Project White Lightning

[mknz]

Don't really get the "90's" joke, Michael ...

I want to monitor the EGTs to fine tune water/meth injection and decide if I may need an intercooler.

Back before widebands were cheap and available enough people used EGT as a reflective indicator of AFR.

Do you have knock output or logging from your ECU? I'd be looking at that. Similarly for intake air temp if it's after the injection kit. EGT is good for getting a reflective indicator on many things, but it doesn't beat direct measurement (except price).

[Benckj]

EGT is useful for fine tuning individual cylinders or on diesels to adjust fuel flow. To ascertain the effectiveness of WI on forced induction it’s best to monitor (and log) your IAT & ambient temps. This will only give an indication of your air charge temp that is one benifit from WI.

[mickeyduck]

On another note Ivor, I don't think it would hurt at all to add an intercooler. As long as your ECU, pump and injectors are able to supply more fuel when the engine gets more oxygen. If you've ever noticed that an engine produces more power on a cold night or early morning, it's hard to imagine why it might be a bad idea...

As for the EGT gauge, I don't see that having one will hurt. I check the recorded high on mine after each drive, just to ensure all is well.

A wide-band makes sense of course as a way to check your tune, seeing as leaning out is a major contributor to blown pistons (along with other things like ignition timing and spark dwell for example).

The last bit of power is always gained on the lean side so a tune needs to be richened up a wee bit after finding the power peak. That's possibly where most folk go wrong, trying to squeeze that last little bit of grunt out.

Or they might do something as simple as fit spark plugs that are standard instead of fitting slightly cooler ones to offset the fact that their boosted engine is now more inclined towards pre-ignition.

And yes checking for knock is a good idea if you have the means. In the old days that meant listening to the engine LOL.

If things do go wrong and combustion chamber temperatures get to pre-ignition / piston melting levels, your pistons will likely blow within a few strokes anyway so it'll all be over before you ever notice a red flashing light on the dash. Whether it's on an EGT gauge or a wide-band one.

Track days can cause the EGT to steadily rise along with various other engine temps (oil, intake, engine bay temps can all rise, even if water temp stays ok...) And the higher the temps get the closer your engine gets to pre-ignition and blown pistons, if it already has a sneaky pre-disposition.

This sums it up fairly well I think: https://en.wikipedia.org/wiki/Pre-ignition

I've only ever blown a piston up on a bike (my old triple, shown in the first post of my Rides thread) and that was due to too much dwell on the points thanks to an old and very worn points cam (which got replaced when I rebuilt the engine). Too much dwell = too hot a spark-plug = pre-ignition even though ignition timing was set correctly. No sensors of any description on that old beast except a rev counter, a speedo and one's own built-in accelerometer. Damn was it fast on a cold night.

Which brings me back to the intercooler. Cool idea.

[psyguy]

Thank for your thoughts guys.
This is my first turbo build and my knowledge is still largely theoretical rather than practical so I may be wrong but this is what I was thinking:

I do have a wideband O2 sensor and AFR gauge. EGT gauge wasn't meant to be instead of the AFR but in addition.
The stock ECU monitors knock and pulls timing if necessary, and I'm going with a safe tune rather than squeezing every last HP out.

As far as I understand it, the W/I injection does not cool the charge air itself but the temp of the gas explosion in the cylinders, and the injection happens just before the throttle body so attempting to measure IATs would be impractical and somewhat meaningless.
The EGTs on the other hand can creep up (especially on track) even if the AFRs are spot on, so this all up is why I wanted to monitor EGTs.

An intercooler would be a great addition but to do it properly (on an MR-S) it would have to be a water-to-air setup with the heat exchanger up front - meaning:
stuffing more lines in the central tunnel under the car (there's already there the A/C lines, oil cooler lines, water cooler lines, etc, so it's getting a little cramped), plus
adding and wiring in a water pump, plus
possible issues with the size of the front bumper air opening (2x water cooling, oil cooling, a/c cooling = 4 radiators). I'd like to keep the A/C.
All issues solvable, but only with $$$ aka the "prohibitive factor"

[Benckj]

WI does cool air charge on entry and also increases density much like an IC. Depending on where IAT located including heat soakage it will pick up the change and compensate. Best to ditch the OEM sensor as they are rubbish and lack fast response.

[psyguy]

OK, we're in business

"Cotronics Resbond" extreme temp threadlock fluid (aka liquid red gold... $$$)
"Inconel" long head alloy studs
Reduced head (10mm) copper coated steel flange locknuts
High tensile grub screws
"Stage 8" bolts with locking washers and circlips

20190810_124926.jpg (284.13 KiB) Viewed 3030 times

While the fasteners are now all good quality there's still the nagging issue of the poorly threaded turbo housing and turbo manifold flange. The studs/bolts are a somewhat overly loose fit and I worry they may not be able to hold the required torque when I tighten everything up. Time will tell.

[mickeyduck]

I need to finish building a new back fence this weekend Ivor, which is likely to take all weekend. But maybe the following weekend I can rock over and take a look with you? Of course you might have it done by then anyway... But let me know.

[psyguy]

I need to finish building a new back fence

Yup, been doing some of that, too

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You're welcome over Charlie... You need to pick up your pot of gold anyhow!

[psyguy]

I got the turbo back on. Reassembly kinda goes fast once you've done it a few times

While in there made the oil feed line longer so it sits further away from the turbo and added a heat sleeve. Heard stories of cars catching fires from the oil feed line melting and spraying hot oil onto the hot turbo housing = instant inferno.
Not on my watch!

[Mr-Paulio]

Looks good mate!
From memory your oil lines were steel braid? So should be fine with heat. (The stories might be fabirc braid or rubber?) But can't hurt aye!

[psyguy]

Installed the AFR and EGT gauges and wired them in. I wish I could have found a more inconspicuous place for them alas the cockpit is so small this placement seemed the best if not the only option.

I had considered a multi functional LCD display for all the gauges but decided it wouldn't suit the car (it's not a Tesla!) plus it would have cost twice as much.

[psyguy]

Looks good mate!
From memory your oil lines were steel braid? So should be fine with heat. (The stories might be fabirc braid or rubber?) But can't hurt aye!

Yes braided SS. But was like just 10mm away from the turbo. So, first I bought the sleeve for it, then realized I had to take the end fitting off to put the sleeve on, then thought bugger it I'll extend the line, then threw on the sleeve anyway cos I had already bought it...

[EssDub]

Out of interest,

Where are you pushing/pulling your water lines from?

I am curious to see your setup.

Ta

G

[psyguy]

Out of interest,
Where are you pushing/pulling your water lines from?
I am curious to see your setup.
Ta
G

From memory:
There's a metal hose attached to the engine on the left side just below the valve cover. That's one.
The second hose (I believe) taps into the hose going from the overflow reservoir.
I'm away til next week so can't have a look to confirm so take this with a grain of salt, my memory may not be 100%

[Jabeo]

i will be interested in seeing how that analog wideband gauge goes, ive been looking at different options for afr gauges but am not a huge fan of digital ones, however ive heard good things about them, but ive not really seen many analog ones used and i prefer the look