At dyno as we speak, low boost, any ideas??

fivelitrecobra

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I have a 2.3 Whipple gen 2 with a 3.0 upper and 2# lower. Car is only making 16lbs of boost on dyno, 520whp. Any ideas what could be causing the low boost readings? Changing to a 1/2" smaller belt as we speak. Other ideas?
 

GodStang

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What other mods do you have? Headers, stroker, ported heads? How much boost do you think you should see? Belt slip?
 

fivelitrecobra

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What other mods do you have? Headers, stroker, ported heads? How much boost do you think you should see? Belt slip?
Longtubes, 2 1/2" exhaust no cats, stock longblock. Was expecting to see 20-21psi.
 
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fivelitrecobra

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Went to a smaller belt but results stayed the same. Checked a few other possible causes, everything was as it should be. No miss-fires, CEL's, vac leaks, etc. Air filter is clean, throttle body is opening 100%, bypass actuator is functioning properly, etc. Final results were 16.5psi and 545whp with 17 degrees of timing on 92 octane pump gas. The car should be 20-21psi and around 600whp in my opinion, my tuner agreed also based on similar setups he's dialed in. We are both stumped, missing 4-5psi and about 60whp somewhere. Only other possible issue we could think of is maybe the intercooler is partially blocked or clogged. Anyone have any ideas?
 

fivelitrecobra

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rsz_20190718_211953.jpg
 

94slowbra1

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just throwing this out there, you DONT want 21.5 psi on 92. if your making 16.5, which i believe is low for your pulley combo, and want another 4-5psi, you're going to need corn fuel. most on here say 18-19 max and thats on 93. i ran 19lbs on 93 (we have very good clean 93 here) and that was pushing it.
so yes you are missing some boost and hp but not as much as you want.
to eliminate the i/c situation just check air intake temps
 

GodStang

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Those are STD numbers. The SAE numbers would be around 500-510. That is real low for his setup. How old is the blower? Whipples are famous for needing to be rebuilt after not too long. You may have a boost leak somewhere also.
 

fivelitrecobra

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Those are STD numbers. The SAE numbers would be around 500-510. That is real low for his setup. How old is the blower? Whipples are famous for needing to be rebuilt after not too long. You may have a boost leak somewhere also.

The car came from a Mecum auction, so I have limited info on it. Based on some of the paperwork that came with the car, It looks like the blower was installed in 2012 or 2013 with roughly 34k miles on the car. It currently has 50k miles, so give or take 15-16k miles on the blower. Whether it was rebuilt in that time, I don't know for sure, making an educated guess I would say no. I'm going to contact Whipple this afternoon and see if they may be able to shed some light on the situation.
 

jwcobra03

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I had an issue like this before. It was down on compression in two cylinders. Wound up being worn valve guides. Hopefully that's not your case but do a compression and leak down test. Good luck.
 

fivelitrecobra

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I had an issue like this before. It was down on compression in two cylinders. Wound up being worn valve guides. Hopefully that's not your case but do a compression and leak down test. Good luck.

Did a compression test before I went to the dyno, 140-150psi across the board. I talked to a tech at Whipple, he gave me a few things to try/look for. Hopefully its something simple.
 

Bdubbs

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You lose a few psi with long tubes that's bout where you should be with 17 degrees of timing.

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Nope. You lose maybe 1-1.5 lbs of boost with headers. I dropped only 1 psi.

Op, did you ever change out your intercooler tube o rings? It's maybe not the problem, but it's happened to some.

But I also wouldn't want to run anymore than 17lbs on 92-93 fuel.

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nfamous

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No that is bout right for what is done here from my car with way more mods. As example.
4.75 stroker built for 1500hp
9.2 to 1
2.3 gen2 whipple
2.9 rr pulley
C&l 125 maf and mafia
Jlt cai
Stage 3 comp cams
Heads springs valves cut ect.
Arh headers
Stainless Bassani open race mufflers
Fore triple pumps wire upgrade
Screenshot_20190720-001634.jpeg


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fivelitrecobra

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Nope. You lose maybe 1-1.5 lbs of boost with headers. I dropped only 1 psi.

Op, did you ever change out your intercooler tube o rings? It's maybe not the problem, but it's happened to some.

But I also wouldn't want to run anymore than 17lbs on 92-93 fuel.

Sent from my Moto E (4) Plus using the svtperformance.com mobile app

Found the culprit. Boost actuator on the rear of the blower is letting boost bleed off once it gets up to a certain psi. Hooked up a manual tester and pumped it up to around 20psi, needle slowly goes down. Tech at Whipple said the diaphragm is bad. Ordered a new actuator, should be back in business with a few extra whp in a few days!
 

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