greggo wrote:So how come there is so little difference on the dyno between the two units when run back to back?

^ What he said!

There are many reasons you may not see a great deal of difference on the dyno. Most dyno operators have inertia dyno's with limited static load test ability. This is not a huge problem because up at race RPM's there is little difference. Also as dyno operators all vary in tequnique when using the throttle and rarely do full maps it is hard to tell what data they are actually testing....Dyno's are of limited use especially when you only get a few runs with no real ram air effect and mostly full throttle or roll on tests. many dyno curves are very crude approximations of actual torque vs RPM curves. In a broad sense this explains the lack of accurate data. The other point is that many would think an HRC box should increase horsepower just by plugging it in. In terms of peak horsepower this is rarely true. One of them main reasons kit boxes are needed in full race spec bikes is due to the increased cylinder pressures at peak torque and HP caused by increased volumetric efficiency and increased comp ratio. In order to deal with this less advance is often required at these points and more advance at points where there are " holes ". So actuall peak power can drop when using a kit ignition box on some bikes, Unless you have specs similar to the Jap superbike specs of the day. cheers

REgards TK400

In relation to unlocking the secrets, To obtain some of this data it takes days of work in the LAB. It is hard to sum all this data up on a forum in a few paragraphs. So what type of secrets are you alluring to. cheers

REgards TK400

im just after 2 figures, idle and full advance on the hrc box. just want to see the difference at these points. im curious as iv'e sloted the std pick up coil mounts. i know this will move the entire curve the same degree's, but if i can find an improvement then great, if not then i'll put it back to std. iv'e got a whole trackday to test.

currently its set at 4 degree's advanced from std. i know for the bike to produce power it needs retarding but the next track is real tight and twisty and any accelleration i can get the better. it already accellerates pretty well but the more the better. the compression ratio has been bumped up aswell approx 14:1.

any info you'd like to share would be appreciated.

2 dann29: Did you got compression ration 14:1 just with HRC box ?

If you are running 14:1 I would not be advancing it at all. The HRC box runs the same idle and 4 deg higher at full rpm.

PARUS wrote:2 dann29: Did you got compression ration 14:1 just with HRC box ?

no, i got that from running rvf pistons and taking .5mm off the head

all the hrc box does is change the ignition timing.


tk400 - "If you are running 14:1 I would not be advancing it at all. The HRC box runs the same idle and 4 deg higher at full rpm."

thanks for that info, the only reason why i was interested in advancing it alittle is the bike was originally designed for 91 ron fuel, im using 98 ron currently which from my understanding burns slower. any other info about this would be appreciated. thanks.

I am not sure of the standard comp on the bike, but one assumes that it was fairly low given the spec of 89 octane. The amount taken off the head is fairly high so I suppose that to indicates the original comp would be fairly low, however I do not know the exact differences between standard and HRC pistons so it is hard to say. In any case if we assume your figure of 14:1 is correct, I would not think HRC would have achieved much higher than this on their machines ( if that ) and they usually assume 98 - 100 RON in Kit manuals. So taking all this into account I would hesitate to run any higher advance than standard. However the main problem of advancing it across the board ( all RPM ) is that some parts lower in the RPM range have huge amounts of advance compared to full RPM. So the problems may exist in those regions. If you were temped to change the advance at any particular RPM that may be OK if it was tested cautiously. cheers

Regards TK400.

PS I am in your half of the world so PM me if you want any custom wiring or testing done...cheers.

tk400 wrote:So actuall peak power can drop when using a kit ignition box on some bikes, Unless you have specs similar to the Jap superbike specs of the day. cheers

That's me...It rides better with a standard cdi (rvf).

I sold the unit to pay for some new tyres...

Out of curiosity what did you get for the HRC unit....cheers

$300, I bought it for less coincidentally because the previous owner didn't see any gains on the dyno!