Does an MFi Series2 really need a D/V?
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As title says, does it?
Reason i ask is i just got hold of a solid boost hose (hard pipe), but it doesnt have the D/V outlet pipe on it. I am using a D/V at the minute, but will have to lose it when fitting this new pipe...unless i modify the new pipe.
My Series 2 has a pretty good Spec i.e Chipped, cammed, larger intercooler blah blah blah, but do i still need a dump valve or can i get away without using one?
Any help would be helpful, thanks
Reason i ask is i just got hold of a solid boost hose (hard pipe), but it doesnt have the D/V outlet pipe on it. I am using a D/V at the minute, but will have to lose it when fitting this new pipe...unless i modify the new pipe.
My Series 2 has a pretty good Spec i.e Chipped, cammed, larger intercooler blah blah blah, but do i still need a dump valve or can i get away without using one?
Any help would be helpful, thanks
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Ok thanks guys
The life shortening of the turbo is nothing too severe tho is it? I only had the T3 refurbed a short time ago, so surely that will allow it to last longer (hopefully)
Kinda feel safe in the knowledge that Christian ran 30psi without one lol
Without it, will the MFi give off that 'flutter' sound?
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Kinda feel safe in the knowledge that Christian ran 30psi without one lol
Without it, will the MFi give off that 'flutter' sound?
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#11
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Bosch KE fitted by Ford on 8psi engine = No Dumper.
Weber Marelli fitted by Ford on 8psi engine = Dumper.
Thats should tell you a lot.
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So Stu, what ya saying is, no it doesnt need one - in your opinion?
No, Ford never fitted one. Reason: At standard spec, there is no need.
But... Did Ford fit modified chips, uprated cams and larger spec'd actuators etc? No...
So the answer could well be on the toss of a coin!
No, Ford never fitted one. Reason: At standard spec, there is no need.
But... Did Ford fit modified chips, uprated cams and larger spec'd actuators etc? No...
So the answer could well be on the toss of a coin!
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What Stu is trying to say is that the KE Jetronic (MFI) doesn't operate very well with a dump valve fitted. Reason is the system measures the amount of air flow passing the metering head. Creating a leak in any way between the metering head and engine causes mixture issues.
In other words, don't fit one when running on MFI, do as you please when converted to EFI.
(must say that I'm running MFI but still have a dumpvalve. It's possible but far from ideal!)
In other words, don't fit one when running on MFI, do as you please when converted to EFI.
(must say that I'm running MFI but still have a dumpvalve. It's possible but far from ideal!)
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So Stu, what ya saying is, no it doesnt need one - in your opinion?
No, Ford never fitted one. Reason: At standard spec, there is no need.
But... Did Ford fit modified chips, uprated cams and larger spec'd actuators etc? No...
So the answer could well be on the toss of a coin!
No, Ford never fitted one. Reason: At standard spec, there is no need.
But... Did Ford fit modified chips, uprated cams and larger spec'd actuators etc? No...
So the answer could well be on the toss of a coin!
Stu stated the same 8 psi boost pressure with the only difference being the management as such you can come to the conclusion that ford did not consider it a requirement based on the management rather than the boost level.
On a side note not all dump valves actually work on MFI, try a diaphragm based dump valve and you will get an erratic idle. I would never personally run any type of dump valve on a MFI based RS Turbo
Last edited by Turbocabbie; 17-06-2008 at 02:22 PM.
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Ford considered it necessary to place a dump valve on vehicles using Weber Marelli management (cossie) with 8 psi unlike the vehicles which ran Bosch KE (Escort) at 8 psi
Stu stated the same 8 psi boost pressure with the only difference being the management as such you can come to the conclusion that ford did not consider it a requirement based on the management rather than the boost level.
Stu stated the same 8 psi boost pressure with the only difference being the management as such you can come to the conclusion that ford did not consider it a requirement based on the management rather than the boost level.
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Seems I have started a healthy debate - against me ![LOL](https://passionford.com/forum/images/smilies/icon_lol.gif)
So yea, you say NO to D/V's on MFi's as, and i have experienced it in the past, messes with air flow etc.
Im currently running a Bailey twin piston 'evo' and see no issues... but my old valve allowed alot of issues, mainly leaking!
As you advise Stu (being the man in the know) I will leave it off and not modify my new pipe.
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So yea, you say NO to D/V's on MFi's as, and i have experienced it in the past, messes with air flow etc.
