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F4R head + valves
- Thread starter philip
- Start date
Hi Ben. First Id like some pictures of the inlet ports to guess what improvements can be obtained vs a standard head. second Id like to have a picture of the valves to see what work can be done on the valve seats. finally inlet/outlet tract piccies would also be nice. valve dimensions and a picture taken from above to give me a good idea if larger valves can be used.
a picture of the inlet manifold port side would also be helpful. I found some good reading material on the subject and Id like to relate that to actual measurements on the F4R.
Thanks
HOLD IT!!!!
Stop right there!
your not going to get any benefit by guessing, nor reading one book, it has taken me yrs and yrs under the teaching of many people in the know about this topic specifically. Your not going to be able to improve it, i promise, well not without a deep understanding of what needed, the ports are lage enough as they are, a few tweeks to the shape and flow patters is where gains are had.
Anyway, i dont have an F4R head from a 172 handy lol.....so no piccies for you, at the moment, but i should be able to get some.
But not the selection your asking for! haha
nxt, the valve seats, as std they are normal 3 angle seats, but playing with teh valve geometry requires lots of flowbench time to see if the gains you get at low lifts (remember the time spent at low lift is totally useless) transfer to teh high lift gains.
The valves are already 35mm inlet (exhaust sizes dont matter that much) and that means bloody HUGE, youve got potential there for 320bhp+. Just think, the XE has 32mm inlets and makes HUGE power, the Mi16 has 32 inlets when modified. So no need to touch them.
What are you plannig to do exactly, you can make huge power on the std head before you even need to touch anything.
Before I get TBs, I want to extract maximum from the head. I need to understand how a company can be telling they will guarantee 200 bhp and agree to do a before-and-after RR session in my presence to show the actual power gains, simply by working on the head+valves.
If they have benchmarked flow improvements of 40+% and say these will translate into 24-25+ bhp, I need to understand how that is possible as it sounds very high. Thats why Im reading on this. I like to know what Im getting into.
On engines like the K series you can get 40+bhp gains working the head and valves etc. I know the F4R is meant to be much better standard, but Id like to have a look at the head/ports/valves myself, hence my request for pictures.
If a company is willing to guarantee me 200 bhp with head/valve work and I get to see the RR tests to show it, whats the downside?
*cough*
LAD?
*cough*
yes, LAD offer this, but K-tec is soon to offer a Janspeed developed head showing 40+% flow improvement, good for a theoretical 24hp. technomap in France do a mild head+cams mod (+remap) and have shown 192-195 bhp on mk1 172s which aint very far. So despite conventional wisdom that there isnt much gained from porting the F4R head + working the valve seats, there must be something to achieve. If I get a guaranteed improvement, what the heck?
you cant quantify a again, its impossible!!!
a 40% gain, gain in what, flow? flow at what lift and at what pressure drop?
you can get 40bhp gain in a K series, but in what state is the rest of the engine, say you run out of flow in the std head ona Kseries at 170-180bhp, and you run all the rear of the engine in race spec with silly wild cams, high CR, tbs etc etc.....your stuck at 180bhp......simply add a flowed head and your back to 235bhp......
Its so hard to try and quantify a head......but suffice to say, the std head flows enough as it is.
The older XE engine, you didnt need to touch the head till you got near 250bhp! and thats got smaller valves.
Itll take you a decent year or two to fully understand the full extent of the engine and just what it represents as part of the engine.
Sorry mate, no pics or single book will explain it all.
But it will help you understand.
*bows down to the god that is BenR*
I dont have the ambition to fully understand the intricacies of engine modifications, but on the other hand I bought the cup with the intention to modify it now, use it on circuit for a couple of years and then move on. If I cant make my modifications by the end of June, thats one summer season wasted.
Im willing to make a few gambles, and if these guys guarantee 200 bhp through head/valve work, Ill have a shot at it. We can either sit here and debate this stuff for ever on the forum or have a go. Im very disappointed with the total lack of performance modifications on the car and let down badly by renaults false claims re performance options. Ill get as much fun out of this car as I can and then move on to something with a more receptive engine, e.g. ford/vauxhall/k-series etc.
