Head Porting

[platty 1]

Can anyone recommend a good company, or individual maybe, around my area capable of doing a good porting and polishing job?

 

Im keeping the standard exhuast manifold, and guessing they will need the new inlet manifold for the Jenveys, to match the ports up, but will they need anything else, ie the new camshafts?

[welshpug 1,661]

forum sponsors http://www.q-e-p.co.uk/ the gti6 head doesn't need much work at all though.

[platty 1]

Cheers Welshpug, Ive already emailed them. I wasnt sure if they actually carried out head porting/flowing as on their website they dont actually state this as an ability of theirs. I'll report back when I get a reply

[Miles 331 1 Cars]

The head flows very well as std, so a set of cam;s work's well these along along with the other normal mod's, QEP sell the CAT cam's which are proven and good quality

[platty 1]

I did have a look at the camshaft page, and I'll be the first to admit, I was out of my depth. There are way too many to choose from for my liking, so I will definately be seeking guidance for the correct camshaft for my particular engine tune.

[platty 1]

Ok, I've got a reply. Twice what I was expecting!, however they are talking about bigger inlet valves. From what you guys are saying about the head flowing fairly well in standard form, I think when it comes to it I'll just get the Dremel out and match the manifold ports up myself. Im only aiming for 200-210BHP which I think should be a realistic figure.

[16v205 9]

I had just over 200bhp with cams, throttle bodies and a standard gti-6 engine. The cams wern't extreme either, infact there the same hydraulic profile im still using now.

 

Rich

[platty 1]

Ah, Im glad you said that. I dont want to get too involved with the engine internals just yet.

[christopher 5 1 Cars]

Ok, I've got a reply. Twice what I was expecting!, however they are talking about bigger inlet valves. From what you guys are saying about the head flowing fairly well in standard form, I think when it comes to it I'll just get the Dremel out and match the manifold ports up myself. Im only aiming for 200-210BHP which I think should be a realistic figure.

 

 

Be careful what you do. it is all too easy to make the flow worse then better & never match the exhaust manifold only the inlet.

[platty 1]

Cheers for the advice.

 

Ive spent hours reading through various websites about head porting, so Ive got a good idea now of what to do, and more importantly, what not to do.

[NColl 0]

Over the years i read many books and listened to people about modifying cylinder heads, it wasn't until i bought a superflow flowbench twenty years ago that i realised that they hadn't a clue what they were talking about let alone what they were writting about, this includes some well known authors. Most of them are trying to make a reputation for themselves and earn a living.

Ncoll

[Sandy 191]

I've found, the best heads are ported by the best people and usually haven't been near a flow bench. I've seen some results of late that challenge traditional views on what does and doesn't work. Despite what many people claim, I've yet to see convincing evidence that mathematical modeling can produce a superior head to someone with a basically good comprehension of what's important. I know it's been said many times, but there is so much claimed by some about their heads, which invariably doesn't come through in the end result. I wish I could be more specific about how disappointing some of the headwork I've seen has been, but there's not much point. Suffice to say though, that IMO the XU10J4R and XU10J4RS heads are probably going to perform as well in standard shape, than modified in most of the engines we discuss here.

[maxi 36 1 Cars]

I've found, the best heads are ported by the best people and usually haven't been near a flow bench. I've seen some results of late that challenge traditional views on what does and doesn't work. Despite what many people claim, I've yet to see convincing evidence that mathematical modeling can produce a superior head to someone with a basically good comprehension of what's important. I know it's been said many times, but there is so much claimed by some about their heads, which invariably doesn't come through in the end result. I wish I could be more specific about how disappointing some of the headwork I've seen has been, but there's not much point. Suffice to say though, that IMO the XU10J4R and XU10J4RS heads are probably going to perform as well in standard shape, than modified in most of the engines we discuss here.