Im currently running a Bailey twin piston 'evo' and see no issues... but my old valve allowed alot of issues, mainly leaking!
As you advise Stu (being the man in the know) I will leave it off and not modify my new pipe.
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Stu, why did ford not use a recirc dumpvalve like on the cossie then?
As IME even with flow meters, they dont effect running adversely, or is mechanical different to electronic in that respect too?
Must confess I know VERY little about MFi as I jumped from carbs to EFi
As IME even with flow meters, they dont effect running adversely, or is mechanical different to electronic in that respect too?
Must confess I know VERY little about MFi as I jumped from carbs to EFi
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Dont get me wronmg, the twin pistons will often work just fine as they only allow an air leak when positive pressure is present at the input stage, and if your happy with it, keep it, but you will find that the engine runs cleaner overall without one due to the archaic design of the metering unit and the way the flap drops shut suddenly when the dumper releases pressure and you get that sudden lurch as the metering unit thinks you have turned the engine off.
Its better without, but a good one will work if twin piston.
Its better without, but a good one will work if twin piston.
Last edited by Stu @ M Developments; 17-06-2008 at 02:48 PM. Reason: Dan Ewan is a doggie dingler
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Dont get me wronmg, the twin pistons will often work just fine as they only allow an air leak when positive pressure is present at the input stage, and if your happy with it, keep it, but you will find that the engine runs cleaner overall without one due to the archaic design of the metering unit and the way the flap drops shut suddenly when the dumper releases pressure and you get that sudden lurch as the metering unit thinks you have turned the engine off.
Its better without, but a good one will work if twin piston.
Its better without, but a good one will work if twin piston.
I do realise EFi is a hell of a lot better than the older MFi set-up, but i didnt realise a lot thats been said in this thread. What started as a simple question has turned into a very informative read
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#23
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further to this discussion stu.. I have a cossie managed escort running a P8 which currently does not run a dump valve.
Considering the management would you suggest running a dump valve or does it not make a great deal of difference
Considering the management would you suggest running a dump valve or does it not make a great deal of difference
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It doesnt read very plain and simple does it lol
Basically, and this is how i have read and understood it, with MFi, ya may aswell remove/not have one because it can mess with the air flow of the metering unit... although Twin Piston ones i.e Baileys 'EVO' valves can work adequately.
I have dug further with this today and many people say that it aint worth having one fitted due to it being a hinderence (spelling) more than an essential part. Others simply say that its better to have no sound than sound like a bus 'dumping'![LOL](https://passionford.com/forum/images/smilies/icon_lol.gif)
Kinda guessing with this thread it aint worth it, unless ya already have one fitted with no issues, but if ya thinking of fitting one... dont bother.
Pretty much down to personal preference, I suppose.
One thing that hasnt been answered yet is what happens when the Turb dumps without a valve installed. I know the pressure goes back to the wastegate and 'stutters' the turbo fins, which inturn can lead to the dreaded word of 'Damage'... but will an MFi 'flutter' like a EFi when dumping?
If it does, the valve is definately staying off as thats a mint sound!
Basically, and this is how i have read and understood it, with MFi, ya may aswell remove/not have one because it can mess with the air flow of the metering unit... although Twin Piston ones i.e Baileys 'EVO' valves can work adequately.
I have dug further with this today and many people say that it aint worth having one fitted due to it being a hinderence (spelling) more than an essential part. Others simply say that its better to have no sound than sound like a bus 'dumping'
![LOL](https://passionford.com/forum/images/smilies/icon_lol.gif)
Kinda guessing with this thread it aint worth it, unless ya already have one fitted with no issues, but if ya thinking of fitting one... dont bother.
Pretty much down to personal preference, I suppose.
One thing that hasnt been answered yet is what happens when the Turb dumps without a valve installed. I know the pressure goes back to the wastegate and 'stutters' the turbo fins, which inturn can lead to the dreaded word of 'Damage'... but will an MFi 'flutter' like a EFi when dumping?
If it does, the valve is definately staying off as thats a mint sound!
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mfi will "flutter" as much as efi, the only differnce is you will hardly hear it due to it being muffled by the metering unit where as on efi the the turbo connects directly to the air filter giving less restriction and not muffling the sound
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ive got mfi and took the dump valve off but the sound off the turbo stall was'nt loud enough so the dump valve went back on but the car did seem to drive a bit smoother in slow traffic
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Out of curiosity how many turbo's are you aware of which have failed or had damage which can be solely attributed to compressor stall and what was the boost level prior to failure.
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