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What boost are you seeing from your blower?

6.6K views 27 replies 9 participants last post by  z28&zr2  
#1 ·
I have a bone stock 2021 Canyon and installed a Edelbrock Supercharger with their tune. With absolutely nothing else done and the tune untouched I feel like I'm getting sort of wonky boost readings. I haven't hit a dyno yet with it but it sure doesn't feel like it gained 80+whp like Edelbrock claims.

Right when I stab it at low RPM it hits 3psi immediately then raises to 5psi for most of the rpm band and finally ramping up to barely touch 7psi right at redline.
Would love to hear what other Edelbrock customers are seeing and would like to compare to what Mallett guys are seeing. Maybe I should have got a Mallett.

It's entirely possible they are doing this on purpose to be within the detonation limits of pump gas and these high compression engines. But with a PD blower I really expected a much flatter boost output.
 
#3 ·
Where are you tapping in to get the boost pressure? I thought I would be able to read it from the computer but can't. I called Edelbrock and they said there is a port on the back near the firewall but I can't find it. Do you have a picture? I'd like to know what kind of pressures I'm getting as well.
 
#19 ·
Just got my supercharger today and the only port I see is at the front of the intake manifold/brick above the TMAP sensor.
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#13 ·
This is proving to be the most important thing to do. I've been adjusting Edelbrock's tune for a couple days and it's performing much better. Their tune is really bad. Runs way too much timing, tons of knock all over the place. I'm much happier now, even smoothed out the rough idle it had.
 
#12 ·
I have the lingengelter (edelbrock) on order just waiting for delivery, I'm going to try to install it during the thanksgiving weekend. I will report back here when I get this thing in the mail and see where on the back i can tap for the boost gauge.
 
#15 ·
Is the edelbrock tune that bad?
 
#25 ·
Hey guys, I saw a post on another thread requesting some Mallett readings for comparison. I'm on a business trip right now, but I can tell you a bit about my Mallett Supercharger going off memory (no pics for now).

I have the Mallett "Stage 2" which has the 4.00 blower pulley. I have tuned my truck above and beyond what Mallett does, primarily in the realm of the VVT, which can affect boost readings. My truck tops out at 11 psi of boost using the stock sensors. I am not using a separate sensor/gauge unit, like the Banks.

Without nit-picking the difference in the kits, one thing that a little birdie told me was that the Edelbrock kit had issues with IATs (intake air temperatures). The Mallett has a fantastic heat exchanger and large reservoir. The hottest I've IATs I've seen on my truck, in Florida (high ambient temps), after MULTIPLE runs back-to-back in the truck, not on a dyno, was 135F. It's usually colder than that, in the range of 10-15F above ambient (which is damn good). Higher IATs would make the engine more prone to knock, requiring two potential corrective actions: 1) retarding ignition timing, and 2) adding even more fuel for cooling the intake air charge. Both of those will reduce power. Ignition is a big one, and easy to do. You can easily kill 30-40hp by retarding the ignition timing. And if the knock sensors detect knock, they will retard the ignition timing. If I recall the default max ignition retard is 8-degrees, and the ECM will retard the ignition timing for a few seconds, and slowly lift the retard out (i.e. advance the ignition timing back toward normal). In the meantime, your engine will feel like it fell on its ass... but it won't blow up... which is the whole point.

For whatever it's worth, through VVT manipulation, I've been able to achieve a very flat peak torque curve of 450 ft*lbs with the Mallett -- AT THE CRANK -- not at the wheel, and also achieve 514 peak horsepower. Through the OBD-II system, there is a PID available for engine delivered torque. It's usually very close on GM vehicles, within 10-15 numbers of a properly calibrated dyno. That is how I acquired the numbers. The engine is the dyno, so to speak. From there, horsepower can be calculated.

I uploaded a screenshot. The boost line is multiplied by 20 for the sake of scale, otherwise it'd be so small and flat you wouldn't be able to read it on this graph. It reads 10.0 psi from 5000 RPM to redline at 6800 RPM. The peak boost is 10.7 PSI at 6200 RPM.

The dip in power at 2000 RPM has been tuned out, and was never felt, only measured. Anyway, it's gone now.

I hope all this helps with the information you sought. May the BOOST be with you.



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#26 ·
I still don't have a boost gauge on my piece so I can't get those numbers. How high do the IATs get in traffic with the edelbrock kits? Do guys get your reading from IAT, IAT1, or IAT2? Currently I'm using IAT pid to get the readings but not sure if thats correct since it gets pretty high in traffic.

Without nit-picking the difference in the kits, one thing that a little birdie told me was that the Edelbrock kit had issues with IATs (intake air temperatures). The Mallett has a fantastic heat exchanger and large reservoir. The hottest I've IATs I've seen on my truck, in Florida (high ambient temps), after MULTIPLE runs back-to-back in the truck, not on a dyno, was 135F. It's usually colder than that, in the range of 10-15F above ambient (which is damn good). Higher IATs would make the engine more prone to knock, requiring two potential corrective actions: 1) retarding ignition timing, and 2) adding even more fuel for cooling the intake air charge. Both of those will reduce power. Ignition is a big one, and easy to do. You can easily kill 30-40hp by retarding the ignition timing. And if the knock sensors detect knock, they will retard the ignition timing. If I recall the default max ignition retard is 8-degrees, and the ECM will retard the ignition timing for a few seconds, and slowly lift the retard out (i.e. advance the ignition timing back toward normal). In the meantime, your engine will feel like it fell on its ass... but it won't blow up... which is the whole point.
You are not lying about the edelbrock kit having high IATs, my IATs get pretty high if Im stuck in traffic but quickly drop 30 degrees in about 15 seconds when I start moving. How high do your IATs get in traffic? I have a 1.75 gal reservoir on mine since its the lingenfelter kit.

First supercharged car so I'm not really sure what's normal but in traffic I'm getting a 93 degrees over ambient temperature which seems high for a nice cool night. Maybe I still have some trapped air in the system or its normal, not sure but it would be nice to find out.
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#28 ·
Thats interesting, it seems like we get about the same temperature drop while moving so it might be normal. I have been thinking about making the zr2 fake hood heat extractor functional to try to lower the IAT temps while idling.