Port, Polish and rematch

[k16eof]

Have been thinking of Porting and polishing my engine and rematching the gaskets for sometime now. This is something I cannot do myself so I'm having to upend the change jar and pay someone to do it for me. Before I do this, I want to hear what other folk have to say about it.

I have an Audi A4 2.8 30v lump and I have heard that these have better flow than the previous 12v's, so would P&P'ing be a worthwhile mod in the first place? I know any improvement will be better than it is, but is it worth the cost? How much should I expect to pay to have this done? How long would it normaly take? and any suggestions as to who to approach to get it done? I live between Brighton and London, but I don't mind traveling if it means getting a better quality service

If this is a viable mod then a remap is without a doubt the next item on the list, if it's not then I will look at performance coil packs, a remap, then NO2:toung:

Thanks in advance

Geoff

 

[obi_waynne]

Have a chat with autocustomengineering, he can probaly sort you out.

A P&P job will certainly help to raise the power and will also often give better fuel consumption. Get a 3 or 5 angle valve job done as well while the head is off.

Power hike will probably be around 10% and even more if combined with other mods like a fast road cam and remap.

I really doubt a performance coil pack will make a noticable difference. You could then run larger spark gaps but a spark is pretty much a spark.

 

[HDi fun]

Please could someone explain to me what is meant by a 3 or five angle valve job. Is it something to do with the angles the valves mate with the ports?

 

[k16eof]

Cheers Wayne, I'll check em out:blink1:

Yes, what is a 3 / 5 angle valve job

You talk about a fast road cams and normally i would totaly agree with you, I had the same thought about my engine but apparently, the cams i have in this are considered "agressive" anyway and by upgrading them, i would notice far less of a difference than with other lumps.

I was at Castle Combe yesterday and went and had a chat with a company under the REVO banner, they said that for this engine, breathing mods will get you better gains and by modding my airbox and doing the exhuast, that when it comes to doing the P&P that i should indeed get a remap to get it to it's new optimum. They were reckoning in the region of a 10% gain with the P&P with a further 15-20% with a remap. A little sceptical at the remap gain as I have a NA engine and not a turbo but if i could be looking at 25% gain (= 55Bhp gain) from P&P/Valves/Remap then i will be pleased Puts me in the 275 bracket for a 100psi nozzle:toung:

 

[pgarner]

think revo are being over optimistic. youd properly be around 30bhp from that. maybe you could get more as revo do aggressive maps to make the car feel alot more powerful lower down

 

[obi_waynne]

3 and 5 angle valve jobs.

3 angle is normally a 60,45,30 degree cut with the valve seating on the 45 angle.
5 angle is more for serious race engines where blending of the three angles adding another two is deemed worth the extra time and money.

Both allow more air into the engine by reducing drag and turbulance. It gives a slightly longer open duration as well as the valve seating drops away more dramatically.

 

[k16eof]

think revo are being over optimistic. youd properly be around 30bhp from that. maybe you could get more as revo do aggressive maps to make the car feel alot more powerful lower down

To be fair, when the figures were mentioned we had been talking about the Stage 2+ remap which they say is pretty much the most aggressive remap that folk go for.

 

[k16eof]

3 and 5 angle valve jobs.

3 angle is normally a 60,45,30 degree cut with the valve seating on the 45 angle.
5 angle is more for serious race engines where blending of the three angles adding another two is deemed worth the extra time and money.

Both allow more air into the engine by reducing drag and turbulance. It gives a slightly longer open duration as well as the valve seating drops away more dramatically.

Thanks Wayne Makes sense when you think about it

 

[MasterAuron]

Methinks 10% is very optimistic for a port and polish.

 

[nig]

Methinks 10% is very optimistic for a port and polish.

would have thought polishing when going maxed out other wize the fuel mix will stick to the inlet track like a manget it need to stay bumpy to keep the the mixture from sticking to the walls or fuel will dribble into the cyclinders and have been know to bend vavles

 

[96AccordCoupe]

I read an interesting thread on the Wizards of Nos forum which mentioned porting and polishing the head not being as beneficial as some folks think, with the 3 angle valve grind being an absolute must.

