16v kr exhuast/inlet cam mod.... who can do this?

[corradlo 0]

As per title, can anybody on this forum supply/ or modify an exhaust cam to fit my kr??

 

Thanks

[starmagsi 10]

I'm sure I have one sat in the garage. I'll take a look next time im round there.

[davidwort 0]

Just get a set of abf cams, more lift and duration than kr cams

[Metallix 10]

Just get a set of abf cams, more lift and duration than kr cams

 

What David said.

 

[davidwort 0]

?..

 

That's neat, I wonder how that's done, some kind of sensor to a computer following the cam profile as it's rotated on a lathe or something?

[Metallix 10]

That was done using one of these:

http://www.audietech.com/cam-pro-plus/cam-pro-plus.html

 

(not by me, I was simply sharing that rather useful cam profile graph)

[cdem 0]

Hmmm think I've got got a spare set of abf cams in the garage....may stick them in the spare kr engine I have :-)

[davidwort 0]

They will make the kr more peaky, IMO the kr cam set is a good compromise and works well on the 2L too, but if you are more interested in peak power than a nice torque spread the abfs will give that. remember that the abf mk3 has a fully electronic injection system and can fill out the torque curve better than k jet with its fuel and ignition mapping. you can get away with abf cams better on a 2L kjet engine as the increased displacement over the 1.8 makes up for a bit of the loss of low down torque.

[Metallix 10]

Getting back to the original question, the KR exhaust cam mod did work,

but as you can see it was simply trying to do the same job that the ABF cams already do.

These were either unavailable or too expensive at the time the KR exhaust cam mod appeared.

 

If you look at the graph you can see the KR exh cam has a pinch more duration than the ABF exh cam.

Though the difference in lift is clear to see.

 

Both of these cams are below the duration figures of the mildest cams you would get from aftermarket.

The figures used by aftermarket being measured at a different valve opening to what OEM specs quote,

ABF items work out about 252 duration whereas Piper fast road start at 264.

Basically ABF cams do not result in an engine that is peaky.

[davidwort 0]

...

Basically ABF cams do not result in an engine that is peaky.

 

have to slightly disagree with that on a 1.8, the KR 16v is peaky enough as it is, not coming 'on-cam' until about 4,000 rpm with standard cams, I understand that duration tends to extend the power band rather than lift, but from experience on the 16v, going the other way, I have overlaid plots somewhere of my KR cammed 2L run back to back on the rollers with a standard 2.0 16v (9A), the 9A has a noticeably flatter torque curve and so doesn't need to be wound-up as much, it does make it feel more like a 2L 8v to drive though, and runs out of steam almost 1000rpm lower than the KR.

Peak power on my 2L with KR cams (small diameter inlet manifold + bit of headwork too) is 6,300-6,400 rpm, peak torque about 5,700, more valve lift is surely only going to send those peaks one way?

I suppose the way to tell for sure is to fit the ABF cams I've had sat in the bottom of my toolbox for a couple of years :) But as my 16v will pull smoothly to the limiter and can nearly manage that in 5th too, I've been loathed to take out the KR's.

[Metallix 10]

The standard 9A intake cam is partly responsible for what you have described there re: flatter

 

9A inlet cam duration 200 deg

KR inlet cam duration 212 deg

ABF inlet cam duration 219 deg

 

9A inlet cam lift 8.8mm

KR inlet cam lift 9.6mm

ABF inlet cam lift 10.8mm

 

Lower lift & duration than KR & ABF.