Need help figuring out boost drop please!
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Former Vendor
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From: Moroso Performance, Guilford, CT, 203-453-6571
Need help figuring out boost drop please!
I don't know if anybody here can help me. The tech guy at Vortech could not.
I have a supercharged/intercooled LS-6. It makes 9 lbs of boost before the intercooler, and only 4 lbs after it. I was thinking that the intercooler we picked was obviously too small, BUT, someone else pointed out that maybe my tubing going from the intercooler to the throttle body is too big and it is letting the boost drop.
The tube to the cooler is the same size as the blower outlet, 2 3/4 inches. The tube out of the cooler is the same size as the throttle body inlet, 4 inches. Should the tube out of the intercooler be the same size as the inlet tube, then necked up right at the throttle body?
The intercooler set-up is custom by me, not a kit. The tech at Turbonetics said he thought the intercooler that I picked would be ok. It is 18.5" long, 6" high, and 3.5" deep. Their site says the flow rate is 1080 and good for 760 hp. My engine only made 617 hp on the engine dyno. The blower is a Vortech V-1T.
Any help would be GREATLY appreciated!
Thanks!
Rick
I have a supercharged/intercooled LS-6. It makes 9 lbs of boost before the intercooler, and only 4 lbs after it. I was thinking that the intercooler we picked was obviously too small, BUT, someone else pointed out that maybe my tubing going from the intercooler to the throttle body is too big and it is letting the boost drop.
The tube to the cooler is the same size as the blower outlet, 2 3/4 inches. The tube out of the cooler is the same size as the throttle body inlet, 4 inches. Should the tube out of the intercooler be the same size as the inlet tube, then necked up right at the throttle body?
The intercooler set-up is custom by me, not a kit. The tech at Turbonetics said he thought the intercooler that I picked would be ok. It is 18.5" long, 6" high, and 3.5" deep. Their site says the flow rate is 1080 and good for 760 hp. My engine only made 617 hp on the engine dyno. The blower is a Vortech V-1T.
Any help would be GREATLY appreciated!
Thanks!
Rick
Pro
Joined: Oct 2003
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From: Grove City Ohio
Hey Rick, do you think that hard 90* turn your charge path makes after the blower could hurt efficiency? Probably not the main concern, but just a thought.
BTW: The tech guys at Vortech are USELESS! I wouldn't even bother calling them. As my car was eating serpentine belt after serpentine belt, all I got from them was
.
BTW: The tech guys at Vortech are USELESS! I wouldn't even bother calling them. As my car was eating serpentine belt after serpentine belt, all I got from them was
.
Last edited by Z06 Tom; Jun 28, 2005 at 10:52 AM.
Supporting Vendor
Joined: Jul 2003
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From: http://www.mphparts.com 800-364-1975
Take all of this with a grain of salt as I'm no expert... 
Keep in mind your 4" plumbing goes into an intake manifold with a diameter larger than 4". Also, it's not boost that's important: it's the amount of air flow going through your motor. If I ran 1 inch plumbing from my turbos through a tiny intercooler and straight to my TB I could make 20psi pretty quickly, but it wouldn't perform nearly as well as the 9psi I am making now because it would be really hot air, and not enough of it.
If it were me, I wouldn't shrink the inlet tubing, I would find an intercooler that doesn't see that big of a pressure drop. As it stands, you MAY be better off without the intercooler you have in place. I bet with that kind of pressure drop, your intercooler is going to heat up real fast under boost and will quickly become an interwarmer.
Keep in mind your 4" plumbing goes into an intake manifold with a diameter larger than 4". Also, it's not boost that's important: it's the amount of air flow going through your motor. If I ran 1 inch plumbing from my turbos through a tiny intercooler and straight to my TB I could make 20psi pretty quickly, but it wouldn't perform nearly as well as the 9psi I am making now because it would be really hot air, and not enough of it.
If it were me, I wouldn't shrink the inlet tubing, I would find an intercooler that doesn't see that big of a pressure drop. As it stands, you MAY be better off without the intercooler you have in place. I bet with that kind of pressure drop, your intercooler is going to heat up real fast under boost and will quickly become an interwarmer.
Team Owner
Joined: Jul 2002
Posts: 37,022
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From: This city NEVER sleeps! Frank's back yard!
Originally Posted by diynoob
Take all of this with a grain of salt as I'm no expert...
Keep in mind your 4" plumbing goes into an intake manifold with a diameter larger than 4". Also, it's not boost that's important: it's the amount of air flow going through your motor. If I ran 1 inch plumbing from my turbos through a tiny intercooler and straight to my TB I could make 20psi pretty quickly, but it wouldn't perform nearly as well as the 9psi I am making now because it would be really hot air, and not enough of it.
If it were me, I wouldn't shrink the inlet tubing, I would find an intercooler that doesn't see that big of a pressure drop. As it stands, you MAY be better off without the intercooler you have in place. I bet with that kind of pressure drop, your intercooler is going to heat up real fast under boost and will quickly become an interwarmer.