I need to do more reading on this.

 

[obi_waynne]

It depends on how it is done and if you take into account the whole engines dynamics. Increasing the air flow rate is not always obtained with wider ports.

Polishing the intake is not beneficial either as the fuel needs to vapourise and a roughish surface helps that happen.

Have a scan through these articles.
http://www.cartuningtips.com/144-port-matching-an-engine
http://www.torquecars.com/tuning/Porting-polishing.php

I'd say it's not a DIY job unless you have a very basic and untuned engine to start with.

 

[FactoryFast]

hmmmm interesting firstly K16oef forget the polishing bit, second you can do it yourself with ease. Buy a manuel take the head off or better still buy a second hand head, inlet mods should be to roof and sides at the bend into seat area blending back towards the port opening (manifold end) leaving 120 grit finshed surface. Floor should be raised using epoxy how much is worked out using percentage of port size near valve seat, then sanded level so you make a nice d shaped port. Skim the head to get compression up and jobs done.. The cost to do this about £150 all in or about £50 if you do it, but is quite simple really.

 

[pikey motorsports]

id like to know where you can get a 2.8 30v head port matched for 150quid..... thats far too cheap.

a 1.8 8v vw head is £300 for port polish and 3angle valve seats.
2.0 16v vw head is £600 for full port and polish, multi angle valve seats and black carbide coated oversize valves. as for gains, 10% is EASILY achievable if they know what they are doing. and i dont think REVO's figures are too optimistic either, a full port and polish, modified airbox with panel filter and decent zorst would quite easily see 50bhp increase on a 2.8....
Just as an idea, my engine is 134bhp standard, and is now around 165/170, with just these mods:Cam upgrade(from earlier more aggressive VW engine), panel filter in modified airbox, larger inlet manifold, 4-1 exhaust manifold and straight through 2.5" system.
once the p&p has been done, 288 deg cam and its remapped properly ill be looking for 190/195.

VAG engines really respond well to P&P jobs.

Also, upgrading the cam is worthwhile. just because your engine has whats considered an aggressive cam doesnt mean it cant be improved, and it certainly wont be in the region of 288 degree.

 

[FactoryFast]

Hi all. I have always struggled with the prices people charge for doing head work but can also understand perhaps a little their mindset, after all they can do it and you cant and what we dont no or understand we pay though the nose for.

Hello pikey Motorsports. In reply to your comment i dont think i have ever charged more then 200 for a head including skimming, i have a milling machine its known to me i use it daily setting a head up takes perhaps 15mins. The porting on any head follows similar principles the tooling is the same again known to me, the prep is mostly cleaning (read ind dish washer press a button have a coffee have a look repeat or move to next step). 3angle valve seats again same angles bigger or smaller holes i use my mill set it level do the seats fit cutter skim the head. Its a process which in time you get quick at, but then i love doing them i work full time and this was my hobby. With regard to power gains, if all i achieved was 10% after spending that much money i would wear a veil and go out only after dark.

 

[FactoryFast]

Gains and percentages

Dont be mislead peeps. 10% is naf all if you only started with 30bhp you now have 33 bhp (30x10%=33). The bigger number you start with the bigger you end up with for same mods, hence would i modify induction on a corsa 1.4 or would i just have the head off first and modify. Hmmmmm Head first then induction etc, yet on the 911 if i wanted to tune it i would look to exhausts and induction, why you ask ????.

iTS ALL IN THE CALCULATIONS.... 08 911 turbo 480bhp 3.5cc so 480/3500= 0.13 . Thats .13 of a bhp per 1 cc of engine or power to weight of 1bhp per 6.5lbs, each hp power has to push 6.5lbs 6 .5 bags of sugar thats why they are quick (a moped gets by with 4 bhp to push 80 lbs).But my r1 07 180/1000=0.18 or p2w of 1hp per 2.5lbs and thats why they are blindlingly fast.

