VW 20v tarmac race engine.

[atecracing]

Dear all.

This is my 1st post as I am new, and I apologize in advance for my poor english - as I am not English!

I do hill climbs and tarmac rallyes on a VW Golf 1.

My car is actually fitted with:

16 inch wheel with michelin N20 tarmac tyres
front 305 mm and brembo 4 pistons calipers.
Rear original VW brake disc
6 speed straight-cut gearbox with LSD
Metalic cluth on a lightened flywheel
4 Proflex adjustable dampers.

The engine is actually an original 16v 2.0l with 45 DCOE Webers and a 4/2/1.

I want to put on a 2.0l engine based on the 1.8l 20v AGN engine (big port).

Is it possible you give me some advice to upgrade this engine.

It will be fitted with 45 or 50 itb's with probably the new S60 DTA management

I need some technical information to choose the camshaft (kent-cams GF5V4 or Cat-cams 1013754 or else??); To port the head; To choose ’‚  CR.

Naturaly cranck, pistons and rods will be carefuly choose.

I would want the new engine to output 230-250 Hp. I plan one r’‚©vision each year after 5 hillclimb and 5 rallyes.

Can this be done??

Naturaly the price is not the first limiting factor.

Best regards

Marc.

[Guy Croft]

Hi, good summary, some pictures (under 300KB) would add a lot of interest, sounds a well developed car.

I'd go fully flow-developed head (incl valve/seat work), 45 throttle bodies, 11/1 CR.

I'll recommend Kent cams, they are good friends of mine and have a good website. If you cannot see a profile and valve springs (must match each other) send them an e mail. I don't want to recommend cams for that, ask them, but I suggest something with 11m lift or more.

Yes race rods and pistons for sure and knowing how powerful VW engines are I imagine that your power target is fine, may well be higher if properly mapped up. But to be honest I'd stick with the 45 DCOE on 40mm chokes and put your money into other more vital things.

Hope this helps for now.

GC

[atecracing]

Hi Guy.

Thanks for your kind answer. You confirm me some technical tips that i was thinking.

When you tell "a fully-flow developped head including valve seat work" is it possible you explain a little more abouth things important to do.

I plan to grind (open) a little the internal diameter of the valves seat in order to have with a two angled seat (30 and 45‚°) a wide of 1mm of contat for the inlet and 1.5mm of contact for the exhaust on the 30‚° angle seat portion.

But how abouth the rest of the inlet and exhaust manifold in the head??

For the cam you indicate a minimal 11 mm lift. have you an indication for the minimal duration (300, 310, more??)

I think that the work on the head is the most important and uncertain job.

The bottom of the engine job will be more conventional and more well knowne.

Best regards.

Marc.

[Guy Croft]

When you tell "a fully-flow developed head including valve seat work" is it possible you explain a little more abouth things important to do.
I plan to grind (open) a little the internal diameter of the valves seat in order to have with a two angled seat (30 and 45‚°) a wide of 1mm of contact for the inlet and 1.5mm of contact for the exhaust on the 30‚° angle seat portion.

OK, if you're doing this yourself I recommend that the only thing you do is put a knife-edge on the port splitter (unless it's one of the very short ones) and smooth the ex and inlet ports all over at 80 grit. Don't use a cutter in the ports, you might make it worse. I would be surprised if the ex seats are 30 deg but I have never seen them. You want to grind the 45 deg contact face to true valve diameter and then narrow the in and ex seats down to 1.5mm each with a 70 deg throat cut. You can buy Neway cutters to do this, see 'Links' on this site where I put their details.

But how about the rest of the inlet and exhaust manifold in the head?
You'll need - (I imagine, as I've never seen the standard thing) a custom made race header, say 3ft long with big bores, and as for the inlet manifold for your throttle bodies, depends what you buy how good it is. Needs to flow as much as the ports, but unless I can test it and the head I cannot give much guidance. You can make a guess by the size - if it's way smaller than the head ports - it probably needs enlarging.

For the cam you indicate a minimal 11 mm lift. have you an indication for the minimal duration (300, 310, more?)

You don't have the experience to choose a cam setup. Talk to Kent. And make sure they have valve springs too. I've known them since the 80s. These guys get feedback. They do know what's best, in my experience, every time.

Never guess at cams based on duration. Ask them what will give the most power where-you-want-it. If they have National Hot Rod profile - use that. Unless you have the head professionally gasflowed and know what valve lift the flow peaks at it's impossible to be too specific about the optimum cam lift. Your standard inlet cam will lift, about 9mm and in fact the head will stop flowing at about that figure. That's how head/cam packages are designed. With the work you're going to do on it it is going to flow better at still higher valve lift. But I doubt that you will need more than 11mm lift and, say, 3mm lift at tdc.

I hope this helps for now.

GC

[Guy Croft]

MD of Kent Cams wrote to me just now, to help with the thread.
It doesn't get much better than that!

Here is what he suggested:


Hi Guy

The parts to use for the VW 16valve

GF1605 Camshafts
CF42 Cam Followers
VSK14K (triple groove type valve collets) valve spring kit
CA68 belt pulley
S69 internal gear pulleys.

Best Regards

Tony

Kent Performance Cams Ltd
Unit 1-7 Military rd,
Shorncliffe Ind Est,
Folkestone,
Kent,
CT20 3SP
England
http://www.kentcams.com