High boost whipple, but boost drops? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Aries240SS · 12-19-2022, 06:36 AM

Forged 376 making 20psi on the hit, but drops to 15psi within 1500rpm. Not sure what is causing this, but we’ve eliminated belt slip and started looking toward the bypass valve or other issues.

Anyone else running this kind of boost and have recommendations?
2.75” Griptek upper, 10% IW overdrive and we’re positive the belt does not touch itself

FasNuf · 12-19-2022, 07:03 AM

The ECM can also limit boost. This is an old video of mine, but maybe it'll help.

https://youtu.be/2Y7rPBwQMWg
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Aries240SS · 12-19-2022, 07:27 AM

Quote:

Originally Posted by FasNuf

The ECM can also limit boost. This is an old video of mine, but maybe it'll help.

https://youtu.be/2Y7rPBwQMWg
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Very interesting. I’ll have a look in the tune later today, but the whipple’s bypass is only vacuum controlled.

cc-rider · 12-19-2022, 08:07 AM

I think your onto it with belt slip. I can’t see how the ECM being able to limit boost with a mechanical bypass as you mentioned. If it was happening, my guess would be that it somehow closes the throttle blade down a bit once it senses high boost. Wouldn’t surprise me if the ECM has some setting burried somewhere about that. Maybe check over at HP Tuners forum.

eLeSthree · 12-20-2022, 10:43 AM

Quote:

Originally Posted by FasNuf

The ECM can also limit boost. This is an old video of mine, but maybe it'll help.

https://youtu.be/2Y7rPBwQMWg
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Interesting. I would think this only applied to ZL1 (lsa) cars. Looking at my cts-v I do see a wiring harness on the boost soleniod, so its very likely the ECM can tell it to open and bleed boost back into the snout.

An SS car would probably not have that soleniod harness and capability. Also, I just checked my old SS tune, and it shows 37psi in that field you referenced, so 22psi would be the limit, tunewise.

I'd be leaning towards belt slip, as its a pretty common problem. There's a user on here called Batman-something with a 800whp whipple. Wonder what his belt setup is.

Badbubba · 12-20-2022, 11:37 PM

Have you logged your throttle body position? A few had problems with it wanting to suck shut.

Aries240SS · 12-24-2022, 09:04 AM

Quote:

Originally Posted by Badbubba

Have you logged your throttle body position? A few had problems with it wanting to suck shut.

Did not think to check that in the logs. It’s a NW 102 that replaced the ported stock TB that was on before. I’ll check this Monday along with pricing on going to an 8 or 10 rib setup.

stevieturbo · 12-24-2022, 09:49 AM

The ecu has no ability to reduce boost, other than either dumping it ( you say no connection to achieve this ), or by closing the throttle.

So these would be obvious first places to look.

But sounds more like belt/slip issues. Why do you think it is not belt related ?

And can you check the bypass valve is not doing something strange when it should not be ?

Batmanntexas · 12-24-2022, 10:21 PM

Quote:

Originally Posted by eLeSthree

Interesting. I would think this only applied to ZL1 (lsa) cars. Looking at my cts-v I do see a wiring harness on the boost soleniod, so its very likely the ECM can tell it to open and bleed boost back into the snout.

An SS car would probably not have that soleniod harness and capability. Also, I just checked my old SS tune, and it shows 37psi in that field you referenced, so 22psi would be the limit, tunewise.

I'd be leaning towards belt slip, as its a pretty common problem. There's a user on here called Batman-something with a 800whp whipple. Wonder what his belt setup is.

The 800whp was accomplished with a 6-rib setup, consisting of a Fluidampr stock diameter balancer and a 3.625" Griptec pulley. That combo made 10-11psi.

When I went down to a 3" Griptec 6-rib pulley, I started shredding belts left and right. I made the switch to the Innovators West 10-rib belt drive setup consisting of their 10% OD balancer and a 10-rib 3" Griptec pulley. Now, it makes around 16psi....haven't made it to a dyno yet, but I'm hoping that i'm knocking on the door to 900+.....

-Scott

SFR7771 · 01-11-2023, 08:55 AM

Wow that is awesome 16PSI on stock is killer you are the man.

Quote:

Originally Posted by Batmanntexas

The 800whp was accomplished with a 6-rib setup, consisting of a Fluidampr stock diameter balancer and a 3.625" Griptec pulley. That combo made 10-11psi.

