Hi I just put a new T4 on my 87mk3 I now have a extrernal wastegate I comfused where is the best spot to hook the vaccum line that hooks from the wastegate to the engine any help or even pics.... thanks
Vaccum line for wastegate
- Thread starter DGmk3
- Start date
if IJ says it than it must be true.:icon_bigg :icon_bigg :bowdown:
i was going to say that where you put the vac line has an affect on your spool. when you turbo spools and starts to make boost, the whole system(pipes,ic, mani) does not reach the same pressure at the same time. the source at your compressor outlet may have 10psi whereas you ic has say 5psi and you mani is still at zero. you can make this work to your advantage(faster spool) with a stratigically placed vac source for your WG.
say you put it right at the TB. the WG will not crack untill your TB has boost, and will not open fully untill the TB has full boost. in other words the turbo will work alittle harder to make pressure in the manifolde, where it counts. this is good right? maybe not. why? because untill the point where the TB has enough boost to open the WG the turbo is spinning as fast as it wants, could be overboosting/spiking. i think this is why IJ answers this the way that he does.
i've thought about putting my wg signal in my upper ic pipes to increase
spool. i still think its a good idea for me because i've read of people spinning a stock ct to 20psi, so i'm not worried about my turbo running alittle more boost in the hotpipe/ic in order to make pressure in the upper ic pipe. i have some room to work with. however if you were running a turbo right at the edge of its limits(at the surge limit) you would not want it to make any more boost than what you have your controller set at, and would therefor want the WG getting its signal from the compressor housing. to make shure the turbo did not overspin itself.
i was going to say that where you put the vac line has an affect on your spool. when you turbo spools and starts to make boost, the whole system(pipes,ic, mani) does not reach the same pressure at the same time. the source at your compressor outlet may have 10psi whereas you ic has say 5psi and you mani is still at zero. you can make this work to your advantage(faster spool) with a stratigically placed vac source for your WG.
say you put it right at the TB. the WG will not crack untill your TB has boost, and will not open fully untill the TB has full boost. in other words the turbo will work alittle harder to make pressure in the manifolde, where it counts. this is good right? maybe not. why? because untill the point where the TB has enough boost to open the WG the turbo is spinning as fast as it wants, could be overboosting/spiking. i think this is why IJ answers this the way that he does.
i've thought about putting my wg signal in my upper ic pipes to increase
spool. i still think its a good idea for me because i've read of people spinning a stock ct to 20psi, so i'm not worried about my turbo running alittle more boost in the hotpipe/ic in order to make pressure in the upper ic pipe. i have some room to work with. however if you were running a turbo right at the edge of its limits(at the surge limit) you would not want it to make any more boost than what you have your controller set at, and would therefor want the WG getting its signal from the compressor housing. to make shure the turbo did not overspin itself.
DGMk3: Well no I mean't on the Compressor housing outlet!
If you move it anywhere else there will be a pressure drop in the signal to the WG and as long as you're aware of this drop it isn't an issue but say you have a 2psi drop across the IC you end up adding this to your total boost!
WG spring 10 psi + pressure drop = 12 psi (could be more could be less)
This is really annoying if you use an EBC and are trying to set up a nice safe low boost map!
SoupraT:Yep spiking can be an issue!
You end up with a very jagged boost curve as it's constantly overshooting and catching itself!
If you move it anywhere else there will be a pressure drop in the signal to the WG and as long as you're aware of this drop it isn't an issue but say you have a 2psi drop across the IC you end up adding this to your total boost!
WG spring 10 psi + pressure drop = 12 psi (could be more could be less)
This is really annoying if you use an EBC and are trying to set up a nice safe low boost map!
SoupraT:Yep spiking can be an issue!
You end up with a very jagged boost curve as it's constantly overshooting and catching itself!
Yeah I'm gonna try to get it as close to the compressor as possible but I don't have any vaccum ports on my housing should I tap a brass fitting on my hotpipe???IJ. said:DGMk3: Well no I mean't on the Compressor housing outlet!
If you move it anywhere else there will be a pressure drop in the signal to the WG and as long as you're aware of this drop it isn't an issue but say you have a 2psi drop across the IC you end up adding this to your total boost!
WG spring 10 psi + pressure drop = 12 psi (could be more could be less)
This is really annoying if you use an EBC and are trying to set up a nice safe low boost map!
SoupraT:Yep spiking can be an issue!
You end up with a very jagged boost curve as it's constantly overshooting and catching itself!
omg DG are you still running the crazy 1.04 A/R hotside on that turbo??? I think i have the same one. well if you are get a smaller one or youll never boost. But Ian you but your vac source on the lower IC pipe??? good idea i might have to try that.
tomz.
tomz.
Yeah that turbo is brand new I haven't even ran it yet I'm think it was a poor choice as my car isn't going to make much low end power but in the high end it should pull pretty good if this turbo sucks I will replace it with a more streetable ARUntouchable7mgte said:
forget drilling
use one of these and you are set
http://www.atpturbo.com/Merchant2/m...OD&Product_Code=ATP-FTG-010&Category_Code=BCS
use one of these and you are set
http://www.atpturbo.com/Merchant2/m...OD&Product_Code=ATP-FTG-010&Category_Code=BCS
I'm ordering one of those tonightfiggie said:forget drilling
use one of these and you are set
http://www.atpturbo.com/Merchant2/m...OD&Product_Code=ATP-FTG-010&Category_Code=BCS