The best my memory can recall it was 10"water.

 

Neat idea, I'd replace the corugated hose with a straight bellow. It takes twice the diameter of corrugated hose to flow the same as non-corrugated.

Airflow doesn't like bends either, since air has mass with develops momentum. It takes a large radius bend and a larger diameter to flow the same as a straight pipe. Minimize the cruves and cross sectional changes and you're on the right path.

Hope this helps,
-Christian

 

Look at a K&H CAI the next time you get a chance and look at the bends,you'll be impressed at how they did it.It does flow in excess of 1300 CFM(just the tubing).

 

10" water would put the 1.5" flow at ~270 cfm. No bueno.

I've seen tests of the round K&N filters, in particular the 12 x 3.5-incher, flow ~875 cfm at 1.5" H20. Subtract 1/2" from that overall height to compensate for edge flow losses and you get ~113 in^2 of effective flow area. That would suggest that the K&N filter element flows about 7.7 cfm per square inch of filter area.

The LT1 filter is 6" (top) x 4.5" (bottom) x 7" long. Subtracing 1/2" from the length again, I get an effective filter area of ~108 in^2. That multiplied by 7.7 cfm gives us ~831cfm of flow. Of course we haven't accounted for frictional losses along the pipe so... was the element flowed with the pipe attached and what was the actual depression used?

I'm guessing, based on these examples, that the depression was 1.5" H20 but we really need to know for sure if we're going to base calcs on 700cfm.

Considering the formula for air capacity of an engine of given size...

CFM = rpm x displacement / 3456

A 383 ci engine turning 7000rpm would ingest 776cfm at 100% volumetric efficiency. So I'm wondering how much the K&N cone filter is hurting performance.

I may make a backup pass without the filter next time I'm at the track to see what happens. Anyone tried this??

-Mindgame

 

I have mounted the K&N with the same end dimensions except 12"long along with their intake tube.That filter flows 1200CFM.I figured if your TB flows 1300 ya need an intake tract to flow with it.
My program says that this engine ingests almost 900CFM@7000???That not what the formulas I have used for years says--but??

 

Yes, sort of (a 'lil off the question even)...

Using a 14" diameter x 3" high K&N ring filter, I made a dyno pass
without the filter installed to test for restriction.

The dyno showed no increase in horsepower/torque so we concluded
that the filter was sufficient for my engine.

355 CID, spinning to 5800 RPM making 270.2 HP at the wheel.

This is an L98 engine breathing through a 700 CFM Holley.

Based on the "area of flow" for the ring filter, it was able to handle ~ 596 CFM (if 100% V.E.)

I have also made passes down the 1/4 with and without the
filter: +/- 1 tenth was inconclusive with 3 attempts.

 

1Racerdude, you mentioned the curvature of the K&N FIPK being interesting. I've been running the Arizona Speed and Marine cold air with a 9" k&N filter IIRC. I decided to pic up the Moroso/ Lingenfelter cold air to do some airflow comparisons. Here are some pics of the moroso if anyone is interested:

http://www.carprogrammer.com/Z28/MorosoIntake/

I'll datalog 3 WOT 3rd gear runs on each intake and compare the MAF readings, I'll share the results on this thread if no one minds.

-Christian

 

That would be great. I don't have the access to things here for testing as I had in CAL. and a test like that would be enlightening for everybody.

Thanks man.

 

MG,
I will see if I can find the paperwork on that test.I may still have it,it's been a few years.
Old fart's and their memory sometimes don't get it done.

 

[QUOTE]Originally posted by Mindgame
[B]10" water would put the 1.5" flow at ~270 cfm. No bueno.

I've seen tests of the round K&N filters, in particular the 12 x 3.5-incher, flow ~875 cfm at 1.5" H20. Subtract 1/2" from that overall height to compensate for edge flow losses and you get ~113 in^2 of effective flow area. That would suggest that the K&N filter element flows about 7.7 cfm per square inch of filter area.

The LT1 filter is 6" (top) x 4.5" (bottom) x 7" long. Subtracing 1/2" from the length again, I get an effective filter area of ~108 in^2. That multiplied by 7.7 cfm gives us ~831cfm of flow. Of course we haven't accounted for frictional losses along the pipe so... was the element flowed with the pipe attached and what was the actual depression used?

I'm guessing, based on these examples, that the depression was 1.5" H20 but we really need to know for sure if we're going to base calcs on 700cfm.

Considering the formula for air capacity of an engine of given size...

CFM = rpm x displacement / 3456

A 383 ci engine turning 7000rpm would ingest 776cfm at 100% volumetric efficiency. So I'm wondering how much the K&N cone filter is hurting performance.

I may make a backup pass without the filter next time I'm at the track to see what happens. Anyone tried this??



Mindgame,

-You are correct-- the number is 1.5" of water.

 

Thanks for the confirmation Larry.

Just hate to assume anything.

-Mindgame

 

By your figures the "standard" 7" K&N does not flow enough for these 650-700HP engines? Or is it borderline,IYO?

 

Now that I'm actually thinking about it (never have really given it much thought til now, thanks LR) I'd have to say it may be "borderline". I plan on doing a bit of experimenting when time allows to find out... cause I'm running that same 7" filter on my setup.

-Mindgame

 

OK

 

Just some info I have from my last dyno runs with the SLP intake and the two tiny filters. Every since this last Dyno I have been planning on doing some thing different for the filters but I need more testing and the test car is down.

Test Engine. Stock LT1 350CI. slightly modified intake, heads ported to 280+@.600,58MM Billet TB, MBA MAF Ends with stock electronics(Tune calibrated for this), SLP CAI with filters.

This Engine made 395 Corrected 409 actual at the rear wheels through an Automatic and a 12 bolt.


Once above 4,800 RPM the Map started dropping from 101Kpa. It hit a low of 89Kpa along the way and hit 380+ GPS on the MAF reading. THE MAP Drop was not erratic spikes but a fairly smooth drop. Peak HP was at 6,900.

I also have some files on our stock LT1. it only took 250ish GPS of air and the Moroso was fine with just little blipps in the MAP.


Just what I have tested thought I would toss it out there for you to add to your tests.