Stage 2 cams (again) - dynos!

[johnnyrod]

If we haven't done this one to death.... did the cam swap at Christmas (thanks Northwind and Itching to go Joe for the info beforehand), got it on the dyno on Saturday morning....

http://www.johnnyrod.co.uk/dyno3.gif
(170kb)

and this is the bit I really like...
http://www.johnnyrod.co.uk/svvs748.pdf
(6kb)

max power figure for the 748 is 90bhp which comes from revving a bit further than the SV.

Brm brrrrrrrrrm!

PS I know it's not the most scientific, but putting it all in Excel made it easier to overlay.

wow, how much?

Fab torque curve .

I wonder how much this will affect reliability?


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[Skip]

Originally Posted by jonboy

Fab torque curve .

I wonder how much this will affect reliability?


.

Northwind is always pulling his to bits - so I guess not!

Sounds like an interesting upgrade - is it really just as easy as swapping the cams - no other parts required??

Good curve although displaying uncorrected dyno figures is absolutely no use to anyone as we cannot interpret the numbers to anything meaningful.

Have you got the corrected figures to hand?

[northwind]

Yup, I'm with Mike, do you have a before/after? I changed too many bits at the same time, so when I do get it dynoed again there'll be no way of telling what's cams, what's the filter, etc... Bit of a shame but it all went a bit wrong.

But y'see the good bit? The way it doesn't have a peak anymore, just a climbing line to the end? That's why I like the cam swap so much. IMO a broader peak is better for a street rider than sheer power at a point, and this mod can basically remove the tail-off completely. (there's still a a higher peak,but it'd be at about 10,000rpm or above) It almost certainly does cost midrange and low end, but not so much as to bother me (and I use the midrange a lot)- still stronger with the ignition advancer and cams than it is stock anyway.

'Tis nearly as easy as just swapping the cams- K3> intakes into het intake side, and your old intakes into the exhaust side (none of the exhaust markings will line up, but that's not a problem) You'll also want a set of cam chain tensioner adjuster gaskets- they're sort of reusable, but there's no point in cutting that corner. £135 or thereabouts all in. (if you have a rattly tensioner, it's a good time to replace it too).

Best practice would be to replace the buckets as well, as that's a matched wear deal, but I didn't bother- high mile SVs show no significant cam or bucket wear even after 100K, so a certain of accelerated wear doesn't concern me too much to be totally honest.

It's possible you'll need to change the shims too, if your post-install clearance check isn't good- seems that most people don't need to, I didn't.

Reliability... Well, like anything else, more power = more strain. But it won't turn your engine into a ticking time bomb, put it that way. I might have my bike in bits constantly but I've never had to go back to the cams since I did it Almost any amount of tuning will reduce your engine's lifespan, but we're talking here about a motor that'll do 150,000 miles without heroic maintenance or any rebuild work. A marginal decrease in longevity isn't something I worry about in the least, personally.

Compared with, say, a 700cc kit, the reliability impact is trivial... And compared with a full system, filter and rejet, the cost is trivial. It's a good mod. But remember, if you get it wrong you'll bend all your valves

And if anyone with a K3> is thinking of doing the same with the cammed model's intakes in their exhaust side, I've got a set in the garage, £50 including the buckets

[johnnyrod]

Mike - not sure how the correction bit works, this is what one run on a dyno I've not used before gave me. Here are the previous ones:

http://www.johnnyrod.co.uk/dynoruns.pdf

"Stock" is really with the Akropovic full system but no rejetting, run at JHS as a baseline. "PDQ" is with Akro pipe, K&N, Dynojet kit and JHS ignition advancer (and 2nd/3rd gear retarder disconnected, for what it's worth) as set up by PDQ. "Cams" is after the cam swap, not made any other engine mods, run by Chris Gunster in Grimsby. Does that help, or what are you after for correction? I gave the guy the bike and he ran it, and we looked at fuelling, I don't know a lot else.

Swapping job was pretty easy, checked all clearances afterwards and they were spot on, have also heard this from other people who have done the same job. Fuelling seems to have been unaffected by the cams (which is a surprise), it does run a touch rich 5000-6500 on full throttle (about 12:1 in stead of the 13:1 optimum) but I was told it was unlikely to worth getting that sorted, and part-throttle was spot on all over.

And it sounds different, and goes different!

[northwind]

The sound I meant to say about that. Hotter exhaust cams = fantastic overrun sounds. Lovely. Also a bit loud, it was the cam swap that made me sell my ridiculously offensive Kenz Sport twin system

When i get mine done i will post my dyno sheets of before and after both from the same dyno. Fingers x if all goes to plan should be done end of Feb.

Cant wait

btw its a thunderbike not a minitwin SV650 so tuning is allowed!

Originally Posted by johnnyrod

Mike - not sure how the correction bit works, this is what one run on a dyno I've not used before gave me. Here are the previous ones:

Still doesn't say much, 3 graphs at 3 different dyno's!

Nick at PDQ always uses EEC correction, not sure about the others but at least they're all Dynojet.
If you look at the top of the graph (original printout) it should say, it will be three letters:-
EEC
SAE
DIN

cant remember the rest