MK3 16v ABF - Dyno Results before and after 261 deg Catcams

some of them have bad access so i recon its the spline thatll work

25nm aftwards though

 

cheers for the replies.

will attack them with some mole grips first then try a spline.... if i can be bothered now ive just driven an m3 [:^(]

 

My head is currently getting a cheeky P+P job with 3 angle valve seats and new guides/stem seals...

is it worth getting the manifolds match ported as well?

been looking at them and they are both matched pretty well to the head. Are there any noticible gains and are they proportionate to the cost/effort of getting the work done?

Also, has anyone got mild duration/higher lift cams such as shricks 260 or catcams 261 to idle spot on with a MK3 on digi?

my current catcams give good torque spread but still havn't got them to idle spot on due to the MAP sensor pulsing.

I thought the inlet timing might have been a few degrees out, but im not sure even fixing this or retarding the inlet more can fix the vacuum differences.

I want the car to idle as good as standard for my new stealth car , so might have to revert to standard zaust/catcam inlet as i can't be bothered to spend ages getting the timing right, put it back together, then take it apart again when i find out the idle is still pretty rubbish!

What i can't understand is why they won't idle when the timings are so similar to standard

Catcams 0/40 41/1 Standard 1/38 39/1

surely as this is so similar, its not this causing the vacuum issues but the lift at TDC (1.05 mm) compared to standard?

Anyone know what lift at TDC is as standard?

 

Interesting read...I use Schrick splits in my 2 litre 9A MK2 valver.....268/276's....giove plenty of torque and good top end punch....I'll dig the dyno plots out.

276's are good on their own......shame Geoff Everett is now gone....the old Amd.....he would have sorted your ECU out.

 

268/268 will not run properly in an ABF...so you have no chance with 276s, or a mix of 268/276.
260s are marginal...

They work fine on earlier engines...but not on Digifant 3.2 ABFs.

Sadly, even Geoff can't.
He tried with mine running 268/268 and couldn't cure it.

 

If they are out of alighment, yes.
If not...maybe not if you are paying someone to do it for you.

If you have a die grinder and a porting kit...and don't mind putting in the hours (I spent 40+ hours on my ABF manifolds) then every little helps.
Get rid of all the casting marks etc...

I just don't think it's going to happen...
You could consider fitting Megasquirt set up Alpha-n and get round it that way?

I think your idle will still give the game away...mine certainly does on 268/std.

 

cheers Glen

in the case i will give up trying to get both cams to work. will give my catcam inlet a go. hopefully as its got a fair bit less duration than your 268 the idle will be slightly more respectably.

what sort of budget/expertise to you need to get to get megasquirt working? How come you don't use it on yours?

If i could do if for the cost of a custom remap which i require, then i might be interested.

If not, hopefully the head modifications will forgoe any losses from losing the exhaust cam.

 

A custom map will be required but you need to consider your engine vaccum will be reduced with longer duration cams. This will mess up the fuel estimation done by the digifant3.x as it will now run at 55-65kPa at idle, when it is calibrated to run at 25-35kPa at 6 deg spark advance and 800+/- 50 rpm. As the part load vaccum can be close to ambient pressure (99-103kPa) at 50-85kpa it is recommend to change controller and run some alpha-N arrangement, where thorttle angle is almost directly porportional to airflow for give engine speed. This wil improve response to WOT. This does not mean WOT will be better or worse between standalone or factory controls. But drivablity will.
On the other hand with a MK3 that still has legal in use emission requirements to fulfil, you may find that such a modification to an alpha-N system may not pass MOT. Neither will the cat function properly without being able to wobble around lambda 0.98 to 1.01.

 

correct me if i am wrong, but its the overlap that causes a loss of manifold vacuum.

Therefore, essentially i need to have the fastest acting ramps and highest possible lift (with regards to protecting the valve train) to improve the area under the curve, while having a similar overlap to standard to keep manifold vacuum in the 25-35kpa region.

currently the catcams have 1 less degree of overlap at TDC (1.0 mm lift), so im guessing the change in vacuum is due to it pushing off its seat earlier so there is greater flow in the overlap period?

 

Ah! Just been doing some reading. Apparently the centerline method of camshaft timing isnt actually that accurate

might explain why i thought it was a few degrees out when i checked it against valve opening times...

will give the cams another go using the valve opening time method, even though its harder. Don't want to write them off without getting them properly set to the manufacturers figures.

 

Hi guys... I am new here, so maybe I am missing something, hopefully someone can explain. After reading a few posts about cams for the ABF, I just cant understand why you guys run such low duration cams and to be quite honest, achieve marginal gains after spending so much money! Im assuming there is no way to custom tune the standard Digi ECU? If so, then why dont you just go with a Unichip or a full aftermarket management system? Like Dicktator or GoTech?

Here in South Africa, a full custom tune is not an option when the guys fit cams, its an absolute must have! My ABF is bone stock, it just has a 4-2-1 exhaust manifold going into a progressive 57mil to 63mil exhaust system, a BMC Carbon Dynamics Airbox and a standard 1.4i VW MP9 ECU that was custom tuned live on the road by a company called Frieling Racing Chiptuning or FRC. What was done to the ECU, I dont know, but the tuner custom tunes everything until the AFR's etc are perfect throughout the graph. The limiter is now at 7000rpm and the car made 155HP ATW on a stock ABF Motor, beautifully smooth as ever, flawless cold starting as MP9 uses an Idle motor in the Throttle body (VR6 OBD2 TB Fitted) and awesome fuel economy too! I mean, when the guys go with cams here, it costs R4500 ex VAT for a set of Estas blanks that Van Der Linde Developments then cuts to spec & thats alot for us! So we expect atleast 15HP ATW Gain and the guys go with a MINIMUM of 268 276. Most guys are running full 276 276 for everyday and are making 170HP ATW easy, with no problems, the idles are lumpy ofcourse, but not bad at all... My 1 friend is running 276 288 cams! And is making 180+ HP ATW!

So whats the problem there? Because from what I have read, you guys are way more experienced and knowledgable than we are with the 16V Motors, so why cant you just set AFRs and stuff with a simple Unichip Q? Every second Golf 1 here has that atleast.