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

[robbo_rb180]

On 04/07/2025 at 9:21 AM, Duncan said:

nah, I'd heard the same, they are not doing well with heat management for track use; they are a street use only thing (sure high power, but not high power over a sustained period)

 

On 04/07/2025 at 9:33 AM, GTSBoy said:

I think that's true for a lot of new performance cars. Just have to watch them being lapped at the 'ring to see how many start squealing about engine or trans temp by the time they get to the climb out of Breidscheid.

Everyone I know with a90 supra at time attack aren't having issues with 3-5 fast laps so far and one is decent powered one too.
Saw a k24 swapped 86 with a 8hp70 and big slicks and aero which had no drama's at QR and Manton Park.

I've stuck a 25 row cooler in my setup with 8hp45/50 in the hopes of keeping the oil cool as I plan on some racing next year that 20-30min sessions. I've also geared my car so won't be using 7th and 8th gear too.

@Dose Pipe Sutututu just needs to get that samsonas in already and have that tassie guy fit a head and rev it too 11ty thousand rpm. 

[Dose Pipe Sutututu]

@robbo_rb180 I already have a NEO head on the shitbox 😎

Just needs beehive springs so I can rev it past the 8600 rpm limiter, then again pointless too, turbo is out of puff lol.

Wen da gods let me win lotto eh?

[MBS206]

1 hour ago, Dose Pipe Sutututu said:

@robbo_rb180 I already have a NEO head on the shitbox 😎

Just needs beehive springs so I can rev it past the 8600 rpm limiter, then again pointless too, turbo is out of puff lol.

Wen da gods let me win lotto eh?

After I win the lottos...
So sounds like Samsonas, valve springs, a new bigger turbo, and maybe a super charger like all the school kids are dreaming of for twin charging, and you'll have the perfect daily driver.
Oh, and maybe Bosch motorsport ABS for you too.

[Dose Pipe Sutututu]

Don't think I even need a super charger to be honest.

Moving to a G35-900, would easily go over 500kW and also come on earlier.

Bosch Motorsport ABS would be amazing, and weld in proper side intrusion bars. I feel unsafe in the shit box on the street. Way too many numpties where I live, accidents daily.

[Dose Pipe Sutututu]

I think I now dislike Century batteries and shall never buy another one.

2.5 years in and the battery on the VW shit box is toast. Barely could start the car, even after I gave it a good zap on the charger overnight. It has been getting weaker and weaker over the past 2 to 3 weeks.

Luckily, there's a 36 month warranty period. Brought it back to Supercheap Auto and they swapped it with a new one, the process took 5 minutes. So good!

Oh yeah, if you own or have owned a VAG shit box, standard shopping list of errors when you pop in a new battery 🤣

And yes, I incremented the serial number to restart the charge strategy. Apparently the VW forum gods believe there is a timed battery charge strategy that reduces the charge with age so it doesn't speed the battery's deterioration over time. 

 

Other than that, Skyline still sucks.

 

[No Crust Racing]

Are you telling me I'm going to need a code reader etc to just change the battery when it dies... 

Why did I let you talk me into allowing Kate to buy this car lol

 

[Dose Pipe Sutututu]

6 minutes ago, No Crust Racing said:

Are you telling me I'm going to need a code reader etc to just change the battery when it dies... 

Why did I let you talk me into allowing Kate to buy this car lol

 

It's recommended, however I can assure you a good amount of people don't bother.

FWIW, the OEM battery lasted 4.5 years and I changed it prematurely too, I reckon could have stretched it to 5 years.

[soviet_merlin]

2 hours ago, Dose Pipe Sutututu said:

I think I now dislike Century batteries and shall never buy another one.

2 hours ago, Dose Pipe Sutututu said:

It has been getting weaker and weaker over the past 2 to 3 weeks. 

Hmmm, what do you mean by getting weaker? And where did you get that test done?

I've been wondering about my battery because the cold starts crank super slowly. The voltage is fine. Not sure if cranking amps can be checked at home. Battery is 4+ years old.

[GTSBoy]

36 minutes ago, soviet_merlin said:

Not sure if cranking amps can be checked at home.

Not properly. You need to be able to dissipate 100 amps or so to doing it meaningfully. You can do it indirectly by watching to see how far the voltage falls during cranking. Unplug the coils or something else to prevent it from starting so you can get a good couple or three chugs. It also helps if you have the multimeter set up reading before you start, and that it has max/min functions. So you can catch the real minimum without having to watch the screen, which often doesn't update fast enough to show the real max/min in dynamic situations. Or use a digital oscilloscope, which can be obtained for <<$100 from Aliexpress (although I'd argue for paying up to ~$200 for a nicer one).

