hey guys, well i got myself a 98 B5, jsut learning about the car really. im a ford trained tech, and this is a whole other ball game. althoug the car isnt much different..

i picked this gem up for a good deal and needs very little. windshield, brakes all around, abs module, and my my air bag light fixed..

im currently working on getting the maintenance items up to snuff.

ive done some searching on the website, im learning a lot about these cars, and im really impressed!

but either ive over looked it, or havent found it yet i dont know..

the big question is how much PSI of boost does this car push, from factory.. whats the max amount of boost it can handle on factory internals. i did read that these can handle up to 400-450 hp on the stock internals. which is pretty impressive!

also i have a hard time understanding this diverter valve deal. i cant remove it, and run a BOV because the MAF is before the diverter valve, and if i run a BOV the air is released to the atmosphere. so air is not returning to the intake side of the compressor, and it will run rich.. that doesnt quite make much sense to me because the MAF is before the diverter valve, how is it supposed to read the air that magically gets to the compressor after it? does the computer assume air gets there between shifts, making it run more rich? because as far as i know, the MAF should only be taking the reading of air flowing pass it, and supply fuel to the amount corresponding to its related factors. so it wouldnt matter if the air was released to the atmosphere or not...

anywho can someone correct me?

 

stock psi is 8. a chip will remap that to 12-18 depending on which chip you get. the max you can get out of the little k03 turbo is around 22 psi, and that will drop rapidly over 4500 rpms.

the stock rods can handle 300-350 ftlb of torque, those are what break first. the pistons and crank are good for alot of power.

you can run a BOV as long as its closed durring idle. i would just get an upgraded DV unless you want the sound of a BOV.

is this a manual or automatic? quattro? il assume its a 1.8t

 

Okay. I'll take a stab. From the factory, if i recall correctly, the 1.8 will output probably about 15-17 psi? That's just what I remember reading. After replacing a DV, you can expect near 20 or 21 psi. And yes, the stock internals can handle quite a bit of power, the problems lie elsewhere... Such as the clutch. I read in a thread yesterday that over like 300 hp, you will tear the stock clutch really fast. I believe it. And about the BOV. There's a thread, most likely in the stickies that explains all the techno-mumbo jumbo. But pretty sure that it doesn't function correctly, because after the air passes through a DV, it goes right back into the intake? But my guess would be that with a DV, you are applying pressure, with a BOV you just have atmospheric pressure. Probably a pretty good difference. So that's why it will throw off your sensors, and thus cause you to run rich. But if you have your heart set on a BOV for some reason, get a splitter/hybrid valve. I have a forge splitter, and it works really well. I build good pressure, and i get a twinge of psh after shifts. But anyway, here's a little info. Anyone, please correct me if I'm wrong. Because I probably am! ha

 

And I just reread your post, and I think the ECU thinks that the air is being recycled by a DV, so your sensor saying you sent this much air to the DV. But then it is coming back differently at the intake if you have a BOV installed. So that would probably be why it would joggle your sensors.

 

And Ghost For The Win! Ha listen to him, he knows what he's talking about.

 

yea what jeff said...
get a forge splitter dv...i also have one on my car and its awesome,
does all the work of a regular dv and gives you the sound of a bov...

and it is adjustable, you can make it fully recirculating, hybrid which recirculates 90% back into the system and blows off 10, or you can make fully blow off, meaning 100% atmospheric, like a bov? it is really a great valve...

and another thing you can adjust the strength of the spring depending on how much boost you are pulling... if you wanna hear what it sounds like let me know i got some sound clips...

 

read my newbie guide at the top. as long as you have a MAP sensor (2000+) you can run a BOV safely and ~20psi safely w/ a cheap zener diode. ~350ft lbs of tq possible w/ stock bottem end. near whatever you want to push with just new rods. head will float a valve past 8k.

stock psi is 8 for an AEB engine, 9-10 for the others. i wouldn't recommend the splitter, only cause the only 2 ones i've worked with personally, caused my friends problems. i'd get a 004 if you have a MAP, or 007 without a MAP.

 

yeah i got a 5 speed, 1.8TQ.

and i read the sticky you mentioned. but it doesnt explain why you cant run the BOV because of the MAF. information i believe is left out. air metered by the MAF should be all that matters as to how much air is flowing through the system. and according to the explanation, the DV is after the MAF, so how would the MAF know if air is being recirculated or not. thats why im confused. and although im in no rush to "modify" my car. i'd like to get into it to help others with related questions.

to me removing the DV for a BOV, sshould make no difference in system performance. other than a DV may help the turbo spool quicker between shifts. (forcing air back into the compressor)

thanks for the info guys. i really appreciate it

my clutch needs replacing as it is also... or is it the norm for the friction point being at the very top of the travel?

 

the stock clutch can last anywhere between 10k miles and 300k miles, its 98% up to how you drive it. you can have a 500HP A4 and drive it on the stock clutch. sure you have to baby it, no launches and no hard driving no fun, but you can do it. if you drive hard, the stock clutch is going to wear hard, even with stock power levels.

changing your DV for an upgraded one will have no impact on how much boost you have (assuming the stock DV was in working condition). you wont magically gain pressure by just changing a valve. your boost is controlled by the N75 valve. whatever pressure your ECU tells the N75 to make, is what it makes. jeff- most if not all of the info you posted is incorrect.

thats because you CAN run a BOV as i said. as long as it is closed at idle and adjusted properly. alot of people will tell you that you cant and that is because its a myth around these forums that you cant and people simply repeat it without knowing better. a DV is easier just because its a strait replacement to factory equipment.

when you let your foot off the gas durring a shift, the fuel injectors are turned off anyways, so it doesnt matter what amount of air is getting past the MAF, you are running full lean. thats the only time the BOV should be open anyways, so theres no harm done. by the time the injectors cycle back on when you get your foot back on the gas, the BOV should already be closed again. you may be out of the perfect a/f ratio for a split second but it quickly corrects itself.

a DV will not help the turbo spool quicker/slower then a BOV. any BOV/DV is used to eliminate compressor stall when the throttle closes and the turbo is still spooling (like between shifts). thats all it does, nothing more nothing less.

yes that is normal. as long as its not slipping then you are good. such is life with a hydraulic clutch.

 

alright, because wheni read the sticky, it was saying it would run rich if i got rid of the DV. which made no sense... lol

and its been said that DV or (recirculation valves) can help spool up times faster than a BOV, because of pressureized getting back in front of the compressor.. but its on an EXTREMELY small scale...

lol brutal about the high friction point in the clutch.. i barely have to push it in to get it to release. i was assuming that it was getting pretty close to no life.. because most of the time as a clutch get higher in its stroke, its a clear indication of life remaining.. but my mustang wasnt the case.. it only seems to be the case with honda's