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Trying new airboxes and intake on my z06 with the Harrop Hurricane
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Don't want to put words into anyone's mouth, but I believe Jim halltech and katech didn't have the best results with this intake either, and ended up switching back to a standard composite setup with 1 TB. That too was on k501 cam and higher compression
Yes, you are right they did try that to what I saw on the forum as well. However, what they posted were trials without airboxes. On an engine dyno that might work out ok, as your engine is not confined in a heat sink, where the radiator is in front of the engine blowing hot air in its direction. On a chassis dyno, you will just suck in hot air, if you do not have airboxes. To what I remember they peaked around the same as a FAST 102, however they lost power under the curve. I'd like to know what their intake temperatures were, but I would bet they were plenty above 100 F.
On the old setup we lost around 40 hp everywhere when we took off the airboxes, so that should be an indicator..
On the dyno comparing OEM and our first setup, you can see how we gained around 60 hp at some RPM. Due to the longer runners of the Hurricane, you will get a lot of torque. They're length reaches an optimum around 5800 RPM. And by having two 4 inch inlets (with airboxes) we lower the intake restriction compared to a composite manifold, so we hope we can keep up with the shorter runner intakes above 6500 RPM through that as well.
Another way to get the Hurricane into the sweet spot around 7000 is to have a cam that has intake valve opening a bit later. That cam would then be terrible on a composite manifold. Or you just use a stroker and rev till 6400 RPM, or CCRP in Austria is trying an LS revving to around 8000 RPM, as the long runners of the Hurricane reach their next sweet spot around 7400 RPM.
Can you please clairify the graphs you've posted, hard for me to depict what is what.
Very interested in this setup as I prefer N/A. Are you planning on selling these air boxes?
So the blue line is wheel horsepower while the red line is calculated engine horsepower (MAHA measures the driveline losses somewhat) with a DIN correction for ambient temperature/pressure effects. However it cannot correct for the fact that on a hot day you have to retard your ignition by a little bit... The orange line shows calculated torque. On the plot where you see 6 lines instead of 3 I am comparing the old airbox setup vs. OEM manifold with a Callaway honker on it. Btw, this dyno seems to underestimate power figures by quite a bit.
Sure, it would be nice to sell a few of the systems, as tooling etc. was not cheap. However I think we are at prices for the entire system with the Hurricane, where most people will probably opt for a supercharger instead. 800 hp is more important to most than nice linear NA power delivery combined with instant throttle response. Plus I would need to find a distributor in the US to make things easier. And most importantly, I have to verify that with a carbon filter box I will gain back around 40 hp, but I am on that with a 3D printer at the moment
Looks like a really great design. My dream manifold is an ITB that can flow like a Holley Hi-Ram.
Thanks . I hope that we will get there. I did try a few things over the weekend and it seems like the hoses are indeed the limiting factor at the moment. But the dynos sadly aren't open over the weekends in Germany.
For anyone who cares, here are some CFD velocity profiles we get at the outlet of the current hose. In CFD of course the hose was better than in realitity as it doesn't have the wrinkles in it.
I compared it to a straight pipe of the same diameter and length and it came out that I loose slightly more than 10% of mass flow. This is due to the flow separation you can see on the blue colored parts of the velocity profile. With the carbon box that flow separation will be gone and a uniform velocity profile such as in the straight pipe will enter the airboxes. More mass flow means more power
Yes, we have designed the filter box, which allows roughly 25% more mass flow at 7000 RPM compared to the hoses. It already has been test fitted as a 3D printed version and is currently in production from carbon fiber. Let's see how much more the engine can actually breath .
It's somewhat similar to my old design that I had for the other airboxes, however much more advanced. The production version will also have the MAF adapter in the filter box on the outside of the passenger side.
Yes, we have designed the filter box, which allows roughly 25% more mass flow at 7000 RPM compared to the hoses. It already has been test fitted as a 3D printed version and is currently in production from carbon fiber. Let's see how much more the engine can actually breath .
It's somewhat similar to my old design that I had for the other airboxes, however much more advanced. The production version will also have the MAF adapter in the filter box on the outside of the passenger side.
07-30-2017, 12:46 AM
. I hope that we will get there. I did try a few things over the weekend and it seems like the hoses are indeed the limiting factor at the moment. But the dynos sadly aren't open over the weekends in Germany.
