TechnoSquare is in the process of finishing up their 07 ECU reflash, some more beta testing and they should be done.. during this process, they've been doing some testing on exhaust pieces and its performance effects on the test car (OEM 07, non modified).

Some interesting results came out of their flowbench tests. They use a Superflow flow bench tester and for this test it was set for 400CFM max flow. After putting on their adapters, and with nothing attached, their average open air flow was around 319CFM. Luckily the 07 owner had purchased a set of HFC from a respectable company so we could do some comparisons. a few months back, i had TechnoSquare make me a prototype set of 2.75 HFCs (using a magnaflow spun metal substrate) for my turbo setup and did some of my own testing comparing that to some 2.25" test pipes that they had also made for me, and i've added the numbers along in the list below.

they are planning on doing dyno comparisons with the OEM cat vs the name-brand 07 HFC and see how much power difference 16 cfm really does make... also note, it is not possible to bolt on an 07 cat to an 06 or older, since the piping flanges are all different.. this is mainly to state the differences Nissan has made to make the 07s VQHRs really good out of the box. (if anyone would like to donate a set of 07 cats so that we could cut off the pre-cat to make it a straighter pipe and use it for flow testing, please contact me):

03-06 OEM Cat: 145 CFM
07 OEM Cat: 180 CFM
07 name-brand HFC: 196 CFM
2.25" test pipe: 225 CFM
2.75" custom HFC: 306 CFM


Discuss.

 

interesting, are those numbers above in CFM?

 

Interesting indeed!

What name brand HFC was tested on the 07?

 

yes. all numbers are in CFM.

the 07 cats perform much better than the 03-06 cats...

 

explain why CFM alone means anything other than it simply flowing more air. (not being a smart ***...)

 

i'm guessing the "name" brand hfcs were crawford? Being ceramic they probably flow less? More info please

 

My rough calculations indicate a need for around 850 cfm out of an exhaust for a boosted vq35 in the 500-550 whp territory. Your flow bench max flow is kind of limited, but I really like the results of your high flow cat (maybe it would flow 400+ cfm - hard to say as it does not appear restricted at 319).

Can you by chance tell me the max diameter and length of the brick as well as the cell rating? I ask because I have a set of custom spun metallic cats waiting to be mated to APS 3.5" test pipes pairing up to an evoTT exhaust. I am hoping I'll hit the 450+ cfm target per cat (200 cell 4.5" diameter, 4" length with 3.5" inlet/outlet). Thanks.

 

all tests were used setting the flow bench to 400cfm. the machine physically has a higher air flow rate capacity, i just didn't set it. if we're looking at percentage change from open attachment (baseline of 318 cfm) the 07 cats are allowing 56% of the air through, while the 03-06 cats are ~45%. my 2.75 hfc are allowing almost 96%. you can read up on my hfc by doing a search in the FI forum. i posted all the info on the build there.

considering that the new oem cats are flowing better than before. my point is that changing to a HFC or test pipes might not yield much performance gain as before.

 

how much CFM does our engine put out per side? I was just wondering if the flow rate of our engines was alot higher that 400cfm you would see different results when the pressure was increased wether it would lose efficiency or possibly gain it.

 

Anyone want to make 07 cats attachable to 03-06 to remain legal. What would you say the max cfm cats have to flow for n/a before getting a negative effect?

 

who made your hfc?

 

where could I get a pair of 2.75 hfc?

 

It would be interesting to see which brand HFC were tested.

If you cannot post them to the public, can the OP please PM me.

 

Different flanges.

 

the 2.75" i am using are custom made.


from personal experience, OEM 03-06 cats were highly restrictive in my boosted application, and prevented me from boosting over 11psi. when i went to a 2.25" test pipe, that problem went away.

as for NA applications, 07 OEM cats flow fairly well, but that much better over aftermarket HFC, that's the question. i need to check up on the dyno results from last friday. it was raining heavily in So Cal, so i dont know if the test happened or not..

 

subscribing.

 

i would like to know how effective that custom cat is....and how is it possible to flow more than a straight non perforated pipe??

 

Just thinking out loud here, but wouldn't the different velocities of the moving air play a role in how restrictive something is or isn't. Air velocity should be lower in the 2.75in HFC than the 2.25in test pipe. Maybe the cat material is providing less restriction at this lower velocity, than the 2.25in test pipes diameter at a higher velocity. Of course I don't really know much about how a flow bench works or exactly what the CFM is measuring, so I could be way off.

TK

 

Custom 3.5" 200 cell metallic cats are being made to mate APS 3.5" test pipes by Sharif's crew at ForgedPerformance. He should be able to get you all the info - though you may want to wait till we see how much power my car makes with them. He can give you the details...

 

CFM is measuring volume of air per unit time, not velocity (distance per unit time). Velocity will be higher in a smaller pipe, no question. It's the total air mass per unit time that's important and for a given pressure and temperature, volume per unit time is a reasonable surrogate.