The Tuning Talk Thread - Forced Induction EFI & JZ Tuning.

[1JZ-Rolla]

I can't read a farking thing off them either, zoomed in and still couldn't see, just assumed my eyes were stuffed

[BLACKCAT]

If you have your car dyno tuned at 11.5 A/F wot on a 30*C day how much would that ratio change in the real world (on road) on a much cooler day, say 15*C?

[oldcorollas]

if the ECU doesn't have air temp compensation? or you mean the AFR you could run for the cooler temp?
(and depends if MAP or AFM)

[wilbo666]

If you have your car dyno tuned at 11.5 A/F wot on a 30*C day how much would that ratio change in the real world (on road) on a much cooler day, say 15*C?

You can use the equation for the change in density vs temp to work this out (in ideal terms)
(Assuming no Air Temp Correction)

http://en.wikipedia.org/wiki/Density_of_air

Cheers
Wilbo

[loop it]

sorry i saved them wrong...

[BLACKCAT]

MAP with no air temp correction.
Well using the figures on those charts the A/F ratio would lean out to 12.1 at 15C & 12.5 at 5C.
I worry when a tuner says they always tune to a particular A/F regardless of the temp on the day & that the car will run richer on the road.
So you should always tune a lot richer on a hot day, assuming the ECU has no air temp correction.

[thechuckster]

So you should always tune a lot richer on a hot day, assuming the ECU has no air temp correction.

is a less-than-satisfactory assumption. If the ECU does to have IAT correction, then I'd seriously consider replacing/enabling it

[oldcorollas]

no air temp correction = no closed loop O2 correction and no coolant temp correction also?

may as well be running a carby...

[BLACKCAT]

It does have coolant temp correction but runs in open loop as its a Microtech.

[wilbo666]

It does have coolant temp correction but runs in open loop as its a Microtech.

As the other guys have said, I don't know if an ECU that doesn't have an Intake Air Temp Sensor (IAT), as well as a coolant sensor...

The air temp sensor should be used to compensate for changing air temps

Cheers
Wilbo

[OnAll-FOUR]

MAP with no air temp correction.
Well using the figures on those charts the A/F ratio would lean out to 12.1 at 15C & 12.5 at 5C.
I worry when a tuner says they always tune to a particular A/F regardless of the temp on the day & that the car will run richer on the road.
So you should always tune a lot richer on a hot day, assuming the ECU has no air temp correction.

I think he is some what correct but maybe not advisable. My Wolf was installed without IAT and it has run pretty well so far. However I think it is a far from ideal setup.

I think what he is trying to say is that if he tunes it for a coldest day ( most air density) then any time the temps get hotter ( less air density) then the car will be over fueling for that situation. So in theory on the safe side.

How advisable that is is a different matter.

[loop it]

anyone have any thoughts on the tune ?

[1JZ-Rolla]

I have finally run the new GT3582 and 6 into 1 manifold setup on the dyno, at a local dyno day today.

Very happy with the result, have cracked 300wkw thorough the auto, and ran consistently within 1kw on all three power runs:



Tune still needs a tidy-up, you can see how the AFR's drop below 11.0:1 as it transitions through a load point on its way to the target 19psi boost. Can still pull some more fuel from 5000rpm onwards, where the motor (with stock cams) starts to lose efficiency.

Also confirmed just how much low/midrange power it's lost coming from the GT3076 and Y-pipe adapter. I can't overlay the dyno sheets, but the chart below shows the lost power until 4500rpm (as a result of the higher boost threshold/response)




In summary, if you want a quick circuit/street car that's ready to go as soon as you drop the hammer, stick to a GT3076, not a GT3582

Cheers
Phil

[thechuckster]

does this mean changes to launch strategy (or a different convertor) for drag racing?

or an excuse to use NO2 ?

[1JZ-Rolla]

Will just try it and see mate, I don't expect it will make boost on the line like it did before though, and hence 60' times will probably suffer.

Its probably at the stage where if the box came out for a different convertor, then it should also get built internals too. A $3000 exercise that i'd rather avoid right now and put the cash into the Supra instead.