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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
I ordered a new air filter element from RockAuto. The part the sent me differed tremendously from the OE Donaldson in my 2013 Z06. I didn't even screw in. Later, I found they'd sent me a LS3 filter. I contacted the dealer and a local Delco store and they both wanted $207 for the replacement. I just ordered a K&N. I've used these before with very good success in my old IROC-Z. In fact, a tuner, Bill Mitchell of Special Vehicle Developments here in CT recommended them over the AC/Delco OEs and used them on his race cars.
So, from going through this thread, it may not even be possible to get the exact OE Donaldson Power Core 2 even from the dealers?
The problem is that GM allowed Donaldson to absorb the LS9 air filter part number into the previous LS3 air filter, so there are essentially no further big-pleat air filters being produced. Small pleat air filters sold under the GM part number that used to be only for the large pleat filters that originally came with the ZR1. F you, C6 ZR1 (and Z06) owners, says GM.
AEM is owned by K&N and they offer drop-in replacement air filters that don't require oiled media - I'd try that before a K&N oiled media air filter. Otherwise, we have to look at that after market CAI's.
The problem is that GM allowed Donaldson to absorb the LS9 air filter part number into the previous LS3 air filter, so there are essentially no further big-pleat air filters being produced. Small pleat air filters sold under the GM part number that used to be only for the large pleat filters that originally came with the ZR1. F you, C6 ZR1 (and Z06) owners, says GM.
AEM is owned by K&N and they offer drop-in replacement air filters that don't require oiled media - I'd try that before a K&N oiled media air filter. Otherwise, we have to look at that after market CAI's.
It's been in the car all weekend. It's too late for me. At least it was only $87 compared to the OEM price. I had a feeling that's what was going on. Since these cars are no longer in production, as long as they can sell something, it's good enough. So I kept my OEM Donaldson PC2 as it still has some service life left. For some reason, I couldn't toss it. I'll definitely keep it as it's now a unavailable OE part.
The BIG thing about the air filter I was sent is it just slid in and don't use those 6 or so star screws to secure it. I was NOT happy about this. At least the K&N seats and seals well with those 2 brackets it comes with.
The way to properly measure air filter restriction is to put a gauge or data logger on the post filter intake tube and take a measurement. On ebay you can buy filter pressure "poppets" that, when a low pressure is detected, they 'pop up' to let you know that a restriction guideline has been met, usually around 1.25 - 1.5" Hg iirc.
You want some slight pressure drop post filter to create PCV action during WOT. Without any pressure drop post filter, the engine will lose its positive crankcase ventilation. If you notice the crankcase feeds from a post filter hose. So using the 'slightly more restrictive filter of the two', so long as it does not exceed OEM guideline of around 1.5" of Hg pressure drop, is actually more ideal for daily drivers and engine longevity, as it will keep the oil cleaner when the engine is run at WOT.
Does anyone know what the maximum air intake rate of the LS7 engine is? K&N claims a flow rate of: 423cfm /w 1.5" H2O restriction.
The formula is
CIDxrpm/3456 = CFM @ 100% VE
where cid is cubic inches of displacement, rpm is the rpm where you wish to evaluate engine flow rate, and CFM is cubic feet per minute of air.
to get to mass from volume/time, you would:
If you then take CFM * 0.069 that assumed an air intake constant to get you into lb/min where 1lb/min = 10 horsepower thus a 65lb/min turbo is worth 650 horsepower
Also remember to multiply a VE into the equation that makes sense. Stock truck 5.3 from 02 would be like 60-70% VE at 6k rpm with the OEM camshaft for example.
So lets try a common example, chevy 355 (0.030 over 350):
355x6000/3456 = 616CFM
If the 355 is at 6k rpm, and has perfect 100% VE (best head/cam/intake more or less) it would flow rate 616 cubic feet per minute of air
... which says nothing of the mass. It can flow 616CFM of air but we have no idea how many air molecules that is, it depends on the temperature and fluid-like momentum of the air, which affects the space between molecules. A maf can measure this because it's hotwire interprets air temperature, whereas a MAP sensor has no idea what temp the air is and relies on IAT sensor. At cold temps there are more molecules in a given space because they are closer together, more well packed, so you can inject more fuel, thats what boost is. Well it is comparable to boost. I.e. lowering my temperature at the same pressure (no "boost") can give me just as many extra air molecules as an extra couple psi of boost pressure at a higher temperature. Its just that boost can keep going, more and more pressure can be squeezed, whereas we can only go so low with air temp easily, its value also increases as pressure rises such that the more boost you run, the more return lowering air temp will have.
