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View Full Version : switching from internal to external???



justin21
04-17-2005, 06:51 PM
k i got a 99 A4 1.8T as far as i know its a stock K03 turbo what would i neet to switch it to a internal wastegate to an external wastegate? is it possible? and no i dont plan on keeping the stock turbo for much longer just till the end of the year. [a4]

k0mpresd
04-17-2005, 06:54 PM
you cant run an external wastegate w/ the stock turbo, not to mention, theres no need to

if youre not sure about the difference between an internal and external wastegate and how they work, then you need to do a little more research before you start thinking about upgrading the turbo

justin21
04-17-2005, 06:59 PM
i mean im no expert but i know a little my friend who runs a shop suggested i get an external wastegate since a bov makes it run rich while upshifting and downshifting. i just want it to be loud like my old gsx with the rfl bov is all.

TomRitt18944
04-17-2005, 07:01 PM
ahahah you got a lot of research to do

k0mpresd
04-17-2005, 07:09 PM
Originally posted by TomRitt18944
ahahah you got a lot of research to do

take it easy on the n00b...hes still learning...lol..[:D]

remember..loud does not mean fast and everything has to work together...

justin21
04-17-2005, 07:12 PM
yeah i know im learning do u mind? im just use to the 4G63 and SR20DEt u know the japanese imports and stuff. i never even heard of a diverter valve before a month ago to be honest. his shop never works on vws or audis just domestics and stuff like that. anyways thanks for ur patience and such.

k0mpresd
04-17-2005, 07:15 PM
no problem, dont take me giving you a hard time serious @ all, its all in fun

keep the ?'s coming, thats the only way you learn...

think of a dv as a bov that diverts the air back into the intake instead of venting it to the atmosphere...they do the same thing, releasing extra boost pressure when shifting and @ part throttle lifts

justin21
04-17-2005, 07:20 PM
yeah i know im just giving u shit is all. yeah i know that much about a diverter valve NOW put what i dont understand is that people are saying that ALL vws audis and cars with mass air meters use diverter valves which is not true or else my old gsx would have used one as well but it used a bov.

k0mpresd
04-17-2005, 07:23 PM
not all turbo cars have to run dv's, bov's work fine in a lot of cars

our ecus are a lot more sensitive than other cars though, thats where the difference comes in

voodooA4
04-17-2005, 07:26 PM
the reason that all vw/audi cars use the BPV (diverter valve) is because that is how the ECU is coded to run...the car runs rich with a BOV because the ECU 'expects' the air to be recirculated, and delivers fuel according to that expectation. If the air is not there (i.e. BOV), then the car runs rich.

When the ECU is taken out of the equation (like some of the big turbo guys have done standalone setups), then you are free to use a BOV if you wish, as long as your setup is tuned for that.

justin21
04-17-2005, 07:26 PM
ahhh thats what i though.. what about a bov that just kept closed at idel and opend up when it needed to let the air out? or do they make one.

RAyala2.7T
04-17-2005, 07:32 PM
they are all set up like that. think of the diverter valve as a one-way check valve. it will only let air go through one way.

justin21
04-17-2005, 07:35 PM
stand alone is expensive though. i would need something like the aem system right? thats about 2k

RAyala2.7T
04-17-2005, 07:39 PM
depends on how big you want to go. there are a few set ups make good horsepower without going stand alone.

justin21
04-17-2005, 07:46 PM
which ones and how much $$ do u think??

k0mpresd
04-17-2005, 07:49 PM
you dont need stand alone...the only time you should ever even think about stand alone is when you get a turbo bigger than a gt28rs...

justin21
04-17-2005, 07:56 PM
im not trying to run anything crazy like 30psi or anything just something nice with good response when money allows i only have about 100-200 a week to spend on parts so i cant buy much and im not good at saving.

