P1SC Belt slip?

Slow 99

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Hey there forum, so I bought this 99 mustang gt that has a mmr 800 short block with heads and a cam. Its also pro charged with a P1SC running a 3.20 pulley and the car makes 471whp. I've had issues with this happening but only in 4th gear and usually in the higher rpm range. Btw I have a twin disc clutch that's rated for 800hp so its not slipping and its not traction issues either cause im running 315s in the rear but it sounds like it in the video... Lemme know what you guys think
 

blownstang4.6

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Prochargers are notorious for belt slip with smaller pulleys. I don't think you can really go smaller than a 3.4 on them. At 471rwhp that blower is pretty much done.
 

Slow 99

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Prochargers are notorious for belt slip with smaller pulleys. I don't think you can really go smaller than a 3.4 on them. At 471rwhp that blower is pretty much done.
thats kinda what I thought as well from what I have read. Does it sound like belt slip to you in the video though?
 

Jwilso53

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Belt slip shouldn’t cause a surge, just less boost. Did you put the clutch in yourself or previous owner
 

DSG2003Mach1

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Prochargers are notorious for belt slip with smaller pulleys. I don't think you can really go smaller than a 3.4 on them. At 471rwhp that blower is pretty much done.

this, that pulley is too small. I think you should be able to make more with a P1 than that but gonna need a bigger blower pulley and then go OD crank pulley.
 

blownstang4.6

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this, that pulley is too small. I think you should be able to make more with a P1 than that but gonna need a bigger blower pulley and then go OD crank pulley.

P1 is done at 13-14psi. Most I've seen a dyno sheet for was like 518rwhp and that was with Trick flow Heads and large blower cams.
 

triple-s

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I had the exact same problem with the 3.2 on my p1sc on my 2v. I fixed the problem by getting the pulley carbonite coated. Only problem with that solution is your going to go through belts faster but I got so good at taking off the blower I did belt swaps in less then 30 min. As far as power wise your about right where I was at but that p1sc is maxed out. I made 496 at 12 lbs but kept the boost up at higher rpms thanks to the pulley coating. You can do what was mentioned above and get the crank pulley which is like 600 bucks when I looked at it last or coat the pulley for 100 bucks but wear belts faster. I was on a budget build so I just coated the pulley.
 

DSG2003Mach1

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P1 is done at 13-14psi. Most I've seen a dyno sheet for was like 518rwhp and that was with Trick flow Heads and large blower cams.

I was forgetting about the whole 2 valve thing, with the 4 valve we detuned mine from almost 500 on 10psi.

I had the exact same problem with the 3.2 on my p1sc on my 2v. I fixed the problem by getting the pulley carbonite coated. Only problem with that solution is your going to go through belts faster but I got so good at taking off the blower I did belt swaps in less then 30 min. As far as power wise your about right where I was at but that p1sc is maxed out. I made 496 at 12 lbs but kept the boost up at higher rpms thanks to the pulley coating. You can do what was mentioned above and get the crank pulley which is like 600 bucks when I looked at it last or coat the pulley for 100 bucks but wear belts faster. I was on a budget build so I just coated the pulley.

hmm, forgot about that coating, might be looking into this
 

triple-s

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I was forgetting about the whole 2 valve thing, with the 4 valve we detuned mine from almost 500 on 10psi.



hmm, forgot about that coating, might be looking into this
worked miracles even did it to my KB setup too turn around time was like a week from when they recieved it.
 

Slow 99

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Belt slip shouldn’t cause a surge, just less boost. Did you put the clutch in yourself or previous owner
the previous owner did, he also put a bbk clutch cable in and the release point is like at the very top with 1 inch left of travel so I worried that its not letting the clutch fully engage
 

Slow 99

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I had the exact same problem with the 3.2 on my p1sc on my 2v. I fixed the problem by getting the pulley carbonite coated. Only problem with that solution is your going to go through belts faster but I got so good at taking off the blower I did belt swaps in less then 30 min. As far as power wise your about right where I was at but that p1sc is maxed out. I made 496 at 12 lbs but kept the boost up at higher rpms thanks to the pulley coating. You can do what was mentioned above and get the crank pulley which is like 600 bucks when I looked at it last or coat the pulley for 100 bucks but wear belts faster. I was on a budget build so I just coated the pulley.
I wound up getting another 3.20 pulley but its coated and I also got another belt with it just in case. But im only at 8lb of boost atm. Thank you for your confirmation though
 

blownstang4.6

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oooohhhhhh, I thought the smaller the pulley, the more boost you ran. Do you think that the p1sc can hold more power like maybe 10psi (3.7 pulley)?

What I'm getting at is there is something wrong with your setup. You're losing boost somewhere or you have extreme belt slip. You should be making 13-14psi with that pulley. Put a larger pulley on it and see if it makes the same boost.
 

blownstang4.6

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How are you verifying that it only makes 8psi? A gauge or actual dyno reading? What is your compression? What heads and cams? At 8psi on a stock motor they make 360-370rwhp. I got a feeling you're making more than 8psi.
 
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Slow 99

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How are you verifying that it only makes 8psi? A gauge or actual dyno reading? What is your compression? What heads and cams? At 8psi on a stock motor they make 360-370rwhp. I got a feeling you're making more than 8psi.
I am reading an aem boost gauge and it tops out at 8 very close to redline, but also the previous owner gave me a dyno sheet. As for the motor, it’s an mmr800 short block, patriot stage 2 heads, cms stage 2.5 blower cam.
 

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