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Discussion Starter #1
I have the following gauges:

Oil pressure, Oil Temp, Water Temp, and EGT. I have been told by a few people that tapping the downpipe for EGT is useless, but does anyone have an effective way of tapping any of the runners on the manifold without having to remove the whole turbo assembly (stock twins)? And any ideas where to tap for the others without a significant amount of work?

TIA
 
Z

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EGT in DP is totally useless. EGt probe HAS to be before the turbo to be accurate. stock twin turbo generates so much heat itself that it will effect the outcome of your EGT. trust me on this one, I changed a brand new fuel system only to find out my EGT reading was wrong cuz its in DP.
as for water temp sensor, I tapped into the metal tube after the upper rubber coolant tube,
 
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Zerosoul said:
EGT in DP is totally useless. EGt probe HAS to be before the turbo to be accurate. stock twin turbo generates so much heat itself that it will effect the outcome of your EGT.
I'd have to disagree with you on this one.

If you think that it's hot at the top of the DP, how hot do you think it is at the manifolds?

Did you use wideband O2 or just your EGT to determine that you were running lean?

FWIW, I currently have my EGT probe mounted at the top of DP. At the top of 4th gear at full boost, EGT reads 550¡ÆC.

IMO, it's too much of a pain in the ass in trying to mount the probe at the manifold for a gauge you shouldn't use to tune your car in the first place.
 

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Discussion Starter #4
Zerosoul said:
EGT in DP is totally useless. EGt probe HAS to be before the turbo to be accurate. stock twin turbo generates so much heat itself that it will effect the outcome of your EGT. trust me on this one, I changed a brand new fuel system only to find out my EGT reading was wrong cuz its in DP.
as for water temp sensor, I tapped into the metal tube after the upper rubber coolant tube,
Coolant tube as in the pipe coming from the top of the radiator?
 
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Monkeyman said:
I'd have to disagree with you on this one.

If you think that it's hot at the top of the DP, how hot do you think it is at the manifolds?

Did you use wideband O2 or just your EGT to determine that you were running lean?

FWIW, I currently have my EGT probe mounted at the top of DP. At the top of 4th gear at full boost, EGT reads 550¡ÆC.

IMO, it's too much of a pain in the ass in trying to mount the probe at the manifold for a gauge you shouldn't use to tune your car in the first place.
550C at top of DP after 4th gear pull you must be runing at least lower than 10:1 A/F.
stock twin turbo is not designed to take much boost, it overheats as its overboosted (over stock boost) and it creats its own heat, and when add on top of exhaust heat,= more heat.
I have done my research and talk to too many experienced supra owner to bull shit about this topic. why do you think those single owners put their EGT probe in #6 runner, before the turbo, not after? sure its hell difficult to put EGT probe at stock turbo #6 exhaust manifold, but thats what gets you the most accuate reading. and yes, EGT is used for tuning together with A/F.
I have wideband O2 mounted in my DP also, still not as accurate, I tune my car with EGT and dynojets WO2.
 
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Monkeyman said:
I'd have to disagree with you on this one.

If you think that it's hot at the top of the DP, how hot do you think it is at the manifolds?

thats why you need the probe before the turbo to know.
 
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demon said:


Coolant tube as in the pipe coming from the top of the radiator?
yes, at the end of that rubber tube its connected a metal tube that goes into the engine and #1 turbo. thats where you can drill a hole and tap your temp sensor.
 

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I agree that a wideband O2 should be used for tuning and the EGT's for a secondary reference. I have mine at the top of the downpipe, which is where SP mounts them. It may be more accurate with a single than the stock twins. I wouldn't mount mine in the exhaust manifold unless you have money set aside for a new turbo. The probes are terrible for braking off and taking out the turbo (when mounted in the manifold). I would rather tune be A/F, use my EGT for reference based on what it reads at a given A/F and mount my probe after the turbo. Just my 2 cents.

BTW I just spent a weekend on the roadcourse. The tightest corner on the track just happens to be before the longest straight. This allows you to go from the top of 2nd gear all the way to the bottom of 6th. If you really want to see what kind of EGT you will generate this will definitely do it. :) My car is tuned for 11.5 a/f across the rpm range (from about 5,000-6,800). On the street at the topof 2nd I would see 650C and at the top of 3rd I would typically see 680C. On the track after a few laps I would see 735C. Did my a/f change? No. There are a whole lot of factors that can change your EGT. Gear, length of pull, intake temps, cam timing, etc. Basically you should tune with a/f and EGT's are just a good reference given everthing else is consistant. I did richen up my midrange (where I had it leaned out) and my EGT's stayed at 715C, but I was shooting flames out the exhaust during upshifts and downshifts. It was pretty cool, but I knew I was too rich.

Later, Steve
 
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IMO... The A/F gauge and EGT can be used together. Putting the EGT in the dp may give a lower reading, but as far as tuning is concerned, you can still look for the peak EGT for a given engine load and correlate that with what your a/f indicator is saying for a little reassurance. Won't peak EGT always be stoich? As a tuning tool, how is the #6 runner better? If #6 is the hottest on 80% of the 2JZs out there, then it seems like the best place to put it as far as reading the max #. For tuning, don't you still want to find out where the peak EGT is in relation to your air/fuel gauge readings?

Do you really want to tune a car to someone elses peak EGT #s?
 

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demon said:
I have the following gauges:

Oil pressure, Oil Temp

TIA
For my Oil pressure I just removed the stock pressure sensor from the crank case and put the gauge sensor in it's place. Of corse this could cause the ECU to think there is somthing wrong with the oil pressure.

For both Oil pressure and temp, there is an adapter you can get that mounts where the oil filter screws in. The adapter has two spots on it for sensors. Mani's store sells one that is supost to fit all Toyotas (sorry don't have the URL right now). But the web page says you have to use the Corolla oil filter, and I'm not sure about a filter designed for a N/A four banger.

Has anybody tried one of these adapters?

edit:
http://www.drift-motorsports.com/toyota/engine_powertrain.htm
"GReddy Oil Filter Block" last thing on the page.
 

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Discussion Starter #11
Sleepr said:
IMO... The A/F gauge and EGT can be used together. Putting the EGT in the dp may give a lower reading, but as far as tuning is concerned, you can still look for the peak EGT for a given engine load and correlate that with what your a/f indicator is saying for a little reassurance. Won't peak EGT always be stoich? As a tuning tool, how is the #6 runner better? If #6 is the hottest on 80% of the 2JZs out there, then it seems like the best place to put it as far as reading the max #. For tuning, don't you still want to find out where the peak EGT is in relation to your air/fuel gauge readings?

Do you really want to tune a car to someone elses peak EGT #s?
That's what I would have thought. As long as you know the highest EGT reading to correlate to an appropriate A/F ratio then surely whether or not the number is 1-200 degrees inaccurate is largely irrelevant. For example an EGT in the 6th runner may read 800 degrees (random number), while in the DP it may read 600. As long as you know this being the peak number does it really matter?

Thanks for the tip about oil pressure and temp - has anyone tried this using a Corrola GTS oil filter?
 
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