[Closed] Borg Warner Efr Series Turbos

[zebra]

Boost doesnt affect Chamber pressure...eg a car making 500hp with a GT42 and one making 500hp with a gt3073 will have very similar chamber pressures, only thing that will throw it would be if you had a massive exhaust manifold restriction. eg a .63 garrett gt30 housing would be too small.

I know Scott will agree with me here, a housing on the larger side and good tuning of the off boost area will give a better/safer result than a tiny housing.

Only time will tell when it comes to whether the EFR integral gates can bypass enough air to keep exhaust mainifold pressures down to under 2:1 exhaust to intake pressure

Quick edit - I also belive that a large turbine housing will give a more progressive boost curve over a small one, even if full boost is reached a little later

[Legionnaire]

Boost doesnt affect Chamber pressure...eg a car making 500hp with a GT42 and one making 500hp with a gt3073 will have very similar chamber pressures, only thing that will throw it would be if you had a massive exhaust manifold restriction. eg a .63 garrett gt30 housing would be too small.

I know Scott will agree with me here, a housing on the larger side and good tuning of the off boost area will give a better/safer result than a tiny housing.

Only time will tell when it comes to whether the EFR integral gates can bypass enough air to keep exhaust mainifold pressures down to under 2:1 exhaust to intake pressure

Quick edit - I also belive that a large turbine housing will give a more progressive boost curve over a small one, even if full boost is reached a little later

Well, pressures may not be similar with a GT42 and GT30 because of different RPM at which those hp are generated. Actually, I'd even say that hp is irrelevant, torque gives more idea about chamber pressures. In-chamber pressure dynamics is a complex subject and OT here, but note how, say, HKS GT2835 usually produce higher peak torque than GT3076, although the latter makes more power. I'm looking for the smallest turbo that gives 500hp, and provides high torque over broad range of RPM, and this is usually achieved with the smallest housing rather than larger ones.

And boost pressure definitely affects chamber pressures - it is one of the reasons why higher boost pressures result in higher torque figures and why low CR-high boost is a better combo than high CR-low boost. Pre-combustion chamber pressure roughly equals to pressure at the beginning of a compression stroke times effective CR^1.4. Since compression precess in not adiabatic, the exponent is lower. You can clearly see that even pre-combustion pressure is affected by boost pressure, peak and mean chamber pressure of course is a function of VE and a pack of other parameters, but pre-combusion pressure is one of them.

EFR wastegates, as per above manual, are engineered to be enough for bypassing up to 40% of turbine flow for T2-flanged "A" housings (55 and 58mm turbine wheels) and up to 45% of turbine flow for T3-flanged "B" housing (64, 70 and 74mm wheels). "B" housing has 36mm WG port diameter and is inclined at an optimal angle for flow - so there is plenty of wastegating, I hope they allow even lower than 2:1 TIP/IMP ratios.

[juggernaut1]

I'm looking for the smallest turbo that gives 500hp, and provides high torque over broad range of RPM, and this is usually achieved with the smallest housing rather than larger ones.

I am a proponent of twin scroll housings and IMO twin scroll housings will provide the best overall torque curve where you want to run standardish rpm. They also provide a more progressive torque curve too because they make boost and torque earlier in the rpm range which is beneficial for traction deficit rwd cars.

Unfortunately the ATP adapted Garrett offerings are not native to the turbines so they may not produce the best overall performance. Adequate for 2 litre 4 cylinders but might come up a bit short on an RB25 in terms of gasflow. This is where I believe the BW EFR twin scroll turbo's will have there place.....especially considering you don't have the complexities, fitment issues and plumbing of two external gates.....and a byproduct will be less heat in the engine bay. The ex manifold design will obvious be much simpler too. Whilst the EFR turbo's might have an initially higher cost, the overall package will be much cheaper given that 2 external gates alone and associated plumbing fabrication will conservatively cost upwards of $1K - $2K. I like the robust looking bearing design of the EFR turbo's too compared to Garretts plastic cage design, especially as E85 service stations are rolled out and more boost is shovelled through the turbos.

Edited February 20, 2011 by juggernaut1

[Lithium]

GT2835s make more peak torque than GT3076Rs? I'm not convinced, if all things are equal

[badhairdave]

Has anyone else had a play with match bot?

The smaller turbos with small housings don't seem to work right. You end up venting over 40% of exhaust to keep boost in check which apparently is choke flow? I'd have thought these were the small 4 cylinder bolt ons but they seem to work better in twin config and for small 4's you need the .92 T/S t4 housing so not really a bolt on anymore and a big chunk of the market gone.

[zebra]

Insert very long post here

HP is torque with a multiplication factor.

As for low comp/high boost.

I take it you have never driven a 6.5/7:1 comp turbo car.

they are crap.

As for more boost means more torque...well yes and no.

Boost is just inlet restriction, say 1 car is running 25psi with a dead standard Rb25 and makes 500hp, then another car with the same turbo but has cams and headwork is also making 500hp but only needs 20psi to do so.

