Which Cam, Xu10j2

[Atari Boy 11]

I need to get my valve stem seals replaced, so whilst the head is off I want to fit a better cam. I use the car mainly for track days and as a weekend toy so it dies not need to be too sensible. I plan to fit carbs or bodies to it in due course also but not straight away. I am using the standard 1.9 8v cam at the mo as it is better than the oe XSi one.

 

What would be best chaps?

 

Thanks

 

Jonny

[Baz 421]

285 or so is going to be a little on the lumpy side for std inlet and managment tbh, although ok on carbs etc, but as you haven't got them yet, the next one down in easy terms is the 270/272 options, Kent PT36, Piper 272 etc.

[Luca 1]

I've got 292 on standard ignition and it is good for the weekends.

[Atari Boy 11]

How bad ok standard inlet would a 285 be? Totally undeivable or just a bit of a pain at the lights?

It would be a shame not to use one if at all possible.

 

Thanks

 

Jonny

[MrG 3]

It'll be a pain and bog down at low revs, I think (and many will probably correct me on this) but these are better suited to high up the rev range. The car I drove with my head and cam, that was on injection, was not very nice in traffic or around town. But you may find it acceptable for the short term?

I'd wait for the carbs Jonny otherwise you could end up buying another later and doing the fitting again unless you decide to stay with injection. Are the seals very bad? If not then wait a while (or to ask another question, when do you plan the TB's/Carbs?)

[Atari Boy 11]

I would like to do it all together but I can't justify it right now. The car us quite smokey which us why I thought I would do that bit now, I don't want to change the cam twice though.

I suspect that there might be a month or two gap between no carbs and carbs.

[MrG 3]

in that case (and the fact its a 'weekend to' type of car), then I'd do it? All it will mean is for the time being you'd have to give it plenty of throttle in order for it to be driveable around town etc for that short time.

[James_R 3]

I've just put a 282 catcams job in and it idle the same as std and spins up fine, you'll want a 1.6 dizzy and about 10.5:1 minimum compression though. I'd also suggest BCR8ES plugs with that.

 

The whole lumpiness thing seems to be more internet tomfoolery as usual.

[welshpug 1,661]

I would leave it till you fit the throttle bodies, save you having to re-shim and run a cam in twice, I don't know about Jetconic but mine on Motronic with a standard compression ratio doesn't like being under 2.5k with a cam that's around the 285 mark IIRC, I would suspect that being Flap AFM based it'd be even worse around town.

[MrG 3]

My old Mini ran a hot cam and idled very lumpy on its SU's, as did my Ford mexico at the time, even my 205 now runs lumpily at idle, all came alive at their designated rev point though, but then again all were/are on carbs.

[Luca 1]

If it's one step at a time then get the bottom end done first and then maybe save more over time for the top end. Especially if you're going for a hot cam and mappable injection or carbs. My experience is that you won't have too much a problem with a big cam and higher comp apart from a s*itty sounding idle.

 

All my mates tell me I need a new exhaust, but it's just a lumpy cam and a s*itty idle sound.

[sub205 5]

If it's one step at a time then get the bottom end done first and then maybe save more over time for the top end. Especially if you're going for a hot cam and mappable injection or carbs. My experience is that you won't have too much a problem with a big cam and higher comp apart from a s*itty sounding idle.

 

All my mates tell me I need a new exhaust, but it's just a lumpy cam and a s*itty idle sound.

a german company called "dbilas dynamic" (dbilas.de) is making custom camshafts.

 

i got a 280° with 12mm hub, runs great with original springs. at ~5000rpm you get some kind of v-tec rush, on lower rpms the torque is great.

 

the opening angles are 30°/70°/70°/30°

[Baz 421]

Just bare in mind the higher you go the further you push the power band up, which is all well and good if you run a short ratio box and do fairly open trackdays etc, but the drive-ability throughout the rev range attracts me more, certainly coming from a sprint/hillclimb POV, as you need the power all over the rev range to pull you out of corners of differing tightness, without having to tickle the gearbox as you would with a peakier delivery, as that wastes time.

Edited May 27, 2009 by Baz

[sub205 5]

Just bare in mind the higher you go the further you push the power band up, which is all well and good if you run a short ratio box and do fairly open trackdays etc, but the drive-ability throughout the rev range attracts me more, certainly coming from a sprint/hillclimb POV, as you need the power all over the rev range to pull you out of corners of differing tightness, without having to tickle the gearbox as you would with a peakier delivery, as that wastes time.

 

yes, thats right.

but with a good hub (12mm is ok) even a cam with 280° will outperform a standard cam in lower revs, at least it has the same amount of torque.

over 280° it may be worse.

 

my 268° 12mm schrick was ok, i dont know how many degrees the normal cams have...

[Luca 1]

if the cam is the only variance in the modifications any cam between 270 and 295 wont show much of a difference. the cam mod always need to be coupled with another mod or another couple like head skim, polishe and port and valve seat cuts etc..