Alright, a few weeks ago I posted on here about the belt slipping off of the pulley, that has since been corrected, so I think. The car was running fine and my tuner SGT wasnt having any problems with the car at the time. As of late another problem has arose, it is holding boost until approx 6500 rpms and then losing it. Boost falls from about 12-13psi to about 5psi and then back up to 10psi close to redline. The belt is currently at max tension and doesnt seem to be slipping like it was before. Any solutions to this would be greatly appreciated, I NEED to get this car running right. Thanks. Joe.

 

Those pulley's are known to cause belt slippage. You should get the one from Jim at Motorvations.

 

Remember that BOOST is a representation of how much air the engine CANNOT injest. Just because your boost drops off midrange doesn't mean you're not making the same amount of positive pressure with the supercharger. It simply means that the boost is going somewhere... most likely through your engine. Radical cams and mechanical changes to timing will cause this to sometimes happen. This holds very true to VTEC engines and especially those of the DOHC type. This is due mostly to valve overlap... which VTEC creates. Remember that VTEC was designed to help open the valves more during the cycle, but also to increase duration... you increase this duration enough and you create valve overlap which creates more power. This overlap also causes outgoing exhaust gases to help siphon in incomming air and fuel.... etc, but of course you knew that.

Anyhoo, if you have a VTEC controller turn VTEC off and see if the problem is still there... if not, you know why it's happening. Also, it may not be this if your power dies while boost is dropping to 5 psi.

Enjoy

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spunkster &raquo;</TD></TR><TR><TD CLASS="quote">Those pulley's are known to cause belt slippage. You should get the one from Jim at Motorvations.</TD></TR></TABLE>

Not banging anyone, but I've had mine for 2 years and it's been fine... I push 10 psi all day and I don't slip... and mine's a 3 rib belt. Your B series 4 rib shouldn't even be thinking about slipping. If it does, then the belt if old and worn out.

 

Vtec was turned off for testing and the problem still exists. It isnt that the boost just drops, the power curve takes a nose dive as well.

 

Boost drop at high RPMs has always always always been, in my experience and in my case, a representation of belt slippage.

Steve is probably sick and tired of your charger at this point...but honestly, if he can shoehorn on a smaller belt or try varying tensions, I would do so. Try loosening the alt belt a bit and seeing what happens...you'll see varying boost for sure. Are these new belts? How many times were they retensioned?

 

OK, well in that case it's one of two things then. Belt slippage which doesn't make sense because it's fine at 7k+ rpm right... (Unless that's because the belt slips and heats up and then grabs all of a sudden.) Either that or the boost pressure is going somewhere as in a leak of some sort. Does this happen religiously at the same rpm in any gear every time like clockwork? I have a hard time beliving that belt slipage can be that predicatable. Sounds more mechanical then anything. You know... sometimes these blowers if spun too fast can loose volumetric efficiency and cause boost to seem like it's dieing. Just a thought. If you're pushing 12-13 out of this, have you done anything internal to the blower? Has any work been done to it... did anything else come off the car at the same time you upgraded the pully? I guess I'm trying to figure out if anything else may have changed and is causing this.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JRSCCivic98 &raquo;</TD></TR><TR><TD CLASS="quote"> Does this happen religiously at the same rpm in any gear every time like clockwork? I have a hard time beliving that belt slipage can be that predicatable. Sounds more mechanical then anything. </TD></TR></TABLE>

Same rpm on the dyno. every time.
Idont hear the belt slip, i dont smell any burnt rubber. belt is tight as hell and
idler is about at max adjustment. I doubt its slipping. Any and all suggestions
are welcome.

 

Man, it sure sounds like something else other then belt slippage. It can't be that. You've had this charger on before and it didn't drop right? Did anything else change when the pully changed? At 6200 or so the dual runners would normally open up. Obviously that's all gone now... it's just weird. Have someone watch the bypass valve actuator while you're doing the run. Make sure it's not cycling at that rpm. I've seen weirder things happen. Maybe even block all vacume lines going to charger that aren't important... like the break booster and other ****. That boost is going somewhere.