 

 

My recent RS build had extensive headwork to the exhaust ports and bigger valves. Its flowed amazingly on the bench. The engine was around 30BHP under what it should have made. There is a lot of sense in whatyou are saying Sandy, just because the flow bench says yes im not convinced it automatically means more power.

 

Maxi

[DanteICE 72]

I find I'm always quite nervous about people who use a dremel style tool because that allows for human error, I'm more for a well trained CNC machining expert like Ric Woods CNCheads.co.uk. I read about a guy who wanted his cylinder head done, the works, these guys got spare heads for his type of engine and cut away at them to give themselves a blueprint of that type of cylinder head so they knew what the head could take before it broke into the water and oil passage ways. And with the CNC machine it mapped it all out for them to the micron, each port will be exactly the same as the one next to it! Being a computer man, I like computer controlled stuff like that, little chance of human error and its calculated to be perfect.

 

However the idea that a head which has been tested on a flow bed and is shown to present fantastic flow, then produces very little is quite worrying and a totally new concept to me. You would have thought flow benching would give perfect results?

 

Does make me think what qualifications these car tuners have? I reckon a well trained University graduate engineer would make a head flow as smooth as water down a stream!

 

Oh has anyone tried CNC heads of Ric Woods?

[pdd144c 0]

Ric built the lump going into our new Mondeo. All 710 bhp of it!

[DanteICE 72]

WOW I knew he was good, he's not too far from me either, just been looking through his website, he looks so professional, I know he is ofcourse, its just it really shows. The fact he does major racing teams is always a good sign!

[Sandy 191]

The concept of CNC head machining is great, but there are a few issues I'm concerned about...

1. Core shift, which is very evident in some Peugeot heads and mastering off one head will not eliminate break through or thinness on another.

2. The "master" used must be a good head to start with, it's only as good as this.

3. What I would call "proper headwork", is tailored to each engine specification and will not be a one design fits all. The time and cost of mastering a head for CNC machining will inevitably lead to one design being used and not modified.

4. If there is a casting or core shift imperfection in a given head, manual porting can work with or around it.

 

I've been working on a TU5JP4 engine build with a friend of mine (who's one of the top Vauxhall engine builders). The customer bought and supplied a "CNC" head to be used, which didn't look like it had been CNC machined IMO at all, each port was slightly different shaped and the original imperfections had only been smoothed moderately and not re-profiled at all. The port profiles were simply not good enough for the customers target power and wouldn't have worked, (TBH they didn't look optimised at all, just smoothed over). The customer had paid around a £1000 and the head had to be ported afresh, it was one of the most appalling heads I've seen at any price and I don't say that lightly.

[James_R 3]

Flows all well and good, but you can't measure port speed which is another big factor in how a head performs.

 

It's such a dark art

[platty 1]

I find I'm always quite nervous about people who use a dremel style tool because that allows for human error

Im simply talking about matching the inlet ports, with the new inlet manifold to ensure there isn't any nasty step from the Manifold to the Head (although I've read having a step from the Head to the Manifold discourages negative flow when the valves are closed). A Dremel should be perfect for that. I agree though, if your paying a professional to flow your head, him having a Dremel in his hands wouldn't inspire confidence. That said, some of the best craftsmen ive seen have some god aweful tools!

[DrSarty 90 1 Cars]

Im simply talking about matching the inlet ports, with the new inlet manifold to ensure there isn't any nasty step from the Manifold to the Head

 

I would suggest that it is ALL you do, as the advice on here from some highly respected forum contributors is simply don't bother. You can translate that as 'great: I don't need to do anything there and can spend my hard earned cash on something that really will benefit the car's performance'.

 

It's up to you of course, but frankly I wouldn't bother.

Edited August 19, 2008 by DrSarty

[platty 1]

Couldn't agree more, advice has been taken, and since followed. Talking to QEP, the route they were looking to take would be for a much bigger power figure, involving bigger valves, forged pistons, and forced induction. For my relatively low power expectations, it looks like the standard head will flow just fine.