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The mkiv Supra Owners Club

EGT difference results (Pre/Post turbo)


jevansio

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Had my EGT probe moved from in the downpipe (right after the turbo) to in the turbine housing (see attachment).

 

I was previously seeing EGT's of 800 deg after sustained 5th gear high rpm pulls, now I'm seeing 1000 deg. I admit I was sceptical about this 200 deg figure but in my case it seems spot on.

 

My AFR's were on the high side for a WOT run (12 to 12.5) which will be sorted by the next mapping session, but I want to get the EGT as low as possible.

 

So now I have to get them down. My FMIC is an unducted XS Power jobbie so going to start by logging intake temps with my current setup, then get it properly ducted.

 

Couple of things,

 

1) If I can reduce my intake temps by say 10 deg does that mean I will see only 10 deg drop in EGTs or is the effect amplified (for example I might see 30-50 deg drops).

 

2) Is the Greddy 3-Row going to p*ss on the XS Power (same dimensions) in terms of reducing intake temps?

 

This nicely moves onto where can I get a quality 4" core (Greddy 3-row or similar) without having to buy the associated hardpipes.

 

Finally when I get the temps down to a reasonable level (around 900 deg say) I'll add the WI to give the extra safety margin.

IMG_1392.jpg

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Hi Jay

Im fitting a EGT on monday mate when I change my turbos.

I spoke to Chris Wilson and he advised that the probe should be fitted pre turbo as turbos are dempen the temp of the exhaust gas so you dont get an accutate reading.

i think I heard somewhere if you fit it post turbo you should add 150 deg.

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Hi Jay

Im fitting a EGT on monday mate when I change my turbos.

I spoke to Chris Wilson and he advised that the probe should be fitted pre turbo as turbos are dempen the temp of the exhaust gas so you dont get an accutate reading.

i think I heard somewhere if you fit it post turbo you should add 150 deg.

Hi John, yeah, I couldn't believe how much dampening the turbo does, I've only moved the sensor under 6 inches & that's 200 deg!

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Who put your probe there. :conf:

Previously (post turbo) was under advice from Michel (other tuners such as Envy also advise there). It's safer there but reading is inaccurate.

 

Now (pre turbo) is general advice from the forum (I know CW has advised this position for a similar setup) and my mapper (Dan T ). I have a tubular manifold which is more difficult to mount the sensor.

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1000c :blink: get that sorted asap!!

 

You must have a strong engine jay, well done michel

I know!!! Boost is back to 0.8 BAR till it's sorted. I know my 0.68 housing isn't helping as when MikeB went from 0.95 to 0.68 his egt's rocketed, but I have a hunch my FMIC just ain't upto the job anymore

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The main problem at the moment is your a/f i doubt its the intake temps unless they are over 60c.

So a remap is on the cards. While I had my EGT probe moved I also had my injectors flow tested & cleaned (which showed up a problem with 1 or 2 injectors even though they were brand new), I guess this affects fueling in the map before & after.

 

I'm going to log the intakes tomorrow, my FMIC is probably considered as a crap one, will be interesting to see just how good an unducted FMIC is & what benefits ducting gives in terms of intake temps.

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...will be interesting to see just how good an unducted FMIC is & what benefits ducting gives in terms of intake temps.

The benefits are mainly under high boost at motorway speeds.

So you'd need a fast reacting sensor sticking out in the airstream after the FMIC

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It's too high at 1000, that's race engine, forged pistons and regular checks/rebuilds territory, looking for maximum performance and fuel economy!! Get the fuelling set up properly, it's far too weak, you'll be detting it soon!!

When you say weak do you mean lean Chris, does this mean a remap is the best way to bring down egt's. Am I barking up the wrong tree about lowering the intake temps?

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Chris, would you say the probe is okay in the where he has it in the turbo...as i was thinking of putting mine there as its easier to fit, instead of in the tubular manifold.

 

Best place for it as it sees all the gas flow into the turbine side. Only better way is six individual probes, one into each runner. I did my Toyota engine in the Zeus like that. The Motec dash logs each runner temp.http://www.gatesgarth.com/probes.jpg

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Best place for it as it sees all the gas flow into the turbine side. Only better way is six individual probes, one into each runner. I did my Toyota engine in the Zeus like that. The Motec dash logs each runner temp.http://www.gatesgarth.com/probes.jpg

 

 

Loving that setup. Oh if only I had an m600 :(

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When you say weak do you mean lean Chris, does this mean a remap is the best way to bring down egt's. Am I barking up the wrong tree about lowering the intake temps?

 

Lowering intake temps may help v.slightly, however your major problem is the AFR. 12.5 is way too lean at WOT for anything but a seriously build block like Chris said. You want them around 11.5 ideally.

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Lowering intake temps may help v.slightly, however your major problem is the AFR. 12.5 is way too lean at WOT for anything but a seriously build block like Chris said. You want them around 11.5 ideally.

Cheers looks like I need a remap then :), will prolly duct the FMIC too though.

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That's interesting reading... good to see it quantified, thanks for posting that up.

 

my egt's are still quite high at the mo with the .68 housing, even with WI... I'd say around 750 + 150 correction sustained multiple wot at 11.3/11.4, I can see my oil temps rise more rapidly these days as well.

 

Was thinking of flow testing injectors and then trying the .82 housing.. when I get my arms fixed :innocent:

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No worries Mike,

 

Just had my injectors cleaned & flow tested, they needed it, flow rates & spray patterns were off on 2 of them. I suppose this will contribute to the incorrect fuelling now.

 

Be interested to see if the .81 gives you the same buzz as the .68, I don't really want to lose the response & low down hit it's currently got.

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