At The Dyno With A Handfull Of Resistors!?!

[CEF11E]

I was at the place where i get my car scerviced today and there was a kid there with his silvia on the dyno.

I got to talking to him as he was tuning his car and i was curious as to what he was doing.

He was doing a power run, looking at the AFR's and then putting a resistor between the AFM and the ECU!!!! he would do another power run and check the AFR's.

I informed him this would lean out the AFR's right accross the range and he looked at me like i was an idiot!! and said to me Look at the afr's man, its rich right accross the range, sure enough he was right!!!

He was upping the resistance value each run by 0.02 of a watt.

I saw the figures, before and after, and he went from 152rwkw to 164rwkw and his afrs were still below 12:1

He said by doing this he had illiminated boost cut, advanced the timing, and was using less fuel.

Not bad for 6cents for the resistor...

[R31Nismoid]

very much backyard, and yeah. been done before

[Zebbie]

He was upping the resistance value each run by 0.02 of a watt.

Don't you mean Ohm, KOhm?

[Roy]

Wouldnt a potentiometer (ie variable resistor) be easier then forever changing resistors? Well thats what those crazy VL boys did back in th eearly 90s to get the things on song cheaply

[MattSR]

This has to be the STUPIDEST thing I have ever heard done to a car.

[MattSR]

And yeah, a pot is a far smarter idea Roy

[CEF11E]

why is it stupid if done monitoring the AFR's?

it is doing the exact same thing as a safc except right accross the rev range. and providing you don't go too lean what the hell is wrong with it?

I think in the right application it is fine.

[dangerous_daveo]

I mean, if worst comes to worst hes only going to blow up a CA or even better an SR. Good for him!

At least he is smart enough to test it, not just read something on the net saying use a xx resitor, it will help.

[scathing]

eBay has a lot to answer for.

[Zebbie]

I wouldn't use a pot, apart from getting the right value, as there's vibration, moisture issues etc...

Once you have the right value, measure the resistance, then put in a fixed resistor - You don't want your afr's changing at every pothole, of it it rains :-D

[CEF11E]

yeah thats what i was thinking about a pot. as soon as you bump it you lean out.

CA's have feelings too! just because they are a bit "special"!!! there seems to be no love for the CA anymore:(

[psybic]

Its just as dodgy as bleed valve boost control. Plenty of people use that without concern.

Both too dodgy in my opinion, but those using bleed valves for boost or fuel cut defender are just as bad. He is loosing flow of electricity instead of air.

[proengines]

BMW's group A cars back in the 80's were tuned using the same method, it worked well for them.

[predator]

ahhh, silvia owners. Got to love it.. where their wallet is as small as their brain..

[CEF11E]

[qoute] Its just as dodgy as bleed valve boost control. Plenty of people use that without concern.

Both too dodgy in my opinion, but those using bleed valves for boost or fuel cut defender are just as bad. He is loosing flow of electricity instead of air. [qoute]

haha! that means I am a bad man... I have a turbotech bleed valve, I am a very bad man...

BMW's group A cars back in the 80's were tuned using the same method, it worked well for them.

Thats very interesting. I used to love those John Player Special little black BM's:)

Edited November 25, 2005 by CEF11E

[GunMetalR33]

I did this on my old VL and there was no issues... as long as you get the afm's right and keep a buffer just incase then I see no dramas...

[R31Nismoid]

Its just as dodgy as bleed valve boost control.

*sigh* i love these types of un-educated comments.

How can you even remotely say that?

I was running a bleeder of my gate upto 24psi... 7psi through the valve and a hold in the line for a bit more

It never spiked, never changed the level of boost, never gave a reason for me to think i'd wasted $10

Correctly done a bleeder can be of the same level as an EBC without the mammoth expense.

[Butters]

I'll point out what i see as an issue with this idea.

he is adjusting the AFM reading accross everything. It is not dependant on RPM / Load / Temp / Conditions.

Sure he is testing on the dyno I assume full power runs at full throttle.

I would say he could get that quite right.

I doubt he tested all rpm / load conditions at all temps.

If he leans it out with this method, everything is leaner !!

Things like close loop driving will be leaner. Light throtle leaner. Cold start leaner etc etc ....

Sure he can leave a "buffer" but as you can imagine it would not be an ideal way to do things.

[benl1981]

Closed loop wont be leaner. It will adjust fueling based on 02 sensor output!!

It's dodgy but hey if you dont go too far it should be ok. I mean you wouldnt do it to an expensive engine..

for the cost of a jaycar DFA or SAFC you are smarter to do that...

[Wazz]

ahhh, silvia owners. Got to love it.. where their wallet is as small as their brain..

<{POST_SNAPBACK}>

you might want to take that back moron.. sure some silvia owners are stingy bastards but you gotta remember were not all like that

im also sure there are skyline owners just as stingy out there aswell

asswipe

Wazz

Edited November 25, 2005 by Wazz