• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

EJOUIE"s 2005 Impala

Definitely. That would help with potential restriction elimination.

Sent from my SM-G920P using Tapatalk
 


I have a hai but it's 4" and I have the l67HVTB but I can get readings if you want.
You also have to remember the more tubing you have= less can, same with 45 and 90 degree bends
 
Good article. Adding length to straight pipe drops minimally due to maintaining velocity. Just have to avoid bends like the plague. Fluid dynamics.

Sent from my SM-G920P using Tapatalk
 
Well, the TB itself is only ~2.5 inches, 3 should be good enough for a while. Considering mine is DBW, my TB isn't gonna get much bigger any time soon. Lol

And mine cost less than 65 bucks. Lol bends don't bother me yet. Later I'll switch to a HAI, but I want to see how cold I can get the intake during the middle of winter...

40 below zero is common up here. Lol
 
Idle: 50 cfm
2000 rpm: 250 cfm
WOT 5500-5800: 1180 cfm

WarStryker, is there possibly an extra 0 on your WOT reading?

Mine maxed at about 5500 rpm so there is definitely room for improvement.

Grimsin, if you would post your info that would be fun for comparison. I am curious to see how much of an improvement your mods have made. Especially since my car will be pretty darn close to a baseline reading.

Sent from my SM-G920P using Tapatalk
 


I don't think your numbers are right.

I don't see our small throttle bodies flowing that much air.


I found a link to a LS1 CFM chart and their stock CFM is 789 with a 75mm throttle body at 900ish.

Seems like you need for a 80-90mm throttle body to see anywhere near 1100 cfm.
 
Last edited:
ZZP got 94 cfm on a stock gt TB with only 1" hg of vacuum.

2"hg is equal to 1 psi. While cruising around 2000 rpm my MAP sensor read around 9 psi.

So 94 x 2 would give us 188 cfm per psi. Following the math we end up at nearly 1700, but that throttle plate in between MAF and MAP can really screw with the numbers. We can use that though get an idea on the theoretical max cfm. So 1180 cfm doesn't seem so crazy to me.

Sent from my SM-G920P using Tapatalk
 
Fivefingerdeathpunch said:
I don't think your numbers are right.

I don't see our small throttle bodies flowing that much air.


I found a link to a LS1 CFM chart and their stock CFM is 789 with a 75mm throttle body at 900ish.

Seems like you need for a 80-90mm throttle body to see anywhere near 1100 cfm.
Click to expand...

Is that 900-ish RPM? Stock idle on a 3800 is around 750 RPM, and ours are seeing 35-50 cfm.

On top of which, air moves faster through a smaller intake when under a vacuum or pressurized, that's why ported blowers and LIMs make less PSI.
 
No that's 900ish CFM.

I just do no not see a small 65mm throttle body being able to flow that much air, without a bench tester it's hard to know for sure.


The math on the ZZP part does not seem right. All the reading I've done and different calculator show that a 90mm throttle body is still around the 1100-1300 mark depending on blade size.
 


You have to think about how fast that air is moving.

At 6,000 rpm each piston is moving up and down 200 times a second.

Times that by 231 cubic inches, which is 0.133681 cubic feet...

200 times a second x 0.133681 cubic feet of displacement = 26.7362 cubic feet per second x 60 seconds = 1604.172 cubic feet per minute. That's a very rough estimate with zero restriction on intake and exhaust.
 
Well, after looking up other companies readings and find the max cfm ...
(5800x231)/3456= 368 CFM at 100% efficiency.

So yeah I think the numbers are off, BUT we are both reading the off of the same crazy scale. So for comparing like to like it still will work. Inflated/crazy numbers compared to numbers that have the same amount of inflation/crazy is fair.

Sent from my SM-G920P using Tapatalk
 
We are talking flow through a 65mm throttle body, I don't care how big the engine is. Those numbers mean nothing when you are trying to figure out how much air you can shove through a 65mm throttle with likely a loss of 7-10mm from the blade and shaft.



I found this article but still it's kind of a guessing game. I took some numbers I had for lb/min (32.5) and tried to make it into CFM but it's different kinds of numbers to be using.

http://www.dsmtuners.com/threads/converting-between-cfm-and-lbs-min.20184/
 
True, but as long as we keep this to N/A 3800 with readings taken from the torque app we can proceed.

Sent from my SM-G920P using Tapatalk
 


CFM is a measurement of volume, not mass or density. The vacuum will make the air less dense, therefore lowering the "friction" it experiences going through the TB.

One cubic foot of air at 10 psi has the same volume as one cubic foot of air at zero psi, and one cubic foot of air at -9 psi. They will all be a different weight, however.
 
EJOUIE said:
True, but as long as we keep this to N/A 3800 with readings taken from the torque app we can proceed.

Sent from my SM-G920P using Tapatalk
Click to expand...

This whole thing got blown out of proportion... Lol idk what the readings are supposed to be, but if we can see differences using the exact same approach, it will satisfy the curiosity of which intake is least restrictive for this application.
 
Kaiser, if you want to post your findings then go for it. More evidence to claim that our readings are crazy, but consistent would be helpful.

Sent from my SM-G920P using Tapatalk
 
You must log in or register to reply here.
Back
Top