Dose's Sometimes DIY and Pay Someone Home & Boat Improvement Thread

[soviet_merlin]

On 26/04/2025 at 10:14 AM, Dose Pipe Sutututu said:

the last time I went there were too many numpties on the cruise sessions. Nearly caused a few accidents holding up people and a few guys initiating massive kerb to kerb drifts with heaps of cars right behind them. Not to mention, there were guys on the track session using it as a power cruise session.

Hmpf, that doesn't sound great. That makes it feel like it might be better to put the money towards a track day instead. It didn't seem that bad the two years before.

 

On 26/04/2025 at 9:53 AM, The Bogan said:

Is there an actual website thingie for peoples who don't have Facebooks?

As Brett mentioned it'll be on the roll racing website. Sale starts 6pm on Wednesday. Tickets may sell out quickly so if you want to go, set an alarm and get them at that time

[r32-25t]

As long as the website doesn’t crash again 

[The Bogan]

1 hour ago, soviet_merlin said:

Hmpf, that doesn't sound great. That makes it feel like it might be better to put the money towards a track day instead. It didn't seem that bad the two years before.

 

As Brett mentioned it'll be on the roll racing website. Sale starts 6pm on Wednesday. Tickets may sell out quickly so if you want to go, set an alarm and get them at that time

All I want to do is be a spectator and check out the cars in the show and shine

[soviet_merlin]

23 minutes ago, The Bogan said:

All I want to do is be a spectator and check out the cars in the show and shine

Oh, right. In that case there is no rush. It's the car entries that are quite limited and can sell out quickly.

[Dose Pipe Sutututu]

2 hours ago, soviet_merlin said:

That makes it feel like it might be better to put the money towards a track day instead

That's correct, suits my requirements a bit better.

Sure there are also numpties there, however it's generally a different vibe and more my kind of vibe.

[Dose Pipe Sutututu]

Great read about manifold design, twin scroll with the division all the way to the wastegate seat/fire ring 

https://www.facebook.com/story.php?story_fbid=1088497013319763&id=100064784224104

This is why I bought a Sinco manifold for my shit box and not a 6Boost due to wastegate design.

[r32-25t]

Or just do it properly and get a manifold with 2 gates 

[Dose Pipe Sutututu]

1 hour ago, r32-25t said:

Or just do it properly and get a manifold with 2 gates 

how is a manifold with the pulses split all the way to the gate seat any different?

Same outcome.

[r32-25t]

It’s doesnt matter how good anyone thinks their fabrication skills are it’ll never be a 100% fit 

[Dose Pipe Sutututu]

Just need to remember how lazy exhaust gasses are, it's travelled down the runners, into the collector and up through a divided wastegate path, even if it's not a 100% divided seal at the wastegate piston/valve, it's not going to travel all the way up, down, then back into the opposing cylinders.

Anyhow, each to their own, nothing wrong with twin wastegates. I just prefer 1x huge one.

[MBS206]

3 hours ago, Dose Pipe Sutututu said:

Just need to remember how lazy exhaust gasses are, it's travelled down the runners, into the collector and up through a divided wastegate path, even if it's not a 100% divided seal at the wastegate piston/valve, it's not going to travel all the way up, down, then back into the opposing cylinders.

Anyhow, each to their own, nothing wrong with twin wastegates. I just prefer 1x huge one.

Actually, that's what that post is saying is happening, with only the LAST 10mm to the wastegate flange not divided.
A whole single centimetre is what they're claiming caused that change.
However, I haven't actually punched the numbers in etc to do any mafs, but they're talking 26PSi + of boost, and it taking nearly 2 seconds longer to climb a further 200rpm... Yep, it was in 4th gear, but, say that car does 2800RPM at 100km/h, they're talking a car making 26PSi, is taking an additional nearly 2 seconds to go from 128km/h, to 135km/h... That's pretty extreme to me.
Also interesting as you scroll down through the comments and I started reading there was someone who's done very similar testing, on a hub dyno, back to back without even pulling car off the hub dyno, and barely saw any change what so ever on a stupid powered car.

[Dose Pipe Sutututu]

I was more referring to Brett's 100% fit comment, where there isn't a perfect seal between the wastegate piston/valve.

I do not believe at that point there would be a discernible difference in spool/engine efficiency.

Where as the usual 6Boost style of "twin scroll" which doesn't divide the pulses to the wastegate versus something like a Sinco twin scroll, which is split all the way to the wastegate piston/valve, you'll definitely see a difference.

[MBS206]

1 hour ago, Dose Pipe Sutututu said:

I was more referring to Brett's 100% fit comment, where there isn't a perfect seal between the wastegate piston/valve.

I do not believe at that point there would be a discernible difference in spool/engine efficiency.

