[Closed] Borg Warner Efr Series Turbos

[sneakey pete]

I understand that the 8374 does come on early, yes, but how much earlier would the 7670 be is the crux of the issue, in effect. I'd happily trade 50-80kw out of the top end for say*, 500rpm earlier boost and even better transient response. I'm not going to miss those 50kw on the street. I may on the track but i'd only be there for fun so I guess i'd just have to steer better to make up for it

I'm going to try hunker down tonight and get my head around the BW turbo selection system.

*yes I understand its probably a bigger difference than that if I were to properly lean on the 8374, but honestly I probably wouldn't lean on it to get that extra kw's up top.

[XGTRX]

I think the 7670 on a 2J did OK but only got spun to 6500 and it was all happening by 3500.

[NISR32.5]

Will you have problems running the 7670 to hard? Over speed?

[HarrisRacing]

I understand that the 8374 does come on early, yes, but how much earlier would the 7670 be is the crux of the issue, in effect. I'd happily trade 50-80kw out of the top end for say*, 500rpm earlier boost and even better transient response. I'm not going to miss those 50kw on the street. I may on the track but i'd only be there for fun so I guess i'd just have to steer better to make up for it [emoji14]

I'm going to try hunker down tonight and get my head around the BW turbo selection system.

*yes I understand its probably a bigger difference than that if I were to properly lean on the 8374, but honestly I probably wouldn't lean on it to get that extra kw's up top.

I honestly don't think it will be as large of a difference as you think. You've got cams which moves your VE up to the top end and VE decides a whole lot about response. I think it's backwards thinking to try to put cams in a motor then put a smaller turbo on. My match bot has what I think are pretty good VE numbers in them. Also the haltech thinks in VE numbers so I'll see what my map looks like today and give you an idea where to start. I will set up a match bot for you.

[Mick_o]

I understand that the 8374 does come on early, yes, but how much earlier would the 7670 be is the crux of the issue, in effect. I'd happily trade 50-80kw out of the top end for say*, 500rpm earlier boost and even better transient response. I'm not going to miss those 50kw on the street. I may on the track but i'd only be there for fun so I guess i'd just have to steer better to make up for it

I'm going to try hunker down tonight and get my head around the BW turbo selection system.

*yes I understand its probably a bigger difference than that if I were to properly lean on the 8374, but honestly I probably wouldn't lean on it to get that extra kw's up top.

I highly doubt transient will be any better between the 2 turbos you are looking at. The 8374 is INSTANT. Even when shifting at 5000 if you snatch the gear quick enough it just goes WHACK straight back on its f**ken unreal!

So 3 questions...

1. Do you still want it low mounted? Because if thats a yes it eliminates the 8374 straight away cos that f**ker is huge!

2. Are you 100% set on IWG?

3. Will you be willing to settle for 360-380kw to keep the 7670 happy? I.E from overspinning it.

Consider these things Pete. The price of a custom low mount manifold.

The price of a custom manifold will probably offset the cost of twin gates and plumbing them in.

While twin gates will probably still be more expensive the EWG 1.05 will give the 7670 a better chance of survival because the larger rear will slow spool down a tad down low which will probably increase your power curve over all.

It also keeps your options open if you choose to go a different path in the future.

Low mounting your manifold will increase your runner length which will effect your torque curve.

Won't make boost threshold any later but may shift your torque curve to the right. It also makes it hard to optimise merge angles on the collector also going lowmount. All things that effect the efficiency of your setup.

Just to add i drove Intunes 9.0:1 compression RB30 with poncams & 8374 on the weekend and the thing starts to rip your face off at 3500 in 2nd gear its insane! Its honestly not like any RB ive ever driven before. Id expect very similar/the same spool from your higher comp larger lift cam setup. Its in no way unresponsive. If you read the EvoM forums you will see a common trend. Everyone that put on a particular sized EFR all wished they went bigger haha!

Hope this helps.

Edited May 30, 2016 by Mick_o

[sneakey pete]

1 and 2, Yeah you are right, I had come to a similar conclusion, low mount doesn't seem like an option realistically, doubt you'd get a 8374 to fit down there, and wouldn't want to use external gates on it, but would probably want them for a 7670 due to the size of the turbo compared to the engine, so that wouldn't work.

As for 3... Depends on how much difference there would be between the two

The more and more I look the more and more i'm moved towards the 8374 (IWG).

