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New BW EFR turbos coming soon through FR!!!!

LittleBlueGT

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integroid Proficient

integroid

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A sleeve is well over 3mm thick of iron. We don't have 1mm of iron in our blocks

 

 

LOL, still fighting it even though everyone has pretty much stated you are wrong including Geoff at Full Race.

 

Every aluminum block I have built has had factory sleeves in it that were iron. I didnt see why the Subaru block would be any different.

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Scooby2.5 Grand Master

Scooby2.5

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You lose again weiner, give it up

 

Dictionary:

liner

noun

a lining in an appliance, device, or container, esp. a removable one, in particular

• the lining of a garment.

• (also cylinder liner) a replaceable metal sleeve placed within the cylinder of an engine, forming a durable surface to withstand wear from the piston

 

 

 

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ClimberDHexMods Grand Master

ClimberDHexMods

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incorrect... most aluminum block engines (subaru included) have cast iron sleeves, which are ribbed externally and then the block is poured around that.

 

something i learned from the cosworth machinists is that many subaru blocks do not have perfectly straight cylinders, so when cosworth builds motors they will sometimes reject brand new subaru blocks because the machinists there demand such precise tolerances

 

sarg - i agree, the most efficient turbo setup possible combined with conservative timing is the way to go.. ive never understood some of the aggressive ignition timing or small turbo philosophies, it just doesnt work nearly as well in the real world

 

A lot of established folks are saying exactly this, to make power with boost, not timing. At least per this thread, hopefully the EFR units will make this more livable in traffic and around town.

 

Geoff I'm dying at your recommendation for folks to go with the 7670 for big street use. It is almost the same compressor map as the S200SX 75-70, which no Subaru has ever used in straight BW form TTBOMK. If people start buying the 7670 all of a sudden, it will only be because of your recommendation, and I would bet money on that. It appears Subi folks jump from singlescroll anything right up to twinscroll 35R or greater, with very very few exceptions of twinscroll <35R. I too see the 7670 as being a street beast. The S200SX 7570 was spectacular on an EVO, can only imagine it on a 2.5L with upgraded bits... Hope to work on this project with your help in the future.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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Sarg Explorer

Sarg

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I am not sure that the 7670 is going to be for "big" street use. I think it is just going to be more of a spool happy little turbo that is 30Rish in size.

 

Personally on the 2.5 block that is the absolute smallest I would go. With a 35R sized Borg we were able to make 12 psi off the line, 28 psi by 4700 in 3rd (6 speed) and 28 psi by 4200 in 4th. That to me is just about right. I guess it is all about what you are trying to accomplish. It's probably not good for autocross, but then again, I don't spend too much time racing around parking lots.

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LittleBlueGT Grand Master

LittleBlueGT

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Which one of the "bolt-on" turbos would have the same or greater top-end vs. a 20G or 68hta, but much better spool. Also, are all variants offered TS? Which TS piping do you have to use?

 

I would think the 6758 in SS would.

 

It might not reach 20 psi in 3rd at 3100 rpm like a 68hta, but it would likely match the spool of a 68hta in the lower gears, which is what matters. It would also have quicker boost recovery when above the boost threshold point, and react quicker to partial throttle adjustments mid-corner, or while adjusting your 40 mph drift in the snow.

 

For TS (FR should have a full kit minus intake for that soon) the 7064 would likely respond the same as the 6758, but have a bit more top-end. Get the 0.92 a/r T4 TS turbine housing.

 

FWIW someone on NASIOC posted some prices, and they were in the 1700 range. Not sure if that is correct or not, but it seems like the street price will be a lot better then $2500 for the 7064 and 7670.

 

All the above is just MO.

Full tune of 68HTA, KSTech 73 MAF, Racer X FMIC and ID1000s................by the DataLog Mafia!!!
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praedet Grand Master

praedet

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Would the 6758 come in TS? I would rather keep the same top-end as the 68hta and get even better low-end...

 

I understand the comparison you are making about low gears though...

 

Here is the part I am trying to get from the literature.

 

Lower mass turbine wheels only effect transient response, not boost threshold per say. Blade Aero is what pushes boost threshold down.

:spin:
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ClimberDHexMods Grand Master

ClimberDHexMods

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Can somebody help me out with the Flow vs RPM calcs for these? The SquirrelPM utility gave me the following RPM plots:

 

I haven't done the actual math yet (and am hoping to not need to), but don't know VE on a stock motor anyways... anyone have a better reference set straight away?

 
RPMx1000	2	3	4	5	6	7	choke
lbs/min 	19	32	39	43	47	49	64
kg/sec  	0.14	0.24	0.29	0.33	0.36	0.37	0.48

 

Note: Multiply lbs/min by 0.00756 to get kg/sec.

 

Just putting these points on an EFR 7670 map, the outcome is downright nasty. Compressor efficiency can be kept above 70% from 3-7k rpm if you're not afraid of boost... and I'm not.

 

Edit:

These Calcs are probably a lot better, but aren't much for the turbo spinning out to 7k at really high Pressure Ratio, and don't account for compensations such as intercooler pressure drop.

 

kg/sec	lb/min	L	RPM	VE	Boost	PR
0.08	10.3	2.5	2000	90	10	1.8
0.16	21.7	2.5	3000	90	20	2.5
0.26	34.8	2.5	4000	90	27	3.0
0.33	43.6	2.5	5000	90	27	3.0
0.40	52.3	2.5	6000	90	27	3.0
0.46	61.0	2.5	7000	90	27	3.0

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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sumfoo1 Rising Star

sumfoo1

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Climber, when playing with engine parameters I usually go to not2fast turbo calculator with either a dyno of the stock car or sae crank numbers and reverse engineer the VE from that. Then I take those numbers and increase boost etc.
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Full-Race Geoff Apprentice

Full-Race Geoff

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A lot of established folks are saying exactly this, to make power with boost, not timing.. It appears Subi folks jump from singlescroll anything right up to twinscroll 35R or greater, with very very few exceptions of twinscroll <35R. I too see the 7670 as being a street beast. The S200SX 7570 was spectacular on an EVO, can only imagine it on a 2.5L with upgraded bits

 

agreed on all points!

 

Would the 6758 come in TS? I would rather keep the same top-end as the 68hta and get even better low-end...

 

For the setup you are proposing, i would tend to lean towards the 7064 Twinscroll, .92 a/r and dual internal gate setup. I expect this would outperform the 6758 in a twinscroll - in all respects.

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Hops Grand Master

Hops

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For the setup you are proposing, i would tend to lean towards the 7064 Twinscroll, .92 a/r and dual internal gate setup. I expect this would outperform the 6758 in a twinscroll - in all respects.

 

That's exactly what I want! I emailed you earlier... Need a manifold and V-band downpipe.

Buy my cars!
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