k0mpresd
04-17-2005, 07:59 PM
i would suggest saving your money for a chip, thats going to be the best bang for the buck, after that should be an exhaust and then go from there

the amount of boost pressure isnt what matters..its the amount of air being flowed, bigger turbos flow more air and make more power, not always more boost

justin21
04-17-2005, 08:06 PM
even with all those miles u think it allright to put a chip on?? dosent it run about 16-18 psi? what about the a/f mixture does it mess with that or the timing? i was going to just buy one from bahn brenner the other day when i got the filter but they were busy and dident have time to do one. they wanted like 225-250 installed. it was an upsolute chip i believe.

k0mpresd
04-17-2005, 08:10 PM
it should do fine, unless you have a lot of miles, 150k+ plus or so...

it changes the fuel map and plays with the timing a little bit

dont get an upsolute chip, get a giac or apr..both should put you @ a little over 200hp

what year is your car?

justin21
04-17-2005, 08:17 PM
A 99 A4 1.8T with almost 150 thats what i was trying to tell u its a lot of miles and i want to do a rebuild on it before i get a chip turbo etc just basic bolt ons for now u know the easy things the car is in good condition though when i changed the plugs the #1 cyl had some oil on the spark plugs well i think its the #1 cyl the one thats closest to the radiator.

HotSauce
04-17-2005, 08:42 PM
Alright, no one has really answered your question.

The air comes in, through the intake, and is then "Counted" by the MAF. The ECU takes note of this number, and calculates, and prepares to add the appropriate fuel, for the correct air/fuel mixture (12.5:1 I think...).

When you let off the throttle, there is turbo pressure, with no where to go. It can't enter the combustion chamber, as the car is trying to slow down, not speed up. The air, with no valve, would be forced to stop, causing the turbine on the turbo to stop violently...This is EXTREMELY detrimental to the life of the turbo. There are a few solutiosn. A BOV would just vent this air into the atmosphere. A BPV/DV will instead recirculate the air BEHIND the MAF. Doing so, will keep all the air, tha has already been counted, in the system.

Releasing this air (Using a BOV), will cause the car to run rich. This is because the car is still assuming that the air it took in, is still there.


Hopefully that clears things up. You can run a BOV if you really want to, but you risk performance loss, clogged cats....Etc. Etc.

The bottom line: Chipping your car will create enough boost to give you a pretty nice sound. Running this with a more heavy duty DV such as the 710N (Stock in the TT), or with an aftermarket valve like the Forge, Bailey etc. will give you the best results, in both performance, and can give you a decent sound.

justin21
04-18-2005, 09:51 AM
yeah i know that the chip is the biggest power increase for the money im just nervous because of the mileage and it being my only mode of transportation to and from my two jobs. and i cant afford the downtime. So i have been looking into exhaust because it seems to be pretty restrictive due to the cat being right after the turbo then the downpipe.

GlacialBass
04-18-2005, 03:21 PM
Originally posted by HotSauce
Alright, no one has really answered your question.

The air comes in, through the intake, and is then "Counted" by the MAF. The ECU takes note of this number, and calculates, and prepares to add the appropriate fuel, for the correct air/fuel mixture (12.5:1 I think...).

When you let off the throttle, there is turbo pressure, with no where to go. It can't enter the combustion chamber, as the car is trying to slow down, not speed up. The air, with no valve, would be forced to stop, causing the turbine on the turbo to stop violently...This is EXTREMELY detrimental to the life of the turbo. There are a few solutiosn. A BOV would just vent this air into the atmosphere. A BPV/DV will instead recirculate the air BEHIND the MAF. Doing so, will keep all the air, tha has already been counted, in the system.

Releasing this air (Using a BOV), will cause the car to run rich. This is because the car is still assuming that the air it took in, is still there.


Ok Justin, your DSM worked this EXACT way. Yes, it is called a BOV on a DSM, but it still vented back into the intake. the only way that you can safely vent to atmosphere is to go to a blow through system, not a draw through. that is why a lot of DSMers use a GM MAF and a MAF Translator.

justin21
04-19-2005, 10:36 AM
ahh ok thanks for the advice glacial