Was just thinking that earlier when I was canning it, would love the pshhht sound when changing gears..
Would soon get sick of it though..
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remap 170tdi leon
- Thread starter redrobo150
- Start date
Was just thinking that earlier when I was canning it, would love the pshhht sound when changing gears..
Would soon get sick of it though..
Yes you can put a dump valve on any turbo'd car. All it does is release the air pressure built up between compressor and engine when the throttle is closed. This has the benefit of allowing the turbo to continue to spin at near max rev's so the next time you hit the throttle it takes less time to spin up and re-apply the pressure hence reduces lag. Also has the side effect of reducing wear on the turbo internals as it doesnt stop suddenly from extreme high revs. The better type of dump valve (imo) are recirculating types which not only dump the pressure from between the compressor and engine but reapply the pressure back to the other side of the turbo which keeps it spinning at higher speed than if the pressure is just dumped to atmosphere. There are staged dump valves as well but obviously price goes up.
Dump valves correctly fitted and suited to engine performance can give performance gains (but most fit for the noise, which is hardly aparrent on recirc type by the way). Recirc types are fitted as standard on Subaru Impreza's and you cant hear them.
Dump valves correctly fitted and suited to engine performance can give performance gains (but most fit for the noise, which is hardly aparrent on recirc type by the way). Recirc types are fitted as standard on Subaru Impreza's and you cant hear them.
Interesting reading thanks - would there be much of an advantage to fitting one on the TDI engine though?
You mention its better for the turbo since it isn't stopping suddenly, though - wouldn't the turbo be under increased stress since it will be circulating more than before..?
You mention its better for the turbo since it isn't stopping suddenly, though - wouldn't the turbo be under increased stress since it will be circulating more than before..?
spuds
Guest
Yes they are which is probably more to do with manufacturers aiming to get more reliability out of the turbo's than for performance. Never used to be the case though (e.g my old RS Turbo never had one and what a motor that was at 250bhp at the wheels but turbo was only good for up to 30,000 miles if you were lucky)
Fitting to a TDI, yes would give exactly same benefit as fitting to a petrol, allows less turbo lag, the quicker the air pressure is up to max, the quicker the ECU can put in max fuel = the quicker you get max BHP
Going back to the stresses input into a turbo, imagine your doing 1000 miles an hour and then stop virtually dead, the G involved is potentially massive, but if you can freewheel without much resistance (remember the bearings are designed for something like 10,000 rpm +) the wear and tear is actually minimal as your still moving in the same 'designed' direction.
The most damage usually done to turbo's is by excessive heat which can bake the oil used to lubricate the bearings to the very same bearings. Thus this will disintegrate those bearings. Now bear in mind (especially all of you who have had a turbo go bang on a car) the oil used to lubricate AND cool the turbo is the very same oil passing around your whole engine. If the turbo goes bang, all those metal particles are now wearing the living s*!t out of you engine internals. Alot of the heat generated is by running a turbo at max chat and then generating massive friction by stopping it and the restarting it.
Other good ideas (imo) are seperate oil reservoir, oil cooler and pump for turbo which runs on after engine shuts down for 1-2 mins, pumped water cooling for turbo (which runs on for 1-2 mins after engine shuts down. A high spec recirculating dump valve.
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Fitting a dump valve to a TDI is utterly pointless unless the sound of one tickles you somewhat. Diesel engines do not have throttle valves and constantly suck huge amounts of air in compared to petrol engines. Whereas a petrol when lifting off the gas you shut the throttle valve which creates a massive build up in pressure can stall the turbo. Because TDI's don't have the throttle valve this pressure cannot build upto levels that can stall the turbo hence no need fro a dump valve.
So if you want your TDI to sound like the local chavs subarooo then go for it otherwise there is absolutly no performance to be gained.
So if you want your TDI to sound like the local chavs subarooo then go for it otherwise there is absolutly no performance to be gained.
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Hmm well it seems to improve response on a friends TDI. When you close the throttle on a diesel it stops demanding air and fuel the same as a petrol which will give a certain back pressure between turbo and engine.
It was specked with a two stage recirc dump valve, hybrid Honeywell (Garrett) turbo. There is NO lag what so ever, but then TDI's don't suffer from lag then from your statements........ah but yes they do and quite a bit I might add. If your statements were true then it would be zero lag?
As suggested in previous posts, the reason for fitting isn't the noise its to improve turbo response. You'd be hard pushed to hear much wooshing above the clatter of the diesel anyway really.
