Optimum ignition timing for a KR ?

[Sideways Steve 10]

Ok folks my question is this. I know the stock timing figure for the KR is 6 Deg BTDC at idle with the coil red wire disconnected.

 

However as with tuning any petrol engine more advance on the timing generally = more power so has anyone on here experimented with that theory and increased the dizzy advance ? If so what value have you found to be ideal ?

 

On the old mk1 MX5's the stock setting was 10 deg BTDC but I always found they ran far better set to 12 deg BTDC until you boosted them in which case I used to use a piggy back ECU to remap it and pull the timing right back under load and on boost. These adjusted values used to see me getting 129bhp @ 12 deg from the stock N/A cars as opposed to the factory 116bhp @ 10deg and additionally in the region of 240bhp from the boosted 1.6's with the remap and otehr supporting mods.

 

I assume similar gains should theoretically be possible from the KR ?

[tony_ack 0]

6 deg is pretty conservative and supposedly suited to running 95 ron, so if you're running 97 ron or above, try increasing to 8 deg. The first restriction is going to be engine knock, as the KR has no knock sensor.

[Wild-Animal 0]

I was under the impression the KR engine had to run on 98 octane with 6 degrees, my fiiller flap says it on it on the inside 98 octane, and i know mine does not like it when you run normal 95 octane.

 

As for ignition timing I amsure someone on here will be able to tell you

[davidwort 0]

Depends on the individual engine and the setup of the metering head and warm up regulator for fuelling.

On some you can get away with a fair bit more base advance, even for regular unleaded.

It's best optimised on a rolling road though, to make sure you're not getting slight pinking you can't hear and to get the best balance of power and torque.

As a guide, if you advance a degree at idle and it still doesn't pink when hot up a hill in 5th with your foot to the floor at say 2,500 revs you should be fine.

 

Mine is set up (on rolling road) to 8.5 degrees, but has fuelling to match and has a gasflowed and polished head which helps avoid pinking, it's a KR head but on a slightly higher compression 2L bottom end.

[Sideways Steve 10]

I also was under the impression that the 6 degrees value was for 98 RON. I will have a look over it again tonight and possibly advance it to 8 degrees and see how it gets on :)

 

---------- Post added at 03:13 PM ---------- Previous post was at 03:05 PM ----------

 

Depends on the individual engine and the setup of the metering head and warm up regulator for fuelling.

On some you can get away with a fair bit more base advance, even for regular unleaded.

It's best optimised on a rolling road though, to make sure you're not getting slight pinking you can't hear and to get the best balance of power and torque.

As a guide, if you advance a degree at idle and it still doesn't pink when hot up a hill in 5th with your foot to the floor at say 2,500 revs you should be fine.

 

Mine is set up (on rolling road) to 8.5 degrees, but has fuelling to match and has a gasflowed and polished head which helps avoid pinking, it's a KR head but on a slightly higher compression 2L bottom end.

 

Cheers for that David, I used to have some det cans for remapping all the jap stuff I was into but when I got rid of the car I also sold off all of my gear such as my cans and my wideband kit. Kinda wish I had kept them now as Id have been able to get some good advance dialed in and been able to hear the DET before it was at a damaging level.

 

I think I will go for 8 degrees and see how it feels/sounds then take it from there.

 

I am also taking it to a guy I used to use years ago when I had my Mk2's called Ralph Payne. He was part of teh VW motorsport team and was teh head VW tech who actually wrote some of the VW factory tech manuals and procedures. Hes actually got a genuine copy of the Digifant set up procedures in his workshop and its a genuine VAG copy and he was the author which is kinda cool.

 

Im really just popping along so that he can set my mixture properly as I know for a fact its miles off. I usually dont use garages at all but this guy is a pro when it comes to these old Dubs so I trust him.

[Kevin Bacon 5]

I didn't think you could adjust the KR's off idle ignition advance? Or does clocking the dizzy round advance (or retard) the whole rpm band? I'm sure the KR had a little ignition box up by the wipers that took care of the timing, but it's been a while since fiddling with these engines.

 

Saw a 16V Turbo Technics engine on the floor of Stealth's workshop on Saturday, which was very nostalgic for me :D

[Sideways Steve 10]

What your saying is correct, you cant actually adjust the off idle advance, but if you adjust the base advance it has an overall effect on the advance over the whole rev range.

 

The wee box you mention controls the advance during actual running but uses the base timing setting as its starting point which is in turn set mechanically by moving the dizzy.