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Sticky beak @ CHI 4v's

5K views 30 replies 11 participants last post by  351AFD 
#1 ·
I thought a few of you guys might want a peek. I have a full res pic if anyone wants a closer look.

 
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#7 ·
4Vman said:
Excellent! i'll be interested to see the kind of power they make, if its significant there goes the myth that 4V ports are too big to make decent power!
:hy: Even though these have 4V port locations I think you'll find deficiences in the cast iron 4V's have been reduced in the alloy version. For example : The opening might be the same size but the runner won't be.

From what I can see, this is what is happening. The port gets smaller the further you move into the head. It's a bit hard to tell with the top one on the angle though.
 
#8 ·
brenx said:
:hy: Even though these have 4V port locations I think you'll find deficiences in the cast iron 4V's have been reduced in the alloy version. For example : The opening might be the same size but the runner won't be.

From what I can see, this is what is happening. The port gets smaller the further you move into the head. It's a bit hard to tell with the top one on the angle though.
Actually If you look at a cross section of an iron 4V head it dramatically tapers upwards from the manifold face to the tight radius in a similar fashion, the port fillers actually fill this area to leave the top 3/4 of the port to flow.
As you know the iron 4v port is higher in the head than the 2V port hence it gives a straighter shot at the valve.
Ill be very interested to see how this head performs against the 2V and 3V versions.

Am i correct to assume the 3V version is just a copy of filled iron 4V port placement? (obviously with better shapes and better exhaust port.
 
#9 ·
4Vman said:
Actually If you look at a cross section of an iron 4V head it dramatically tapers upwards from the manifold face to the tight radius in a similar fashion, the port fillers actually fill this area to leave the top 3/4 of the port to flow.
As you know the iron 4v port is higher in the head than the 2V port hence it gives a straighter shot at the valve.
Ill be very interested to see how this head performs against the 2V and 3V versions.

Am i correct to assume the 3V version is just a copy of filled iron 4V port placement? (obviously with better shapes and better exhaust port.
Incorrect the CHI 4V isn't just filled. If it was, you'd have to also epoxy your manifold to get it to match. Hence the ports perfectly matching up to any 4V running gear. That's why I said it looks like the opening is 4V but it tapped down as it reaches the valves and combustion chamber area?

Fire me off an email and I'll send you the high res pic. Let me know if you see the same as I see?

brenx@internode.on.net
 
#10 ·
brenx said:
Incorrect the CHI 4V isn't just filled. If it was, you'd have to also epoxy your manifold to get it to match. Hence the ports perfectly matching up to any 4V running gear. That's why I said it looks like the opening is 4V but it tapped down as it reaches the valves and combustion chamber area?

Fire me off an email and I'll send you the high res pic. Let me know if you see the same as I see?

brenx@internode.on.net
Sorry my bad, i meant the CHI 3V has same port locations as filled 4V iron heads!

Email on its way. :hy:
 
#11 ·
4Vman said:
Sorry my bad, i meant the CHI 3V has same port locations as filled 4V iron heads!

Email on its way. :hy:
Yup, thats what I thought. If the CHI's had that, it'd make manifold fitment an issue. As the air flowing at the bottom of the manifold would run into a wall. They retain 100% of the stock standard 4V inlet port size so this doesn't happen.
 
#13 ·
351AFD said:
But what are the flow figures of these.
I know what they were in Nov 05 and that was more than the 218cc 3V's. I've emailed John for some flow figures. Not sure when I'll get them though. Don't want to say what I saw flowed incase they've changed since then.
 
#19 ·
LTD351T said:
Either way that big 4V runner will flow more, but that doesn't make it better!

I can't see the logic in using these new castings just to keep a 4V manifold, a high ported 3V would kill it.
Only the port location and size is the same. I think you'll find the runner is very different to a factory 4V head.
 
#20 ·
xdclevo said:
The 4V TFC and FW are suited to filled heads. I was asking if these Heads come setup like that as well.
The TFC and FW come in many different configs just like cylinder heads. Graham at TFC and Terry at FW would ask the right questions when selling a manifold as not everyone has filled cast iron 4V's.
 
#21 ·
brenx said:
Only the port location and size is the same. I think you'll find the runner is very different to a factory 4V head.

Yeah I know, its a 3V head with the runner tapered out to match the stock 4V port location, but its still bigger than the 3V.

I think it will have a good demand with people who already have 4V intakes but too me it seems like going backwards, you have the smaller more usefull 3V port and then you hack it out to match up with a std 4V port and manifold runner.

Its only use is saving people money by being able to use existing or cheaper std 4V intakes.
 
#22 ·
LTD351T said:
Yeah I know, its a 3V head with the runner tapered out to match the stock 4V port location, but its still bigger than the 3V.

I think it will have a good demand with people who already have 4V intakes but too me it seems like going backwards, you have the smaller more usefull 3V port and then you hack it out to match up with a std 4V port and manifold runner.

Its only use is saving people money by being able to use existing or cheaper std 4V intakes.
From flow figures I saw last Nov. Dare I say it's not exactly going backwards. We know though flow figures don't mean everything. Not sure whether the flow figures are like now. What I saw in Nov 05 looked good. I'll post figures when I find them out.
 
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