a little scared of 1.05 ar with ~2.6l for the street car.

I don't know anyone who have gone with the 1.05 and regretted not going smaller, I know plenty who have gone the other way though.

  • Like 5

8374/1.05 over a 6266/0.84 ALL day. 

Nismo 3.2ish went between those two turbos and the 8374 was on significantly earlier.

Buraz went from a 6262/0.84 to a 9180/1.05 and down low it drove MUCH better.

8374.. do it.

  • Like 2
5 minutes ago, Piggaz said:

8374/1.05 over a 6266/0.84 ALL day. 

Nismo 3.2ish went between those two turbos and the 8374 was on significantly earlier.

Buraz went from a 6262/0.84 to a 9180/1.05 and down low it drove MUCH better.

8374 1.05.. do it.

 

Ftfy :)

Also, bare in mind the 6266 turbine is the same one used on the 6466 and 6766 - so for all intents and purposes from the Precision range it is probably not really apples and apples with the 8374 turbine, and more comparable with the one on the 9180.   

I have in my head you already have a GTX3582R... I'm not 100% sure that it'd be worth changing unless you have a really good reason?  What is the motivation for the turbo change?

  • Like 1
42 minutes ago, Lithium said:


I have in my head you already have a GTX3582R... I'm not 100% sure that it'd be worth changing unless you have a really good reason?  What is the motivation for the turbo change?

Yes i have chinese GTX35 with bigger intake wheel [in 63/ex 87 mm] with open t3 0.82.

On 27 psi it make 635hp :P 

It feel laggy, even after change gear it build the boost from 1.5 to 1.9.

4th gear spool video

100-240kmh video

 

Thanks Piggaz, Lithium i going for 8374/1.05 :11_blush:

 

Edited by Snara

Well i can w8 a few months :P Yes but i think G25-660 is too small to hold 660hp in 2.6l for the 8200 rpms. And it have max flow rate 61 lb/min while efr 8374 have 79 lb/min. But we will see in january potential of G25 orrr maybe G30 later.

5 hours ago, Snara said:

Well i can w8 a few months :P Yes but i think G25-660 is too small to hold 660hp in 2.6l for the 8200 rpms. And it have max flow rate 61 lb/min while efr 8374 have 79 lb/min. But we will see in january potential of G25 orrr maybe G30 later.

They did say on one of their sites that there were other models coming soon, but so was the 8474  :) 

On 07/11/2017 at 10:11 AM, Snara said:

Well i can w8 a few months :P Yes but i think G25-660 is too small to hold 660hp in 2.6l for the 8200 rpms. And it have max flow rate 61 lb/min while efr 8374 have 79 lb/min. But we will see in january potential of G25 orrr maybe G30 later.

Yeah I was more thinking about the potential for a G30-range :)

 

  • 3 weeks later...

is anyone using an Emap sensor with these turbos?

I'm going an emtron KV8 and the fuel model has EMAP compensation calculated from compression ratio, so I'm adding an EMAP sensor.

I have a single turbo 2.6l rb26, running an EFR8374 with a 1.05 rear and boost up to maybe 32-33psi depending where top speed is.

what kind of peak emap am I likely to see at sea level on a cool day? i want to use a sensor that has the span but don't want to lose too much resolution if possible. being conservitive im guessing 2.5x is a possibility?

5 bar abs sensor?
7 bar abs sensor?

thanks.

matchbot is telling me for 32psi of boost at redline its only 40psi EMAP. that seems very low considering its way off its efficiency there (compressor is at stonewall)

Edited by burn4005

Compressor efficiency doesn't really have an impact on what the ex manifold pressure needs to be.  That's a function of how much power is needed to drive the compressor to do that work times the various factors involved. Granted, comp efficiency is one of those factors.  But the big one is what the match between the exhaust side and the comp side is like.  OEM street turbos are very likely to end up with 2+ times boost pressure in the ex manifold.  Outright race setups where the engine is supposed to be run flat out up on the power curve all the time might be as low as 1x boost pressure.  So it's not surprising that a well matched EFR only wants to do a reasonably small factor on top of boost pressure.  You'd very much expect a turbo chosen for a performance application to be <2x.

