Heartbeat, Being Ordered
Race Director
Joined: May 2004
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From: Raleigh, NC
St. Jude Donor '15
Correct... the trigger on the ECS one is backwards from most (though I prefer it)
When the trigger is connected to ground the BAP is OFF on theirs
Trigger disconnected from ground (on purpose or if wire is broken..) then the BAP is ON
That's for ECS one...
Others are opposite of that as far as I know
When the trigger is connected to ground the BAP is OFF on theirs
Trigger disconnected from ground (on purpose or if wire is broken..) then the BAP is ON
That's for ECS one...
Others are opposite of that as far as I know
Thread Starter
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Finally all fixed now. It was a journey battling with many electrical issues.
Although I ordered 81mm pulley but boost came around 5.5 psi which is low. I expected around 10 psi. I had the intake and filter that came with blower installed. Would this be a reason for low boost. Do you run the blower intake kit or do you go for others?
Although I ordered 81mm pulley but boost came around 5.5 psi which is low. I expected around 10 psi. I had the intake and filter that came with blower installed. Would this be a reason for low boost. Do you run the blower intake kit or do you go for others?
Le Mans Master
Joined: Apr 2013
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Finally all fixed now. It was a journey battling with many electrical issues.
Although I ordered 81mm pulley but boost came around 5.5 psi which is low. I expected around 10 psi. I had the intake and filter that came with blower installed. Would this be a reason for low boost. Do you run the blower intake kit or do you go for others?
Although I ordered 81mm pulley but boost came around 5.5 psi which is low. I expected around 10 psi. I had the intake and filter that came with blower installed. Would this be a reason for low boost. Do you run the blower intake kit or do you go for others?
Just guesstimating, I would say that your boost should be double that with an 81mm!
I cant see the intake being the problem. Oldmotorhead tested the inlet/filter assembly on his car and found there was no restriction. There's no way that the inlet could cause that kind of loss of boost, IMV (unless it has some rags stuffed up in there!). You must have severe belt slip or something. I recorded a peak boost of 8.4 psi on my car last night with a 90mm pulley. I'm also running the standard Magnuson air inlet/filter assembly.
What are you logging boost with? You have the ZR1 MAP installed, correct? If so, it could be a table or something with the tune that's not adjusted for the new MAP. Hopefully, Andy or one of the other guys will chime in and enlighten us on this.
Race Director
Joined: May 2004
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From: Raleigh, NC
St. Jude Donor '15
What are you reading boost with?
There are two values on the ECM that tell it how to interpret the MAP sensor signal, but those may or may not be a potential problem depending on how you're reading boost.
There are two values on the ECM that tell it how to interpret the MAP sensor signal, but those may or may not be a potential problem depending on how you're reading boost.
Last edited by schpenxel; Feb 25, 2016 at 03:44 PM.
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Thread Starter
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The MAP is the stock one. Boost is measured by an external gauge from the blower.
However, since boost is mechanical via belt, why would MAP sensor or ECM impact boost psi. Boost is mechanically driven by pulleys and belt unlike ZL1 and cts-v where ECM.
However, since boost is mechanical via belt, why would MAP sensor or ECM impact boost psi. Boost is mechanically driven by pulleys and belt unlike ZL1 and cts-v where ECM.
Race Director
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From: Raleigh, NC
St. Jude Donor '15
That's why we were asking where you were getting the boost # from. If it's from a mechanical gauge, the MAP won't make any difference. If you're using a different MAP and the settings for it aren't changed properly then you will get incorrect readings at the ECM
Is the throttle opening all the way? Sounds like a dumb question but I've seen some complaints of that happening
Is the throttle opening all the way? Sounds like a dumb question but I've seen some complaints of that happening
Le Mans Master
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The problem is that the stock MAP sensor, which is calibrated to read vacuum in the stock naturally aspirated intake manifold, can't "read" positive pressure or "boost" in the supercharger manifold (at least it seems, no higher than 5.5psi). The ZR1 sensor, on the other hand, is designed to read both vacuum and boost, and is a simple, easy fix for us FI guys, once the requisite tables in the tune are adjusted. That's what the guys in the know, including schpenxel, taught me when I did my Heartbeat install. Mine works fine. I'm actually seeing boost peak at 8.4psi@6300rpm with a 90mm, so yours should be much higher with an 81mm.