Want to go fast but on a budget reduce weight corsa 1.4 (specs says 840kgs) =1851 lb bhp 90=0.04!!! Spend bucks on engine = 120/1851= 1500 quid or = 0.06 hp/lb. Get the weight down to say 1100 prob imposs = 0.08HP/LB, double the p2w but not twice as fast....

I am tired so above may not be quite right but i no you get the point its why we have min weights in motor sports. of course if you can afford it do both ...

 

[Sid447]

This is a link to information only,

On another forum for a cylinder head that has had light attention to the valve seat and bowl area only (see attached pics).

http://www.ls1tech.com/forums/new-products-showcase/1065910-new-243-cylinder-head-option.html

Simply changing the stock heads for these, increases flow by around 25%.

Using the simple formula for 2-valve head-flow hp potential, means on an 8 cylinder engine this should be good for 660hp. Whereas the stock untouched factory heads were good for "only" 525hp.

 

[FactoryFast]

Hmmm a formula for measuring what excatly ???. And whats this flow you mention ??.

 

[HDi fun]

I have to admit that I'm slightly lost as to the purpose of this post as well.

Mass/power derivations don't mean that much in isolation.

As for 'twice as fast' I have no idea at all what it is that you're presenting.

 

[FactoryFast]

It is in response to an earlier reply regarding potential power gains, i posted the comment explaining my take on how i read it. The topic went along the lines of getting a gain of 10%, its my view that this is a silly way to look at modifications to increase performance.

As my post says 10% of 30 bhp is 3 bhp and that the bigger the number you start with in terms of power the bigger the gain, as for weight the smallest number makes the most of any gain you achieve as well as to a degree being a free modification. The examples of power to engine cc show the difference between a manufacture designed performance engine and a run of the mill engine, a well designed engine nearly always works out at between .12-.21 a run of the mill .03-.09. One is designed with shopping in mind the other scaring in mind, as for power 2 weight this i would have thought was pretty obvious.

It explains you can do expensive first or cheap first, shedding weight wont make the engine more powerfull but it will be quicker to 60. The overall point is look at what you are starting with consider your goal and look at best solution to achieve it, getting rid off any excess weight is the quickest cheapest route to improved road performance.

 

[BluntyR5GTT]

as with any car i think porting the head is always a great idea as this is where the power is made really, as been stated go for a full 3 angle etc job and if you can bigger valves as this will up the cfm a bit, its also a good idea to stick some fast road cams in at the same time as doing headwork as the new better flowing head will release the full potential of the cams once all set up properly. also dont look at porting just for a peak power gain all 4 cars iv owned iv had the head ported etc and trust me its the best mod iv done as overall response and the willingness to pull through the revs is improved loads more

 

[FactoryFast]

Thats pretty much on the money of course up the comp while your at it, also dont rely solely on big cfm numbers from a flow bench your looking at making the head flow beyond the suck phase. And is the reason the high velocity method gives best gains. If your interested check out mototunesua site this explained how to do this and give the reason why, sure its aimed more at bikes but same works on cars..

 

[BluntyR5GTT]

good example is with my car everyone on the rtoc told me i was wasting money getting a full ported head as they reckon the standard one is fine up to 200ish bhp but i though no chance no matter what car or state of tune a better flowing head is a winner also it goes with my spec as i want an ultra responsive car hence why i coupled this with a bigger downpipe and a custom bored/machined out turbo elbow, now as soon as i drove the car i knew it was money very well spent i just wish id of done a before and after rolling road test as maybe paek power gains may not be great but i bet it gained everywhere in the rev range especially high up

 

[FactoryFast]

turbo 5gt i am guessing???. always the problem with turbo cars poor low down response. because you using forced induction or i think a better term is" ram it in and lots of it" you have to run a low compression ratio and the more boost you run the lower it has to be. Normally there is no cure for this you have to put up with this lag untill all hell break loose when the turbo spools up, the bigger the turbo the bigger the lag but there is a cure.....