Keep in mind your 4" plumbing goes into an intake manifold with a diameter larger than 4". Also, it's not boost that's important: it's the amount of air flow going through your motor. If I ran 1 inch plumbing from my turbos through a tiny intercooler and straight to my TB I could make 20psi pretty quickly, but it wouldn't perform nearly as well as the 9psi I am making now because it would be really hot air, and not enough of it.
If it were me, I wouldn't shrink the inlet tubing, I would find an intercooler that doesn't see that big of a pressure drop. As it stands, you MAY be better off without the intercooler you have in place. I bet with that kind of pressure drop, your intercooler is going to heat up real fast under boost and will quickly become an interwarmer.
Sounds like a huge pressure drop - if the intercooler represents that big a restriction, either the inlet/outlet isn't in ideal locations, or it is poorly designed from another standpoint. The author above is right - with that big a loss in pressure comparing inlet/outlet of the intercooler, it will likely be an inter-heater!
Drifting
Joined: May 2001
Posts: 1,770
Likes: 2
From: IL
Why don't you ditch the intercooler, and Run some Methanol to cool the charge. You Will run more boost, and it will still be cool with the Sprayed meth.
If you have any interest in trading you T trim for an S trim + some $$ I could make a deal with you.
If you have any interest in trading you T trim for an S trim + some $$ I could make a deal with you.
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Brett Foote
Supporting Vendor
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From: http://www.mphparts.com 800-364-1975
Originally Posted by SS930
Sounds to me like you have a leak somewhere that may only show up under boost, or a partialy clogged IC core.
The tubing size is fine...
The tubing size is fine...
Drifting
Joined: Oct 2000
Posts: 1,957
Likes: 1
From: Albuquerque NM
I don't know why everyone thinks there is a problem here. You are supposed to lose pressure after you run through an intercooler. It's called thermodynamics. That along with the fact that you may have a bigger volume in your piping after the IC than before can easily explain the pressure difference. Like noob said, boost readings mean nothing so don't get caught up in them. I would be more interested in seeing the temperature difference pre and post IC than boost levels.
Find out what a standard kit makes with the same size pulley that you have and compare that to what you are making.
Find out what a standard kit makes with the same size pulley that you have and compare that to what you are making.
Race Director
Joined: Nov 2000
Posts: 11,221
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From: CA
2017 C5 of the Year Finalist
St. Jude Donor '08
Hey Rick!!
We spoke on the phone about 4 years ago. Greg Carrol gave me your name as a reference before I bought my kit. I also purchase some spark plug wires from you for my 66 Fastback.
I run that same bracket on my setup. I too fabricated an aftercooler to the original kit, as well as added Meth Injection.
When we first fabbed the tubes from the outlet of the aftercooler to the throttle body, I too lost 4#s of boost. I was making right around the same boost and had similar problems. My first set of pipes we made a few years ago from the aftercooler to TB were only 2.5 inches and had two 90s in them. We then put together a set of 3" pipes with two 45s. This made the difference for me. I'm now making between 12.5 and 13 PSI in the intake maniflod and losing about 1.5 from the blower outlet.
I can only tell you what worked for me.
I run a 2.75 tube out of my blower to the inlet of the aftercooler. I then run a 3" tube from the outlet of the aftercooler to a coupler that expands to 4" so as to fit the TB.
JB
We spoke on the phone about 4 years ago. Greg Carrol gave me your name as a reference before I bought my kit. I also purchase some spark plug wires from you for my 66 Fastback.
I run that same bracket on my setup. I too fabricated an aftercooler to the original kit, as well as added Meth Injection.
When we first fabbed the tubes from the outlet of the aftercooler to the throttle body, I too lost 4#s of boost. I was making right around the same boost and had similar problems. My first set of pipes we made a few years ago from the aftercooler to TB were only 2.5 inches and had two 90s in them. We then put together a set of 3" pipes with two 45s. This made the difference for me. I'm now making between 12.5 and 13 PSI in the intake maniflod and losing about 1.5 from the blower outlet.
I can only tell you what worked for me.
I run a 2.75 tube out of my blower to the inlet of the aftercooler. I then run a 3" tube from the outlet of the aftercooler to a coupler that expands to 4" so as to fit the TB.
JB
Melting Slicks
Joined: Apr 2005
Posts: 3,418
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From: Chicagoland Area IL
Something does not make sense to me. The pressure drop is far too high. The first turn (hard 90) is probably your first big hit. It’s hard to tell, but it looks like your supplying and discharging intercooler at about 90 degree hard turns to.
As far as intercooler sizing, I think it’s a bit on small size. But your passage area shouldn’t cause that big a drop.
18.5 * 3.5 * 0.45 = 29.1 in^2 (0.45 is effective flow area multiplier)
4 inch pipe has a cross sectional area of 12.6 in^2 so the HX is not that restrictive. Looking at JB's picture, the aftercooler may have less effective flow area.
