ABF or KR cams in a 9a?

[pumbaa 0]

Hi,

 

I'm the proud owner of a moonlight blue 2.0l 16v as of about 6 months ago. I've spent the last 6 months making a few cosmetic repairs and changes (some interior plastics, ice, eyebrow, passat handles..... ect) and i'm starting to think about some engine mods.

 

Ive been told that due to emissions the 9a was somewhat restricted on performance. I'm fortunate enough to own '92 reg which has had the cat removed ..... legally! And ive been told that swapping the 9a cams to KR or ABF ones will give me a large bhp increase.

 

I was wondering what would give me the best improvement, KR cams or ABF? and should i change the head to a kr or abf one too?

 

I have aquired a set of ABF cams, if these were the way to go, would i require anything else to fit them?

 

My dad's a mechanic but isnt too clued up on specific performance upgrades to vw's, he can fit anything needed but doesn't know whats best for what im after. He'll also offer mates rates (body and mechanical work) for anyone who will help me out, he just doesnt know it yet. :grin:

 

Thanks very much,

 

Kunaal

[Swompy 0]

dito on the question? as im considering getting a kr cam for my 2lt 16vl

[davidwort 0]

KR inlet cam (exhaust cams on KR and 9A are the same) is a noticeable improvement at the top end, much higher lift than the 9A inlet. The ABF is even more lift but with the ABF exhaust has less duration IIRC so swings and roundabouts.

An ABF inlet cam with the 9A/KR exhaust cam might be interesting but probably very little in it. It's possible the 9A engine management might not like the emissions of an ABF inlet/KR exhaust combination, not sure.

KR inlet is tried and tested though, good enough to get near 170/180bhp with a gas flowed head. Probably give you nearer 150 on a standard 9A

[swiftkid 1]

As davidwort said, the KR cam mod would give better top end but iirc sacrificies low down torque. my friend did the mod using KR cams in a 9a but didn't like it, really depends on the person really

 

You don't need to swap heads because its just the cams that make the difference and they are easy to change.

[odub 0]

Just to hijack the thread a bit, as mentioned at the top is it ok to decat a 92 j plate 2.0 16v and make it through an mot? I thought it was 92 the emmissions got more stringent. Thanks

[krnau 0]

and... what about abf inlet & kr outlet cams into kr engine?

[davidwort 0]

and... what about abf inlet & kr outlet cams into kr engine?

it might work well, it might not, the abf inlet has a bit more lift but TBH I can't be bothered to try it when it will probably just shift the torque curve up a bit and my car pulls fine to the red line with the KR inlet.

[krnau 0]

hmmm if only i could do the modded kr exhaust cam...

[deMK1 0]

ive just been speaking to some people on other forums about this, here's the info that i collected from different sources:

 

The reason they use the cam over the 9a is:

 

2L 16V ABF cam specs:

Intake - 219deg @ 1mm, 10.8mm max

Exhaust - 220 deg @ 1mm, 10.8mm max

 

1.8L 16V KR cam specs:

Intake - 218deg @ 1mm, 9.6mm max

Exhaust - 226 deg @1mm, 10.2mm max

 

9A pre 94 specs

Inlet - 8.8mm max

 

Mike "the man in the shed" from Clubgti, in a conversation i found talking of the same subject and also talking about the WUR mod, states:

".....It's a case of making sure. Ideally you need a rolling road session to set this up properly, but it will be worth it to make sure the car is running right.

 

Chances are on any old car, that the fuel pressure isn't at the original factory spec any more, so it's well worth having this done.

 

If everything else is standard on the engine, then with the KR cam and WUR mod you should be around 160 bhp. Mine was at this spec till recently, and it's quick enough to surprise loads of flash, newer cars!!"

 

 

As someone else on the same thread wrote:

(referring to someone that was thinking of using the inlet from the KR, as the inlet for a 9a):

".............Do you also have the exhaust cam? If you do you will get even better gains by using that as an inlet cam with the pulley chopped off."

