4722 replies to this topic

[Nev]

At least you drive it

 

True, I do get a lot joy out of it.

 

Also, I've had a sneaky plan to possibly get me under the 105 dB limit for some tracks. It's occurred to me that I can plug my laptop into the ECU and use that to control the revs at precisely 4500. I've noticed that when I do this, that the engine a lot more settled and consequently I think it might make less noise.

 

Yesterday I was talking to some of the marshals at Castle Coombe and one of them had a cheapo hand held dB measuring device sitting on a tyre wall  by Avon bridge. So I asked him if he was the "drive by" monitor, he said he was, so I then asked him what filter he was using to measure the sound. He hadn't a clue, none what so ever and wasn't even aware of the significant differences between "A", "B" & "C" filters. It just highlights what a lottery and ambiguous pile of crap all the noise testing is. Typical clueless human beings in charge of things they shouldn't be

Edited by Nev, 22 June 2016 - 09:29 AM.

[siztenboots]

you could adjust the low load part of the map in the rpm area for static testing and put in a big load extra ignition timing

[Nev]

you could adjust the low load part of the map in the rpm area for static testing and put in a big load extra ignition timing

 

Hmm, it's true I could make a few mods and store a "noise test" map. However, in my case I actually have a simpler "map" on the ETB controller (which is both physically and software independent from the main ECU). I think it will be easier and quicker to manipulate this as it is simply a case of adjusting a single box that sets the idle from 1100 RPM to 4500 RPM. 

 

If it stops raining on Friday, I'll go to the track and get it tested with this approach and see if it helps.  

It's occurred to me that another way to "nurse" the noise test is to make a (switchable) electronic interface that intercepts the signal to the RPM meter. If this device multiplied the signal by say 50%, then the dash would indicate 4500 RPM when in fact the engine is only doing 3000 RPM!  *norty mode off*

Edited by Nev, 22 June 2016 - 10:50 AM.

[stu8v]

Sounds like you're trying reinvent the wheel.

[ChrisS1]

Devious. Did you ever work for Toyota WRC team?

[CHILL Gone DUTCH]

Just tell them you have a rev limit of 6000

[Nev]

Just tell them you have a rev limit of 6000

 

Ha ha, I don't think even the testers at CC would believe that. When I went previously on various occasions they test at 4500 regardless of what engine you seem to have.

Edited by Nev, 23 June 2016 - 04:11 AM.

[MAXR]

At Castle Combe I'm always asked to Rev to 4500RPM. However, I only actually do 4000rpm as there is only one bored guy doing the static testing. But I still hit 99-100db there. 

 

 

[Nev]

At Castle Combe I'm always asked to Rev to 4500RPM. However, I only actually do 4000rpm as there is only one bored guy doing the static testing. But I still hit 99-100db there. 

 

 

 

I think you got lucky, on the 3 occasions I've been there has been 2 blokes, someone looking at my tacho and someone at the tailpipe.

 

 

Edited by Nev, 23 June 2016 - 09:19 AM.

[Mopeytitan]

Do you have a cat replacement silencer Nev?

[Nev]

Do you have a cat replacement silencer Nev?

 

Nope, its just 3.5 inch flexi pipe instead.

Edited by Nev, 23 June 2016 - 12:53 PM.

[Nev]

Ha ha, as if by magic my embarassing "cant believe my eyes" thread has disappeared.

[Mopeytitan]

Do you have a cat replacement silencer Nev?

  Nope, its just 3.5 inch flexi pipe instead.

have you thought about fitting one?

[siztenboots]

Ha ha, as if by magic my embarassing "cant believe my eyes" thread has disappeared.

you were joking? okay , its back...

[Nev]

 

Ha ha, as if by magic my embarassing "cant believe my eyes" thread has disappeared.

you were joking? okay , its back...

 

 

I was only joking, I don't care either way, I'm sure I've made worse oversights in my VX ownership!

