For those who have followed my progress, you would know that I have had some fairly extensive work performed on my CA18DET head. The following is a scan of the printed flowbench results I was able to pickup this week...

On testing the stock head, the stock inlet manifold and subplenum was used with butterflies, on the modified test the aftermarket manifold and modified subplenum was used no butterflies.



One thing to note is the stock flow capability with inlet butterflies just over 216cfm at peak lift/valve speed... This should hopefully provide some solid data for people wanting to rip the butterflies out because of the percieved restriction the butterflies cause....

As a before and after comparison, it is interesting to note how the inlet flow rate is similar to the stock at lower valve lift speeds but then gradually pulls away on the ramp up from about 160cfm/200 thou then really starts to pull away from 200cfm/300 thou up to near 280cfm/600 thou...

The exhaust side has improved markedly with near 200cfm/600 thou, but still keeping a similar lower lift/valve speed on the ramp up...

Hope this provides some useful data for those folk out there who are interested...

Cheers,

Matt

You just helped me win an argument, thanks!

So you're telling me to get off my duff and port the head, right? haha. Thank you for the real numbers my friend.

Sold. I'm taking out the butterflies.

isnt your head a 8 port that is made into a 4 port head? or is a a propper 4 port head.

thanks heaps for the data mate, thank fu(k some one did it lol

It is an eight port head.. but it is definately not made into a four port head like the euro head...

I have turned it into four ports, but the configuration is like an infinity symbol..

The euro head has oval ports...

No worries on the data I hope people find it useful...

Buddyworm wrote:Sold. I'm taking out the butterflies.

Im afraid you have not understood the information posted.

If anything its definitive proof that they hardly pose any of this 'internet' restriction.

Others need to realise that the graph shows the stock head tested to standard lift(close to 9mm) with the modified head tested to approx 15mm lift. The modified head picks up approx 10% at off the shelf lifts.

niscort wrote:
Im afraid you have not understood the information posted.

If anything its definitive proof that they hardly pose any of this 'internet' restriction.

Others need to realise that the graph shows the stock head tested to standard lift(close to 9mm) with the modified head tested to approx 15mm lift. The modified head picks up approx 10% at off the shelf lifts.

So....is this apples to oranges then?

mbmbmb23 wrote:So....is this apples to oranges then?

so... are you disagreeing with what ive said?

otherwise please elaborate on the reference as whatever you are implying beyond me

you dont have a stock head and runners v stock head and butterflies removed do you?

some one oh here said they got almost 100cfm from taking out just the butterflies in the runners but i want to see wat the stock head can flow verse wat the runners can flow

can you post close up pics of you inlet and exhorst ports. if you want to

oohh and also is this a vacume test or pressure test?

Unfortunately I do not... I can tell you that the head itself only flows 220 cfm but as I wasmore concerned about the flow with manifolds bolted up so I never asked for the info.

I would be questioning the accuracy of 100 cfm as the drop in pressure with no inlet manifold is just on 4cfm between head on it's own and manifold attached.

If you have a look at my thread I have posted pics of the head

niscort wrote:
so... are you disagreeing with what ive said?

otherwise please elaborate on the reference as whatever you are implying beyond me

I think were in agreement but I was simply making sure that, by what you've said, that you're implying that the differences in the graph are less butterfly related and more headwork/cam related. I didn't get what you meant by " 'internet' restriction" however, lost me with that.

So to sum up the graph into a Cliff Notes version: we have butterflies vs. non-butterflies...but non-butterfly head was ported and has higher lift cams and the butterflied head was oem. Is that what I'm reading in this thread?...apples and oranges? Don't get me wrong, I love when people to back to back comparisons and share their tech with the community, but if the variables change between tests then I cant make the jump (and will keep my butterflies for now).

-m

mbmbmb23 wrote:I didn't get what you meant by " 'internet' restriction" however, lost me with that.

BQ.05.TD wrote:some one oh here said they got almost 100cfm from taking out just the butterflies in the runners ...

ok 100 cfm?! prime example of my reference... reguritated infomation with no factual basis.

which leads into my point...

the graph shows the same head, stock and modified.

With the extensive work done on Matts head and the sub manifold, not just the porting but the additional use of rb valves, the overall "gain" at the standard lift of sub 9mm, was approx 10% gain in flow.... say 20cfm for argument sake. Undoubtly the extensive work on matts head has been performed to create massive gains in airflow in the later end of the graph as the lift increases... iirc he is running somewhere over 13mm of lift.

Thus begs the question... how much of this 20cfm gain was benefitted by solely the removal of the secondary butterflies?

As a performance modification constantly quoted on the internets world wide by CA fanboys, the graph above pretty much nails the coffin shut on the 'assumed' restriction of the terrible butterflies.

Its not ultimate proof of a 'with vs without' test... but its a much safer assumption than 100cfm gains

how many people would actually reach the limit of 220cfm anyhow?

I said 100cfm, but if everyone was to read it was done on a DIY bench, and I did NOT test the head, only the intake manifold. I also did a lot of port work on the lower manifold, matched the plenum to a larger throttle body...

I would never expect to pick up a 50% increase in flow through the head with such a little modification. Nissan wouldn't have used it if that were the case.

niscort wrote:
Im afraid you have not understood the information posted.

If anything its definitive proof that they hardly pose any of this 'internet' restriction.

Others need to realise that the graph shows the stock head tested to standard lift(close to 9mm) with the modified head tested to approx 15mm lift. The modified head picks up approx 10% at off the shelf lifts.

Ah, thanks for clearing that up. Guess I shouldn't try and analyze graphs after wake-n-baking.

mbmbmb23 wrote:
I think were in agreement but I was simply making sure that, by what you've said, that you're implying that the differences in the graph are less butterfly related and more headwork/cam related. I didn't get what you meant by " 'internet' restriction" however, lost me with that.

So to sum up the graph into a Cliff Notes version: we have butterflies vs. non-butterflies...but non-butterfly head was ported and has higher lift cams and the butterflied head was oem. Is that what I'm reading in this thread?...apples and oranges? Don't get me wrong, I love when people to back to back comparisons and share their tech with the community, but if the variables change between tests then I cant make the jump (and will keep my butterflies for now).

-m

It was never intended to be a dedicated comparison with or without butterflies, as I know that the stock head on its own flows 220cfm @ 350 thou... I just didn't ask for the information on paper unfortunately

So 216cfm with the stock inlet manifold and butterflies attached would mean that removing the butterflies would only give x amount between 0 and 4cfm in additional flow if any at all (considering the manifold drop)

So its not apples and oranges as such, but it is a before and after... With some real data on the stock head flow which I could never find...

Cheers

wakenbakin' ftmfw

^ FTW indeed