BorgWarner EFR or Holset?

[A6_quattro]

Hi all

Think this is my first post here.

I would like some advise regarding choice of turbo on my Audi S6 2,5 stroker.
I'm currently running E85 with an super HX35 and would like to hit 600 - 700 hp on the crank. Is the EFR 7670 worth more than double price compared to Holset super HX40?

How is the spool-up and durability on the 7670?

Regards
Hans

[Ruffiano]

EFR easily, such a better design than a holset

[rst]

I am owning Holset HX40 super but if i had to choose again turbo then it would be Borg Warner EFR series or Precision.
EFR8374 would be more comperable to HX40S. These two have roughly the same size compressor and turbine wheels. EFR should spool ~300rpm faster (efr 2bar boost about 4000rpm, hx40s 4300rpm) and respons would be much better.

At the moment this site has very good price for EFR turbos to the end of the year.

http://www.turbozentrum.de/en/turbos-co/borg-warner-efr/

[Billman]

EFR is more high tech than the holset. Impeller design and efficiency should be the same but the EFR should spool faster due to the bearing and Gamma Ti turbine material.

Holset's are cheaper easy rebuildable and super durable.

EFRs reliability is yet to be found out as very few run them.

[A6_quattro]

Thanks for quick replies!

Ok, seems like the EFR is the better choice after all despite the pricing of it.

Regards
Hans

[Tille]

Sunday i mapped my first EFR. 2.2l with Sportquattro exhaustm. with 9180 1.05A/R internal WG, n75 and blowoff. 4th Gear 2bar@5000rpm. This turbo is able to produce 900hp+.

I think EFR Turbos are really good. I would wait for reliable experience.

Greetings.

[orignalS60]

EFR is the latest and greatest in turbo technology.
I know Hank @ Iroz motorsports shop car (urs4)
makes over 700whp & 500wtq with really nice spool.

[Thuppu]

4th Gear 2bar@5000rpm. This turbo is able to produce 900hp+.

Holset Pro52 will perform the same, or at least really close.

[A6_quattro]

The thing that concern me about the super HX40 is the lag. The performance at high rpm´s is good but the car is a street car so I want as early boost as possible. I know that I have to compromise between high power and early boost.
I'm really ambivalent when it comes to choose the turbo now and maby the Holset is a good compromise for the money...

[Thuppu]

Well, you get two HX40S for the price of one EFR8374. Maybe the spool and responce is little better with the BW but have anyone compared them with the same setup..? So can't be sure about it. At least Holset is super reliable. HX40 is usually choosen with a #16 turbine housing that is a good compromise between spool and top end power. It's also available with a smaller #14 housing.

[A6_quattro]

I've searched for som dyno comparisons with the same setup between the two but don't had any succes. Would be very interesting to see the diferences.

When it comes to the cost of buying one the Holset is definatly the winner and the money left you could spend on other performance stuff. At the end maby the differences is only detectible in the dyno...

[vti2]

Pick up a nice K27 From Vidaar here or from TTE and you have a State of Art Turbo.

[rst]

EFR comes with internal WG, bypass and boost solenoid. Also you dont have to make separate exhaust pipe for WG. So all in all EFR will not be twice as price as holset or any other regular turbo. On 2.2t for me at least hx40s 16# is too laggy, max torque is at 5000-5500rpm depending on setup.

[PRY4SNO]

If spool and transient response are your primary goals, the EFR is your winner. Hands down.

If initial cost is your primary concern, the Holset is your winner. Hands down.

They may perform similar jobs, aka forced induction, but the way they produce results puts them in different categories.

[Ruffiano]

Pick up a nice K27 From Vidaar here or from TTE and you have a State of Art Turbo.

... a k27 even with a billet wheel might be a piece of art, but is NOT new technology.