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04-18-2002, 11:13 PM
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| Turbo, MAF, and BOV Guys i need help... 1. Some say that with a turbo (94 325is) the b.o.v. must be routed back into the system, and some say its fine to vent into the atmosphere.. So which is it? 2. With a 4mm copper headgasket what will the new compression be? And what is a safe level of boost to run? 3. Where can i get a set of 42lbs injectors for a good price?? Thanks a lot for all of your input!!      |
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04-19-2002, 03:13 AM
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| Re: Turbo, MAF, and BOV Quote:
2) sorry....no clue 3) I think 42lbs injectors would be complete overkill...but I do know that injectors off of a mustang are direct PnP for our cars. You can pick up a nice 30lbs or 35lbs set for damn cheap if im not mistaken.
__________________ saeed ~333 |
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04-19-2002, 06:13 AM
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| im getting a turbo system this weekend, the guy i am buying it from says that bmws have to use the one that go back in the system to keep teh car from stalling. |
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04-19-2002, 06:35 AM
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| With a MAF meter you need to vent back in so you don't stall coming off throttle. The MAF measures how much air goes into the intake and adjust fuel, if you vent the air out you loose the air and get the extra fuel and that's why you stall, stalling is worse with cold weather for some reason. One way to get around it if you must vent to the atmosphere (cool sound), is to get an adjustable BOV, like the Greddy, so you can tighten the spring pressure and only let a little air out. One other reason to blow it back in, is to use that air pressure to blow against the turbo and keep the blades spinning. You won't notice a performance increase by venting to the atmosphere. |
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04-19-2002, 07:32 AM
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| You actually gain more power venting it back into the MAF, venting into the atmosphere is mainly for sound, BMWs you have to route it back or else you will stall the car. In order to run open bov you would have to get software that bypasses the MAF so it will not sense the lost of air.
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04-19-2002, 08:35 AM
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| yup these guys are all correct... when you vent to the atmosphere, you dump aready measured air out of the system and it runs RIIIICH... depending on PSI and other things, it might not run that rich (low boost/small turbo won't dump as much air) but yeah, you'll probably want to route it into the intake so it doesn't cough and stumble... if you don't mind that, well, it will sound "cool" - btw this is worse when its cold because cold is more dense anyway, so when you vent some, it dumps even MORE o2 then hot... you also make more power on cold air.... personally i don't like the sound that much. *braces for flame broiling* 42lbs injectors... seaarch around on the mustang sites... SVT uses bosch as well as bmw, so you can get them for cheap from the ford guys (thank god)... find out what the stock bore and stroke are, along with compression, and punch some numbers and find out the new compression... i'm just a bit hung over and too lazy to find the stock #'s...  Last edited by pete : 04-19-2002 at 08:38 AM. |
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04-19-2002, 09:21 AM
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| Quote:
__________________ saeed ~333 |
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04-20-2002, 01:56 AM
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| Easy answer. Blow off valves provide ZERO power gains. None. They aren't for adding power. They keep back pressure from spinning the turbine blades in reverse and wearing out the bearings on the compressor prematurely. They may improve throttle response a bit. On a vehicle that blows THROUGH the MAF (like the mechtech), you route the BOV relief to atmosphere. If you are pulling through the MAF, like AA, you blow off into the intake. Reason being just like stated above, sucking through, the maf thinks that there is air going into the engine, so it compensates with fuel, and there in reality is no air...so the engine wants to stall. With mine blowing through, the MAF knows that the air has been blown off already, so it compensates for it. |
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04-20-2002, 02:32 AM
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| Nicely put everybody...  My BOV goes out into the atmosphere...and it often stalls. |
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04-20-2002, 02:28 PM
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| First of all thanks for all the info! Brad.. can you expand on the push pull factors... (basic setup of each).. A Tire question... What is the widest tire possible that can fit on a 7.5inch rim? ps.. yes i will need the 45lbs... and does anyone know who can program software for cheap? aa wants 600!!! i'm sure its good but i may incorporate a standalone in the future.. soo... Thanks |
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04-20-2002, 06:34 PM
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| For a standalone computer... kinda expensive... but go with the Motec System http://www.motec.com/home.htm Gene used to run a Electromotive TecII in his turbo M3 before. |
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04-20-2002, 07:23 PM
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| bad thing with blow through setups is the stock computer only measures the amount of air going through, not its pressure... so the stock computer has a bitch of a time dealing with boost when set up this way... when you set it up pull through, the sensor sees a whole bunch of air going by, rather then about the same amount, except at higher pressure. motec... sweet if you have the $$$ otherwise i'd get the unichip, its almost as programmable as motec, easier to set up and just taps into the stock wiring... with motec, you'll probably also need different gauges, which is another fairly expensive item. (stacks or pi preferably)... nobody can really program OBD II for cheap... to tell you the truth dinan and AA are the two places who can do it well (with the bmw setup), and they are $$$ 600 is a decent price. |
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04-20-2002, 09:44 PM
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| Sorry about that its OBD 1.. |
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04-21-2002, 07:37 PM
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| 45lb injectors Quote:
With 45lb injectors, your car will probably idle and low-load part throttle cruise like crap!! Steve |
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