Where as the usual 6Boost style of "twin scroll" which doesn't divide the pulses to the wastegate versus something like a Sinco twin scroll, which is split all the way to the wastegate piston/valve, you'll definitely see a difference.

I guess the question becomes, if 10mm gives 1.7 seconds of spool difference, what does 1mm give?

Because you'll need a gap. Even if you're the world's best fabricator and can get that fitment PERFECT, you have two metal surfaces about to heat up and expand. So you need to leave a gap. Realistically, they're likely to leave a couple of mm for most fabricators, so how bad is 5mm compared to 10mm? Or more so, how much worse is 5mm vs twin gated?

But then, if it merging before the gate is bad and hurts spool, I wonder, what would happen if you keep both gates completely separated in their own exhaust systems too?

Would there be any benefit anywhere to keeping them fully split?

Would there be a benefit like with an NA V engine at running an X pipe or a H pipe?

[GTSBoy]

35 minutes ago, MBS206 said:

what does 1mm give?

My guess? Almost perfect separation. The pressure pulses would bleed across, but because they have to squeeze through the gap, they will be substantially attenuated.

35 minutes ago, MBS206 said:

I wonder, what would happen if you keep both gates completely separated in their own exhaust systems too?

Would there be any benefit anywhere to keeping them fully split?

Given most twin gates are plumbed back to atmosphere..... I would say that experiment is well understood. But in reality, it would make no difference to spool at all, if they are 2 completely separated gates. What happens downstrema of them will not affect spool at all.

 

[MBS206]

11 minutes ago, GTSBoy said:

My guess? Almost perfect separation. The pressure pulses would bleed across, but because they have to squeeze through the gap, they will be substantially attenuated.

Given most twin gates are plumbed back to atmosphere..... I would say that experiment is well understood. But in reality, it would make no difference to spool at all, if they are 2 completely separated gates. What happens downstrema of them will not affect spool at all.

 

I'm thinking beyond spool. The claim in this alone shows evidence for spool only. But spool is one thing, what about the rest of our power band?

And if we say 1mm is negligible, what is the relationship like for the gap? Is it linear? Exponential? Linear to a point and then it just doesn't matter anymore and stops getting worse?

These are just all the questions... I don't know the answers definitively either.

[Kinkstaah]

I'm going with "Just run two gates". Fix the problem conclusively. It's the only way you'd ever truly know, right?.

This is all pretty much splitting hairs. Even the extreme example where it takes two whole seconds at 100kmh or something sounds monstrously dubious.

And anyway, when you're punching the throttle when you 'need' this power, you aren't at 2800rpm in the wrong gear. Test it at 5600rpm in 3rd gear, when you're traction limited punching out of a sweeper. Much difference there when you account for traction?

[GTSBoy]

1 hour ago, Kinkstaah said:

when you're punching the throttle when you 'need' this power, you aren't at 2800rpm in the wrong gear.

Actually, I'd argue that that is exactly when having the wastegate/scroll isolation correct would show the most benefit.

[Dose Pipe Sutututu]

In other news, my shit box R33 is Gregged.

I kid you not, 3 months ago it drove perfectly fine, parked it and it sat on the trickle charger for about 2.5 months. A few weeks ago, noticed the charger stopped working. 

Oh wells, 15 years out of a CTEK charger, across 3x shit box JDMs (and other dailies) you've done well.

Went to try start the car today, nothing. Thought, yeah ok, let's get the jumper leads on.

This is where shit escalated lol... Initially popped on the leads and noticed a great deal of sparks, not to worry. Let's triple check shit and try again, yep same. Thought perhaps was just an initial current draw from the 2x audio amplifiers, etc. nope, leads got warm and the fuse box jump point started to GLOW! 🥲 

Luckily the Tiguan wasn't on, I can't imagine what Christmas lights combination would have appeared on the dash if the motor was running.

Anyhow, hastily gave up and messaged Brett for a laugh, or commiserate whatever you want to call it.

Skyline (Shitbox) Lyfe 😂

[GTSBoy]

Test actual voltage on battery. It's probably way low and possibly got a shorted cell. Something that might explain everything in your report.

[Dose Pipe Sutututu]

34 minutes ago, GTSBoy said:

Test actual voltage on battery. It's probably way low and possibly got a shorted cell. Something that might explain everything in your report.

Oh, I thought of that too... I disconnected the battery and hooked up the leads direct to the car without the battery in place.

Sparks...

I suspect the following:

• Alternator has decided to kill itself
• Starter has decided to kill itself

I'll recharge the battery, then unplug both, and go from there.

The above might take 6 months - however I did buy a Victron 15 AMP trickle charger, apparently it's better than CTEK? Amazon, delivery by tonight.

https://www.amazon.com.au/Victron-Battery-Charger-15-Amp-waterproof/dp/B07P4LMMMD?ref_=ast_sto_dp