cylinder head
Turbo Mini Forums

yes vmax does build engines - mainly for existing customers - ,so many variations i find whatever i list its not what i get asked to build, i already have lots of work so pointless to advertise because i would have trouble getting through it , maybe i need to get lots of employees to do my work for me ,then it would give me more time for writing and singing theme tunes!

stuart you looking for an 'apprentice'?


worth a try lol

dont mess around GAV get a head off
stuart gurr - vmaxscart

enough said

okey dokey

i would, my engine came from stuart and im chuffed with it (although still waiting to get it fully run in)

id recommend him to anyone, and more sensibly priced than you would think!!!!

Purely from the theory point of view (as usual with me) Running a larger exhaust valve causes the valve to flow quicker and the associated pulse to spool up the turbo quicker. The pressure gradient at the front of the exhaust "slug" is higher and this is the deal for turbos. (Which I know nothing about). Going from 29>32 on the exhaust valve gives about 10% more area for flow at any life (15ish% increase for 1.5 rockers).

I'm not sure about how the overall valve sizes work with varied boost but obviously as you produce more combustion products, you need to get rid of them more with less pumping losses and no torque loss. Which was the last 2L you looked at which had a 29mm exhaust valve? Obviously you compensate with duration and lift but there comes a point where this starts to interfere with your inlet timing (the back edge of which is critical for power production).

The head I'm using for my supercharger setup is a 35.7/32 (AEG 163) with 1.3 rockers, giant exhaust ports with a large "Dave" radius and the controlled vortex nonsense eliminated.

I'm using the PH2 cam with the extra duration and it's about time someone had a think about making a proper supercharger cam. (The symmetric ones need the extra exhaust duration IMO).

Stu (Spouting loads of bollocks as usual and not getting oily enough)

Bugger off, I'm getting there.

Quote: Running a larger exhaust valve causes the valve to flow quicker and the associated pulse to spool up the turbo quicker

A larger valve means less gas velocity which will NOT spool upt the turbo quicker.

And a 32mm valve in a 163 head.. Brave man :)

ok now confused there seems to be a bit of confusion, then again theres never really a straight answer lol, the general impression i got was that larger ports give better top end but less low end driveability, on a different note a 30cc chamber in the head with 18cc dished pisons what comp ratio am i looking at, sorry about all the questions just spent a lot of money on my first turbo wanna do it better this time :)

30cc's in the head and 18cc pistons will give a very low CR.

Im thinking more 23/25cc's for the head should give me around 8:1 CR. cant remember exactly last time i played with the calculator. that was with 18cc pistons.

whats the cc in the head as standard?

20-23ish IIRC varies a lot. i was thinking i could nearly get away with std chambers.

think 20ish is more common, also account for the fact some may have been skimmed as well.

21.4cc is "Quoted" as standard. Though they can vary quite a bit as already said.

Phil.

WWW.TURBO-MINI.COM

Large valves/ports does generally improve top end, and reduce mid range.

Low CR increases the boost capability (more boost) but reduces the mid range, and kills off boost power.

You may play around with these to get what you want. This obviously means that all Chavs on here will lower the CR, increase the boost and valve sizes to get more hp. But, Dave will still kill you on the strip AND on the road. Why?? Because it's not max hp that counts, but the area under the hp-graph.

Also, it's better to have 8,5:1 CR with a decent squish area than it's to have 8:1 with the pistons being halfway down the block on TDC. You have a better combustion, and less chance for pinking with a bit of squish. This means more mid range and same top hp, but MUCH better driveability.

cheers for all yhe input guys, so money no object what would be your ultimate spec for a road car, oh and is anyone selling an efi kit for us yet cant be bothered to set it up, megasquirt etc?

i fit the emerald m3d system to my supercharged engines 138 bhp on a standard cam ! pulls from 800 rpm
Ultimate spec ? 1330 cc omega cast pistons,286 ,1.5 rr ,36x 31 head 8:1 comp m45 supercharger 12 psi boost: 184 bhp @6 ,167@5 ,154@4 ,198 ft lbs@4
ok not the ultimate spec but how easy was that !!!!!

Stuart, I using the emerald M3d on my mini turbo, it works very well, but Dave walker does not know Su's very well, how well do you know the software, and how much would you charge to tweak my map and check / correct fueling?

Team Racing

Ring him welsh boy....

http://www.vmaxscart.co.uk/

jimster ,are you using ignition only ?

how much are those m3d systems and what options do they have?

www.emerald3d.com
everything you need to know

lots and lots..........