B16A/B, B18CR/5/6 and B18C1/4 (GSR) Head differences


KieranEG6

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Right something i havent seen covered before and i just happend to have both in bits on the bench so here we go.

The difference between the usual PR3 b16a/b, b18c5/6 and the P72 GSR, b18C4/1 head designs.

Difference between the combustion chambers.

P72 C4 HEAD (GSR/C1)
[/IMG]

PR3 B16a/b, B18c5/6 Head


As you can see the C4/C1/GSR head has flat face either side of the pairs of valves giving that extra CR when used on other B series Bottom ends. Where as the usual B16a head has a complete round shaped combustion chamber. The flat parts of the combustion chamber is called the Quench Area. Having these there aids swirl and combustion of the mixture as it rises up into the chamber. But the PR3 may have the advantage when it comes to volumetric efficiency as with the rounder more open shaped chamber I would have thought it better for the air entering and exiting the cylinder. Flowing smoothly out into the cylinder and back out into the exhaust ports, where as the P72 quench area's might to be as friendly to the air flow having the flat face and sharper edge's :nice:

Edit: Thought I would add some usefull info I forgot to put in.

The difference in compression between either head is around 0.25-0.3:1. So if you say fitted a PR3 head onto a GSR/C4 B18C then you would actually loose almost 0.3:1 of compression.

Difference between the intake ports:

P72 C4 Intake port



PR3 B16a Intake port



As you can see the P72 head takes a more direct downward port path witch in turn is larger.
The PR3 is more sticking with the conventionl "S" flow path through intake manifold to port and then cylinder. But in turn looks smaller in size.

It seems as the P72 port is more direct and bigger at the entrance. this shows how it would give better throttle response and more torque in the mid range. But then become restrictive as it doesn't have as much of a refined flow path as the gasses get faster in the higher RPM. Where the PR3, which has the more natural S type design of gas flow path witch in turn allows smother flow in the Higher RPM. This is usualy show as B20's with PR3 heads tend to have peak power higher up the rev range than the ones with P72 heads. (or so from what i have heard and seen so far)

(nothing here is fact except the picture's. Its just my conception of my thoerys from engine tuning that i have read up on. Im not 100% on how acurate my description is. But hope im somewere near the mark and making sense :nice:)

Oh and also got the coolant jacket hose difference.
P72 C4/GSR

PR3 B16a/b, b18c5/6


Could Be Helpfull as a STICKY :nice:
 

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KieranEG6

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I believe the word your looking for is "Quench Area"?
Good info
Thats the one i was thinking like "Squench" area but didnt want to put up and look a tit haha

Surprised there was anyone on here when i posted it at 1am lol
 

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Topher-EK9

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nice one Kieran, love this type of thing its why i joined the forum...
good write up i nevver really noticed how obvious the difference is between the heads.
like yaisr said just look at them and you can see the difference.
sweet man. thanks
 


Kozy

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Thats the one i was thinking like "Squench" area but didnt want to put up and look a tit haha
You are combining the two usual terms, 'squish' and 'quench'.

Squench... I like it! :D

Good info too! :nice:

Squench is good because it forces the mixture towards the centre of the combustion chamber on compression, condenesing it all around the spark plug for a better combustion.
 



Rich777

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Thats the one i was thinking like "Squench" area but didnt want to put up and look a tit haha

Surprised there was anyone on here when i posted it at 1am lol
Thank you for making the effort to post this up. It's nice of you to do so.

Yeah that area on the c4 head the callled the "quench area" its also refered to as the "squish area". With the right pistons and deck height it can work as a fake octane to reduce detonation and improve combustion. I think Endyn's Roller waver pistons would work really well wth this head. They have a lower quench area on the exhaust side of the piston so as the piston approaches TDC the mixture is forced across to the the exhaust side of the combustion chamber in a tumble effect which helps homogenize the mixture further. I will try and post a picture up later of what i'm on about if i get chance.
 

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KieranEG6

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The question is which one is or could be with a bit of PP the better head for a B20Vt build.??

Could do with DNR sheding some light as im sure they have done tones of builds with both different heads.
 


tama666

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The question is which one is or could be with a bit of PP the better head for a B20Vt build.??

Could do with DNR sheding some light as im sure they have done tones of builds with both different heads.
I would think the B16a/b, B18c5/6 Head

Thank you for the write-up, picture illustration and captions; very clear communications.
 


Rich777

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I think it depends on the setup and application. They both have there pro's and con's....
 


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great write up,
i hope someday someone will come up with a way of
fitting a b18c5/6 inlet manifold to a b18c1/4 head..
 


rvm

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thanks for sharing! sticky! :bow:
 


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I think it depends on the setup and application. They both have there pro's and con's....
Exactly what I was gonna say. I personally like a flat and broad power band so I'd probably go with te GSR head for the slightly better Mid-Range and keep whatever power it does make nice a "flat" so to speak till redline.
 



KieranEG6

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i have b16a2 inlet manifold on gsr p72 head,but i have smal watter leaks :(
i modify the holes to fit on it and work much beter now.
I didnt realise the bolt pattern was the same.

Did you have to do any more mods??
 


noodels

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well explained +helpfull photographs, Endyn's Roller waver pistons looks great but unavailable,only in complete head package though. nice shape the c4 ports and valve comb-area as said for mid torque ect . maybe not a over radical cam application advised with the c4 profile head with stock inlet mani and pistons . s9b box just tall to keep in vtec,anoyingly the s80/y21 ect £s to high and the lotto game in getting a good one..
Nice read thanks.
 



Stock96EK

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Hey I bought a 2000 EK with a JDM B18 ITR engine. But I wanted to know if it was a legit JDM ITR B18, The head code reads PR3-1? What does that mean? Is it a real B18 Type R head?
 


Ryzen_Core

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1994 Honda Civic Del Sol Vtec Coupe 2door 1.6L I4 DOHC VTEC (B16A3) Y21 Hydro Trans
Hey I bought a 2000 EK with a JDM B18 ITR engine. But I wanted to know if it was a legit JDM ITR B18, The head code reads PR3-1? What does that mean? Is it a real B18 Type R head?
the type-r and b16 heads i beleive are identical to each other... b16 vtech also has the PR3 Vtec Head, tho my b16a3 Del sol head code is PR3-3, tho i have to re-check, could be wrong but there is codes on head that can be PR3-1, PR3-2, PR3-3 ETC.

so yes i do believe that it is a type r head... u need to check the block... of its a JDM ITR B18 ,, the eng code stamp should read.... B18C (no numbers) or B18C-R or something like that.. check the engine block code, search on google you will find it!!!!

https://www.google.com/search?rlz=1C1CHBF_enUS801US801&biw=1920&bih=938&tbm=isch&sa=1&ei=LEz5W7PpII3XjgTKwrSYCA&q=JDM+B18+ITR+engine+enfine+code&oq=JDM+B18+ITR+engine+enfine+code&gs_l=img.3...2370.5927..6058...0.0..0.95.980.12......1....1..gws-wiz-img.HIalJFCOw-o
 


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