Head work..

Quote:

---

So a little later than expected...

Headwork should really be carried out by someone who knows what they are doing, but who also has access to a flow bench.

The above factors are as important as each other, because if someone doesn't know what they are doing, they will end up taking too much material off and will hit a water / oil gallery, which would make your head dead.

The flow bench is also equally important, as how do you know the work that is being done, is actually yeilding improvements, when it could actually make it worse? Then how do you know that the work that has been done to one set of ports, be exactly the same on the rest? You can not match the same results by eye alone.

Final point, how do you know that the work has been done, is actually flowing the air correctly into the cylinder?

With a flow bench, you have facts and figures and help work things out, but no figures could mean good head work or could mean bad headwork, with no 2 results being the same on each cylinder

---

but surely there are other people who know what they are doing and have access to a flow bench Are these not criteria to keep in mind before letting someone near your head rather than a reason why you should use one person in particular?

Quote:

---

but i believe that a 10% increase in flow through the head will give a 10% increase in power.

---

Quote:

---

Beggars!I dont think its fair on others who are interested in this Tuning area, by giving out misunderstood theories without any solid evidence & experience to back it up.

---

There is plently of misunderstood theories on the forum, but not many people know if it is / isn't correct and not many people chip in to what they do / dont know.

So i may have got 1 bit of info wrong, i dont see you putting out any theories, helpful infomation or even correcting me, just agreeing with what JohnS has said.

So if you have something to contribute, then please do

Quote:

---

Power Rog!What ever happened to your fantastic Power headwork you was offering a while back with flow charts and all?

---

and who are you (somebody we all know )

closely following my progress are you?

no rest for the wicked!

Quote:

---

not really sure how someone can consider themselves a performance engine builder without one

---

Have to disagree, we have never needed to use one to get the results we need.

Quote:

---

Have to disagree, we have never needed to use one to get the results we need.

---

get to work you ,you don`t have time to get involved in bickering on here ...................I and the rest of the coupe owners who you have re worked the head in their car, know you have done a great job on it............people seem to forget you worked for a good few years at EVO,and got plenty of experience working with fairly heavily tuned Integrales,and `early on` coupe tuning etc etc,therefor not just from `pottering about` guessing the work needing on coupes,I reckon,good understanding of what a specific engine requires, is just as,if not more, important than anything else.......I`m sure you have trialed plenty of things with head work on coupes and found what does, and what does NOT work,thats what R&D is all about...............
I can`t think of a better way of finding out what does and does not work on a specific engine...........

Guy Croft is a excellent, and very, very ,reputable person in this field...........and given most engines, would leave Barbz guessing what to do,but given the time and experience Barbz has on the coupe engine.....I`d highly recommend him above anyone else

Quote:

---

Barbz, thought u werent allowed to use the internet. Your missus was telling me the other night!

Back on topic :

Results are the main thing. If you have had headwork done and you get the results you are looking for from that headwork then whos to say it wasnt done right? Or a flowbench wasnt used.

Fleas results show that *with headwork* great things can be achieved. Whether or not a flowbench was used is irrelevant.

Ross

---

What I want to know is what the hell was done to your head to get your low down torque figures

Quote:

---

Now a few points about my production engine, its on std rods, std pistons, damn near std inlet cam, and std exhuast cam,

---

I thought u were running 5 door pistons (148bhp), columbo inlet cam and 5dr exhaust cam.........

Quote:

---

Rich I know Ve is isn't flow but relates to the % of air so 1000cc would see 950cc filled at 95% and of course it is a dynamic state. The headwork should allow for better flow, certainly at the top end on a race engine where the power band is, so by having more efficient airflow the engine requires less "pump" energy to fill the cylinder which means increased Ve and more power What I was interested in was your figures i.e. what flow increase did the flow bench report and how did this relate to overall Ve and power where it matters at high rpms?

---

Quote:

---

)
Nyssa racing - 562Bhp (lag master special)

---

Quote:

---

Rich - in the "pump" comment above, you mentioned that the "pump" is atmospheric pressure.

Surely an awful lot of VE is cylinder scavenging, meaning that the exhaust valve lift and duration, together with exhaust header tuned length is a major part in VE as well

I don't know much about it, but I used to run two stroke bikes, so I remember that getting the exhaust gasses out at the right rate could massively help the next lot of mixture going in

And I know 2 strokes and 4 strokes are *subtly* different - just seemed to recall that exhaust could play a big part in cylinder filling

---

But more like a vacuum then a pump. But you right Nigel, the negative pressure from exiting gases on the NA engine make a huge contribution, I read a figure somewhere, something like 70% compared to the piston induction stroke motion, why getting the header correct makes a huge differnce, i'm aware of this, but I guess this is why NA tuning gets crazy imagine having to test just 3 designs, big budget. Although this is vital on 2 stroke hance why the exhaust design makes or brakes engine in 2 stroke you'lll have seen that. Of course this effect is very different on a turbo car, as you have to have overlap for the exhaust gases to 'suck' in the inlet gases.

Trev you have 4000rpm power range, less then the gear seperation so thats not laggy, as you know a change down puts you at the start of the band -well if the rest of us are lucky you might be out of the power band with no boost....in the way.ha ha

Quote:

---

@Rich...surely though, the race head you have had made has made little or no improvement over a standard 5dr engine with cams, a chip (or suitable mapping), exhaust, air filter etc etc...Surely the same or more gains are achieved with a stock head? ?

---

Quote:

---

Markus its not a 5 door engine. 'The same of more gains with the std head'? erm what?? So you think if my head was std but with the same stuff around it it would have produced the same output? Maybe, I dont think so though, I dont know why you would think that you're only guessing.

---

Note really.......Tipoboys first 16v engine started off as a 3dr engine with no headwork except 3 angle seats, standard 5dr pistons, 5 dr inlet cam, exhaust, air filter and unichip and achieved an amazing 166bhp

Quote:

---

If I suffer an engine failure its me that has to change the unit and fork out for the costs. My investment was in a true race engine, and professional level of assembly where every bore, journal, shell, clearance and tolerance were checked. I paid extra for cross drilling the crank and addition of grub screws instead of bearing plugs on the oilways, one example of a modification for race that no average road car owner would ever consider, certainly not before 'what chip' should 'I' use. Similar for the colisbro race valve guides, tripple race springs, paddle clutch, capilary gauges, pressure accumulator, dry build - these are power 'hop up's' but risk management. I invest in build quality now it saves me money in the long run.

---

Surely though you should have considered forged pistons and Forged rods Why go to all that effort and use standard fiat internals?? doesnt make sense to me

Anyway this thread is going off topic some what. We should be discussing the gains of headwork and my comments are only coming from my experiences in the coupe circles

Quote:

---

I can't comment on a lot of the technical stuff posted here - I just dont know enough! Interesting to read though However for people reading this it's worth remembering that it's not just headwork that will enable you to run good power at very (or comparatively) low boost.

On the same spec head I currently have, but with a 3 inch downpipe (with V-band and dropping to 2.25 mid section back) I got 308 bhp at 1.4 bar at PTS. My car without the headwork would have got the same IMO.

However, when I opened up the exhaust to a full 3 inch and ditched the vband I got more power with SUBSTANTIALLY less boost. (half a bar less! )....it was very clear that the increased flow of the head could not come into effect until the rest of the setup could take advantage of it. I'm tempted to run a aquamist with a bit of methanol - but with the ammount of ignition advance I can run safely without it I suspect I would gain very little, and add something else to go wrong!

---