When I went down to a 3" Griptec 6-rib pulley, I started shredding belts left and right. I made the switch to the Innovators West 10-rib belt drive setup consisting of their 10% OD balancer and a 10-rib 3" Griptec pulley. Now, it makes around 16psi....haven't made it to a dyno yet, but I'm hoping that i'm knocking on the door to 900+.....

-Scott

Batmanntexas · 01-11-2023, 08:58 PM

Quote:

Originally Posted by SFR7771

Wow that is awesome 16PSI on stock is killer you are the man.

Thanks

Aries240SS · 01-18-2023, 08:17 PM

Looks like you guys were right. Belt slip on the crank pulley. Going to the full innovators west setup now.

12-19-2022, 06:36 AM	#1
Aries240SS Drives: 2011 1SS RS Camaro, 1995 LSX 240SX Join Date: Mar 2011 Location: Austin, TX Posts: 461	High boost whipple, but boost drops? Forged 376 making 20psi on the hit, but drops to 15psi within 1500rpm. Not sure what is causing this, but we’ve eliminated belt slip and started looking toward the bypass valve or other issues. Anyone else running this kind of boost and have recommendations? 2.75” Griptek upper, 10% IW overdrive and we’re positive the belt does not touch itself __________________ 2011 Camaro 1SS Whipple Supercharged street monster

12-19-2022, 07:03 AM	#2
FasNuf Drives: 2014 Camaro ZL1 Join Date: Jul 2019 Location: Oregon Posts: 1,619 View My Garage	The ECM can also limit boost. This is an old video of mine, but maybe it'll help. https://youtu.be/2Y7rPBwQMWg . . . . . . __________________ . . . . https://www.youtube.com/channel/UCgN...etl17hA/videos

12-20-2022, 11:37 PM	#6
Badbubba GrINned & JUICEd Drives: 15STI, 10Expy, 10 2SS/RS M6, 47KB1 Join Date: Nov 2009 Location: Pittsburgh, PA Posts: 1,247	Have you logged your throttle body position? A few had problems with it wanting to suck shut. __________________ GPI SS3 Cam & stuff,N.O. Plate(dedicated fuel tank,progressive,fuel hose upgrade,remote opener,heater,console switches),LNC2000,CTAP,ARH 1 7/8" LTs/gutted cats/X pipe/mufflers,Jet Hot coated LTs,GPI HPT Tune,CAI, Scoop,Rx Catch Can,Gates heater hose relocation, Remote clutch & auto brake res,Metco loop,Momentum Tunnel Brace,TSW Nurb 18",555 & 05,Pfadt trailing arms & toe rods,Autometer WB,Fesler Pillar Pod,LED strips (int),Lloyds floor & trunk mats,LED DRL/front turn & license plate,DRL harness,VLEDs tail lights,Plasticoat Bowties. Ord: Oct 5, 2009 Rec: Nov 19, 2009 13.17@112.6 stock

01-18-2023, 08:17 PM	#12
Aries240SS Drives: 2011 1SS RS Camaro, 1995 LSX 240SX Join Date: Mar 2011 Location: Austin, TX Posts: 461	Looks like you guys were right. Belt slip on the crank pulley. Going to the full innovators west setup now. __________________ 2011 Camaro 1SS Whipple Supercharged street monster

12-19-2022, 08:07 AM	#4
cc-rider Drives: 2010 Camaro SS Join Date: Dec 2006 Location: MN Posts: 1,172	I think your onto it with belt slip. I can’t see how the ECM being able to limit boost with a mechanical bypass as you mentioned. If it was happening, my guess would be that it somehow closes the throttle blade down a bit once it senses high boost. Wouldn’t surprise me if the ECM has some setting burried somewhere about that. Maybe check over at HP Tuners forum.

12-24-2022, 09:49 AM	#8
stevieturbo Drives: it changes Join Date: Nov 2010 Location: Norn Iron Posts: 1,126	The ecu has no ability to reduce boost, other than either dumping it ( you say no connection to achieve this ), or by closing the throttle. So these would be obvious first places to look. But sounds more like belt/slip issues. Why do you think it is not belt related ? And can you check the bypass valve is not doing something strange when it should not be ?