[Closed] Borg Warner Efr Series Turbos

[Nee-san]

We need two of the big ones, and we need them by tonight.

[bradsm87]

match bot says it can be done at 2600 but i'm not crossing my fingers for that lol but around 2800-3000 is definitely acheivable. The S14 made full boost at 3000 and that was 2L and 9:1 comp with a .86 turbine housing. The compressor wheel is smaller on the 7064 than the 2871r and the turbine wheel is lighter. It's not a big turbo. The anti-surge comp housing and divided turbine housing just make it look big.

[Lithium]

No it will hit 14psi as soon as possible (est. around 2800rpm) and hold flat until the torque starts to drop off (est. around 4200rpm) and boost will slowly increase to counteract the drop-off of torque and hold the torque flat. The turbo is not too big for the application at all. Upsize engine and plan to run low boost and make efficient power = bigger turbo required.

On match-bot, with NOTHING changed but going from 6758 to 7064, efficiency is higher across the board because the 7064 has a lower trim compressor wheel and anti-surge housing. Also the exhaust manifold pressure is considerably lower with the 7064. The twin scroll setup helps response as well.

Going by some of the estimations you've made there I'm wondering what you've put into matchbot, and suspect it could be giving you quite "off" results based off what it has been given to work with. I am also a bit suss of the fact that you only changed the turbo - there are various other numbers which should be updated to suit the turbo to make the calculations work correctly, if you didn't do that it would explain some weird results as I think matchbot defaults to a 7064.

I ended up giving matchbot a bit of a crack with your setup and the points of compressor efficiency were all within a couple of percent of each other between the two turbos - especially at so low boost level you won't see the result of that one way or the other.

I also found that the exhaust manifold pressure (going by my calcs) for a .64 EFR6758 only exceeded that of the EFR7064 at around 5000rpm, and peaked at 17% higher at redline. The calculated required wastegated sizes for the EFR6758 and EFR7064 respectively were:

2000 3000 4000 5000 6000 7000

11 17 25 28 30 32

4 12 21 25 27 28

I agree the twin scroll is a nice advantage, but maintain that (in my opinion) the advantages of the TS EFR7064 do not outweigh the fact it is too big for your requirements. I'd love to see full boost at 3000rpm with one, or even with a EFR6758 - but it just ain't happening in the real world.

Lithium, I won't be doing a flat boost curve because the clutch or gearbox can not handle any more torque through the midrange. Instead, less peak torque will be made but higher average torque across the RPM range because torque will not drop off at all until about 6800rpm so it will be a very fast car.

This makes the most sense to me - how did you decide on a 'pull the plug' torque level? And how do you know what boost level will reach that if you don't know what power it is going to make?

[bradsm87]

This is compressor efficiency followed by exhaust manifold pressure for the 6758 up top then the 7064 below. I'm very comfortable with match-bot and the VE numbers are definately in the ball park. I'll post links later as I didn't save them.

2700 3600 4500 5400 6300 7200

59 68 72 74 74 68

9.4 11.6 14.3 18.4 23 27.2

63 73 76 75 73 71

7.3 9 11.3 14.7 18.5 21.3

[Dale FZ1]

less peak torque will be made but higher average torque across the RPM range because torque will not drop off at all until about 6800rpm so it will be a very fast car.

My 30DET produces torque much the same way - peak torque from 3400-6900 in a wide dead-flat plateau.

It makes for an incredibly easy drive, as for track work it is never really out of its "best" zone. Reviewing data it seemed to matter very litle whether some technical sections were run in either 3rd or 4th gear - point to point there was little variation in time.

With that style of delivery there does not seem to be that "rush" generally associated with some turbocharged engines, and traction relatively easy to find, even running 225/50 semi slicks and knocking out a conservative 415rwhp. I get Brad's approach, although it might not be for everyone's preference.

