BlackC230Coupe

I know blow off valves are for turbo charged cars but i went to a turbo shop in Miami and me and the guy that works there were talkin about blow off valves so i said i would love to get one to bad my car was not turbo charged he asked what i have i said a c230 coupe he said ohh yea well those are supercharged and i said i know he said u can put a blow off valve of there. i was like really he said they have done it to some supercharged cars before. he said if i want he will get the the blitz or greddy blow off valve but i said i am not sure will it do anything bad to the car and he said no.
but i wanna hear all your opinions about this is it really possible? will it do any harm? will i gain anything? will it still make the cool sound it does with turbos? and would u do it?

thanks

Mike T.

Do you mean a valve to release "excessively" compressed air, sort of like a turbo wastegate?

Why on earth would you want to do that? Would it not just decrease effective blower pressure, thereby reducing engine power?

Or does the C 230 K already have such a device and what you really mean to do is raise the threshold at which the existing blow-off valve releases?

I actually thought that the C 230 K, having a low pressure blower, would not need a blow off valve...I could be wrong though.

BlackC230Coupe

it might be similar to a wategate but its a blow off valve and what do u mean why on earth would i want one u obviously dont know what they sound like there awsome. at least on a turbo charged car. thats why i am asking question about it for a supercharged car because i know its not to common. i am not sure if it will reduce engine power or not thats why i am asking all these questions.

mdp c230k

A blow off valve lets maximum pressure be generated at a rpm lower than redline. If the turbo is allowed to increase in speed, and thus output pressure, it might well exceed the maximum the system can take. The designer might want to reach max pressure at 4000rpm but the engine redlines at 6000, without a blow-off valve the turbo will exceed the limit as it rises above 4000rpm, the blow off is a limiter. It does not release all the pressure, just the amount over the set threshold. I'm sure you see whats going on with the blow-off now, right? You don't need one on our car as the system is designed to reach the designed pressure by the superchargers speed vs engine rpm. By seeing how a gear change can increase hp it is obvious that the stock cars pressure is well under the limit that would make a blow-off necesary.

dj-po

Plus, there is already a by-pass valve built into your system, it releases excess pressure back into the intake.



John.

SoCal240/6

Just when I thought the postings on this board could not fall any further . . .

Anyways, maybe this is what you are looking for:

http://www.lilviv.com/pictures/nabvalve.jpg

(seriously, this is the price that is paid for moving downmarket).

Mach430

John is completely correct. Why change it?

gab

i think i read somewhere that you can modify the by pass valve to route it to atmosphere to make the psshhhh psshhhh sound. how to do it i dont know

sdcaclint

i just wasted two minutes of my life reading this thread, and an extra 30 seconds writing this

Mike T.

Cool, that's the supercharged car equivalent of the sound of a hockey card clicking against bicycle spokes, right?

vadim

Ok, let's make this thread a little more interesting...

If there is a bypass valve relieving excessive boost pressure (which was my understanding, too), then what is the point of installing a bigger crankshaft pulley? The idea is to create boost pressure higher than stock, but then the bypass valve will just stay open longer and kill it all!

Another angle is: what if there is a way to fool the bypass valve and have overboost (that was my understanding of what an upgraded chip does) - obviously the result would be the same as... pulley upgrade (hmm... see above )

This leads to a question: how does the M111's ECU map its parameters? Based on RPM only, or is there some sort of boost pressure sensor? If there's no sensor, and the RPM is the only input, the the bypass valve must be "hardcoded", that is, mechanically pre-set to certain boost value and will open when this boost has been reached no matter what...

Spyke

Tee hee hee... that's the best comment I've seen on this thread so far!

So here's what you do. Get a tank of compressed air. Hook a valve up to it. When you want to impress whoever it is that's impressed by flow noise, you release the valve and PSSSSSTTTT... Heck, with MY method you don't even need a BLOWER. Hang on! Wait... BONUS POINTS: Paint the air tank blue and put NOS stickers on it! That'll REALLY impress the homeys!

Dang... I think I'm on to something... Anyone care to help with the marketing? I'll do the development... hmm, where's my blue Krylon?

But seriously, Vadim is absolutely right. IF there is excess pressure being bled already, there'd be no reason to have a larger pulley. Bleed off pressure, lose power. Thems the rules.

And... excess pressure is bled back to the INTAKE?

Explain this to me, cuz the way I see it, if you bleed the excess pressure downstream of the blower, you're trying to bleed it back on to itself.

If you bleed excess pressure upstream of the blower... I'll have to think about that one...

mdp c230k

Maybe this 'bypass' that they a talking about is not on the supercharger but the one thats on the exhaust system that pumps air in the exhaust before the cat when the car is cold. That makes some sense. As I stated earlier, bigger pulley= more pressure. That would be made useless by a bypass valve, wouldn't it?