You mentioned VE and that is how efficent the engine is, the more efficient the head(s) the more power you will make (given the turbo can flow enough air in your application)

My way of thinking is, a turbo is just the air pump (sure there are good and bad ones) but its not the be all and end all of making power.

So I wouldnt be spending all my cash on just a turbo and injectors and a tune.

Find a turbo that flow the air you need and then spend some coin on the head, I give no shit that the standard head and cams in a 25 can flow 375rwkws...its pushing shit uphill to do so.

TL;DR make the engine more efficent and the power will come no matter what turbo you have.

[BMYHOE]

Hey Guys,

whats peoples thoughts on this turbo; Borg Warner s366 with extended tip.

spec;

Twinscroll T4 flange V band out beveled 4.21" Full Marmon flange

.91 turbine a/r

Flows upto 80lbs/min

Supports upto 800hp

included: T4 mounting gasket and oil drain gasket

Turbine housing V band outlet can be machined down to a flat 4" upon request after purchase if desired

Looking at selling the GT35 T3 1.06 for this... whats peoples thoughts?

its going onto a RB30 Twin cam??

Edited February 21, 2011 by BMYHOE

[zebra]

Thoughts....its big...and thats all I can tell you without knowing what you want to do with the motor

[BMYHOE]

its a track car mainly for curcuit racing but i want to do some draging as well.

the motor is dry sumped & built etc..

going to run e85 and want to rev the car to around 8000RPM would like 450RWKW any more is a bonus,..

Edited February 21, 2011 by BMYHOE

[Lithium]

I think its not an EFR turbo, and I suspect its probably a Bulls Eye power one with that naming convention. Its probably for a different thread to be honest.

EFR9180 would be a good alternative to that, and go very well on a built RB30

[BMYHOE]

I think its not an EFR turbo, and I suspect its probably a Bulls Eye power one with that naming convention. Its probably for a different thread to be honest.

EFR9180 would be a good alternative to that, and go very well on a built RB30

Your right Lithium...

i rang up GCG and got a price on the EFR9180 which wasn't to bad at all price wise.

might give them a call tomorrow and check pricing on the EFR8374 as i think this would best suit my setup..

does anyone know some running these turbos yet?

a dyno graph or something?

Thanks

Dan.

heres a pic i found of one not sure what size turbo though

Edited February 21, 2011 by BMYHOE

[BMYHOE]

heres a good link about the turbs i just found.. decisons decisons

[badhairdave]

might give them a call tomorrow and check pricing on the EFR8374 as i think this would best suit my setup..

does anyone know some running these turbos yet?

a dyno graph or something?

there's a comparison with a 3582 posted earlier in the thread.

[Lithium]

If you are going to run an RB30 to 8000rpm then I'd recommend going a bit bigger than an 8374 - it would be ridiculously torquey on an RB30 but the EFR9180 would guarantee no restriction at the higher rpm, and it will not be laggy. Having the headroom to make near 1000hp on E85 would make an unbelieveable all arounder.

[GTScotT]

If you are going to run an RB30 to 8000rpm then I'd recommend going a bit bigger than an 8374 - it would be ridiculously torquey on an RB30 but the EFR9180 would guarantee no restriction at the higher rpm, and it will not be laggy. Having the headroom to make near 1000hp on E85 would make an unbelieveable all arounder.

I encourage the to build me a 1000hp, E85 guzzling, 8000rpm spinning, not laggy RB30 with an EFR9180.

Thanks,

[Lithium]

Haha if I were building one it'd be going in an R33 GTR with LITH as the licence plate on it, I'd probably have won lotto, but you could get a ride if you came and visited NZ

[BMYHOE]

there's a comparison with a 3582 posted earlier in the thread.

do you know what page it is cause i went through the whole thread & didnt see it...

ill check over it now.

[GTScotT]

Come to Aus first and Ill take you for a wrap in a Hyundai Excel.

I will have my passengers handbook ready with the accidental death policy highlighted.

[Lithium]

do you know what page it is cause i went through the whole thread & didnt see it...

Pump gas GT3582R .82a/r (magenta) versus EFR8374 .83a/r (green) - both T3 open housing on a K20A Honda motor running 1bar of boost - clearly doesn't need huge boost or fancy fuel to give gains, and no more lag.

[BMYHOE]

Another result from someone with an Integra running a built K20A on race gas who went from a .82a/r GT3582R (around 650hp @ hubs) to an internally gated EFR8374:

If I read it right, the owner believes that with a stiffer wastegate actuator so can holds 30psi to redline could yield some substantial gains - he is pretty confident there is a fair bit left in the turbo. Very impressive gains over the GT3582R with no more lag!

HEY LITH,

can you post this agian or pm me these pics for some reason they are not showing on my computer..

Thanks mate!

**EDIT**

just seen your post thanks lith..

Edited February 22, 2011 by BMYHOE