A >4 yr old battery will very likely be well down the path to the knackery. Many only last 5-6 years these days.

The cold weather lately will definitely make it worse.

[No Crust Racing]

46 minutes ago, soviet_merlin said:

Hmmm, what do you mean by getting weaker? And where did you get that test done?

I've been wondering about my battery because the cold starts crank super slowly. The voltage is fine. Not sure if cranking amps can be checked at home. Battery is 4+ years old.

how do you know voltage is fine? 

quick easy test is connect DMM up and put it on max/min mode, remove fuel pump fuse, crank car for 3-5s, go check min voltage

You'd be surprised how many "healthy" batteries are showing under 10v during this test in cold weather. 

[soviet_merlin]

26 minutes ago, GTSBoy said:

Not properly. You need to be able to dissipate 100 amps or so to doing it meaningfully. You can do it indirectly by watching to see how far the voltage falls during cranking. 
...

A >4 yr old battery will very likely be well down the path to the knackery. Many only last 5-6 years these days.

The cold weather lately will definitely make it worse.

Thanks! Supercheap has a sale on this weekend so might be a good opportunity to get a new one. I do have a decent multimeter so I'll give it a try either way.
 

19 minutes ago, No Crust Racing said:

how do you know voltage is fine? 

quick easy test is connect DMM up and put it on max/min mode, remove fuel pump fuse, crank car for 3-5s, go check min voltage

You'd be surprised how many "healthy" batteries are showing under 10v during this test in cold weather. 

Hah, you got me! I do not. All I know is that the battery holds charge and sits at an okay level before I start the car. Doing the full charge and rejuvenation cycle on a trickle-charger seems to not really make a difference to the cold start behaviour. I'll try and measure it during cranking and see what it does. It's likely terrible; it certainly feels terrible. 

I'll be happy if it is really just the battery and I don't have to dick around with the alternator or starter motor.

[MBS206]

56 minutes ago, No Crust Racing said:

how do you know voltage is fine? 

quick easy test is connect DMM up and put it on max/min mode, remove fuel pump fuse, crank car for 3-5s, go check min voltage

You'd be surprised how many "healthy" batteries are showing under 10v during this test in cold weather. 

I find most vehicles dip into the mid to high 9 volt range, even with a good battery.
Hitting the low 9s, and especially hitting into the 8s is pretty indicative of a dieing battery.

The other part to look at is the battery voltage after the battery has been fully charged. They should be sitting at 12.8V, as lead acids are dieing, they head down low and lower. Often getting as low as 12.0 - 12.2. You'll start seeing this when the engine is cranking over slowly.

Interestingly, depending on the vehicle, when batteries get really bad, you can see some REALLY funky things going on. From very low voltages, to higher than 16V too. Something I totally didn't expect! This part of the super low and super high voltages I've been seeing on motorbikes, I need to do some further studies on cars. I suspect cars will act a little bit different though for a couple of reasons.

[No Crust Racing]

2 minutes ago, MBS206 said:

I find most vehicles dip into the mid to high 9 volt range, even with a good battery.
Hitting the low 9s, and especially hitting into the 8s is pretty indicative of a dieing battery.

The other part to look at is the battery voltage after the battery has been fully charged. They should be sitting at 12.8V, as lead acids are dieing, they head down low and lower. Often getting as low as 12.0 - 12.2. You'll start seeing this when the engine is cranking over slowly.

Interestingly, depending on the vehicle, when batteries get really bad, you can see some REALLY funky things going on. From very low voltages, to higher than 16V too. Something I totally didn't expect! This part of the super low and super high voltages I've been seeing on motorbikes, I need to do some further studies on cars. I suspect cars will act a little bit different though for a couple of reasons.

Can't remember the last time I saw a good, healthy battery dropping into the 9s during cranking, 

Too many variables to say anything about it with any certainty though. 

A float voltage of 12-12.2 is tired AF and given how AGMs handle high C rate and DOD, will just die faster and faster with each cold start. 

 

[Dose Pipe Sutututu]

2 hours ago, soviet_merlin said:

Hmmm, what do you mean by getting weaker? And where did you get that test done?

On cold start cranks, you can tell the starter motor isn't as "crisp" sounding.  Especially cars with stop/start "technology" (not really technology, it's garbage).

Test was done at Supercheap Auto, it's part of their warranty claim process.

 

2 hours ago, soviet_merlin said:

The voltage is fine.