2 hours ago, burn4005 said:

is anyone using an Emap sensor with these turbos?

I'm going an emtron KV8 and the fuel model has EMAP compensation calculated from compression ratio, so I'm adding an EMAP sensor.

I have a single turbo 2.6l rb26, running an EFR8374 with a 1.05 rear and boost up to maybe 32-33psi depending where top speed is.

what kind of peak emap am I likely to see at sea level on a cool day? i want to use a sensor that has the span but don't want to lose too much resolution if possible. being conservitive im guessing 2.5x is a possibility?

5 bar abs sensor?
7 bar abs sensor?

thanks.

matchbot is telling me for 32psi of boost at redline its only 40psi EMAP. that seems very low considering its way off its efficiency there (compressor is at stonewall)

Who is your tuner?  Sounds like questions you should be talking to them about as that's who you work with an need to be on the same page with.  I'd be content with a 5bar sensor, myself - I'd not want to be going over 500kpa one way or another.

Just for sanity here, 32psi boost and 40psi are equal to 318kpa IMAP, 372kpa EMAP at 100kpa baro.   I'm pretty sure @Piggaz said his EMAP peaked at 360kpa and he was getting ~122000rpm so loosely speaking the Matchbot numbers sound fairly on point.  

The EFR8374 with 1.05a/r seems a really really good match between compressor flow, turbine flow and response for a "nice" sub 3litre responsive RB setup - turbine inlet pressure is essentially starting to climb relative to inlet manifold pressure when you hit stonewall, so still "breathing" well while also not wasting turbine energy in the "transient" turbine rpm range.

Edited by Lithium

I'm the tuner. have never seen results of EMAP from an EFR so was a sanity check. will start with a 5 bar sensor and see how we go with that.

using one of these with a honeywell PX2 sensor and stainless tubing to the T04 collector of cyl1-3:

http://fullfunctioneng.com/product/ffe-emap-canister/

20151022_113226-e1446044231578-349x300.j

 

I'm running 8374 EFR .92 on a 2.75L stroker and it's ALL IN at 3600 rpms. Actually on the new EMU Black (just switched from Haltech Platinum) I accidentally setup the boost wrong and it made 36 psi at 4700 rpms!! Anyway I do like the .92 IWG for simplicity and I think 2.6L guys pass them up for some reason, but I think it is a good fit on a 2.6L. That being said...I'd still go with an external gated solution because of exhaust housing options. That .92 housing looks like a "catch-all" housing and my ONLY upgrade from here is a 9180 .92...which seems counter productive at my level.

About matchbot - Fuel is a HUGE driver on it. Look hard between pumpgas and E85...I have recently considered the jump to E85 (actually redoing all of my fuel now in preparation for it), but ALL of these turbos really take off and stretch further on it. They are better in the compressor maps as well if you pay close attention to what they are changing. I am at 636 whp on 21 psig with 93 octane and a *little* water meth just to fight knock on the street (since I haven't installed my giant intercooler yet) and I get an extremely responsive fullboost at 3600 rpms. If you really plan on running 30 psi you will likely need to taper off boost as fast as it onsets to keep speeds down. On pumpgas at 21 psi I'm already at the limit on the 8374 .92 on top end. E85 will stretch this a good margin, but 30 is just going to blow tires or break things for sure as hard as the car already pulls. 

very interested to see what i'll be getting with boost control setup on mine. Just using the WG (turbosmart) only getting 14psi at 4000ish RPM, i wonder if there's something else in my setup bringing it back a little compared to yours, or something that i'll pick up in the tune...

Need to get the engine back in and get cracking I think

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