Factory Flow Rate for S13 Cylinder Head?

[2_Liter_Turbo]

Anyone know the intake and exhaust port flow rate for a factory S13 cylinder head?

[2_Liter_Turbo]

Nevermind, Alex sent me a couple links. Looks like around 204 CFM on the intake and 115 CFM on the exhaust side for a factory high port SR head...

[2_Liter_Turbo]

Ok, I'm not so sure on that exhaust port flow rate, seems a little low after getting my numbers back, lol.

[jr_ss]

I've typically seen them in the low 200's on intake and low 100's on exhaust.

[2_Liter_Turbo]

Interesting. Well I got some numbers back on my highport cylinder head (oversized valves and ported). I got 240CFM @ .5" lift on the intake and 184CFM @ .5" lift on the exhaust. Little more than a stock VE on the exhaust side and a little less on the intake side. Both heads tested on the same machine; I'll have pretty exact numbers later tonight.

[Def]

I wouldn't just look at peak numbers. The valve spends very little time there. Integrate the area under the curve for a given cam profile.

[2_Liter_Turbo]

I definitely am not. I have both curves, and will be posting a comparison chart tonight when I get it together. I think it'll help out the comparison discussion a bit. I know the VE head is better, but It would have cost me a LOT more money to go that route than just stay with the DE head. If I didn't already have a bunch of head parts already, the cost is about the same, but I already had the extra parts on the DE head.

[jr_ss]

Here is what my completely stock VE head flowed;

Intake
Lift CFM
.050-49
.100-86.2
.150-122.6
.200-158.6
.250-192.5
.300-225
.350-249.2
.400-263.5
.450-272.9

Exhaust

Lift CFM
.050-46.5
.100-86
.150-118.5
.200-147
.250-171
.300-183.5
.350-188.8
.400-193
.450-196

[2_Liter_Turbo]

Here is what my completely stock VE head flowed;

Intake
Lift CFM
.050-49
.100-86.2
.150-122.6
.200-158.6
.250-192.5
.300-225
.350-249.2
.400-263.5
.450-272.9

Exhaust

Lift CFM
.050-46.5
.100-86
.150-118.5
.200-147
.250-171
.300-183.5
.350-188.8
.400-193
.450-196

Which is fairly close to the chart that I have, but the exhaust port wasn't as good. It was done by the same machine at the same company, so I think the results are comparable. Some pretty good numbers for sure though, lol. I'm not saying the DE head is better or even "as good" (because it isn't, lol), I just wanted to compare.

[2_Liter_Turbo]

Posted the comparison in my build thread:

http://nissanroadracing.com/showthre...t=2222&page=14

[jr_ss]

From my understanding and research, the best way to have the head flow benched is to have the intake and exhaust manifolds bolted up, to give you a "true" reading. I didn't have mine done that way. In the future I plan on having my or another head ported for max flow. I'd just like to finish my build currently and get it running/driveable, it's been down for almost 3years now.

[2_Liter_Turbo]

it's been down for almost 3years now.

I hear you on that one... lol

[Pavel!]

This is flow bench test I did a few years ago.

FWD SR20DE high port head ported on intake and exhaust.
-stock valves
-3 angle valve job done in a Serdi
-replaced guides
-all test performed on a SuperFlow 600 bench at 28" water using Audie Technology Digital inteface with a Mitutoyo stepper motor, aka put in desired lifts in program and it runs/records all data on its own.



For some reason I cannot locate the file/data testing the exhaust ports

SR20VE is definitely the way to go. I just bought a complete head with manifolds for $250. I will need to get it set up sooner or later.

[2_Liter_Turbo]

Taken from my build thread I linked earlier:

They also bench tested my cylinder head. I honestly forgot to have them flow test it as stock, so I'm pretty bummed about not having stock numbers to compare it to, but I do have numbers (from them) from when they tested a stock SR20VE cylinder head. I know the SR20VE head is much better than the standard highport DET head (especially after some work), but I just couldn't afford to make the swap. However, I'm fairly happy with the results I got back from the DET head. Looks like the exhaust side flows a tad better than a stock VE head now, but still lacking a little up top for the intake side. I'm OK with that though. I know other people have gotten different numbers for both heads, but I figured since these were both tested by the same company on the same equipment, that it would be a reasonable comparison. Here's a little chart I put together comparing the two:

[jr_ss]

Based on the information in both your's and Pavel's posts, it's safe to say anything over .450"/11.5mm of lift is pointless and doesn't net any real additional flow on the DE/T head. I understand it still increases, but it's marginal at best.

With that said, I wonder why Tomei, HKS, etc have cams with 12+mm of lift, when it doesn't exactly produce any positive results? Possibly to take full advantage and cram as much air in as possible? I know there is more to cam design than peak lift, such as ramp up profiles, duration, etc. I wish more information on cam design for the SR was available.