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What can you do to really improve a cylinder head?...

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What can you do to really improve a cylinder head?...

Post by jmc on Fri Aug 06, 2010 5:08 am

Just about to pick up a spare cylinder head for my G60 (right price, right place, in case I ever need a spare) and it go me wondering what it would be possible to do to one to make it the best efficiency I can for a G60. Mine is currently ported and polished, and is definately a good head - a G-werks fast road head, no change in valve size from original from memory. The inlet manifold has not been port matched to the head, nor had the inlet manifold been flowed. Cam is a schrick 268/276 assymetric. As I say it just got me wondering given a blank canvas is there anything else that could be done to improve breathing efficiency given the inherently very inefficient counter flow setup? Is there anything new to try or has it all been done before? What is the answer to life the universe and everything? Right more coffee needed....
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Re: What can you do to really improve a cylinder head?...

Post by mrbeige on Fri Aug 06, 2010 6:45 am

jmc wrote:what it would be possible to do to one to make it the best efficiency I can for a G60.
Give it to JNL! He did a bespoke 'job' to Chris's to suit his setup perfectly. The numbers told the story Smile

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Re: What can you do to really improve a cylinder head?...

Post by jmc on Fri Aug 06, 2010 7:46 am

Yeah, I had a feeling that would come up as a response very quickly Laughing
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Re: What can you do to really improve a cylinder head?...

Post by mrbeige on Fri Aug 06, 2010 1:49 pm

Tis a dark art that's for sure. Can't really offer any Sad

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Re: What can you do to really improve a cylinder head?...

Post by jmc on Sun Aug 08, 2010 12:34 am

I suppose what I was wondering, are things along the lines of when it is worth using uprated spring and valves, and if it's ever worth getting a custom cam, etc on a road car? And yep, totally agree, it is definately a dark art and not something that can easily be undone.
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Re: What can you do to really improve a cylinder head?...

Post by mrbeige on Sun Aug 08, 2010 10:02 am

I was always under the impression that stronger valve springs were to facilitate higher engine speeds? Valves however, can have different cuts etc. in conjunction with P&P heads. Custom cams, I think, require a lot of thought. Perhaps we need to prod Chris (ctwg60), as he did his own didn't he?

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Re: What can you do to really improve a cylinder head?...

Post by dirtytorque on Mon Aug 09, 2010 7:47 am

uprated springs and vales are getting more power from your engine by spinning it harder as said above.
Won't get more air into your engine on their own,and that is the name of the game.
U have a cnc head do u not J ?
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Re: What can you do to really improve a cylinder head?...

Post by jmc on Mon Aug 09, 2010 11:05 am

Yep I do, one of Gwerks fast road ones. So a pretty good head already. However you never know - if there is a better way of doing things, I am always open to it. For instance the inlet manifold was never flowed or ported, or matched to the head, is the Shrick the right cam, or is that fine for mildly modded G60's, given I'm now revving to 6800 is it time for different springs and valves, etc?
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Re: What can you do to really improve a cylinder head?...

Post by dirtytorque on Tue Aug 10, 2010 2:48 am

always chasing down those extra ponies *salutes* lol
U could re-build the topend of your engine and up your rev limit slightly.
But theres that little silver achilles heel at the front of the engine bay to worry about lol.

I think Chis had his inlet manifold matched at the same time as having his head flowed by JNL.
Maybe drop him a pm on here.
I think he hangs out on the s2 forum aswell?!
Might be wrong.
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Re: What can you do to really improve a cylinder head?...

Post by Yandards on Wed Aug 11, 2010 12:03 am

No point sticking uprated valve gear in a head unless you wind the rev limit upwards, uprated springs and titanium retainers all remove mass to allow a higher rev limit. Whilst you will get a little unnoticeable amount of extra go from running lighter valve gear it is not worth it.

For a stock G60 you are better off going for bigger valves to make best use of the charger, this keeps the rev limit down as bigger valves have more mass and hence more inertia but allows you to safely run a smaller pulley.

As for getting the best out of the head, as the other guys have touched on, it's more a question of getting all of the inlet and exhaust tracks to be as well matched as possible through use of the same diameter pipe, knife edging and pipe joins and port matching the inlet and exhaust manifolds.

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Re: What can you do to really improve a cylinder head?...

Post by jmc on Wed Aug 11, 2010 1:45 am

Yep, makes sense guys. I presume then when going with larger valves, making them lighter is a good way of not sacrificing rev limit. Also I was thinking, if I can lower the inlet pressure, by making everything flow better, wotn that put less stress on the charger, as there'll be less back pressure.

All of this is a little academic at the moment now. I got the dreaded ABS light of doom yesterday which is going to be the next job, especially seeing as this came on 2 days afer I paid for the Stealth Racelogic traction control group buy. I think my car knew what I'd done. Old cars, don't you just love them Laughing
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Re: What can you do to really improve a cylinder head?...

Post by dirtytorque on Wed Aug 11, 2010 2:03 am

prob just a wheel speed sensor.
get vagcom on it.
if it is that shouldn't be too expensive.
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Re: What can you do to really improve a cylinder head?...

Post by jmc on Wed Aug 11, 2010 2:27 am

Yeah, bit of an odd one. The light doesn't go off at all, and I thought with the wheel speed sensors the light usually went off, and then came back on over 5mph. Also the ABS relays under the dash click on, when the ignitions on and then off again a few seconds later. Is that normal?
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Re: What can you do to really improve a cylinder head?...