[Lithium]

Aside for the whole full boost before 3000rpm thing out numbers can't be too wildly different:

21.3psi = 2.45 pressure ratio

27.2psi = 2.85 pressure ratio (~16-17% higher for the .64 EFR6758 at worst)

And the compressor efficiency is within a few points at worst - so obviously the EFR7064 is a bit more efficient, the twin scroll advantage can't be denied but when you look at all those details to me it shows that you are only JUST scratching the areas where it might show a bit of advantage.

Looking forward to seeing the results, they should be decent - it will make very respectable power, and be a cool looking power curve as well as make an SR20 feel revvier than they naturally do. Definitely not how I'd have gone about it, but each to their own... seems like you've put some thought into it and know what you want - just don't hold your breath on full boost before 3000rpm, or even 3500rpm to be fair.

[bradsm87]

6758:

http://www.turbodriven.com/performanceturbos/matchbot/index.html#version=1.2&displacement=2.16&CID=131.8032&altitude=250&baro=14.604&aat=70&turboconfig=1&compressor=67x80&pt1_rpm=2700&pt1_ve=88&pt1_boost=13&pt1_ie=93&pt1_filres=0.08&pt1_ipd=0.15&pt1_mbp=0.7&pt1_ce=59&pt1_te=75&pt1_egt=1580&pt1_ter=1.57&pt1_pw=11.65&pt1_bsfc=0.43&pt1_afr=11.5&pt1_wts=300&pt1_wd=83&pt1_wd2=74&pt1_wrsin=69033&pt2_rpm=3600&pt2_ve=97&pt2_boost=13&pt2_ie=90&pt2_filres=0.1&pt2_ipd=0.2&pt2_mbp=0.9&pt2_ce=68&pt2_te=73&pt2_egt=1620&pt2_ter=1.68&pt2_pw=31.99&pt2_bsfc=0.45&pt2_afr=11.5&pt2_wts=320&pt2_wd=83&pt2_wd2=74&pt2_wrsin=73635&pt3_rpm=4500&pt3_ve=100&pt3_boost=14&pt3_ie=87&pt3_filres=0.12&pt3_ipd=0.25&pt3_mbp=1.1&pt3_ce=72&pt3_te=72&pt3_egt=1650&pt3_ter=1.83&pt3_pw=40.71&pt3_bsfc=0.48&pt3_afr=11.5&pt3_wts=340&pt3_wd=83&pt3_wd2=74&pt3_wrsin=78238&pt4_rpm=5400&pt4_ve=100&pt4_boost=15.5&pt4_ie=84&pt4_filres=0.15&pt4_ipd=0.3&pt4_mbp=1.4&pt4_ce=74&pt4_te=71&pt4_egt=1650&pt4_ter=2.02&pt4_pw=44.69&pt4_bsfc=0.5&pt4_afr=11.5&pt4_wts=368&pt4_wd=83&pt4_wd2=74&pt4_wrsin=84681&pt5_rpm=6300&pt5_ve=98&pt5_boost=17.5&pt5_ie=81&pt5_filres=0.18&pt5_ipd=0.35&pt5_mbp=1.7&pt5_ce=74&pt5_te=70&pt5_egt=1650&pt5_ter=2.26&pt5_pw=45.73&pt5_bsfc=0.52&pt5_afr=11.5&pt5_wts=400&pt5_wd=83&pt5_wd2=74&pt5_wrsin=92044&pt6_rpm=7200&pt6_ve=91&pt6_boost=19.5&pt6_ie=78&pt6_filres=0.2&pt6_ipd=0.4&pt6_mbp=2&pt6_ce=71&pt6_te=70&pt6_egt=1650&pt6_ter=2.5&pt6_pw=44.86&pt6_bsfc=0.55&pt6_afr=11.5&pt6_wts=400&pt6_wd=83&pt6_wd2=74&pt6_wrsin=92044&

