ALFAGTV6.COM

[Micke]

My turn for a question again.

The right spark plugs for std engines are easy. But what about tuned/racing ones. Is there any way to determine the right plug temperature?
I used both NGK 7 and 8 and didn't feel or see any difference. Should I just use 8 to be safe or what should I do?

This topic came up cleaning my garage (Don't worry. The 9's are for my snowmobile) :

PS! Measured the plugs in a dyno once. The 7 EV increased the power by 1% compared to Lodges. Did 3 runs each for better accuracy. I think they are called X nowadays.

[Jim K]

If everything else is so perfect you're down to looking for horses with different plugs I envy you! A friend here spent a day on the dyno changing plugs and gaps on a special street Renault Williams 2liter engine I built and the best he could see was 1-2hp in a total of 182hp, which starts to fade into tolerances, uncertainties and so forth. He had much better luck adjusting and regulating the voltage to the fuel pump with a gizmo mounted right next to it and even more power and acceleration was found by disconnecting the alternator at WOT (DemonTweeks had this special relay). He also got more power by running minimum oil level (which speaks a lot for baffles, trays etc). All these tricks added together gave about 5-7hp.
If you have a good powerful spark, you can use NGK B9ES and Champion N2C all year round for road and track. If you can afford the real serious MSD boxes, go for them. We got a couple of HVC sets (box+coil) from US eBay and they are excellent stuff, if its good enough for NASCAR they're good enough for us too, don't you think?
Jim K.

[Micke]

Everything else isn't perfect I'm afraid.

However, I was on the dyno and this was an easy thing to check. Tried race gas as well but it brought less than the plugs. Both on a mildly tuned Spider with ~145 hp (10.5 CR, headers, mild cams, 40/34 carbs)

The fuel pump won't help on my carb engine I guess

I'm no elctrical guru but how can I easily do this alternator mod? I actually thought about it a long time ago but forgot it.

You didn't really answer the question. Of course I can use 9 temp plugs but if 7 or 8 work the colder shouldn't help any do they?

[Jim K]

Right, plug heat range doesn't do shiit for power as long as they're not too hot to cause problems or too cold to foul.
The alt cutoff device can be a simple 40A relay operated in two possible ways: simplest one is with a microswitch on the throttle lever and the one the commercial unit uses is intake vacuum, adjustable value.
Jim K.

[la_strega_nera]

The alt cutoff device can be a simple 40A relay operated in two possible ways: simplest one is with a microswitch on the throttle lever and the one the commercial unit uses is intake vacuum, adjustable value.
Jim K.

For internally regulated alternators the relay splices into the the small "signal wire" for the Alternator?(I can't think of the correct name for it! Field wire?)

Otherwise you're using a 40A relay to switch a source that could be pulling 80-90-100A? (I realise you'd be in full power sink mode at these amperages and be running the battery very flat)

I'm very interested in using this trick... (actually, I remember thinking about it years back for my GTV...)

[Jim K]

I'm pretty sure they diconnected the alternator output wire. In practical terms, I wouldn't think that all possible electrical loads can be turned on while someone floors the paddle during a dragrace! The instructions warned against prolonged actuation of the device as very likely to result in a dead battery.
Jim K.

[la_strega_nera]

I'm pretty sure they diconnected the alternator output wire. In practical terms, I wouldn't think that all possible electrical loads can be turned on while someone floors the paddle during a dragrace! The instructions warned against prolonged actuation of the device as very likely to result in a dead battery.
Jim K.

I was thinking along the lines of using it for circuit racing...