Those evo guys were all upgrading before they got their turbos though, chasing power.

[Sub Boy32]

Longshot......

If anyone is running a 8374 1.05a/r and wants to swap the rear housing to a 0.92a/r IWG, I have a HPC ceramic coated one with both the Med and Hard wastegate cans and a brand new TurboSmart wastegate. Flick me a PM or post on here. Cheers.

[Mick_o]

^^^See proof Pete! Told you everyone wants to go bigger when it comes to EFR's haha

[HarrisRacing]

Ok so I drove my car to work this morning. The single turbo lag is totally livable but I could see someone going 7670 if you wanted all out response and wanted to keep revs down. Can't hurt to try other than fitment. The 8374 shares dimensions with the 9180...the 7670 does not. Meaning if you get tired of the 7670 and want to go bigger, you can't make it just a bolt on affair.

But honestly. I would like to see what you could get it to do with 7670. It would be insanely responsive.

[HarrisRacing]

Here you go...I'll compare my 8374 EFR matchbot numbers to the 7670 EFR:

Ran the Matchbot numbers on my setup from my dyno this past weekend to reverse engineer the VE values for my engine. I used my 2.75L stroker, 8,000 rpms and assumed a 15% drivetrain loss from my Wheel HP numbers. My engine is ported head, removed squish pads, 8.5:1 CR, SS +.5mm valves, Hypertune V2 manifold, stock intercooler (which works extremely well BTW!), 3" exhaust, BC stroker crank, stock 86mm bores.

The VE's that I came up with for my setup are:

3000 - 72

3500 - 72

4000 - 87

4500 - 91

5000 - 99

5500 - 108

6000 - 113

6500 - 113

7000 - 113

7500 - 111

8000 - 111

8500 - 105 (I made up this arbitrary assumed low VE just to show you the differences in turbos. I did NOT run my engine to 8500 yet)

First 8374 EFR:

Low RPM data here

High RPM data here

Then 7670 EFR using the same everything including my VE's:

Low RPM data here

High RPM data here

After you digest that, note that I bumped my BOOST numbers to an even 19 psi (nice round pumpgas number) and plotted it in excel. (see the attached theoretical dyno chart converted by reducing matchbot power 15% to reflect WHP ). I also over-laid a match-bot 7670 chart based exactly on my VE's and the same 19 psi boost.

So here's what happens:

7670 gets to 10 psi by 3,000 rpms and is at 19 psi by 3,500.

From 4,500 the 8374 EFR is also at 19 psi and the two turbos produce nearly exactly the same power since the efficiencies of both compressors are very close and the engine VE's are identical.

at 7,000 rpms however, the 7670 is starting to drop out of efficiency

at 7,500 the 7670 is unable to hold the full 19 psi without risking overspinning the turbo, but the 8374 is still chugging happily.

at 8,000 rpms the 7670 is absolutely on the limit of the overspin threshold and must be limited to 16 psi...and the 8374 is still happy and making 50 more BHP.

at 8,500 rpms the 8374 is STILL making more power and is still not maxxed out on airflow.

Since my motor can take 9k rpms, and I didn't want to limit it to 7,750 rpms (what I would consider the absolute safe limit of the 7670 EFR on this setup) I choose the 8374.

If you want me to run numbers for E70 at higher boost let me know, but that will NOT help the overspin problem. Don't forget you very well have more top end VE than I do since you are on BIGGER CAMS than me !

[sneakey pete]

There's a few take home messages from those numbers I think. First is the 7670 falling over by 8000rpm's obviously, but the gap in the theoretical rpm's for full boost between the pair is much larger than I'd have expected, and the power difference between the pair given that boost is much smaller than i'd have expected.

The E70 numbers would be very interesting to see. Obviously the 7670 is going to fall flat on its face even worse but it would be interesting to see if the difference between boost and power comes down a bit due to the 7670 not getting the same efficiency gains, or not.

That being said, 99% 8374 at this point given all of that.

[HarrisRacing]

Correct. Power difference AT 19 PSI AND ON PUMPGAS is definitely not all that great...sure you get 500 rpms and more ultimate power on the dragstrip...but dare I show what happens when you turn both to 25 or 30 psi?

[Nismo 3.2ish]

Correct. Power difference AT 19 PSI AND ON PUMPGAS is definitely not all that great...sure you get 500 rpms and more ultimate power on the dragstrip...but dare I show what happens when you turn both to 25 or 30 psi?