7064:

http://www.turbodriven.com/performanceturbos/matchbot/index.html#version=1.2&displacement=2.16&CID=131.8032&altitude=250&baro=14.604&aat=70&turboconfig=1&compressor=70s75&pt1_rpm=2700&pt1_ve=88&pt1_boost=13&pt1_ie=93&pt1_filres=0.08&pt1_ipd=0.15&pt1_mbp=0.7&pt1_ce=63&pt1_te=78&pt1_egt=1580&pt1_ter=1.43&pt1_pw=0.83&pt1_bsfc=0.43&pt1_afr=11.5&pt1_wts=300&pt1_wd=83&pt1_wd2=74&pt1_wrsin=69033&pt2_rpm=3600&pt2_ve=97&pt2_boost=13&pt2_ie=90&pt2_filres=0.1&pt2_ipd=0.2&pt2_mbp=0.9&pt2_ce=73&pt2_te=75&pt2_egt=1620&pt2_ter=1.51&pt2_pw=23.4&pt2_bsfc=0.45&pt2_afr=11.5&pt2_wts=320&pt2_wd=83&pt2_wd2=74&pt2_wrsin=73635&pt3_rpm=4500&pt3_ve=100&pt3_boost=14&pt3_ie=87&pt3_filres=0.12&pt3_ipd=0.25&pt3_mbp=1.1&pt3_ce=76&pt3_te=72&pt3_egt=1650&pt3_ter=1.64&pt3_pw=32.31&pt3_bsfc=0.48&pt3_afr=11.5&pt3_wts=340&pt3_wd=83&pt3_wd2=74&pt3_wrsin=78238&pt4_rpm=5400&pt4_ve=100&pt4_boost=15.5&pt4_ie=84&pt4_filres=0.15&pt4_ipd=0.3&pt4_mbp=1.4&pt4_ce=75&pt4_te=71&pt4_egt=1650&pt4_ter=1.8&pt4_pw=35.64&pt4_bsfc=0.5&pt4_afr=11.5&pt4_wts=368&pt4_wd=83&pt4_wd2=74&pt4_wrsin=84681&pt5_rpm=6300&pt5_ve=98&pt5_boost=17.5&pt5_ie=81&pt5_filres=0.18&pt5_ipd=0.35&pt5_mbp=1.7&pt5_ce=72&pt5_te=70&pt5_egt=1650&pt5_ter=2.01&pt5_pw=36.52&pt5_bsfc=0.52&pt5_afr=11.5&pt5_wts=400&pt5_wd=83&pt5_wd2=74&pt5_wrsin=92044&pt6_rpm=7200&pt6_ve=91&pt6_boost=19.5&pt6_ie=78&pt6_filres=0.2&pt6_ipd=0.4&pt6_mbp=2&pt6_ce=71&pt6_te=70&pt6_egt=1650&pt6_ter=2.17&pt6_pw=35.91&pt6_bsfc=0.55&pt6_afr=11.5&pt6_wts=400&pt6_wd=83&pt6_wd2=74&pt6_wrsin=92044&

Obviously with Ethanol in the fuel, EGTs will be lower, BSFC witll be lower which sorat cancel each other out to an extent so I just left the default petrol figures in there. VE is a guess for the engine with Tomei Poncams.

[Lithium]

Looks like we used very very similar settings - almost identical actually, except you are a lot more optimistic about spool. Looks like you had a fail with the VE plotting too, the EFR6758 is 71% efficiency for the 7200rpm spot.... see what I mean about them plotting through very similar? Interesting that the EFR7064 is a bit more generous at low rpm, probably the antisurge housing - ironically the EFR7064 will be lazier at those RPM so in real life the EFR6758 will probably "stand up" quicker at those rpm, more than enough to nullify the slight compressor efficiency advantage.

[bradsm87]

Match-boit will tell you if boost is possible or not at a given RPM once you map the turbine curves. 2700 is pushing it very fine I know because the % of wastegated gas is pretty much nothing. I more chose the 7064 for the lower ex manifold pressure than anything else and it looks to be considerably lower, especially up top. That way, timing can be advanced more, exhaust gas can escape easier and VE will be higher. Technically, I should raise the VE numbers a bit for the 7064 due to this.