Oh just to clarify the mate, like myself isn't some 20 year old boy racer (not suggesting any of you are either its just a clarification) and has actually designed and in process of producing a new jet engine (he's an aviation engine specialist as his his father who is one of the worlds formost on C130 Hercules engines). Just to note, most jet engines are really just big turbo's with combustion chambers fitted so he knows what he's doing, as do Rolls Royce, Bristol University, BAE, Thales etc to name some of the company's he's dealing with at the moment.
I don't mind being proved wrong, but all I am saying is, it has worked so far on his, max torque was developed around 750 rpm earlier on a dyno showing before and after fitting results during testing.
By the way its only people with a lack of knowledge (and as mentioned 'CHAV's) that fit Blow off valves to Subaru's, they work better with CBV's, Compressor Bypass Valves, as do all modern Turbo'd Cars
It was specked with a two stage recirc dump valve, hybrid Honeywell (Garrett) turbo. There is NO lag what so ever, but then TDI's don't suffer from lag then from your statements........ah but yes they do and quite a bit I might add. If your statements were true then it would be zero lag?
As suggested in previous posts, the reason for fitting isn't the noise its to improve turbo response. You'd be hard pushed to hear much wooshing above the clatter of the diesel anyway really.
Oh just to clarify the mate, like myself isn't some 20 year old boy racer (not suggesting any of you are either its just a clarification) and has actually designed and in process of producing a new jet engine (he's an aviation engine specialist as his his father who is one of the worlds formost on C130 Hercules engines). Just to note, most jet engines are really just big turbo's with combustion chambers fitted so he knows what he's doing, as do Rolls Royce, Bristol University, BAE, Thales etc to name some of the company's he's dealing with at the moment.
I don't mind being proved wrong, but all I am saying is, it has worked so far on his, max torque was developed around 750 rpm earlier on a dyno showing before and after fitting results during testing.
By the way its only people with a lack of knowledge (and as mentioned 'CHAV's) that fit Blow off valves to Subaru's, they work better with CBV's, Compressor Bypass Valves, as do all modern Turbo'd Cars
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http://www.dwdiesel.com/PEPGarrett.htm
Here's a quick link to D & W 'DIESEL'.
They use Garrets 50MM blow off valves as part of an upgrade for the Ford F350 Diesel
By the way the correct term isn't the commonly called dump valve thats actually old technology. The correct application is a 'COMPRESSOR BYPASS VALVE...CBV or also known as a COMPRESSOR RELIEF VALVE.
I know a little teeny bit about engine's as well (Qualified level 2 Cummins Diesel Technician is just one certificate I hold),
I actually go to Honeywell 'Garrett' in Waterford, Ireland every year as its one of the many companies I work with as well.
But again I am willing to be proven and will freely accept if I am wrong. I do like to discuss what does and doesn't work, and how things work.
Here's a quick link to D & W 'DIESEL'.
They use Garrets 50MM blow off valves as part of an upgrade for the Ford F350 Diesel
By the way the correct term isn't the commonly called dump valve thats actually old technology. The correct application is a 'COMPRESSOR BYPASS VALVE...CBV or also known as a COMPRESSOR RELIEF VALVE.
I know a little teeny bit about engine's as well (Qualified level 2 Cummins Diesel Technician is just one certificate I hold),
I actually go to Honeywell 'Garrett' in Waterford, Ireland every year as its one of the many companies I work with as well.
But again I am willing to be proven and will freely accept if I am wrong. I do like to discuss what does and doesn't work, and how things work.
Oh lets not start an argument here plenty of those in the past have got out of hand. 
I appreciate your point and expertise but all I was trying to point out was that a 'COMPRESSOR BYPASS VALVE' works far more efficently on a petrol engine than a diesel due to the throttle valve snapping shut when lifting off the gas. My point of being utterly pointles may be dumbfounded but why don't manufacturers fit them to mainstream turbo diesel cars or is this a future development that may appear in TDI's ?
It is all very interesting technology and I am sure we are all open to be educated.
I appreciate your point and expertise but all I was trying to point out was that a 'COMPRESSOR BYPASS VALVE' works far more efficently on a petrol engine than a diesel due to the throttle valve snapping shut when lifting off the gas. My point of being utterly pointles may be dumbfounded but why don't manufacturers fit them to mainstream turbo diesel cars or is this a future development that may appear in TDI's ?
It is all very interesting technology and I am sure we are all open to be educated.
Last night I was floating along quite quickly about 70mph and when I began slowing down something came up on the dash about the DPF, though it only flicked up for about a second and I didnt get reading it.. Anyone know what it would have been?
Also, sometimes after driving quite hard, and I let the engine idle, it idles a little bit over the 1k mark, why would this be?
Thanks
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