jd5217

Are these usefull & where would I get one?

Peanuts

iTrader: (15)

depends on the level of tune, in a fairly standard "woolly" kind of tune its money better spent elsewhere.
If you tune to your car to somewhere near the limit then its useful.

the search function on here is buggered but I believe Lascar and Nomad do some quite nice.

look for a high refresh rate, no point monitoring temps if you only get a reading every 10s. a lot can happen in that time.

When the search is back up look under CT gauge

silent running

Yes if you're interested in your charge temp. It's pretty fundamental to how a turbocharged car performs. It always surprises me that so many drivers of everyday road-going Scoobies are so worried about monitoring detonation with knocklinks yet they don't bother with their charge temps!

What you want is a two channel gauge, take channel one from just after the outlet of the turbo, channel two from just after the intercooler. From this you can tell how efficient your intercooler is, how the weather and road speed affects it and exactly how hot the charge going into the engine is (assuming the heat picked up through the inlet manifold is more or less constant).

Autometer make one that unfortunately only reads in imperial, but they can't be the only makers that do charge temp gauges.

silent running

I agree, it's not necessary in low tune, but I think that there are a lot of people get caught up in fussing about wide band lambda readings, different degrees of knock detection etc etc, when monitoring these kind of things in a road car is overkill. I'd always be looking at charge temp first. If you can't keep charge temps under control, you'll always struggle with knock.

As far as refresh rate goes, if you get a cheapo electronic temp gauge then get the best rate you can afford. Maplin do a unit for less than a tenner IIRC that updates every second, reads -20 to +70C, is powered by a watch battery and has a probe on a long length of lead that will easily reach from the cabin into the engine bay. It has a big LCD display although unfortunately not back lit.You just need to be able to solder a connection.

I've seen other gauges that were more or less the same thing, sold for automotive use as some kind of high tech tool, going for £40 or £50. Complete waste of money. Either get a cheapo basic Maplins job or get a full house proper 2 1/4" gauge with fast acting thermocouple probes. There is no in-between.

PICKLE

Nomad racing one fitted to my car. Reads upto 70'c from memory (It hit that in traffic when on TMIC in summer one year!!!! )

It reads in 0.0'c and is constantly variable, so it reads up and down in hundreths of seconds, and is backlit green etc..



You will need to cut off the Plastic fitting on the end carefully, and punch a small hole in the Throttle Body hose. Poke probe through so its half way across the throttle body width, then dab some super glue round the outside of the hose to secure, and make airtight.



Available from here: http://www.nomadracing.com/catalog/p...8c8ff8cc039a2a

T_H_E__c_R_O_W

very nice looking, very stock

DubaiNeil

I also wanted to assess the charge temperature, but also wanted to be able to trigger an event if the temperature exceeded a set threshold (i.e. switch water injection on).
All of the displays I would find (and I bought most of them!) are just a fancy thermometer, and just provide real time information.
I personally didn't consider this that useful, as when on boost, when I would want to know what the charge temperature was doing, I tend to be a bit busy trying to keep the car on the road!
Pretty much as Silent Runnings said, I ended up going with SPA digital gauges and currently measure oil temp/oil pressure + charge temp/boost of two dual function gauges. They have seperate sensor channels with high/low alarms that can be used to trigger external relays - so meeting my needs there. They also have a recall facility for highest values recorded, so I can review the value after a 'spirited' test run.

Having gone to all this trouble. I then found that my charge temp is consistent, or slightly cooler, than the ambient temp - so I am now undecided if I need to have WI fitted or not!

The SPA stuff is not cheap, costing me approx GBP400 for the guages and sensors, fitting is obviously extra, and required a fair amount of work to plumb all of the sensors in place.

john banks

When you have an often deaf knock control system that sometimes even has a failed knock sensor and shows no fault, fragile MAF sensor that can fail without a fault being shown, fuel pumps that weaken and aftermarket regulators that fail, and an ECU that doesn't know the real AFR or EGT, then a wideband and knocklink are not overkill on a modified car. Charge temperature is nice, but less so if you have a nice big intercooler, but if it is high enough to cause damage it will probably result in your knocklink lighting up. Conversely, if the charge temperature is fine but the engine knocks for another reason, your charge temp gauge will show you nothing.

If I had to have two gauges in a Subaru I'd have a knocklink and wideband AFR (or EGT) over any others for these reasons. Then oil temperature.

Bob Rawle

Pete Lewis will give you a good arguement though John. Charge temp is a good thing if you are determining how your intercooler is working and whether it needs upgrading, given correct fueling and ignition then a visual knock indicator is the real thing to have.

As John says good for info but not going to offer info that will assist in a det related incident necessarily.

Coolant temp and egt gauges come high on my list in addition to oil pressure and temp. Coolant temp is very sensitive to problems.

bob

PICKLE

As Bob says, I fitted the above to the car when running a Hybrid Turbo, but was still on the STI5 TMIC. Gauge was fitted to monitor charge temps then, so when I went FMIC I kept it to see the difference it made.

You would not believe the difference in CT from the TMIC to the FMIC!!
Used to climb when on boost upto around 50'c in summer months (TMIC)

Now it stays around 2-3'c above outside temps

silent running

I can see where you're coming from, but your point seems to be that because every single component in a car can and does fail at some stage, you need to monitor every single thing that could possibly go wrong. So where do you draw the line? When you've got so many gauges and meters everywhere that you can barely keep your eyes on the road? I've driven, modified and tuned various cars myself in the past, the last one to a pretty serious level, and I've fallen into that trap of having 6 or 7 gauges in front of me and constantly having to watch them all to make sure that the engine was in no danger of knackering. OK perhaps Subarus have particular recurrent faults, but then so does every make in the world.

Are you saying that the Subaru ECU does not monitor AFR from the lambda sensor in the downpipe and operates in closed loop all the time, fuelling off a look-up table? Or are you saying that the Subaru runs fuel injection just like every other car in the world, but for some reason its lambda sensor is sub-standard compared to others?

As far as the knocklink thing goes, yes I would agree that there is a case for one on a highly modified engine, running very close to the edge of detonation, as it should be if its tuned properly. I just question why there are that many road-driven Subarus out there that have been tuned that edgy that they have any need to monitor knock at all. Doesn't the ECU measure air temp itself anyway? Surely if it sees a rapidly rising inlet temp, along with full boost and full throttle, the most basic response must be (or should be) to pull the timing...regardless of what the knock sensor is saying. Are there NO failsafe systems at all in a factory Subaru ECU?

I'm saying all of this on a technical level, not in the hope of getting into an argument :-) I'll freely admit I've only owned and worked on my wagon for 6 months, but I've got a fairly good idea of general principles. It has never failed to surprise me how fragile and badly engineered the Subaru seems to be regarded as, by modders and tuners who appear to know about such things.