Boost Plummets at WOT

[haze324]

Recently I had a new clutch, Exedy twin disc, put in the car and went ahead a changed out a few things - green belt, BOV, air filter, etc. I'm running a P1SC on a 16GT with a 3.5 pulley. I was seeing about 9psi of boost on the digital gauge at WOT till about 7k rpms. After the few upgrades I would hit WOT and the car would see 4-5psi and immediately drop to 1psi. On the tune air fuel look good, but at the point of it plummeting load plummets too. RPM and speed increase steadily. I thought maybe the blower took a crap....I put a friends P1X on the car and same thing happened. It's getting worse, I'm only seeing 3psi before it drops. I've out a griptec pulley, pulled the bumper and checked every coupler, and the BOV. The only thing I haven't done is pull and inspect the intercooler.

I'm stumped here and the only thing I can think of is the clutch wasn't installed correctly. I don't feel a jerky movement like the clutch slips and RPMS race up with little movement. Just not sure what else it could be or what else to check??

Any ideas. I can post pics of the logs if it would help. Cars been tuned by PBD and Juggernaut...same loss of boost with both tunes.

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[SolarFlare]

make sure your BOV its closing. this requires someone watching it while another person gives the throttle some quick stabs. Also airload on log before vs now.... does it go up to same level? Does it plateau or drop? Belt dust in engine bay indicating belt slip? Specially on driver side fender about blower.

 

[haze324]

make sure your BOV its closing. this requires someone watching it while another person gives the throttle some quick stabs. Also airload on log before vs now.... does it go up to same level? Does it plateau or drop? Belt dust in engine bay indicating belt slip? Specially on driver side fender about blower.

Thanks SF, those are all the things ive been checking with no luck. I was running a Summit BOV with no issues so I ordered a new one just to check and still had the issue, I even changed the spring to a TIAL spring. No belt dust, and I've tried every combo of either micro v, or green belt and tension and now have a griptec and still no luck. Juggernaut initially said they didn't see anything in the air that would indicate a leak. I'm going to run some new logs this week and see if he can pinpoint something.

Car feels great putting around town and just driving normal and getting a little boost the car feels fine, but once I get on it....it just falls flat. It felt a little jerky today at WOT.

 

[Cory S]

How many inches of vacuum are you seeing at idle and during part throttle cruising?

 

[haze324]

Thanks SF, those are all the things ive been checking with no luck. I was running a Summit BOV with no issues so I ordered a new one just to check and still had the issue, I even changed the spring to a TIAL spring. No belt dust, and I've tried every combo of either micro v, or green belt and tension and now have a griptec and still no luck. Juggernaut initially said they didn't see anything in the air that would indicate a leak. I'm going to run some new logs this week and see if he can pinpoint something.

How many inches of vacuum are you seeing at idle and during part throttle cruising?

At idle they're mostly around 19.2-19.5. Occasionally it spikes to 20, and/or drops in the 18's but stays at 19.2ish most of the time.

Today I did a few pulls with the new blower and sent Juggernaut the logs. I loaded one of his first tunes that had no additional timing (car was slow) but it made close to 6psi of boost on that pull then plummeted. So the blowers working. Once I put the normal tune in it didn't go past 3 psi. No clue what this means.

 

[Proshop]

What “digital boost” gauge are you using?

 

[SolarFlare]

Very weird that a tune change drops boost like that. Maybe new file was choking car using cam timing which is why boost spiked to 6 but car was slow. Could be gauge, how are you watching? You peaking over as you do a wot pull?

 

[haze324]

Very weird that a tune change drops boost like that. Maybe new file was choking car using cam timing which is why boost spiked to 6 but car was slow. Could be gauge, how are you watching? You peaking over as you do a wot pull?

Figured out the issue. Somewhat embarrassing (don't ask!! ). The filter on the charge pipe had fallen off, and the blower sucked in some foam, spit it out and clogged up the IC. I was able to vacuum it out and took the car around the block and immediately hit 8psi. I didn't drive it much, since I'm not sure if any of this foam made it through the IC.

My next dilemma now is do I pull the IC and try clean any of this that could be left inside, or eat the loss and just order a new IC and know it's good to go. At this rate I have a new P1X, new BOV, new pulley, new belt...etc!! lol. A new IC sounds great, but damn another expense. What do you think?

Thanks for the help and advice guys.

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