Hmmm....
(426*7000)/3456=862.847 cfm at 100% volumetric efficiency (VE)
862.847*0.069=59.536
Therefore: 862-60 (I'm just rounding off here) is approx= 802 CFM at the throttle body entry?
Lets say the efficiency is 70%
802CFM*.70= 561 CFM ?
Or am I missing something here or using the wrong the wrong units/time? But, this does seem a reasonable number. So under ideal conditions, the filter I install should be able to flow a minimum 561 CFM when clean and new under WOT conditions?
Does the engine match to the predicted 60lb/min or 600brake horsepower (approx 520rwhp perhaps) in the equation? If so the initial estimate is fairly close of 862cfm. Otherwise, scale the equation as necessary. I bet VE is better than 70% in a vette engine late model, not 95% but not 70 either on an OEM cam/head.
Still we can stop here with some common sense approach. lets say its between 900 and 700CFM, shoot for the higher number since more flow is more flow, but don't be upset if you get only 750 take what you can get. Then measure it in real time or make plans to enlarge the surface area or change the element. For measuring, It doesn't have to be a gauge or logger or mercury. Inches of vacuum can be in water, run a hose from the post filter tube to a graduated cylinder and count how many graduations it rises at max flow conditions you are worried about, that would be inches of water of vacuum in the post filter as opposing the atmospheric pressure on top of the water.
As for enlarging or changing element, the application is extremely important. Endurance sand racing for example, would want a large filter box, inside a larger filter box, inside a larger filter box, etc... multiple stages of protection. And the engineer would use a bench to pull air through them, add the sand and dirt from the track in copious amounts, to measure effectiveness. If you want it to last you think of everything.
The problem is that GM allowed Donaldson to absorb the LS9 air filter part number into the previous LS3 air filter, so there are essentially no further big-pleat air filters being produced. Small pleat air filters sold under the GM part number that used to be only for the large pleat filters that originally came with the ZR1. F you, C6 ZR1 (and Z06) owners, says GM.
I suspect that Donaldson had nothing to do with the decision. My guess is GM's "Customer Care and Aftersales" division which is responsible for the ACDelco brand decided to discontinue the 09-13 ZR-1 and 12-13 ZO6 air filter because of low sales numbers and, perhaps, the higher cost of Donaldson's PowerCore G2 media.
Doesn't hurt the ZO6 much..4 to 5-hp but I bet it take more of a bite out of the ZR-1s 638-hp.
The filter with G2 media was said to be capable of 850-cfm.
Last edited by Hib Halverson; 04-18-2018 at 07:43 PM.
I just went onto Amazon today and they have the DPC-2 filter for $86. For those who want the exact replacement, I recommend getting it now before they disappear. I was really surprised to see that filter both available and go for so cheaply. Just a FYI for anyone who might be interested.
I just went onto Amazon today and they have the DPC-2 filter for $86. For those who want the exact replacement, I recommend getting it now before they disappear. I was really surprised to see that filter both available and go for so cheaply. Just a FYI for anyone who might be interested.
If I'm not mistaken, while that is the same GM part number for the LS9 filter, the actual filter media is the LS3 media with the smaller pleats. Would love to hear Tadge explain what all the LS9 guys are supposed to do.
My curiosity got the better of me and I saw Corvette Central was selling a specified Z06 and ZR-1 Donaldson filters as the OEMs of the 2012 Z06 and ZR-1 upgrade filter. So I decided to order one. I have the OE filter from my 2013 model year Z06. Here are pictures of the filter I ordered from Rock Auto a couple of years ago.
The filter on the left is the one from RA and the right filter is from Corvette Central.
Top is from RA, bottom from Corvette Central
Top is Corvette Central, Bottom is from RA
And when I looked at my OE filter, it looks pretty much the same. So I'm not certain of CC is selling a pup or if any of these filters are all that different. Just thought I'd stir the mud a bit more.,,,.
Looking on rockauto right now I see two delco part numbers: A3077C and A3107C, the latter looks like the ones you have. Given that "powercore" appears to be a registered trademark of Donaldson Co, maybe they started making them again!
04-16-2018, 02:17 PM
