boost drop off

scooter k · 06-01-2018, 09:00 PM

Running a Whipple supercharger, 3.25 upper, 9.17 lower, 38% cam, DSX aux fuel system, etc. My boost peaks about 5700 at 19psi and drops off after that to 6500. I have the blower speed maxed out but would think it wouldn't drop off. What do I need to do because obviously it's making less hp after 5700. Larger blower pulley?

scooter k · 06-01-2018, 09:05 PM

Looking at the log even the airflow goes down. 5700 I have 19psi, 6500 I have 12 psi. Belt slip??

scooter k · 06-09-2018, 09:03 PM

Changed out the tensioner with an American Racing Solutions LT4 billet tensioner. Didn't make any difference at all.

Ricco · 08-19-2018, 09:16 PM

Quote:

Originally Posted by scooter k

Running a Whipple supercharger, 3.25 upper, 9.17 lower, 38% cam, DSX aux fuel system, etc. My boost peaks about 5700 at 19psi and drops off after that to 6500. I have the blower speed maxed out but would think it wouldn't drop off. What do I need to do because obviously it's making less hp after 5700. Larger blower pulley?

Did you get this figured out?

scooter k · 08-19-2018, 09:27 PM

Quote:

Originally Posted by Ricco

Did you get this figured out?

Yes, tensioner and shorter belt

Ricco · 08-19-2018, 09:29 PM

Quote:

Originally Posted by scooter k

Yes, tensioner and shorter belt

Awesome, so belt must have been slipping I guess.

scooter k · 08-19-2018, 09:33 PM

Quote:

Originally Posted by Ricco

Awesome, so belt must have been slipping I guess.

The clock position on the new tensioner is different so with the same belt as before the belt actually was less tension. I had to get a few belts to get the right one but now the boost stays within 1 psi of max. If you need the belt numbers I'm using I can get those for you.

Ricco · 08-19-2018, 09:39 PM

Quote:

Originally Posted by scooter k

The clock position on the new tensioner is different so with the same belt as before the belt actually was less tension. I had to get a few belts to get the right one but now the boost stays within 1 psi of max. If you need the belt numbers I'm using I can get those for you.

Thanks. I think my Whipple came with a replacement belt so I assume that one should work fine but I'll let my tuner figure it out

What power are you making with the Whipple and what are your supporting mods?

Drsagacity · 08-20-2018, 12:50 AM

You kids are crazy. 19psi!

19PSI, Is that about 800whp?

Ricco, what boost are you running to get 644 whp?

ShizzySupra · 08-20-2018, 08:53 AM

Should be way over 800 at 19 psi unless something is wrong. Kaizenspeeds Whipple ZL1 at 15 psi is 860 something.

Quote:

Originally Posted by Drsagacity

You kids are crazy. 19psi!

19PSI, Is that about 800whp?

Ricco, what boost are you running to get 644 whp?

Ricco · 08-20-2018, 09:12 AM

Quote:

Originally Posted by Drsagacity

You kids are crazy. 19psi!

19PSI, Is that about 800whp?

Ricco, what boost are you running to get 644 whp?

LOL.. I'm more familiar with boosted Subaru's so 19PSI doesn't seem very high to me

Not sure what my boost level is right now but I have stock upper pulley and 9.17" lower. I asked my tuner.

Drsagacity · 08-21-2018, 08:11 PM

Quote:

Originally Posted by ShizzySupra

Should be way over 800 at 19 psi unless something is wrong. Kaizenspeeds Whipple ZL1 at 15 psi is 860 something.

Looks like on another thread, the Whipple running 14psi is at 750whp. Can't wait to see it regardless.

ShizzySupra · 08-22-2018, 08:45 AM

Quote:

Originally Posted by Drsagacity

Looks like on another thread, the Whipple running 14psi is at 750whp. Can't wait to see it regardless.

Ya that guy was on pump gas. Maybe Kaizenspeed just has the magic sauce lol

06-01-2018, 09:00 PM	#1
scooter k Drives: ex-wife's car Join Date: Jan 2011 Location: Iowa Posts: 258	boost drop off Running a Whipple supercharger, 3.25 upper, 9.17 lower, 38% cam, DSX aux fuel system, etc. My boost peaks about 5700 at 19psi and drops off after that to 6500. I have the blower speed maxed out but would think it wouldn't drop off. What do I need to do because obviously it's making less hp after 5700. Larger blower pulley?

06-01-2018, 09:05 PM	#2
scooter k Drives: ex-wife's car Join Date: Jan 2011 Location: Iowa Posts: 258	Looking at the log even the airflow goes down. 5700 I have 19psi, 6500 I have 12 psi. Belt slip?? Last edited by scooter k; 06-01-2018 at 09:41 PM.

08-20-2018, 12:50 AM	#9
Drsagacity Drives: 2017 Camaro 2SS Nightfall Gray vert Join Date: Jan 2018 Location: Swansea, IL Posts: 1,219	You kids are crazy. 19psi! 19PSI, Is that about 800whp? Ricco, what boost are you running to get 644 whp? __________________ 2017 Camaro 2SS vert - Nightfall Gray Magnuson Heartbeat SC - Tuned by JRE Racing 776whp/745wtq (12psi) 2018 Corvette Z06 vert- Black To be tuned by JRE Racing TBD performance

06-09-2018, 09:03 PM	#3
scooter k Drives: ex-wife's car Join Date: Jan 2011 Location: Iowa Posts: 258	Changed out the tensioner with an American Racing Solutions LT4 billet tensioner. Didn't make any difference at all.

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