I'll bet if you install the ZR1 MAP you'll be pleasantly surprised with the boost you're actually making.
I'll find the part # for the ZR1 MAP and post it shortly.
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Yes, boost is "generated" mechanically through the drive vs. driven pulleys via a belt.
The problem is that the stock MAP sensor, which is calibrated to read vacuum in the stock naturally aspirated intake manifold, can't "read" positive pressure or "boost" in the supercharger manifold (at least it seems, no higher than 5.5psi). The ZR1 sensor, on the other hand, is designed to read both vacuum and boost, and is a simple, easy fix for us FI guys, once the requisite tables in the tune are adjusted. That's what the guys in the know, including schpenxel, taught me when I did my Heartbeat install. Mine works fine. I'm actually seeing boost peak at 8.4psi@6300rpm with a 90mm, so yours should be much higher with an 81mm.
I'll bet if you install the ZR1 MAP you'll be pleasantly surprised with the boost you're actually making.
I'll find the part # for the ZR1 MAP and post it shortly.
The problem is that the stock MAP sensor, which is calibrated to read vacuum in the stock naturally aspirated intake manifold, can't "read" positive pressure or "boost" in the supercharger manifold (at least it seems, no higher than 5.5psi). The ZR1 sensor, on the other hand, is designed to read both vacuum and boost, and is a simple, easy fix for us FI guys, once the requisite tables in the tune are adjusted. That's what the guys in the know, including schpenxel, taught me when I did my Heartbeat install. Mine works fine. I'm actually seeing boost peak at 8.4psi@6300rpm with a 90mm, so yours should be much higher with an 81mm.
I'll bet if you install the ZR1 MAP you'll be pleasantly surprised with the boost you're actually making.
I'll find the part # for the ZR1 MAP and post it shortly.
Le Mans Master
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ZR1/LS9 MAP Sensor
Here's the sensor you need, shown on summits website. You can also get it from a number of the CF vendors or a GM dealer, which is where I got mine from:
http://www.summitracing.com/int/parts/nal-12592525
http://www.summitracing.com/int/parts/nal-12592525
Le Mans Master
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Le Mans Master
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From: Southeast TX
You should be seeing about double your 5.5psi. Any chance you're running an under driven crank pulley? Are you running the smallest serp. belt you can get on there? It's easy enough to check to see if your throttle body is opening fully. You don't even need the engine running.
Le Mans Master
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Something's wrong then. Seems to be leaking boost, maybe?
The most obvious thing to check would be to see if the bypass linkage didn't get bent or adjusted. The bypass comes from Magnuson adjusted properly and they tell you to be very careful not to hit or bend the linkage when lifting the blower or installing it in the car. If that valve is even cracked open slightly, it will bleed boost and be down on power.
The most obvious thing to check would be to see if the bypass linkage didn't get bent or adjusted. The bypass comes from Magnuson adjusted properly and they tell you to be very careful not to hit or bend the linkage when lifting the blower or installing it in the car. If that valve is even cracked open slightly, it will bleed boost and be down on power.
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Checked throttle. . It's ok.
I have this cam and not sure if it bleeds boost?
225/230
.617"/612"
114 LSA
Also... What timing are you running guys? I'm running 14.
I have this cam and not sure if it bleeds boost?
225/230
.617"/612"
114 LSA
Also... What timing are you running guys? I'm running 14.
Last edited by VetteArts; Feb 27, 2016 at 01:53 PM.
Le Mans Master
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Rodney aka oldmotorhead is running a 224/234 116 cam IIRC, and I believe he's making over 10psi with the 81mm and stock dia. Balancer, which is what you should be seeing.
As per Rodney's question above, what size lower pulley are you running on it, and what size belt? Is there any sign of belt slip? If you have a stock sized balancer and the belt is not slipping, then my money is on the bypass leaking boost.