Porting a head is always good, when its done as it need to be.
as a lot of people open the first 2" of the ports, this is the bad thing to do.
you want smooted the bowl area and make the flow "Laminar"
clean up the ports with Dremel and 80 grit roll sand paper, have a valve job by RaceHead and youll get more flow.
More flow dosnt increas CR but it will make more air go in. so youll make more compression.

 

Oh I thought that it would lose compression. And who is RACE HEAD? Oh and if the head is ported I would have to get it tune right?

 

Well I think I'm going to buy a p8r head b/c I have a p75-1 head.

 

Ported P-75 flow well with a Race valve job
RaceHead is Carlo's Shop.
17550 Amell rd
St-Andrews (Ontario)
K0C-2A0
1-613-933-6061

Other shop can make race valve job, but it wont be Carlo valve Job
P.S. of course you always tune a modified motor when you make any change.

 

Subscribed!!

I have an extra P8R im sending to get a P&P, 3 angle, blah blah..

I was wondering about what/where can get replacement valves?

I will be running Crane Cams/spr/ret

heres the specs..
Adv. Dur. 232 Int./250 Exh., Valve Lift .400 Int./.388 Exh., Lobe Angle 109 deg.

^^ which is close to a Crower stage 1

But any info for me to know would be appreciated. Im running 10lbs of boost also.

 

I use the stock Honda 33mm valve in my head.
They flow very well.
Just have a Race valve job done to it.
Send the flow results if you can when the head is floed.
I realy would like to make your porting in that P8R
Hope you dont pay to much for it !
They need a lot of material to be removed.

 

ok, how much am i looking at?

Ive gotten 2 quotes already which are both in the same ballpark.

Then ill have my P8R that is on my car now ill have for sale later on.

 

I just finish porting a GSr head. let compar the flow numbers...

 

This is the GSr port still ruff 80grit

 

^^^ LOOKS GREAT!

 

Looks clean.... What do you guys think about square ports? On a ls head or p8r? Would their be a better flow?

 

Never in an N/A motor.
First 1 1/2 inch should not be open or work.
I would never go in there.
have a old head with one port done square and get it flow, Stock port and ported one.

 

So... porting the head square is not recommend? what would be the consequences if going over 1/2?

 

Yup yup.

 

Opening the first section of the port will decreas air velocity in this area. and this area is what is feeding the port.
You have to understand that this place of the port is already bigger that where its spliting in 2 for each valve...

Imagine that you blow air from your lung in a 3 inchs pipe,
Your lung will be empty in 2sec. creating no velocity in that big pipe.
Then blow air in a 2 inchs pipe, the result may be the same,
as you gonna reach 1 inch pipe you maybe gonna take 2.1sec to empty yours lungs but you create velocity in that pipe, and even if the pipe was 48" long,
youll trow air from your lungs to 48" far from you in 2.1sec. The 3 inchs pipe will Never make it at 48 ( you may be able to wandle a little the flame from a candle with that low velocity.)
With the perfect size without restriction or obstacle in the (air flow) way,
There at 8000rpm you will have bit less air flow in 2sec from the little pipe,
But you will have velocity to fill the cylinder way faster.
This is why we say: BIGGER IS NOT ALWAYS BETTER !!

 

A good rule for street motors is not to bother with the first 1/2" of the port, but I wouldnt say never.

 

the entire intake path needs to be looked at as one system so if the overall system was upgraded to the point where this type of modification was required in the first place then i would want to go with gasket matching as a minimum

 

When i match port some IM from Honda/Acura. There is a minimum work to do there.
They are almost perfect fit even wit an Si-R IM on P-75 Head.
But when it come to match port a S2 IM to dont say the name LOL
Or any after market Intake Manif. that i saw by now.
There is more work to make before get the perfect matck
An Intake Runner lill smaller that the Head port is nothing bad...
Of course. depending on the runner size, motor cc's and HP etch etch.
But my GSR IM (ported plenium) stock runner size@the Head are Big enaugh for what i want.
So im saying that they can feed easily 180fpt and 260Whp@8200rpm

 

Up for the (NonVtec stuff), Stuff that should be more use in your powerfull projects.

 

hate to dig up an old thread but i was in the garage today measuring some cams and I compared the P8R cams vs the PR4 cams and the PR4 cams were actually bigger...any info on this? Markings on the P8R intake cam is R7.

 

What are you measuring? If you're just measuring the overall height of the lobe, that doesn't necessarily tell the whole story. The base circle dimensions play an important role in the lift and duration of the cam lobe. An OEM cam with a smaller base circle could have more lift and duration (that's how reground cams are made) than another cam with a larger base circle.

 

Try measuring the lobe at max height and subtract the smallest diameter of the cam. Although this won't tell you anything about the duration it will give you a rough max lift of the camshaft.

With a few cam caps, a degree wheel and a dial gauge you can figure out the duration if your interested.

 

Hey Frank, i have my old take off P8R that im not using..comes with OE springs/retainers. If your interested, throw me an offer. 786.216.5354 or PM me

 

Good job François

 

Any info on that these heads flow on the exhaust side?