Your temperature should be high but not the pressure drop.
Check for leaks, try dish soap and look for bubbles.
Clean up the first turn, air is moving at least 160 MPH (at higher RPM) and that’s too fast for a hard 90.
Mike
As far as intercooler sizing, I think it’s a bit on small size. But your passage area shouldn’t cause that big a drop.
18.5 * 3.5 * 0.45 = 29.1 in^2 (0.45 is effective flow area multiplier)
4 inch pipe has a cross sectional area of 12.6 in^2 so the HX is not that restrictive. Looking at JB's picture, the aftercooler may have less effective flow area.
Your temperature should be high but not the pressure drop.
Check for leaks, try dish soap and look for bubbles.
Clean up the first turn, air is moving at least 160 MPH (at higher RPM) and that’s too fast for a hard 90.
Mike
Thread Starter
Former Vendor
Joined: Oct 2001
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From: Moroso Performance, Guilford, CT, 203-453-6571
Thanks for all the input guys!
I have a tube that we made to go in place of the cooler. I think I will try that just to see what happens. If it works I will put on a bigger cooler. If not, I might go with a little smaller tube from the cooler to the intake. The boost gauges are right before, and right after the cooler, so I don't think (but I am not sure) that the 90 degree turn out of the blower is bothering it. I bought just the core from Turbonetics, and we fabed the hosing around it ourselves. Maybe I have the flow screwed up there. The tubes are entering and exiting the cooler at 90 degrees, but we put the biggest radious we could on boxes to try to keep the flow good.
I appreciate all your help, and will let you know if my "test" tube works.
Rick
I have a tube that we made to go in place of the cooler. I think I will try that just to see what happens. If it works I will put on a bigger cooler. If not, I might go with a little smaller tube from the cooler to the intake. The boost gauges are right before, and right after the cooler, so I don't think (but I am not sure) that the 90 degree turn out of the blower is bothering it. I bought just the core from Turbonetics, and we fabed the hosing around it ourselves. Maybe I have the flow screwed up there. The tubes are entering and exiting the cooler at 90 degrees, but we put the biggest radious we could on boxes to try to keep the flow good.
I appreciate all your help, and will let you know if my "test" tube works.
Rick
Thread Starter
Former Vendor
Joined: Oct 2001
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From: Moroso Performance, Guilford, CT, 203-453-6571
Well, I took off the intercooler, and put in my test pipe. The intercooler is definitely too small. With the "test tube" in place, it makes at least 9 lbs of boost now. I have not had it back to the dyno, so I don't know what the power gain is yet. I have an appointment in a couple weeks.
If the boost was about cut in half with the cooler that I had on it, would it make sense that the new cooler should be twice the size? What do you guys think?
Thanks again for the all the help!
Rick
If the boost was about cut in half with the cooler that I had on it, would it make sense that the new cooler should be twice the size? What do you guys think?
Thanks again for the all the help!
Rick
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Joined: Jul 2003
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From: http://www.mphparts.com 800-364-1975
Don't know much about intercoolers, but I would say you probably should differentiate between a size issue and a flow issue. Theoretically, a very small intercooler could work in your application, but to flow well it likely wouldn't cool very well. You need to find a good balance of size and flow, and in this case, bigger is not always better. There are plenty of large, ineffecient, and poorly flowing intercoolers out there
Glad you were able to identify the IC was the issue though.
Have you thought about maybing going air/water on this setup? It will be harder to get installed and working properly but may allow you to get away with an intercooler that will fit in the space you had the older intercooler but still provide decent cooling.
Glad you were able to identify the IC was the issue though.
Have you thought about maybing going air/water on this setup? It will be harder to get installed and working properly but may allow you to get away with an intercooler that will fit in the space you had the older intercooler but still provide decent cooling.
Team Owner
Joined: Oct 2001
Posts: 46,765
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From: Boynton Beach Florida
St. Jude Donor '07-'12, '20
Hi Rick, why not give a call to the guy's at East Coast Supercharging? I'm sure they will aim you in the right direction for the IC. 
When you get it all done, get down here to the track.
Bob
When you get it all done, get down here to the track. Bob
:o
Pro
Joined: Feb 2004
Posts: 657
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From: michigan
Originally Posted by Rick Moroso
Well, I took off the intercooler, and put in my test pipe. The intercooler is definitely too small. With the "test tube" in place, it makes at least 9 lbs of boost now. I have not had it back to the dyno, so I don't know what the power gain is yet. I have an appointment in a couple weeks.
If the boost was about cut in half with the cooler that I had on it, would it make sense that the new cooler should be twice the size? What do you guys think?
Thanks again for the all the help!
Rick
If the boost was about cut in half with the cooler that I had on it, would it make sense that the new cooler should be twice the size? What do you guys think?
Thanks again for the all the help!
Rick