Had my head flowbenched... data inside.

[SuperHatch]

I had my stock head flowbenched. This is a USDM 94 (Oval Port) VH45DE Cylinder Head. Cylinder 4 if anyone cared...



I plotted the data versus a USDM 4G63 (6-bolt big port) and a USDM B16A (5G Civic)

All of this data came from the same cyliinder head shop on the same flowbench at the same parameters...

I am considering taking one of my 91 siamese port heads to have it checked just for my own education... anyone else interested?

[perana]

hi, thats a great comparison but i would be interested in a comparison between a vh and aftermarket american v8 heads. if one can even compare?cheers
Modified by perana at 10:26 PM 2/22/2008

[mtcookson]

I'd definitely be interested in the siamese port results.

Perana, here's some data I can find so far... though being on different benches it'll be hard to perfectly compare them.

http://www.topcatautosports.com/air_flow_data.htm

LS1:http://www.topcatautosports.com/air_fl10.gif

[perana]

hi,mtcookson thanks for that.kind of hard to tell from diffrent benchs.what i'm trying to compare is a american v8 to say a stroker vh.cheers

[tmorgan4]

Good info!

As a newb to this, why are intake flow rate so much higher than exhaust?

[SuperHatch]

hi, thats a great comparison but i would be interested in a comparison between a vh and aftermarket american v8 heads. if one can even compare?cheers

Modified by perana at 10:26 PM 2/22/2008

What american V8 heads would you like it compared to?

I compared it to other import heads that are known for making good power, because they typically are 4-valve configuration and operate in the same lift range as the VH, if I compare to an american V8 the numbers will look significantly different since they typically experience lift that is double that of a VH.

[Q45tech]

1.5" intake vs 1.3" exhaust valve diameter, however the expansion of exhaust gases and extreme temperature increases flow pressure which cannot be duplicated on a room temperature flow bench.

[perana]

i would like to know how a stroker vh compares to a dohc cobra 5.4l with the same amount of lift.the reason is i'm going to start spending some $$$ on my vh.something i dont realy do,but i wanna know what it can realy do?the n/a 5.4 like those in the falcons over here.
Modified by perana at 2:33 PM 2/23/2008

[SuperHatch]

i would like to know how a stroker vh compares to a dohc cobra 5.4l with the same amount of lift.the reason is i'm going to start spending some $$$ on my vh.something i dont realy do,but i wanna know what it can realy do?the n/a 5.4 like those in the falcons over here.

Modified by perana at 2:33 PM 2/23/2008

Here you go...



As you can see, stock vs stock the VH does very well up to the same lift. With a full CNC race port the Cobra head does very well on the intake, but only alightly better on the exhaust. I'm not sure if there is a lot to be gained by going to a bigger lift on the stock head, but I'm curious to see what kind of gains can be had out of porting.

[perana]

yo,now thats what i'm talking about.so a ported,lowcomp,highlift,stroker @ 1bar should easly see 1000hp.thanks alot thats what i needed to know.cheers

[SuperHatch]

yo,now thats what i'm talking about.so a ported,lowcomp,highlift,stroker @ 1bar should easly see 1000hp.thanks alot thats what i needed to know.cheers

You could probably see 1000HP without porting. A fully ported Honda head that flows ~290CFM will make 1200HP at 50PSI. But that is one head and 2.2L of displacement.

[Q45tech]

What is so important is the SUPERIOR low lift flow [<7mm], pretty amazing for a stock lux car engine. I believe the stock limit at 6,900 rpm is 0.390"?

It would be nice to see the head with a full oem runner [cut from plenum] to determine the resistance of the tuning length and diameter.

Just fully confirm my premise that for normal NA nothing is needed headwise.

Did you by chance do a reversion [reverse] flow test to measure what might happen during overlap before VVT gets rid of 28>8 degrees

[ScottJackson]

pretty impressive showing. Good low lift flow comes from having a good valve seat job. I believe the stock VH has a 5 angle job from the factory, which is impressive. But low lift flow doesn't really translate much into big power because the air/fuel isn't coming in at a very high velocity during those times. Looks like with a little porting and cams with .500" or so lift, it could be a screamer.

[tmorgan4]

Just came across this chart for VG33s.



Do VGs really have .65" valve lift?

[mtcookson]

Highest I've ever seen anyone take a VG to is around .465" or so.

[SuperHatch]

Just came across this chart for VG33s.



Do VGs really have .65" valve lift?

Good data, but it's hard to compare against what I posted, especially without the pressure...

[Clifton]

I am considering taking one of my 91 siamese port heads to have it checked just for my own education... anyone else interested?

I would love to know which one flows more and if so, by how much. I know there is always internet speculation but number would put it to rest.

[sijoko]

I would love to know which one flows more and if so, by how much. I know there is always internet speculation but number would put it to rest.

My money is on the oval ports.

[Mettler]

I'd say they'll be very close... I mean, the port splitting into two still happens with either motor, it just happens higher up on the siamese port motor, in the base of the runner.

I theorise that if the oval ports are actually capable of higher CFM, then it will be at the expense of port velocity, as it seems to make sense that two smaller ports would each have higher velocity than the oval.

Then again, as clifton said, it's all just speculation. Halfway up the intake runner it's all still the same :p

[Q45tech]

Actually the difference is ~ 2" out of 18"..........14.0 or 16.0 of single port vs 2" or 4" of dual port. Added runner since worthless to compare heads without runners.

[BADA$$240]

I can't see any of the data from the bench flow test?

[klh6686]

I believe it was this chart:


I will add my SIAMESE ('91 model year) heads to the mix:

[BADA$$240]

If that's a stock 94 vh45de oval port head then that's really impressive. Is it stock or is that ported?

[XJared]

Impressive stuff for sure for a stock head. Anyone have numbers for a VK45 or VK56 head?