What would you use for the VE figures for those RPM points with Tomei 256 cams and a mild port job? I thought mine were about right but I really don't know what the real-world VE numbers would be.

[Lithium]

I don't know for sure tbh, I just threw in some thumbsuck stuff and it turned out real similar to yours - can't remember the exacts but I think we were on the same wavelength. Doesn't mean it's right, but it has to be worth something? haha

PS. Just because matchbot thinks it is physically possible to get that boost with that turbine configuration doesn't mean it will. I am incredibly dubious of using that method to determine spool tbh - I had a quick play with it using that method and if it had any credibility then we should build SR22s and put EFR9180s onto them with 1.05a/r turbine housings and hope to hit 50psi by 3600rpm and dominate EVERYTHING

[bri73y]

ok enough talk, more results...

Second stage of tune completed over the weekend. My GTR is running a Motec with knock control so Phil Armour spent all day Saturday making my brand new engine knock on 91oct before loading it up with E85 and pushing her once again over the edge before bringing her back to a happy place.

For a better explanation see... http://www.motec.com.au/aboutknockcontrol/knockoverview/

Bottom line is we're pushing these little 6258's pretty hard now with no sign of them letting go. All's good with EFR once again!

Stage 3 tune will be more revs, play around with cam timing to optimise area under the curve, and keep 30psi in her for the whole rev range.

Should be pretty special when finished! As my tuner said on Saturday "Happy Days!"

[Lithium]

Argh Brad - I see why you asked about VE, when I said you had a fail with VE plotting I meant compressor efficiency... my bad.

ok enough talk, more results...

Second stage of tune completed over the weekend. My GTR is running a Motec with knock control so Phil Armour spent all day Saturday making my brand new engine knock on 91oct before loading it up with E85 and pushing her once again over the edge before bringing her back to a happy place.

For a better explanation see... http://www.motec.com.au/aboutknockcontrol/knockoverview/

Bottom line is we're pushing these little 6258's pretty hard now with no sign of them letting go. All's good with EFR once again!

Stage 3 tune will be more revs, play around with cam timing to optimise area under the curve, and keep 30psi in her for the whole rev range.

Should be pretty special when finished! As my tuner said on Saturday "Happy Days!"

dyno637hp.jpg

Wow. This result is on E85 and stock displacement RB26 right? That should be a bunch of fun - glad they are working better for you now!

By the way, you have some intensely awesome toys - I've been waiting with eager anticipation for the HTA GT3076R and mid way through the anticipated you out of the blue post something which I'd be looking forward to just as much... good man Cheers for sharing the goodness!

[bri73y]

RB28 - Tomei Stroker, E85 is correct though.

Turbos came on earlier with the last build even with bigger cams, so with a bit of fiddling we should be able to get her back to 20psi before 4000rpm.

Atleast that's the plan.

The HTA will hit the rollers again this week sometime...

[Lithium]

Very interested to hear how both results turn out - 30psi all around eh? The GT3076R-HTA on an RB25 compared with EFR6258s on an RB28 with fuel and boost will be interesting to compare drives/results too.

[Piggaz]

RB28 - Tomei Stroker, E85 is correct though.

Turbos came on earlier with the last build even with bigger cams, so with a bit of fiddling we should be able to get her back to 20psi before 4000rpm.

Atleast that's the plan.

The HTA will hit the rollers again this week sometime...

What cams are you running?

[bri73y]

264 x 10.5 in and ex

I was running 272 x 10.8 in and ex

Not a big change I know.....

[Lithium]

What was the reason for the change?

[bigmikespec]

Ok, I am thinking of trying an EFR 9180 with 1.45 A/R... if anyone wants to help out, please buy these: http://www.skylinesaustralia.com/forums/topic/420205-single-turbo-and-bov-700-800hp/

[bri73y]

What was the reason for the change?

When I built the head my engine was still only 2.6. Now it's stroked I thought smaller cams would be better suited as I don't rev her as high now. I was also just looking for a little more response.

[Lithium]

Sweet Sorry for millions of questions - curiousity is a bit of a vice with me.