So, Ben, given that Im a stuborn so and so and will have the head/valve work done anyway, whats your advice on particular things I should watch out for, etc. assuming I then add TBs, my thinking is that head/valve work cannot do any harm.
Ben you fool the XE has 33mm inlets and the MI16 (the decent one the 1.9 not the sh*tty cast iron 2 litre/S16 piss) has 34.6 mm valves and the Mi16 seats can take 36.5 mm inlets before they need changed.
When you have modded a fair few heads for a while you can guess whether or not a head will flow well. You can usually also tell if it will burn well and where improvements can be made.
In some cases its not hard (older 8 valve engines for example) on good old pent roof 4 valve per cyl heads its a bit trickeir due to better castings to start with, you can usually spot what will mess up flow but you cant really give an accurate guess. You can say a baseline but unless you have a done a few similar heads you cant say it will produce and extra 13bhp and a cuppa tea every morning.
I have never read a book on head tuning whats in them? Crap I would imagine.
CHris is indeed right, dont ask me where i pulled that from in my already twisted brain.
Anyway, back on track. Try what you will or want, but stuck ok the std manifold and TB, your not looking at much.
40% gain, i still dont know how this is a claim. The Kseries comes with 27.7 mm inlets with scope for 32-33mm inlets, and after all your port work and its perfect, your looking at a total true flow gain of about 20%, and its not like race K series dont make the power. 40%.......that means nothing unless they can make the 300bhp+ that equates to.
Chris, Ive been reading a very useful document put together for k-series tuning etc. not a book as such, but very useful. If you want to I can PM you the link. Ben two questions:
1- whats the likelyhood head/valve work will increase power atw by 20 bhp (13%). consensus Ive got from 4 different companies Ive spoken to is that gains will be 10-12%. whats my downside if a company guarantees 170+ atw and lets me witness RR
2- any head/valve work I do may not be fully exploited now given TB/manifold restrictions, but those mods will pay up big time when the manifold+TBs are fitted, right?
lol Ben.
Philip is it Dave Andrews of DVA power fames web page? Its not bad, I know him from migweb hes on blat chat caterham forum as well. He does know what hes talking about as well.
20bhp, hmm thats gonna require a fair bit of work, unless the castings really bad then it should be easy enough.
Also its foolish for any company to bet the far that your car will put a certain amount of power down. As it is your car may only be putting out 145bhp if that. Not a flow prob but another fault somewhere. Never make promises unless you run the car up first even then you cant say for certian about anything.
Even the standard heads potential is not fully exploited with the standard TB etc. So when you do fit throttle bodies you should get a a decent gain.
Ask them exactly what they will do, I have seen many so called ported heads in my time, some good, some bad, mostly bad. A ported head does not equal a flap wheel stuck up the port or a boring machine recutting th eport straight.
If they a re a proper outfit expect deck heights, combustion chamber capacities etc etc
So true Chris, off the shelf heads can be so sh*te, and a really really good head done by a specialist proficient in that area costs a hell of alot......
Philip, post the URL, id like to read it.
The likelyhood of gains of 20bhp.....um....thats a very bold claim, like chris says, unless your engine is making a shed load less then its meant to be and they rectify teh problem, the 20bhp could be found outside the head just as easy.
Any gains will be exploited when you fit TBs, but the std head is still nowhere near its limits on the std cam, its a good cam profile, but the exhaust cam is quite conservative, although i do not have that much detail on them.
Id get them to financially back it up, if they say 200bhp, then it should make 200bhp......all day long.
all night long, all night, all night loooong - you got me going on those good old Lionel Ritchie tunes.
how do you suggest I verify my 200bhp has all day staying power? (although the owner has impeccable credentials I hasten to add..)Thats the plan. If I am standing there during the "before" RR and same spot "after" RR and I see 200bhp and a nice flatish improved torque curve, than I stump out. If not, no cash. Howzat for a plan?
