AlanG

That's all right Jim, not long to wait at all.

lol. I'm surprised they've not clocked on to your interest in the cars and start askin' you stuff about yours. Anything to stop learnin' what they're meant to!

Yes.

Exam time Welsho? Sittin' on yer butt while those poor students sweat buckets?

How long have you got to wait before it gets mapped? Can it be driven just now?

I agree. 3500 - 4000rpm tops depending on rev limit.

In terms of external wastegate, you have the choice of an open pipe (called a screamer pipe) or return back into downpipe. My preference is to return because of noise issues cause if you think about it, those exhaust gasses leaving a screamer pipe is basically an open ended exhaust with no silencer. I did try the first set-up with a screamer pipe cause i wanted to run the car and was too lazy at the time to do the pipework to return to downpipe and it was very loud when on boost. It also gave a lot of vibration through the floor under my feet which also made it sound like someone was having a great big fart!

That's it John. The exhaust gasses naturally want to go through the turbine housing, through the exhaust wheel and then through the downpipe and out the exhaust. With the wastegate open you give an alternative route for the exhaust gasses to go through, hence less pressure through the exhaust wheel and hence less boost pressure created by the compressor side. Back in the late 90's early 00's, there was work done on the exhaust housings of some turbo's and downpipes in trying to keep the wastegate gasses separate from the exhaust gasses, as some turbos when the wastegate opens, causes those gasses to run straight into the path of the exhaust wheel gasses and can limit potential output. You may have seen some downpipes with splitters in them. This was designed to ensure no turbulence from the exhaust wheel of the turbo.

There's more to my previous answer John,but i didn't want to confuse any further! You can sometimes see circumstances where the exhaust gas pressure into the turbo is so great that it can also open the wastegate, but the idea is that it's boost pressure which controls when the wastegate does and doesn't open.

I agree. Why would you want to go external with a turbo which has an internal one? If you've got problems with the internal 'gated turbo, then the problem lies elsewhere.

yes

The pressure is mechanical John. If you have, say a 1 bar spring in the actuator (to the wastegate) and you have a hose from the inlet manifold to the actuator, then as soon as the inlet manifold is pressurised to 1 bar, the actuator will open and hence open the wastegate to allow exhaust gasses which would normally have gone through the turbo to go down the wastegate path and hence keep the boost pressure at 1 bar. In other words, you're limiting the speed of the exhaust wheel in the turbo to limit the boost pressure created by the compressor wheel. In terms of ECU control, if you can imagine putting a valve in the hose between the inlet manifold and the actuator (the 2 port or 3 port solenoid), then the ecu can open and shut this solenoid very quickly. If that solenoid was to stick in the closed position, then that would mean that the boost pressure from the inlet manifold wouldn't reach the actuator and so the wastegate wouldn't open, which means you'll have excessive boost pressure. With that in mind, then you can see that if you open and shut that solenoid many times a second, you can set your boost pressure to whatever you want i.e. if you have a 1 bar actuator and you want to run 1.4 bar boost pressure, your ecu can open and shut that solenoid many times a second to achieve the desired boost pressure. In terms of wategate John, you would have either an internal one or an external one, not both, so you can't go out and buy one to add to your spec as is.

Yes, it's a twin scroll. You don't need twin wastegates though.

up-pipe and external wastegate pipe (non RCM) Pipe in place (turbo sits on that 4 bolt flange

You mean twin wastegates or twin dumpvalves? If twin wastegates, most likely the car is using a twin scroll turbo.

Cheers Paul. I don't see it going away though. There's too many companies have managed to stop the final salary pension scheme for new starts due to costs. Will be interesting to see how it pans out.

Is it really worthwhile boxing in your air filter? after all the air is going to be compressed (which heats up air), then has to be cooled back down again by the intercooler...

What happens next from the last strike? Not been looking at news much recently.

Thanks Paul, hadn't looked at that link. FWIW when i did the AP fronts and Brembo rears, I removed the dust covers (if applicable), pistons and seals. There's little time involved in stripping them right down. I didn't replace the seals/dust covers/pistons as they were in good nick, but you should be able to get an overhaul kit quite easily if necessary. Reasons for doing this was i bead blasted the calipers to get all remnants of paint/debris/lacquer off them before powdercoating. It's not that easy to get into all the nooks and crannies with emery paper. Just rubbing down with emery paper and not getting all the old paint/lacquer/powdercoat off means you'll see exactly where you've missed after powdercoating or painting. Another reason for stripping was to look at the condition of the pistons and bores for pitting. The Brembos calipers compared to the AP's are well coated from the factory as they took a lot longer to get all the gold coating and lacquer off. (plus i took the black undercoat off the Brembo's i.e. back to bare metal) Preparation is the key. Do it right and it will look factory new

What did he do with his calipers?

I'd powdercoat instead of painting and probably just as cheap. IMO painting most often tends to look like someones tried to paint them. Powdercoating makes them look original and you can get whatever colour you want. There's very little involved in stripping the calipers down and rebuilding plus you've given the calipers a mini overhaul/check that all's well in this area before refitting and bleeding the brakes again.

and on level ground...

You wouldn't get into trouble with the DVLA vans as their system would show that you have paid your license fee. Yep, seen them regular on Renfrew Road looking down on to the M8 before the flyover for the airport.

Yes, though tax discs are only valid for 12 months. Having said that, you can get tax discs which are longer than 12 months, though this usually applies to new car sales only i believe i.e. the tax disc will state 12 months + 2 weeks. Having a quick scan of the DVLA site on licensing, i would read their comments as being that you have a valid tax disc, even though it's not due to start until the beginning of the following month.

Thanks Speech. I wondered cause *technically* it's not valid for 12 months (or 6) until the start date of the disc. I'd be surprised if there would be a potential fine involved cause to obtain a license up to 14 days beforehand would mean that you have a current license in force, whereas, (i'm a bit hazy on details here) if the vehicle was sorned or purchased without a disc, you can only apply 2 days before start date?