KJ-TypeR

Actually, the statement above is incorrect.

A WASTEGATE is responsible for bleeding off excess boost to maintain a limit on boost pressure. So the description above applies to a wastegate, NOT a blow off valve.

A BLOW OFF VALVE releases excess pressure in the piping between the throttle body and the Turbocharger when off the throttle. Since compressed air is flying through the open throttle body, a problem occurs when you shift because you take your foot off the gas and all of a sudden, the throttle plate slams shut forcing all the compressed air being pushed by the turbo to go BACKWARDS. This is HORRIBLE for throttle response, and can cause serious damage to your turbo as well. Normally aspirated cars do not have this problem since there is no pressure in the intake piping.

This is where the Blow Off Valve comes into play. When you take your foot off the throttle, the blow off valve opens to relieve the pressure. Without it, damage to your turbo could result, or even worse, damage to your engine. If pressure is allowed to build up in the intake piping from say your regular 6 psi to 12 psi, problems arise when you get back on the throttle and your engine ingests air compressed to 12psi. If your lucky, you'll only get compressor surge, but sooner or later, you'll just end up blowing your engine.

A Blow Off Valve releases regular air whereas a wastegate releases exhaust gasses.

mdp c230k

your right, my bad.

avlis

The bypass valve I think he's refering too is shown in the picture below. It's at the end of the air box, just above the blower pulley. It's in the silver housing under the black plastic 90 degree elbow. If you take your air filter out, you can peek through the hole and see the butterfly in the housing.

I think this valve bypasses the blower and feeds uncompressed air through the intercooler into the intake manifold. My guess is that this valve replaces the electronic clutch that is found on some superchargers.

I have yet to find a valve that feeds air into the exhaust. I believe it's in there somewhere but I can't see it. It's probably near the exhaust manifold under the shielding.

KJ-TypeR, thanks for clearing that mess up. The misinformation on message boards like this is frustrating.

KJ-TypeR

I think trying to put an aftermarket blow off valve on would really mess things up.

My friends Audi TT 225HP has this problem where the blow off valve breaks every 12,000 kms and it gets fixed under warranty. It's total BS how Audi is handling it, but what can he do? He tried using an aftermarket blow off valve but started getting check engine lights so he took it off.

I have to admit though, the sound of a blow off valve is beautiful. After taking the Turbo charger off my Type-R, it's one of the things I really miss (next to blazing fast acceleration of course. hehehe).

BlackC230Coupe

Can someone please tell me why if people complaigning about boaring threads (like this one as they were refering to). do u actually keep reading and even worse REPLY. i posted this thread to ask questions as i was not getting much maybe the only help was KJ-TypeR i only wanna know if a blow off valve will cause any problems and so on as i posted earlier in this thread. I am almost 99% sure i would never put one on this car but i thought i would like to hear about what people know about them on supercharged cars. As its not to popular. It was basicly just for fun since they sound cool. i was not planing on replacing it just to have a new blower i only wanted it because they sound cool (really cool). i am sure more than half of u dont know what a blow off valve is exactly so thats why it might sound crazy. But keep the comments comming.

And by the way KJ-TypeR why did i take your turbocharger off the type r?

BlackC230Coupe

i was not asking for immiture replys like this one and what do u mean by (seriously, this is the price that is paid for moving downmarket). asking a question about a blow off valve is down market????????????????? i dont consider your c240 6 speed such an upscale car if u consider the c coupe a downmarket car then i could say u bought the cheapest c class sedan they make. the cars i own are a little more upscale then yours. so just asking simple questions about a c230 coupe as u consider MB's downmarket car is not stuipid. if u have any more stuipid remarks i think u should keep them to your self.

i would never belive how people can find things to PICK about on every damm thread. The is a Fourm there ment for asking questions. Weather u like them or not.

vadim

How is this reply immature??? All you want is "cool sound" - you admitted it yourself - even at the expense of your engine being seriously screwed up, and here is a safe solution!

BlackC230Coupe

did i say i was getting one? did i really even say i want 1? if u read my posts they are all questions thats all i wanted were my questions answered.

vadim

Your own words:

KJ-TypeR

I bought a 2002 BMW M3 which will arrive in late June. I was planning to sell the Type-R in early June, but I got an offer for the car and another offer for the Turbo Kit that I couldn't refuse.

So I ended up selling everything last week and will have no car untill the end of June. Untill the M3 arrives, I'm stuck sharing my GF's C230K which isn't such a bad deal if you ask me.

BlackC230Coupe

dam a 2002 M3 thats a nice car i am sure u will have alot of fun with that.




vadim- I said that for a turbocharged car.

avlis

I don't think the "complaigning" (complaining) was about the thread being "boaring" (boring).