Boost question
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Racer
Joined: Apr 2014
Posts: 482
Likes: 13
From: Wildwood MO
Boost question
New procharger installed - when under boost it sounds like my grand national - normal? sounds like a turbo spooling up - I have the factory airbox on the car
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 920
From: Lehigh Acres FL
Tech Contributor
To check for boost leak you need to make a boost leak tester. Heres a link to the one I made when I had my Evo IX. Basically, build it, connect it, pressurize it, see if pressure drops. If so, listen for a hissing sound, tighten clamps, repeat.
http://www.evolutionm.net/forums/evo...er-5-02-a.html
http://www.evolutionm.net/forums/evo...er-5-02-a.html
Pro
Joined: Oct 2008
Posts: 606
Likes: 7
From: Nashville, TN
To check for boost leak you need to make a boost leak tester. Heres a link to the one I made when I had my Evo IX. Basically, build it, connect it, pressurize it, see if pressure drops. If so, listen for a hissing sound, tighten clamps, repeat.
http://www.evolutionm.net/forums/evo...er-5-02-a.html
http://www.evolutionm.net/forums/evo...er-5-02-a.html
Instructor
Joined: Apr 2005
Posts: 245
Likes: 16
From: nj
If you were to have a leak I highly doubt that it would be something that would cause the car to jerk. It is going to be something subtle and also pretty consistent.
If you decide to do a pressure test then I would also remove and cap the charge tube going to the throttle body. There is no sense in stressing it and it may not be completely closed anyway as the blades are usually adjusted slightly open to prevent them from sticking.
You probably have certain parameters that are not adjusted correctly that cause this to happen under the right circumstances. Make sure your vacuum line going to the blow off is kink free and if all the clamps are tight on your ducting you should be good and not need to pressure test.
If you decide to do a pressure test then I would also remove and cap the charge tube going to the throttle body. There is no sense in stressing it and it may not be completely closed anyway as the blades are usually adjusted slightly open to prevent them from sticking.
You probably have certain parameters that are not adjusted correctly that cause this to happen under the right circumstances. Make sure your vacuum line going to the blow off is kink free and if all the clamps are tight on your ducting you should be good and not need to pressure test.
New procharger installed - when under boost it sounds like my grand national - normal? sounds like a turbo spooling up - I have the factory airbox on the car
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
Pro
Joined: Oct 2008
Posts: 606
Likes: 7
From: Nashville, TN
New procharger installed - when under boost it sounds like my grand national - normal? sounds like a turbo spooling up - I have the factory airbox on the car
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
Intermediate
Joined: Jan 2005
Posts: 31
Likes: 0
From: Wayne IL
St. Jude Donor '05
New procharger installed - when under boost it sounds like my grand national - normal? sounds like a turbo spooling up - I have the factory airbox on the car
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
I also have the Procharger on my car and I have noticed a similar condition on my car. It only happens at a particular throttle position and rpm. Approximately 3/4 throttle and 4500 rpm. Never at full throttle, or any other position.
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Intermediate
Joined: Jan 2005
Posts: 31
Likes: 0
From: Wayne IL
St. Jude Donor '05
New procharger installed - when under boost it sounds like my grand national - normal? sounds like a turbo spooling up - I have the factory airbox on the car
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
I also have the Procharger on my car and I have noticed a similar condition on my car. It only happens at a particular throttle position and rpm. Approximately 3/4 throttle and 4500 rpm. Never at full throttle, or any other position. To me it seems more like something in the tune than dropping off boost. Do you have the stock tune?
Safety Car
Joined: Jan 2012
Posts: 4,885
Likes: 484
From: Cin City
St. Jude Donor '14
are you guys running the atmosphere vented race valves? the red valve has a set screw on it to adjust the opening/closing. i'm guessing you're reaching the point where the valve shuts to force ALL of the air into the IC and engine and that is what you're feeling
Team Owner
Joined: Mar 2005
Posts: 20,933
Likes: 905
From: salem OR
New procharger installed - when under boost it sounds like my grand national - normal? sounds like a turbo spooling up - I have the factory airbox on the car
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
ALso, a few times when I am accelerating the car jerks - hard to explain, but my first thought was I was not pushing the accelerator pedal (maybe I was a little light on the throttle) and the car would feel as though its coming out of boost quickly and jerk - but I don't hear the blow off valve when it happens......
I was reading another post about a boost leak - maybe?
What can I do to check to make sure no boost leak, etc?
I did adjust the throttle boost with my diablo tuner that came with the kit to 10% maybe I should go all the way to 20% (thats the way I had it before the install of the procharger)
out on it's own. The throttle is dumping closed for some reason.
Former Vendor
Joined: Feb 2012
Posts: 1,095
Likes: 70
First and foremost.... if you load the 10% throttle tune thats in the Diablo, it will mess with the TQ tables that we have programmed into the car. And can cause very bad throttle results...likely the root cause of your "jerk". Do not add anymore percentage, or you could end up with a run-away like condition in a parking lot.
That throttle "boost" is already built into our tuning, to match the airflow and TQ of the blower.
Ideally, just leave the tune as it came from us. There should be no reason to modify it. There are hundereds of Dyno pulls, days of road corse testing, track testing, and many many BETA cars to develop that tune.
That throttle "boost" is already built into our tuning, to match the airflow and TQ of the blower.
Ideally, just leave the tune as it came from us. There should be no reason to modify it. There are hundereds of Dyno pulls, days of road corse testing, track testing, and many many BETA cars to develop that tune.
