Thread: 4BD1T Turbo Sizing and Performance Prediction.

Originally Posted by c.h.i.e.f

Looks the goods there Dougal....you care to take a guess (with your calcs) at what boost I could expect to see when running max fuelling with a non waste gated gt3582 0.63a/r hot side?

You're in uncharted territory there Cheif. You're going to have to tell us.

Originally Posted by Dougal

You're in uncharted territory there Cheif. You're going to have to tell us.

Yeah thought that may be the case

Originally Posted by Dougal

<snip>

Wastegating can be a problem with high boost. It's hard to find a good acuator. I've got a 22psi unit but even on my T25 it struggles to maintain 20psi at higher rpm.
So I've ordered a Kinugawa rebuildable wastegate actuator with 5 springs. 2.0bar (30psi), 1.7bar (25psi), 1.5 bar (22psi) and 1.2 bar (18psi).



I ordered through Kando Dynamic on Ebay Australia.

Is the issue just that the high drive pressure forces the wastegate open against the actuator spring pressure?
If so, whats different about the Kinugawa actuator that prevents it - larger diaphragm and heavier springs?

Steve

Originally Posted by steveG

Is the issue just that the high drive pressure forces the wastegate open against the actuator spring pressure?
If so, whats different about the Kinugawa actuator that prevents it - larger diaphragm and heavier springs?

Steve

Pretty much yes...hole diameter then becomes an issue

Originally Posted by steveG

Is the issue just that the high drive pressure forces the wastegate open against the actuator spring pressure?
If so, whats different about the Kinugawa actuator that prevents it - larger diaphragm and heavier springs?

Steve

The advantage is the range of different springs.

On a wastegate you've got two concerns. One is the opening pressure, the other is how far and fast it opens from there.
The opening pressure sets the boost around max torque, the movement from there sets how it behaves at higher rpm for max power.
Right now I've acheived the opening pressure I want, but I have 4mm or so preload on a spring that's a bit too soft to get that. So when it opens, it then opens too far and drops boost.

Going up to a stiffer spring and less preload will give me the same opening force, but it won't open as far as quickly and will hold higher boost later in the rpm range.

I don't think my drive-pressure is that high, I think the current wastegate isn't living up to it's 22psi rating. But I can't find the bracket I had to hold my drive-pressure guage to test it.
What I want to acheive is the wastegate cracks open just before the turbine would choke-out and then continues to open further and bypass more exhaust but keeping boost steady or even climbing slightly with increasing rpm.
Right now I've got a wastegate that opens too far too soon and boost drops with increasing rpm.

[QUOTE=Dougal;1892335]The advantage is the range of different springs.

Right now I've acheived the opening pressure I want, but I have 4mm or so preload on a spring that's a bit too soft to get that. So when it opens, it then opens too far and drops boost.

QUOTE]


i cant remeber what turbo you have, but with a 5 bolt we would weld a bit more meat on, then tap a tread and run a bolt though to limit the opening travel of the waste gate valve. more Blead less dump sort of thing

I checked out ebay for a BW EFR 7064 cost $1621 reasonable freight $561 although I think I might be aiming a bit high and a slightly smaller
unit would be the go
BORG WARNER 179355 EFR 7064 BALL BEARING TURBO 300-500HP T3 STAINLESS .83AR 3"
Thoughts please

Am

Originally Posted by Ancient Mariner

I checked out ebay for a BW EFR 7064 cost $1621 reasonable freight $561 although I think I might be aiming a bit high and a slightly smaller
unit would be the go
BORG WARNER 179355 EFR 7064 BALL BEARING TURBO 300-500HP T3 STAINLESS .83AR 3"
Thoughts please

Am

Have you tried the locals?
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