 

But it's not as simple as just cutting off one end, the keyway needs machining in another place on the chain sprocket end in order for you to get it all timed up again properly. (when using the KR exhaust as the inlet for the 9a).

 

Also for anyone interested (that hasn't swapped cams before then here's a little guide, not by me)

http://www.clubgti.co.uk/forum/showthread.php?t=184663

 

So as far as i know, the ABF are best option, then the KR, but as someone said, depends what you want to achieve with it.

 

I'm just about to try the Exhaust mod, if i can't do it, then i'll just pop the inlet in.

[aide 0]

But it's not as simple as just cutting off one end, the keyway needs machining in another place on the chain sprocket end in order for you to get it all timed up again properly. (when using the KR exhaust as the inlet for the 9a).

 

i've got into arguments about this before, so i will only state the only reason you need to cut a need a new keyway is if you want to retain the factory timing marks :D as done on my last two valvers I simply rotated the cam and marked a new timing mark - easy peasy, and all as a now picture less vortex thread http://forums.vwvortex.com/zerothread?id=691425

 

if you want to do a better job and play with the power band then you can always get an adjustable cam gear, vortex thread recommends 4.5degs advance

[deMK1 0]

i should have used quote marks for that, i didn't write that, that was copied from some more messages i got given.

 

one thing i did find was, i read that people took the sprockets off and rotated 6 degrees? :shrug:

 

anyway from what i've been reading, unless someone else can show me otherwise, ill just put the inlet cam from KR in.

i would like a full guide of how to use exhaust cam, or i won't try it.

[aide 0]

it's honestly really easy to do, the hardest bit is spending an hour and a half chopping through the cam - THEY'RE REALLY HARD :D

 

between that post on club gti and some photos which i may find my way to PMing to you from the vortex thread i posted it's a doddle

[deMK1 0]

But it's not as simple as just cutting off one end, the keyway needs machining in another place on the chain sprocket end in order for you to get it all timed up again properly. (when using the KR exhaust as the inlet for the 9a).

 

i've got into arguments about this before, so i will only state the only reason you need to cut a need a new keyway is if you want to retain the factory timing marks :D as done on my last two valvers I simply rotated the cam and marked a new timing mark - easy peasy, and all as a now picture less vortex thread http://forums.vwvortex.com/zerothread?id=691425

 

if you want to do a better job and play with the power band then you can always get an adjustable cam gear, vortex thread recommends 4.5degs advance

 

ok, pics would have helped a little, but what else did you need to do other than that?

ive read the thread, and seems to be quite useful.

is EVERYTHING else standard? you didnt buy a vernier pulley or anything?

 

(i just read your comment before i post this)

thank you and i love you (ish) lol

that will really help, and also if it works will throw it in the faces of the people that said it wouldn't.

we have plenty of air tools at my mates garage, so will give it a go, after i get the PM :) :cheers: :clap: :notworthy:

[aide 0]

yep - everything completely standard, just chopped and flipped over, i will be trying it with an adjustable cam gear but that's a few months away yet :(

[krnau 0]

should cam belt be removed in order to replace the inlet cam? (and timing chain too?

[Swompy 0]

Would replacing the 9a exhuast cam with a KR exhuast cam make any difference ( along with a KR inlet cam)

[aide 0]

kr and 9a exhaust cams are the same so no difference i'm afraid, maybe try the kr inlet if you havn't already

[dirtytorque 0]

should cam belt be removed in order to replace the inlet cam? (and timing chain too?

yes.

[Swompy 0]

kr and 9a exhaust cams are the same so no difference i'm afraid, maybe try the kr inlet if you havn't already

 

Ahh right ok just wondering thats all.

 

so if the exhuast cams are the same in the KR and 9a engines, why are the inlet cams different?

[davidwort 0]

to bring the torque curve down the rev range, as the 2L 9A red lines about 700rpm lower than the KR, this is partly because the 2L doesn't rev quite as keenly as the KR with it's bigger pistons but the same con rods, but also to make the 16v feel better to drive in lower revs with the relatively heavy Corrado body and then being a little restricted by having to have a cat (the catalysed 1.8 16v was only about 125 bhp)