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 920
From: Lehigh Acres FL
Tech Contributor
First and foremost.... if you load the 10% throttle tune thats in the Diablo, it will mess with the TQ tables that we have programmed into the car. And can cause very bad throttle results...likely the root cause of your "jerk". Do not add anymore percentage, or you could end up with a run-away like condition in a parking lot.
That throttle "boost" is already built into our tuning, to match the airflow and TQ of the blower.
Ideally, just leave the tune as it came from us. There should be no reason to modify it. There are hundereds of Dyno pulls, days of road corse testing, track testing, and many many BETA cars to develop that tune.
That throttle "boost" is already built into our tuning, to match the airflow and TQ of the blower.
Ideally, just leave the tune as it came from us. There should be no reason to modify it. There are hundereds of Dyno pulls, days of road corse testing, track testing, and many many BETA cars to develop that tune.
Former Vendor
Joined: Feb 2012
Posts: 1,095
Likes: 70
However what I can say is, its crazy the number of people running the "stock" tune that we send. (Even lots of very well known big name shops) since it flat out works great, and is very repeatable. (Much like dodge kits)
We know of some supercharger companies that send out the tunes with VERY soft settings, that can leave 50-60HP on the table. THAT is not the case with ours, we want customers to get the best bang for the buck, and spent a good deal of time getting it there.
You can always run the stock tune, and then if you want to have a shop custom tune it to see if they can get a bit more out of it, you can since its not locked, or hidden in anyway.
Melting Slicks
Joined: Jan 2011
Posts: 2,195
Likes: 19
Its as aggressive as we can make it, taking in account the variation of fuel quality across the US. So if your in California it would be considered VERY aggressive, but if you are in a place that has high quality 93, then it might be a little conservative.
However what I can say is, its crazy the number of people running the "stock" tune that we send. (Even lots of very well known big name shops) since it flat out works great, and is very repeatable. (Much like dodge kits)
We know of some supercharger companies that send out the tunes with VERY soft settings, that can leave 50-60HP on the table. THAT is not the case with ours, we want customers to get the best bang for the buck, and spent a good deal of time getting it there.
You can always run the stock tune, and then if you want to have a shop custom tune it to see if they can get a bit more out of it, you can since its not locked, or hidden in anyway.
However what I can say is, its crazy the number of people running the "stock" tune that we send. (Even lots of very well known big name shops) since it flat out works great, and is very repeatable. (Much like dodge kits)
We know of some supercharger companies that send out the tunes with VERY soft settings, that can leave 50-60HP on the table. THAT is not the case with ours, we want customers to get the best bang for the buck, and spent a good deal of time getting it there.
You can always run the stock tune, and then if you want to have a shop custom tune it to see if they can get a bit more out of it, you can since its not locked, or hidden in anyway.
Former Vendor
Joined: Feb 2012
Posts: 1,095
Likes: 70
If a person is installing a tune labeled 91 octane, or 93 octane, that is NOT a tune to be used with a supercharger, and that is just the generic Diablo tune that comes in the programmer for a stock C7. If any tune is installed other then the one labeled "ProCharger" that would be disaster for the engine.
Just like GM sends all C7's out with the same tune, no matter what state you live in, we do the same. Tuning for specific fuels to maximize power potential is up the customer and a shop. But as stated, there really isn't "that much" to be found.
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 920
From: Lehigh Acres FL
Tech Contributor
Its as aggressive as we can make it, taking in account the variation of fuel quality across the US. So if your in California it would be considered VERY aggressive, but if you are in a place that has high quality 93, then it might be a little conservative.
However what I can say is, its crazy the number of people running the "stock" tune that we send. (Even lots of very well known big name shops) since it flat out works great, and is very repeatable. (Much like dodge kits)
We know of some supercharger companies that send out the tunes with VERY soft settings, that can leave 50-60HP on the table. THAT is not the case with ours, we want customers to get the best bang for the buck, and spent a good deal of time getting it there.
You can always run the stock tune, and then if you want to have a shop custom tune it to see if they can get a bit more out of it, you can since its not locked, or hidden in anyway.
However what I can say is, its crazy the number of people running the "stock" tune that we send. (Even lots of very well known big name shops) since it flat out works great, and is very repeatable. (Much like dodge kits)
We know of some supercharger companies that send out the tunes with VERY soft settings, that can leave 50-60HP on the table. THAT is not the case with ours, we want customers to get the best bang for the buck, and spent a good deal of time getting it there.
You can always run the stock tune, and then if you want to have a shop custom tune it to see if they can get a bit more out of it, you can since its not locked, or hidden in anyway.
Last edited by FYREANT; Oct 24, 2014 at 06:53 AM.
Former Vendor
Joined: Feb 2012
Posts: 1,095
Likes: 70
I'm in southwest Florida and I like to think I get pretty good 93 octane gas here. Don't get me wrong, my planned mod list does include a line item specifically for "ProCharger" as I love your all in one package, but I do think it would be prudent to offer an option to use a 93 octane specific tune directly offered from ProCharger. I guess I would consider that to be like the last 5% of a perfect setup.
I think you might be pleasantly surprised.
We used 93 with no ethanal when testing our supplied tune.
Sure a guy could add a degree or two of timing while on the Dyno.
And "maybe" sneak a couple more HP out of it. However we wouldn't suggest leaving it like that, since we all know how much harder a car can get loaded on the street then a dyno.
Our tune wasn't just Dyno tested, not just street tested, but also spent hours and multiple days on a road course at WOT. That way we could ensure the safest, and most powerful tune possible.
Due to C.A.R.B. reasons, and other factors us (as well as others) will only have one tune supplied.