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What are you IAT's pre and post 'spirited driving'? When we use things like "Recovery" that makes me go "If they get hot when I putting the hammer down the most, then why would I care if they're low during cruising or recover quickly?"
(I like road courses, maybe that's my problem)
I agree a pump could be worthy upgrade if the HE are excellent, moving more water could result in less pronounced spike in IAT. My initial discussion was an out loud rambling about what the bottle neck actually is:
Heat Exchanger
Blower Coolant Getting Warm
Not enough flow to keep heat exchanger cool
All seem to be possible places to reduce the 'spike' of IAT when you're pushing the blower.
I agree Meth may really be the best answer for maximum effort sustained load applications (road racing, mile/1/2 mile events etc) where recovery is meaningless: it's all about under load. I'd be very curious what the temp of the blower coolant is during those IAT surges. If the coolant is getting hot, that's one thing to tackle, etc.
The temperature is always going to rise when you're making boost. It's just what happens when you compress a gas. Not only that, but the rotors, intercoolers, etc. are located in an area of the engine that can get very hot. My car is a street car, so recovery time is important. Mainly, I want to keep the IATs out of the zone where timing is pulled. How quickly the IATs "recover" after a hard pull (or after shutting the engine down and heat-soaking the blower) are important.
My goal is to have those air temps as low as possible during normal driving, so that when I want to wail on it through a few gears, I'm not anywhere near the range where timing is pulled. And my system does that, so I really don't have anything to complain about. Last time I had the car out in the canyons, I was having a hard time getting the IATs over 100 degrees. I'm talking spirited street driving with other cars on the road. Not road course stuff, but plenty of mid-range boost and acceleration with temps around 80 degrees.
The ZR1s seem to do just fine on a road course, though. The GM supercharger tune files are a little strange in how they have their IAT/spark table set up, but they generally take away timing as IATs increase. Timing is added at lower temperatures and taken away at higher ones. When you look at the table and multipliers, though, it isn't as big a difference as you might think.
Here's the IAT/spark table and multiplier from a stock CTS-V. At ~200 degrees IAT temp, it's pulling about 3.5 degrees of timing. At a lower/normal IAT temp like ~100 degrees, it's adding about 1.75 degrees. So we're talking about 5 degrees of timing difference.
Meth would be the best bang for the buck. That's assuming you're not already running some type of higher than 93 octane fuel. I'm not a big fan of porting the LS3 heads or even aftermarket heads. The stock heads are pretty damn good at just about any power level the HB can support. Sure, there's power to be made there, but I don't know if the end result would justify the means.
I'll have to wait for late October. I'm excited to see how it does in the 1/4!
Car pulls soo hard. I'm curious what meth, heads and a custom cai would do for the setup. I plan to enjoy it the way it is until at least December.
Nice times. I'd have to agree that meth is probably your best option at this point. And since you're basically pulley limited right now, I'd think improvements pre-blower would net you some gains. Intake and throttle body might get you a little more boost. I'd think you're on the edge as far as boost vs. octane goes, though. So be careful with that unless you add meth or race fuel.
Yeah I am thinking of getting a custom cai and meth. And see if that gets me to 650whp.
Are you shifting that bad girl yourself or letting the PCM do the work? Your cam must not be too big as your 60' times are good. Or maybe it's all that uncontrollably nasty low end power helping you outta the hole....Stock converter?
I'm wondering if there aren't many of us running this blower myself. Although it seems like less people post results on this forum than other forums I have been on.
The temperature is always going to rise when you're making boost. It's just what happens when you compress a gas. Not only that, but the rotors, intercoolers, etc. are located in an area of the engine that can get very hot. My car is a street car, so recovery time is important. Mainly, I want to keep the IATs out of the zone where timing is pulled. How quickly the IATs "recover" after a hard pull (or after shutting the engine down and heat-soaking the blower) are important.
My goal is to have those air temps as low as possible during normal driving, so that when I want to wail on it through a few gears, I'm not anywhere near the range where timing is pulled. And my system does that, so I really don't have anything to complain about. Last time I had the car out in the canyons, I was having a hard time getting the IATs over 100 degrees. I'm talking spirited street driving with other cars on the road. Not road course stuff, but plenty of mid-range boost and acceleration with temps around 80 degrees.
The ZR1s seem to do just fine on a road course, though. The GM supercharger tune files are a little strange in how they have their IAT/spark table set up, but they generally take away timing as IATs increase. Timing is added at lower temperatures and taken away at higher ones. When you look at the table and multipliers, though, it isn't as big a difference as you might think.
Here's the IAT/spark table and multiplier from a stock CTS-V. At ~200 degrees IAT temp, it's pulling about 3.5 degrees of timing. At a lower/normal IAT temp like ~100 degrees, it's adding about 1.75 degrees. So we're talking about 5 degrees of timing difference.
Great info here, I'd love to compare this to the stock heartbeat tune they're shipping...
Wish more people had Heartbeat results. Doesn't seem like many push them.
Being that's it's still fairly new, I don't think there are all that many out there. On top of that, the C6 version is pulley limited. I'm not sure why it's any different than the version Magnuson makes for the CTS-V, but the 81mm pulley is it. I think that's what you have, right?
While a great blower system, I don't think it's one people will likely buy when searching for big power.
Yeah I have the 81mm. It's my understanding the shaft diameter is the limiting factor. I think for anyone wanting to bolt on an easy 150whp this kit is the nail on the head. Or even someone wanting as much as 650-700whp. I don't think the blower can get more than 700whp in a Vette though. I don't think the lower pulley can go bigger than an 8"? Mine is a 10% overdrive and it looks tight enough to not allow any bigger.
I love this blower, a lot actually. I'm just trying to decide if I want to swap to a Procharger or see where this takes me. Problem is that I would normally make as close to 700 as I could and then spray a 100 shot. However, with the high compression of the LS3 I don't think that is wise. So my option would be to install heads with a lower compression and then spray it. But by the time I buy the heads and nitrous setup I could have swapped to a Procharger. So I'm trying to figure out if I can be happy with 650-700 or if I need to swap. I am going to the 1/4 mile track on the 25th. If I trap 140 I will probably keep the blower because I can go 145ish with another round of mods. Truthfully this car scares me with the power it has. It's not like any other car I have had. The rear end likes to fish around in this car.
Yeah, it's a shame that the C6 is limited to crank pulley size, and that the blower shaft limits the blower pulley size. The blower itself has loads of potential. There's ZL1 guys making 850+ rwhp with it, but they have bigger crank pullies and smaller blower pulley options.
But I guess the question is: how fast do you want to go? The kind of power you could make with your pulley combo and meth would probably be a serious handfull on the street.
09-23-2014, 10:08 PM
Well done
