Porting and polishing turbo housings

[buguy]

Good to know. I'm getting a trans soon and want a shifter that doesn't feel like it's going to break in half when I shift.

[Dan Dryden]

This is the one I have:

https://www.vwheritage.com/ac711500-sca ... r-vw-spare

[Dan Dryden]

Another video...... hope you enjoy it!

https://youtu.be/QRMO8xICPwg

[Dan Dryden]

Time to revive this thread!

The car has been off the road since January having various jobs done to it.
One of the more interesting jobs was to carry out some more subtle flow modifications. These included knife edging the throttle body and match porting the inlet manifold to the base of the throttle body (something I’d neglected to do until now). This removed a 4mm “step” on one half of the intake opening!
I took the car for a run and found myself hitting boost cut in 4th gear! The boost gauge was reading around 1.6ish bar, which made sense because boost cut is set at 1.64 bar.
So... tonight I managed to do a data log and found that I’m actually hitting 1.7 bar!
When the car was mapped back in 2013, it was running 1.4 bar, so the mods I’ve carried out seem to have increased flow enough for the turbo to make an extra 0.3bar (around 4psi) of boost.
Now I’m faced with the decision to either wind the boost back down by adjusting the boost control settings or raise the boost cut threshold and continue running 1.7 bar.
The engine seems to handle it.... but not sure I’m pushing the little TD04 turbo too hard and way beyond its efficiency zone.
Average air temps were 45*C - 50*C, but did spike towards the end of the log at 62*C after my last full throttle 4th gear run... although, 7 seconds later the air temps dropped back down to 47*C and stabilised at 45*C.

[buguy]

I'm planning to run mine to around the same psi. At 30 psi i went through one real TD04 and one Chinese knock off. Real one was used when i got it. No clue if the pressure is what killed them or not.

[Dan Dryden]

To give a bit of perspective, here’s a compressor map for the TD04-13T turbo I’m using.

I would say that 1.4 bar hits the sweet spot, whereas 1.7 bar is pushing to the outer limits of its efficiency.

Buguy, 30 psi looks way outside the map and most probably over speeds the turbo above its 170k rpm limit.

So, I think I’ve answered my previous question and need to bring the boost back down to around 1.4 bar... any more and it looks like the turbo just becomes a heat pump (which would explain my air temp spike at 1.7 bar).

[buguy]

30psi is definitely way outside. It was worth the sacrifice because it was really fast there! Granted for me it wasn't there long. With all stock internals it was time to shift right about there.
I'm sure at 1.4 bar it is plenty fast! And you already know it's safe there.

[Dan Dryden]

The car is booked for a Dyno run on 17th October, so we’ll see what effects these mods have had.
I’ll share the results when I get them.

[buguy]

Very nice. That's on a 1776cc?

[Dan Dryden]

Very nice. That's on a 1776cc?

Yes, 1776cc

[buguy]

Awesome! Any idea what kind of HP it is going to make?

[Dan Dryden]

In 2013 it made 194hp / 222 lbft.

Would be nice to see it closer to 200hp.

[buguy]

Dang! That's pretty good!

[Dan Dryden]

Today was the day!
It was on a different Dyno to my run I did in 2013 and the rest of the car club I was with were getting numbers around 20hp below what other Dynos had given them in the past.

However, the result was 191 HP / 230 lbft.
So, the HP is down 3 but torque is up by 8 lbft.

Think I’ll have to take it back to the original Dyno in the New Year, just to insure I’m comparing eggs with eggs.

I also have a video but wonder what is the best way to share it on here?

[woodsbuggy1]

Great Job Dan! I will be getting my 1776 with TD0413T turbo finished up in a couple months, was previously running a TD0412T,(much smaller turbo for offroad riding) will now be in street buggy. Torque #'s mean much more to me than HP.
Kenric