Post by jmc on Wed Aug 11, 2010 4:58 am

Aha, looks like it is the passenger wheel speed sensor. Drivers one approx 1100 ohms, passenger one completely opne circuit. Looks like it's time for a new sensor.
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Re: What can you do to really improve a cylinder head?...

Post by kevhaywire on Wed Aug 11, 2010 6:19 am

Yep, bigger valves is the way to go. They are after all the final floodgates in the intake/exhaust system.

Bigger valves can actually be lighter.
My VR6 valves are bigger than standard, but are made of inconel (lighter than stainless), have dished faces instead of flat ones and the stem diameter is reduced. They are a LOT lighter than the OE ones Very Happy. I also have uprated springs with titanium caps and colletts, so it will easily spin round to 7500rpm.

I wouldn't worry about the intake. Turbos and S/Cs work against a restriction at all times anyway, so any gains here would be virtually nil, unless the intake is horrendously poor, which the 8V one isn't to be fair as it was designed to keep low rpm torque up.

How does the crossflow 8V head compare to the standard one? Obviously there is the 16V head route aswelll, but it's a lot of work.

Speaking of the Racelogic, can't bloody wait. I was getting complacent with the traction in this dry weather, but when it rained yesterday, progress was erm, slower than usual Laughing

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Re: What can you do to really improve a cylinder head?...

Post by jmc on Thu Aug 12, 2010 1:21 am

Suppose I could go the crossflow or 16v way, but I've always wanted to keep the essence of the engine the same - 'within the confines of the 8v counterflow G60 engine what could VW have got from it and still had it reliable enough to use as a daily'. I think I've answered that in a way, having taken it from 160 to just under 250bhp. Just made me wonder about what compromises were made when I built this one.

Yeah the Racelogic will be fun. Just need to get my ABS fixed now. Sensors on order.
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Re: What can you do to really improve a cylinder head?...

Post by Yandards on Thu Aug 12, 2010 3:24 am

Given the low boost linear nature of the G60 and the fact that below 60% throttle the boost is going back to return then there are some gains to be had by port matching the inlet and exhaust.

Although the amount of work required will not give you huge power if you are chasing that holy grail of ultimate output it all adds up.

Kev forgets that the in terms of production the VR6 and the G60 are Worlds apart, some jobs that are just not worth it in the cost Vs performance debate on the VR6 are worth doing on the G60.

I still firmly believe the best way to get a consistant, well performing G60 engine is through a better/modern ECU that fully understands what you are asking the engine to do. MAP prediction using the G60s inbuilt MAP sensor is not reliable enough due to the pressure fluctuations thanks to boost return, without a throttle pot there are points where the ECU just does not know what you want.

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Re: What can you do to really improve a cylinder head?...

Post by dirtytorque on Thu Aug 12, 2010 8:23 am

Lol..i'm gonna fit a TPS to prove u right or shut u up.
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Re: What can you do to really improve a cylinder head?...

Post by mrbeige on Thu Aug 12, 2010 2:00 pm

I'd love to see what would have been achieved with a standard G60 and the Bosch ME7 ECU

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Re: What can you do to really improve a cylinder head?...

Post by dirtytorque on Fri Aug 13, 2010 2:02 am

i think the gains would just be in terms of driveability and response.
I don't think u will unlock hidden horsepower over say a good chip map in the standard digifant ecu.
I couldn't replicate my jabba chip at the time with my megasquirt,although I think I could have a beter go at it now.

If I had spare space/time and money i'd like to try a 9.0:1 8v g60 on megasquirt running a 68/65mm pulley...
If I hadn't already built a 16v engine.
I'm dreaming of turbos now because the g60 just doesn't put out enough boost so you have to make sure you are efficient with how you use it i.e the right cam and a good ecu map.The biggest downside of a factory ecu over an aftermarket ecu is that it is a black box.
Never knowing exactly what the thing is doing.Running logs really are a powerful aid in learning how your car is running and this is where the tuner ecus come into their own I think.
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Re: What can you do to really improve a cylinder head?...

Post by Yandards on Wed Aug 25, 2010 1:34 am

dirtytorque wrote:i think the gains would just be in terms of driveability and response.
I don't think u will unlock hidden horsepower over say a good chip map in the standard digifant ecu.
I couldn't replicate my jabba chip at the time with my megasquirt,although I think I could have a beter go at it now.

If I had spare space/time and money i'd like to try a 9.0:1 8v g60 on megasquirt running a 68/65mm pulley...
If I hadn't already built a 16v engine.
I'm dreaming of turbos now because the g60 just doesn't put out enough boost so you have to make sure you are efficient with how you use it i.e the right cam and a good ecu map.The biggest downside of a factory ecu over an aftermarket ecu is that it is a black box.
Never knowing exactly what the thing is doing.Running logs really are a powerful aid in learning how your car is running and this is where the tuner ecus come into their own I think.

True, but it can also be said that more modern units, ABFs for instance, were downtuned from the factory to give a noticeable difference in engine performance between the 2 ltr 16v and the 2.8 VR6.

and please fit a throttle pot Smile You will no doubt get around to it before I do.....

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