Stage 3 Cam Guy need help PLEASE!!

[justa03]

Got an easy simple question for any guys running stage 3 cams in a Cobra, preferablly Crowers but ill take whatever anyone is running. Ive got stage 3 crowers in my car and am only seeing about 9-8 in at idle. Just wondering what everyone else is seeing? Thanks in advance.

-Dan

 

[venom04svt]

I have stage 3 crowers...what exactly are you asking???

 

[justa03]

What kinda vacuum are you seeing at idle? Ive got a bad hesitation issue and cant figure it out for the life of me, just had the blower rebuilt and put back on with the low vacuum boost bypass thinking that might fix it but still the same issue. Next is gonna be the PPRV delete.

 

[redfr03svtsnake]

i dont have cams but i know ive got roughly 20 psi vac at idle

 

[rich5150]

What kinda vacuum are you seeing at idle? Ive got a bad hesitation issue and cant figure it out for the life of me, just had the blower rebuilt and put back on with the low vacuum boost bypass thinking that might fix it but still the same issue. Next is gonna be the PPRV delete.

That sounds about right... I have the Crower stg 2's and see about 12-14ish...

Did you have the hesitation issue BEFORE you had the blower rebuilt? Did you change the tune at all? Double check all vacuum fittings/gaskets...etc?


Keep in mind that a grind that steep isn't going to be street-friendly. You can band-aid around that a bit in the tune, but don't expect stock-drive-ability.

 

[justa03]

Yea had the hesistation after I built the motor. Car ran strong for a good 4 months after the build then it started to have a hesitation right when it sees boost. Then right before winter hit then blower started to make alot of noise and you could feel the bearings were bad just by touching the case. Sent the blower off had a new low vacuum by pass valve put in along with the blower being rebuilt. Installed new intake gaskets and can not for the life of me find a vacuum leak. Not sure what the vacuum is on stage 3 cams, i know its lower then stock by quite a bit. Also know driveablity isnt gonna be the best but should be better then it is. Put a new SCT MAF on the car and a new FRPS. Now im thinking a PPRV delete but got a feeling this isnt gonna change it either. Any ideas would be great! Thanks, Dan

 

[rich5150]

Yea had the hesistation after I built the motor. Car ran strong for a good 4 months after the build then it started to have a hesitation right when it sees boost. Then right before winter hit then blower started to make alot of noise and you could feel the bearings were bad just by touching the case. Sent the blower off had a new low vacuum by pass valve put in along with the blower being rebuilt. Installed new intake gaskets and can not for the life of me find a vacuum leak. Not sure what the vacuum is on stage 3 cams, i know its lower then stock by quite a bit. Also know driveablity isnt gonna be the best but should be better then it is. Put a new SCT MAF on the car and a new FRPS. Now im thinking a PPRV delete but got a feeling this isnt gonna change it either. Any ideas would be great! Thanks, Dan

Is there anyway you can datalog this with an XCAL2 or anything? Try to log TPS voltage, batt voltage, MAF AD Counts, IAC duty Cycle....etc. From there we can dig down and see what the car is doing vs. what the tune is doing...etc.

 

[justa03]

Well im a tech at the local ford dealership and I went into it with one of our IDS's and I pretty much watched all the PID's and everything seems to look quite normal to tell you the truth. Ive got a Predator, thinking of switching to SCT. I could datalog but the only thing id have would be idling due to the snow and cold weather of ND. Haha, appreciate the help. Just let me know what you wanna know id i'll try to post up what i can get.

 

[venom04svt]

I run about 11-12 pounds of vac with my stage 3 crowers, the hesitation could be from the PPRV, hesitation at the initial hit of the throttle is a symptom, I would really recommend putting it on a dyno and datalogging if you dont have a handheld to do it.

 

[justa03]

Im only seeing about 9-8" of vacuum and I think it might be an issue with the boost by pass since that operates off of vacuum. What seems weird is that there is no hesitation when if you run the car all the way up to redline without seeing boost, but the second you go into boost itll have a hesitation. Not sure kinda lost on this one.

 

[GodStang]

Crower Stage IIIs are a light cam compared to other stage IIIs. I have Crower Stage IIIs and I am seeing around 20psi vacuum if I remember correctly. I had a bad hesitation and it was my tune. Weather (getting colder out) can effect a tune sometimes. Also PPRV delete may help.

 

[justa03]

Yea thats where I think something is up with the car due to the low vacuum. The car isnt running lean at all on the wideband and the plugs dont show lean either, if anything a little too rich. Thinking the rings may not have seaten well and thats the reason for the poor vacuum. Also read about people getting bad grind cams from Crower causing bad driveability issues.

 

[justa03]

Anyone with any thoughts here? Maybe low vacuum messing with the boost bypass valve?

 

[LoudToy948]

Anyone with any thoughts here? Maybe low vacuum messing with the boost bypass valve?

I am just wondering what gauge you are reading vacuum from. If it is mechanical (aftermarket I am sure), what are the chances the tubing is leaking at some point and causing you to see lower vacuum? Just a thought. Something easy that could maybe take the vacuum issue out of the troubleshooting path. At that point, your only symptom would be the hesitation which I would guess like a few others PPRV.

 

[justa03]

Yea ill have to do that, didnt even think of that. Ill grab my gauge outta my box at work tomorrow and just pull the line off the FRPS and see what kinda vacuum ive got. I dont know alot about the PPRV hesitation but does it usually happen when the car sees boost?

 

[justa03]

Anyone know about the when the hesitation for the PPRV usually happens, and also what size of brass coupling is needed to install to remove the PPRV?

 

[04MystiCobra]

The low vac #s are pretty typical for cams like that. Really doubt the 20" of vac on stg 3s.

 

[justa03]

Alrighty thanks, but does anyone know off hand what size of coupling is needed to delete the PPRV if your arent using the kit?

 

[iBiTe03]

I have comp stage 3 and Im around 10, I have no issues at all.

 

[justa03]

Love your car with the cowl! ^^ Thanks for the post!