Not often a good definitive test, as the battery may still show a "healthy" voltage - like mine, in the test you can see it's showing 12.41V

 

24 minutes ago, MBS206 said:

to higher than 16V too

I've seen this too, when you jump start a car with a completely fried battery, just as bad as when you disconnect the battery terminal on a running car and see the voltage spike LOL

[MBS206]

18 minutes ago, No Crust Racing said:

Can't remember the last time I saw a good, healthy battery dropping into the 9s during cranking, 

Too many variables to say anything about it with any certainty though. 

A float voltage of 12-12.2 is tired AF and given how AGMs handle high C rate and DOD, will just die faster and faster with each cold start. 

 

I could probably pull a few logs out of the servers at work, would show it happening a lot.
My job is in vehicle telematics, and I spend more hours than I'd like in data analysis/review for various reasons.

[MBS206]

3 minutes ago, Dose Pipe Sutututu said:

On cold start cranks, you can tell the starter motor isn't as "crisp" sounding.  Especially cars with stop/start "technology" (not really technology, it's garbage).

I've seen this too, when you jump start a car with a completely fried battery, just as bad as when you disconnect the battery terminal on a running car and see the voltage spike LOL

Not just stop start. New modern cars with their stupid "smart" alternators. Even funnier is watching cars when you drop them into eco mode. A lot of them don't crank the alternator up to full charge for very long at all. EVs and how they charge their 12V lead acid battery is even worse!

Also, you should never disconnect the battery, on a running car. The voltage spikes can break things. Basically while it's a "battery" it is also considered a "Capacitor" within the charging system, and helps to keep those spikes non existent. Yay for alternators being inductive.

[Dose Pipe Sutututu]

2 minutes ago, MBS206 said:

Also, you should never disconnect the battery, on a running car. The voltage spikes can break things. Basically while it's a "battery" it is also considered a "Capacitor" within the charging system, and helps to keep those spikes non existent. Yay for alternators being inductive.

Oh there's no way in hell I'm doing it to modern cars.

This was on some lancer shit box decades ago with silly gauges that started beeping when the voltage was outside of operating range

[soviet_merlin]

Holy shit, I'm glad you brought up the battery issue and I'm glad I asked about measuring it.

Old battery was at a healthy 12.82V in the morning with the car turned off. Removed the fuel pump fuse, clamped the multimeter on at min/max/average and cranked for ~3 seconds. It dropped down to 8.30V. So yeah, not surprising it struggled that much.

Picked up a fresh battery from supercheap and it's ridiculous. Haven't done a cold start yet, but man, even with a warm start the difference is night and day. I can't believe I lived with this for so long. Just blamed it on it being an old modified car.

Went with Century because convenient. If they are shit it'll be a future me problem. But just in case I set up a reminder for 30 months - 8 weeks to check on the battery state and get a warranty replacement if necessary. 

[MBS206]

42 minutes ago, soviet_merlin said:

Holy shit, I'm glad you brought up the battery issue and I'm glad I asked about measuring it.

Old battery was at a healthy 12.82V in the morning with the car turned off. Removed the fuel pump fuse, clamped the multimeter on at min/max/average and cranked for ~3 seconds. It dropped down to 8.30V. So yeah, not surprising it struggled that much.

Picked up a fresh battery from supercheap and it's ridiculous. Haven't done a cold start yet, but man, even with a warm start the difference is night and day. I can't believe I lived with this for so long. Just blamed it on it being an old modified car.

Went with Century because convenient. If they are shit it'll be a future me problem. But just in case I set up a reminder for 30 months - 8 weeks to check on the battery state and get a warranty replacement if necessary. 

So many people don't notice it, as batteries decay slowly over time.
Two big reasons people end up noticing and needing to replace batteries:

1) The cold weather. The cold not only makes it harder to turn the engine for a few reasons, but it also increases the batteries internal resistance. So this means you need MORE power to turn a colder engine, AND the battery has a lower limit on how much current it can provide.

2) Something gets modified/altered/added in the wiring, typically an aftermarket accessory, like a dash camera, or an alarm etc, and this adds a small amount extra onto the battery, and pushes it over the edge in its failing days.

But if you hadn't have read this thread, and just pushed through, chances are you might have made it through this winter, just. But come next winter, it would have been kapoot. But the fact you changed it out now, means you've instantly noticed how much nicer it is for starting, and will be less worry for you that the engine won't start now.

[Duncan]

I guess it depends how much you use a car, but my #1 reason for killing lead acid batteries is not driving the car (charging the battery) often enough,. I've got sick enough of dying batteries that I've switched to AGM; they are much more expensive but deal better with cold weather and almost always recover from being dead flat, unlike lead acid ones