[Nev]

Today I finally got round to fitting a vacuum switch into my brake booster circuit. For those of you who are interested (with poorly servoed brakes) here is an explanation:

 

Nipper has some unusual camshafts, these allow reversion of inlet and exhaust gas. As a result when he idles, only a weak vacuum arrives down the OEM vacuum pipe to the servo. This means the servo sees a lot less vacuum than intended, which results in weak braking assistance (i.e. you have to stomp a lot harder on the brakes to make them work).

 

To remedy this, I have installed a Hela UP32 electrical vacuum pump and plumbed it into the system to increase the brake vacuum. However, without some sort of auto cutoff switch this would run endlessly and severely reduce the lifetime of the unit (which was quite expensive). So today, I installed a adjustable vacuum triggered switch. I can set the level of vacuum desired and the switch will turn on/off the vacuum pump when necessary.

 

The system is a bit more complicated than you might imagine, as it is composed of:

 

1. Dashboard on/off switch (master control).

2. OEM vac pipe routed to outlet side of vac pump (with 1 way valve to stop boost going to the pump).

3. Vac pipe leading to 52mm guage on the dash, so I can see the vacuum health going to the servo.

4. The vac switch.

5. One way valve from pump outlet to servo (required as when the pump of off it allows leakage back though it).

6. Lots of joiners to up/down size the vac pipes.

7. Fuse.

 

Anyway, here is a pic. It's a bit messy and hard to package in the space, especially as the T-joiners force certain angles, but as usual it works very well and my brakes are pretty good with strong servo assistance. I can adjust the vacuum anywhere from -200 mBar to -830 mBar, by turning a small adjustment screw on the switch itself.

 

Basically my setup is what most modern diesel cars have.

 

 

 

Edited by Nev, 24 June 2016 - 05:45 PM.

[Nev]

I also tried out my cheapo dB meter today, at 45 degrees and 50 cm  from the exhaust tip.

 

At idle, it registered 98 dB on the "A weighting" and 105 dB on the "C weighting". I didn't try it at 4500 RPM, as the neighbours were in.

Edited by Nev, 24 June 2016 - 07:26 PM.

[hairy]

Today I finally got round to fitting a vacuum switch into my brake booster circuit. For those of you who are interested (with poorly servoed brakes) here is an explanation:

 

Nipper has some unusual camshafts, these allow reversion of inlet and exhaust gas. As a result when he idles, only a weak vacuum arrives down the OEM vacuum pipe to the servo. This means the servo sees a lot less vacuum than intended, which results in weak braking assistance (i.e. you have to stomp a lot harder on the brakes to make them work).

 

To remedy this, I have installed a Hela UP32 electrical vacuum pump and plumbed it into the system to increase the brake vacuum. However, without some sort of auto cutoff switch this would run endlessly and severely reduce the lifetime of the unit (which was quite expensive). So today, I installed a adjustable vacuum triggered switch. I can set the level of vacuum desired and the switch will turn on/off the vacuum pump when necessary.

 

The system is a bit more complicated than you might imagine, as it is composed of:

 

1. Dashboard on/off switch (master control).

2. OEM vac pipe routed to outlet side of vac pump (with 1 way valve to stop boost going to the pump).

3. Vac pipe leading to 52mm guage on the dash, so I can see the vacuum health going to the servo.

4. The vac switch.

5. One way valve from pump outlet to servo (required as when the pump of off it allows leakage back though it).

6. Lots of joiners to up/down size the vac pipes.

7. Fuse.

 

Anyway, here is a pic. It's a bit messy and hard to package in the space, especially as the T-joiners force certain angles, but as usual it works very well and my brakes are pretty good with strong servo assistance. I can adjust the vacuum anywhere from -200 mBar to -830 mBar, by turning a small adjustment screw on the switch itself.

 

Basically my setup is what most modern diesel cars have.

 

 

 

 

Interesting system Nev, wondering if you can have a vacuum tank to save your pump running all the time
 

[The Batman]

i feel sorry for you when you have to change the battery

[Nev]

i feel sorry for you when you have to change the battery

 

I can remove all all that spaghetti and clutter in about 3 minutes and the battery has a massive strap under it as a knuckle/lower back saving device  

Edited by Nev, 25 June 2016 - 06:37 AM.