Do show , please

[Full-Race Geoff]

^^^Harris racing, you need to try a stiffer WG spring!! i'd bet you are blowing the soft standard actuator open

[HarrisRacing]

^^^Harris racing, you need to try a stiffer WG spring!! i'd bet you are blowing the soft standard actuator open

You are (and were) right. I know I am blowing it open because I have it turned almost all the way in. Be ready to send me one tomorrow.

I'll call in the morning.

[R_34]

Matchbot can't simulate the exhaust manifold backpressure effect on the advance you can throw at the engine.

The engine equipped with the 8374 will happily take more advance netting more horsepower per psi.

So even when the compressor efficiency are close, the turbines of both turbos are'nt working similarly, the 8374 will not even peak at 2.5 PR turbine side @8500rpm while the 7670 will peak and stay at 3PR turbine side.

[HarrisRacing]

Matchbot can't simulate the exhaust manifold backpressure effect on the advance you can throw at the engine.

The engine equipped with the 8374 will happily take more advance netting more horsepower per psi.

So even when the compressor efficiency are close, the turbines of both turbos are'nt working similarly, the 8374 will not even peak at 2.5 PR turbine side @8500rpm while the 7670 will peak and stay at 3PR turbine side.

100% true and excellent point. Of course all dependent on the turbine housing selection as well. I know we were talking IWG for both, but yes I'll pull the numbers off the matchbot for that as well because it's 100% relevant. I was talking all in on compressor (one way or another).

[HarrisRacing]

high rpm 8374 EFR at 20 psi boost using my VE numbers: here

RPM, Boost pressure - Exhaust manifold back pressures (psi):

6000, 20 psi - 22.2

6500, 20 psi - 24.7

7000, 20 psi - 27.1

7500, 20 psi - 29

8000, 20 psi - 30.8

8500, 20 psi - 32.5

high rpm 7670 EFR at 20 psi boost (except where compressor won't do it) using my VE numbers: here

RPM, Boost pressure - Exhaust manifold back pressures (psi):

6000, 20 psi - 28.3

6500, 20 psi - 32.1

7000, 19.5 psi - 35.2

7500, 18 psi - 34.2

8000, 16 psi - 32.4

8500, 14 psi - 29.1

The 8374 EFR will make closer to it's theoretical output from 6k on up for sure and is definitely still the better choice on turbo.

Heck the journal bearing version S300SXE 8376 may make a nasty top end turbo as well if you don't need the EFR bells and whistles and would be staying external gate. http://www.full-race.com/store/turbos/borgwarner-airwerks/borgwarner-s300sxe-8376-62mm.html

[HarrisRacing]

Do show , please

8374 EFR low RPM here

8374 EFR high rpm here

The dyno in BHP is like this:

3000 5 psi - 124 hp

3500 10 psi - 172 hp

4000 25 psi - 360 hp

4500 25 psi - 406 hp

5000 25 psi - 463 hp

5500 25 psi - 535 hp

6000 25 psi - 586 hp

6500 25 psi - 611 hp

7000 25 psi - 644 hp

7500 25 psi - 668 hp

8000 22.5 psi - 608 hp

8500 22.5 psi - 567 hp

don't forget to remove 15% for drivetrain losses if estimating WHP.

Of course my car may just be low on power (I'm sure it is because I'm on super conservative timing so far) and my VE estimates could be off, but you get the idea. This bitch is humping at 25 psi!

[Lithium]

high rpm 7670 EFR at 20 psi boost (except where compressor won't do it) using my VE numbers: here

RPM, Boost pressure - Exhaust manifold back pressures (psi):

6000, 20 psi - 28.3

6500, 20 psi - 32.1

7000, 19.5 psi - 35.2

7500, 18 psi - 34.2

8000, 16 psi - 32.4

8500, 14 psi - 29.1

Those exhaust versus intake manifold pressure levels are pretty unacceptable imho. You'll find at that kind of level your engine VE will be plummeting compared to normal, if it's even sustainable My take away from that is the 7670 is a terrible call for that engine setup - at least at those rpm.

8374 EFR low RPM here

8374 EFR high rpm here

Nismo32ish - because the way the thread convo has panned out I feel compelled to point out that these theoretical numbers AREN'T for E70 like the earlier discussion could lead one to think.

Edited June 1, 2016 by Lithium