My engine like all newish 172s properly dynoed was making less than the claimed 172 i.e about 140 atw (mind you, at 31 degrees). it is now making 151 atw. so my measure of success will be 170+ atw which equates to roughly 197 ish atf
as per the URL, let me know what you think
http://members.aol.com/dvandrews/kengine.htm
they only come out with 166bhp anyway.....its no major loss.
do the plan, if they back their product they should support it, if they say no....then everybody in the world will know that they are big fat liers! lol
get it tested at an independant RR, as they can say whatever they want power wise if they say you have to use theirs.......
infact, pop over here, i have my twin hampster rollers that are accurate to 250bhp exactly! i gaurantee i can get you 200bhp with a fuel additive LMAO!
Where are u Ben? might pop in on the way.
yeah pre mods power was 165, post mods/unichip 174.5 talk about a bunch of lying gits at reno.
Ive got good RR results from my unichip fit last week even taken at 31 deg. I will take the car to be remapped at another independent unichip dealer after my head/valve mod for sure, but I wanted a failsafe method to tell theyve actually done the job before I dispense with my hard-earned GBPounds!!
All this talk of headwork reminds me of a thing a few weeks back. ben as your a X-flow man you can appreciate this. A guy chapped on the door and said a mate of mine sent him round. In his grubby mitts he had a x-flow head.
Apparently this was a special, high power head. But he said it seemed worse than the decades old never been of head. So I had a quick look at it.
Out with the steel rule (its not a ruler, rulers run countries etc, a rule measures, *claps hands* terminology kids!) measured the valve spring seats heights. As you can guess not correct and trhe good old stat end seats werre 2mm higher than the opposite end! Nasty and explained why his cam wiped itself out.
The ports, were ahem ported with a file or something, they were nasty anyway.
Point of this story? Well there is none but this head cost him severl hundred and was at beast a paper weight. Larger valve had been fitted but not offset so they were actually touching.
he went away unhappy at the startling truth. I told him if he gets me a head I will sort it for him, so far no word, so dunno whats happening with that. It was in an Anglia which was cool! lol
Anyway a list of the deck heights and to what they were corrected to.
CC of each chamber.
Flow values before and after and with and without valves (a properly modded head will always flow more with the valves IN). You want them equal.
What the new CR will be if deck heights etc were corrected.
Thats what I woudl expect from a pro outlet at least.
Some guy in his shed cant do all of these things himself, so I wouldnt expect him to. I cant give those figures as I dont have the equipment. But if a customer wanted the figures I would get it tested etc no problem there.
you will poo your pants.........
here you are!!!
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http://images.cardomain.com/member_img_a/322000-322999/322115_57_full.jpg
http://images.cardomain.com/member_img_a/322000-322999/322115_58_full.jpg
Some people really shouldnt should they.
I like pics too, saves alot of typing lol.
Good thing he stoped before he touched the exhaust port!
I had to weld some areas up as they were nanometers from breaking through.
http://images.cardomain.com/member_img_a/322000-322999/322115_52_full.jpg
chisel.......i wish, at least the grooves wouldnt be so deep, it was a SP dremel type thing from B&Q with mini carbide cutter and he pressed as hard as he could....lol!
I hope you charge for the help you give...........otherwise people end up taking advantage far too easily.......you become a library rather than a person who helps.
Well I didnt charge him, I usually charge though as I need to eat!
What a muppet, looks like he pressed as hard as he could, must have been a round headed one and used the dremel like a knife (or chib if your glaswegian).
Dunno abotu the pistons didnt look at the site.
Yeah I was thinking that to, just what you need for nice flame propagation etc
CLIO WILLIAMS 2000 cc 16 v
http://www.pistonispeciali.it/immagini/Foto0007.jpgIMG height=111 src= http://www.pistonispeciali.it/Foto0007
ø 82,7 RAPPORTO DI COMPRESSIONE 12.8
SEGMENTI COMP. mm 1 R.O. mm 2 UFLEX
PESO PISTONE COMPLETO Gr. 325
MEGANE 2000cc 16 v. KIT CAR
http://www.pistonispeciali.it/immagini/pistone%20vista%20postr%20revb.jpgIMG height=104 src= http://www.pistonispeciali.it/pistone%20vista%20postr%20revb
ø 84 RAPPORTO DI COMPRESSIONE 13
SEGMENTI COMP. mm 1 R.O. mm 2 SPIRAL
PESO PISTONE COMPLETO Gr. 320
Thats the info from the website about the pistons. Some silly language! lol
