mahoney944

There are several other companies developing turbos like this; Borg's is a nice one but there are some other ones on close release. And its funny in all my years I've never seen a design roll from the design stage to production. Engineers don't understand what can be drawn has physical limitations in the creation stage. Most times qualified machinists have to modify engineers fairy tail drawings to bring them to life. So while you think you get all the credit for something you designed, you should be thanking the machinist that did all the real work.

Dave W.

That reminds me of an old saying,
In theory, reality and theory are the same. In reality they're not.

No I wasn't talking about EFR turbos, although they seem to be on the leading edge of efficiency and performance. Funny you should mention them since I saw an 8374 with a twin scroll T4 housing on a 2.4 liter EVO time attack car that had higher boost for a given backpressure up to 20 psi. At 20psi it was 1:1, as boost went up the ratio became less favorable. That was an eye-opener.

I'd love to see someone install an EFR on a 951 but the amount of custom fab work would be extensive and the turbos are not cheap. Precision is also doing nice work with their new CEA Gen2 wheels. I don't have back pressure readings on them but it seems like every time we put a PTE CEA turbo on a car we have to go back and install a larger wastegate and open up the wastegate passages so we can lower the boost. We're getting to the point on certain cars where the wastegate passage is the primary exhaust path while the turbo gets a lesser percentage of exhaust flow.

Teaser pic;

http://www.hindawi.com/journals/ijrm/2012/589720/fig2/

Here's some light reading

http://www.hindawi.com/journals/ijrm/2012/589720/

Raceboy

My friend has an E34 M5 with fully built 3.6 engine and Borg Warner S480 turbo running at 1.6 bars of boost and having maximum of 1.3bars of TIP Full boost is at 4700 rpm all the way to 8400 rpm.
Standing mile speed is 331 kph and that is with full weight (1820 kg with driver).
I installed and tuned ECU on that car so I have 1st hand information.

TurboTommy

That's doable but difficult.
At what RPM was the 1.3 bar TIP measurement taken?
We have to think about that for second and not just assume it was at max RPM.

Thom

An English guy has done just that, all with twin scroll and twin wastegates, on what seems to be an otherwise stock '89. He hasn't posted much since the car has been running, probably been busy with the tune.

Raceboy

1.3 bar of TIP was measured at 7000 rpm and it did not rise at all from then on.

gruhsy

Leak now fixed on TIP gauge line. TIP at 17 psi boost is now quick spike to 22 psi then drop to 20 psi. Duel port wastegate so 2 psi drop should be related to delay in opening I am sure. Close to 1:1 so pretty happy going by data on RL.

Thom

Sounds good. What cam and turbo are you running again?

gruhsy

Solid Lifter Cam
Web - 457/274 grind:
Intake lift - .495"
Intake duration - 246 degrees
Exhaust lift - .480"
Exhaust Duration - 234 degrees
Lobe center - 112 degree lobe center - 16 degrees overlap

super 75 with T4 hot housing and 3 inch down pipe either .58 or .68 A/R don't remember which one I went with. 2000FCeramic coated headers

67King

That makes much more sense, and is pretty impressive.

gruhsy

Thankyou

So my question now would be hypothetically would a different header change that value one way or another?

Larger diameter, longer tubes, 4-1 or 4-2-1? Tial waste gate??????