18psi

iTrader: (76)

Better check your math.
Last time I checked it was called drivetrain LOSS and not GAIN.


Please explain how with higher compression the power "drops off" past a certain point, I'm dying to hear this.
And what point would that be? (assuming no detonation)

Nagase

iTrader: (6)

I use pure synthetic in my driveline.

It adds horsepower. I read it on the label.

Savington

iTrader: (31)

lol @ "assuming no detonation". That's the entire reason a low comp motor makes more power. High compression will respond better, spool faster, and make less power as the boost levels go up because you can't run the timing a low comp motor can.

Savington

iTrader: (31)

Why? It's a 6mm smaller compressor and the same turbine.

Think about the actual wheel sizes and A/Rs - don't just regurgitate "X=Y because the internetz sed so".

GT2860RS = "6054"
GT3071R = "7160" (assuming true T3 housing)
GT3076R = "7660"
GT3582R = "8268"

Borg is running larger turbines, similar/smaller A/Rs, and relying on the wheel inertia to make up the difference (******* smart - big A/R for top-end flow, good engineering for response). The 3076 vs 7670 is perfectly valid, as the charts show = the Borg gets outspooled by a hair, but the 3076 starts to get trumped up top.

Some of the blithering on this forum is getting out of hand.

18psi

iTrader: (76)

Whats so funny about that?
If he said "higher compression the power will drop off on pump gas" or something to that effect I wouldn't say anything.
But on say race gas or e85, where knock doesn't happen til you hit insane pressure levels, how would higher compression start "dropping off in power"?

Nagase

iTrader: (6)

Race gas and E85 just move the problem up in scale.

There's a large difference between 1.9L at 7400rpm making 400hp and 1.5L at 15,000rpm making 1,200hp (extreme example, 80's F1 engines). All else equal, on a turbo, the higher comp, the more peak power you give up.

kotomile

iTrader: (24)

So much theoretical BS to sift through...

So, any word from the as-yet-unnamed possible people who may or may not exist potentially having or not having one of these EFR turbos on a Miata? Pics? Dynos? Anecdotal observations?

viperormiata

iTrader: (24)

Not much yet. But there have been small snip-its of video and a few pictures floating around the Full-Race website.

In the EFR video on youtube, you can see a miata with a EFR...for like 1 or 2 seconds. Also, in the EFR manual (or whatever they call it) you can see a miata in the shop with a good looking turbo setup.

I feel like a detective

Nagase

iTrader: (6)

There've been dynos of all the B1 series (6255/6258/6758) on a 1.8l miata, but the setup is much less than optimized. Log manifold, stock 94-97 block, stock IM, ect ect. They don't want the dynos released yet because the setups make them look like crap. So, they've only emailed to a few people.

All I can say is that the dynos, for the crappy setups, look pretty good.

kotomile

iTrader: (24)

That helps to explain some of the secrecy, then. Thanks for the insight.

I, for one, want to see how the smaller twin-scroll EFRs/GTXs do. I see the twin-scroll gaining in popularity and hope that some good options for us turbo and manifold wise result from it.

Nagase

iTrader: (6)

Full Race won't be doing any of the B1 series in twin scroll. Testing found them undesirable. Smallest will be the 2 series (7064 and up).

Abe is making my EFR compatible manifold, I talked to Jason (jtothewhat) and he's contacted Abe about a twin scroll manifold as well, for a 7670, I think.

Savington

iTrader: (31)

Since he didn't specifically state pump gas, we get to infer that he really meant race gas, E85, JP6, or No1 Diesel, right?



You're e-thugging the guy for a statement that is true in 95% of cases. Nobody's impressed.

Faeflora

iTrader: (2)

No, look at the wheel sizes.

Hey that's what I just said. Yah I saw that the borg efrs can use larger turbines and attain similar spool because of the lighter weight. Don't compare the EFR to the GT series though- compare them to the GTX series which are in general, bigger all around than the GT series.

18psi

iTrader: (76)

I'm not e-thugging anyone. Stop getting your panties in a bunch so easily, holy ****. Since both you and I are using e85, and since with e85 knock is damn near non-existant til you get to insane pressure levels (and even then I'm not sure it will knock) I wanted to know if he meant overall or "just on pump gas" because that statement wouldn't be true with no knock, and if it was I wanted to hear an explanation.

jtothawhat

iTrader: (7)

Lets all love each other and get back on topic

18psi

iTrader: (76)

So when is your EFR coming in/getting installed and did you opt for iwg/bov?

jtothawhat

iTrader: (7)

April I was told is the ETA, I will be running the IWG and BOV as well with a .92 A/R Twin Scroll housing.

JasonC SBB

Indeed lighter wheel inertia helps with response once above the boost threshold. Great for a track car.

However for a street car, boost threshold RPM is important too; this is more of a function of the turbine and compressor aero characteristics than the inertia. Bigass turbines and compressors, if inefficient at the flowrates at lower RPM, will have a higher boost threshold RPM than smaller turbos, regardless of lighter wheel parts.

jtothawhat

iTrader: (7)

"Alright so i overlaid a couple of graphs, one from today and one from a while ago with the GTX. As i had found with the Medium canister, overlaying the GTX3076 to the EFR7670 actually showed the same response on the road. On the dyno it was worse.

Now that i have the high pressure actuator, i did a couple of road tests and check this out.
I had "Felt" the turbo reacting quicker and here is evidence of it.

Here are two runs overlaid. I tried overlaying RPM, TPS, or Boost to see how they compare. But i thought this one would work great to illustrate what i feel. I thought it was interesting how much later i hit full throttle, and how the EFR hit the same boost target at the same time.



The time frame is .5 seconds later that it was floored(sounds fast, but consider that whole run was about 1.9 seconds.... Then also the RPM difference was about 250. That is i floored the EFR at 250RPM later than the GTX, yet the EFR hit the boost at the same RPM!

More info tomorrow!"


This is a qoute from the subi forums on the 7670 vs GTX3076R which makes thing look a lot better for the EFR.

filphil

Someone on another forum began a 6758 build for on a NC.