Nitros oxide.. you can use a shot of this to overcome the lag kind of masking the issue if you like, rather then wire it for full throttle activation wire it for say 2000 rpm to 3000 then leave the rest to the turbo. By doing this you can use a bigger turbo because you are creating such a lot of exhaust output by virtue of the nitros, or you could tap a plug sized thread into the turbo housing and use a flamer kit to ignite a fuel say petrol to keep the turbo spinning durring gear changes. down side is the massive bangs and pops lol... not really a downside at all if your a petrol head of course and would cure people walking between cars when you set fire to there socks, use the crossing dum ass ha ha

 

[BluntyR5GTT]

yes mate 5 gt turbo i like your idea regarding the nitrous oxide iv just never been a fan of it as i see it as cheating lol, i do get full 16psi boost at 3k in 1st and 2nd gear in 4th and 5th its on full bost at around 2.3-2.5k hehe and you should hear it now mate it pops and bangs like crazy sounds unreal

 

[FactoryFast]

Sounds like a manic ride, of course your enemy is going to be heat build up particuarly in the higher gears where you hang on to the throttle longer. 16 psi is a good figure but i suspect in first and second you seeing 16psi as a spike as the revs build to fast to really hold on to it,the motor is building a lot of heat so look at ways of getting rid of it try spacing the back of the bonnet up by putting risers on the hinges. The fast flowing air pulls the heated air from under the bonnet much like how a carb works pulling fuel though a main jet, high and low pressures. Also from memory the rad sits up high on the gt so look at dropping it down some, look at wrapping the turbo exhaust side and manifold with exhaust wrap if possible go over it double thickness. Use a temp gauge taped under the bonnet to gauge progress this really help big time on these small turbo motors heat just kills the potential and performance.

Have you strapped the standard intercooler if not do so using stuff for banding pallets else you will hear a loud pop and no boost. The diff is a weak area also with no warning the pins from the planetary gears fall out milling a groove though you diff casing, if this happens look at getting the gear set from either the 17 or diesel varients built into the casing and the pins welded in. Exeter gearbox centre could advise you better and well recommended, owners an ex national hotrod front runner and nos his stuff.

Phil .

"If it dont break make it lighter"

 

[BluntyR5GTT]

hi mate cheers for the info ill tell you where my car is at regarding heat etc, one thing i dont want to to is fit bonnet raisers as i hate the look they give so iv bought the next best thing which is a louvered bonnet which should help let a bit of heat out . also iv got the downpipe and exhaust manifold heat wrapped and am looking into getting a turbo heat blanket but i need upgrade to a bigger turbo before i do this lol (good excuse). for the intercooler iv got an uprated alloy double capacity one so its more than capable enough but one thing im looking at is water injection to get the temps down .

 

[FactoryFast]

I no where you are coming from regarding the bonnet risers, another alternative is to get rid of the return on the back edge of the bonnet. By getting rid of this you in effect create an opening that the hot air can get drawn out of by the fast flowing outside air, you could also look at fitting a cover underneath that run from the front cross member back to behind the engine. this want to hug the underneath of the engine pretty closely and have its opening around the area the exhaust drops down. the effect is the same fast air pull out the heated air right where you need it most around the turbo, you could also consider using 2 intercoolers say the standard 1 as a pre cooler if you like before running though the uprated 1. Also try this as it works a treat, get 2 freezer blocks you o the type filled with blue stuff you put in a chill box, freeze them and then while the engine is cold duct tape them to the intercooler. Go for a blast the see whats is like then, this trick has been used right up to f1 for that all important lap.

Water injection is good but try this also instead of wasting the water route it back though its own cooler using a washer motor, a length of brake pipe coiled and installed in direct air flow works a treat. A neater job is to coil it into the front crossmember, then into an alloy resevouir. Use motorcycle main jets soldered into the brake pipe gives a nice fanned spray of water, plus remember the better you atomise the water the better its cooling so aim for a nice spread running parrell with the incoming air. also any no structural bolts and nuts etc change for alluminum as the conducts heat faster the steel further helping the cause.