cheekymonkey Posted January 3, 2008 Share Posted January 3, 2008 I thought my EGT sensor was faulty as it was reading about 20 deg C which is possibly rather cool. It seems have to sorted itself out now, may be an intermittent connection but I had a run just now, and got these sort of figures: Idle: 400-450 ish Normal driving: 550-650 ish On boost: 750-850 (may be a bit less than 850) Also, the numbers were changing VERY quickly (both up and down) and made me think I was getting phantom values, but do EGT gauges really react that quickly? CW mounted my sensor literally centimeters from the head, on the exh manifold. Quote Link to comment Share on other sites More sharing options...
bignum Posted January 3, 2008 Share Posted January 3, 2008 Yes those figures sound normal and the quick reaction of the gauge. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 3, 2008 Share Posted January 3, 2008 The figures are fine, what I would expect. Some undamped gauges are hard to read, I use a rather odd looking RS Components display, and it can read in full degrees with a time axis damping, or real time fractional display. You almost certainly WOULD'NT want it in your car though, it's very industrial looking Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 3, 2008 Author Share Posted January 3, 2008 Thanks guys that has put my mind at rest. Also, Chris, the boost controller is working fine now, it was the hoses the wrong way round as you suggested. Getting EGT of 900 odd at 1.2 bar but it quickly drops again afterwards. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 3, 2008 Share Posted January 3, 2008 Good man, glad it's all fine now Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 Just another little worry (yes I worry too much) I want to monitor EGTs because my first cat is still in place, and I know that it can get very hot and make the turbos run too hot (is that right?) However, with the EGT probe mounted *before* the turbos/cat will it still give me adequate warning of things getting too hot? At what point should I be worried? Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted January 4, 2008 Share Posted January 4, 2008 Just another little worry (yes I worry too much) I want to monitor EGTs because my first cat is still in place, and I know that it can get very hot and make the turbos run too hot (is that right?) However, with the EGT probe mounted *before* the turbos/cat will it still give me adequate warning of things getting too hot? At what point should I be worried? do you still have your cat heat sensor probe in? are you running increased boost?? if so I imagine the cat will get hotter than normal but your cat sensor will kick in if things get out of hand! the turbos shouldn't run hotter, only the components after them will feel the heat, the turbos will get hotter the more boost you try and squeeze out of them quite interested to see how you get on with this as its probably the same route im going to take what with my overboosting problems at the mo, so keep me posted Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 do you still have your cat heat sensor probe in? Not sure mate. If it's in the first cat, then most likely it's still there. are you running increased boost?? if so I imagine the cat will get hotter than normal but your cat sensor will kick in if things get out of hand! I raise the boost as needed with my controller. With the controller off in this nice cold weather I get 1.0 bar at full whack. I crank it up to 1.2 when I'm feeling lucky but not very often *grin* quite interested to see how you get on with this as its probably the same route im going to take what with my overboosting problems at the mo, so keep me posted OK so to give you an idea, I have my first cat only in place, and no backbox. It's a 3" pipe from second de-cat to the back of the car. Nice and loud.. and the first cat seems to restrict the boost to a sensible 1.0 bar. So am I right in thinking I won't know if my tubbies are getting too hot until they blow up? Quote Link to comment Share on other sites More sharing options...
Nic Posted January 4, 2008 Share Posted January 4, 2008 Excessively hot EGT's will do your engine damage first, which is why it is best to mount the sensor as close to the engine as possible, so you get an accurate temp of the gasses in the combustion chamber. If the sensor is mounted after the turbo then the EGT's will be quite a bit cooler (roughly 200C). Here's something else for you to worry about, keep your fingers crossed the sensor doesn't break and take a trip through your turbo(s).... Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 Excessively hot EGT's will do your engine damage first, which is why it is best to mount the sensor as close to the engine as possible, so you get an accurate temp of the gasses in the combustion chamber. If the sensor is mounted after the turbo then the EGT's will be quite a bit cooler (roughly 200C). OK, the EGT probe is in the correct place as far as that goes then. What do you think a reasonable upper limit should be for my EGTs? Should I be worried at 1000 deg or 1200 or what for a stock TT engine? Here's something else to worry about, keep your fingers crossed the sensor doesn't break and take a trip through your turbo.... Haha, thanks Nic Quote Link to comment Share on other sites More sharing options...
Nic Posted January 4, 2008 Share Posted January 4, 2008 OK, the EGT probe is in the correct place as far as that goes then. What do you think a reasonable upper limit should be for my EGTs? Should I be worried at 1000 deg or 1200 or what for a stock TT engine? You'll be picking up bits of engine off the road if you manage to reach 1200C 900C is a safe upper limit, if you have an alarm/warning light on your EGT gauge, set it at 900C and if it goes over that then you are getting into dangerous territory. Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 You'll be picking up bits of engine off the road if you manage to reach 1200C 900C is a safe upper limit, if you have an alarm/warning light on your EGT gauge, set it at 900C and if it goes over that then you are getting into dangerous territory. OK thanks! I did hit 900-and-something last night when I went to 1.2 bar.... will keep an eye on that. Of course it's only for a few seconds while on the boost though... Quote Link to comment Share on other sites More sharing options...
Nic Posted January 4, 2008 Share Posted January 4, 2008 OK thanks! I did hit 900-and-something last night when I went to 1.2 bar.... will keep an eye on that. Of course it's only for a few seconds while on the boost though... It only takes a few seconds of excessively high EGT's to do serious engine damage. Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 It only takes a few seconds of excessively high EGT's to do serious engine damage. Whoops! Will see what I get at a more sensible boost level, also the car is being mapped on Sunday with Ryan at SRR so I'll be getting his advice as well Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted January 4, 2008 Share Posted January 4, 2008 It is something to take very seriously with a stock engine and high EGT's, I lost my engine on the dyno as most on here know and the Defi gauge showed 1000oc peak, it melted piston #2 and damaged #1 and #3, I would as Nic said set the peak at 900 and try to avoid going beyond that Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 4, 2008 Share Posted January 4, 2008 1000+ Deg is Bad. Doesn't matter if it is a stock engine or Built, anything over 1000C is going to start melting things. EGT Probs should really always been placed in the manifold approx a few inches away for the head but some people place the Probes in the Exhaust housing of the Turbo which most of the time shows around the same EGT's if not sometimes higher (depending on the AR size and manifold design) than in the manifold (Stainless steel) due to the restrictive elements of the turbo and the cast metal which retains the heat alot more in that Area. I tested this on a car i was working on a while back where we were placed a sensor in the Turbo Exhaust housing and in the manifold (stainless steel) to compare. With a first decat in place i would want to keep the boost down to around 1bar ideally as too much exhaust gas heat will start melting the internals of the Cat which can then cause a restriction. Ryan Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 Thanks guys I will turn the wick down a bit for now. Would my first cat being in place be responsible for my high EGT... would this restriction downstream of the engine be causing it? Quote Link to comment Share on other sites More sharing options...
Nic Posted January 4, 2008 Share Posted January 4, 2008 also the car is being mapped on Sunday with Ryan at SRR so I'll be getting his advice as well That's good, Ryan should see you right Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 4, 2008 Share Posted January 4, 2008 If you remove the BOTH cats you'll see a reduction in EGT's, and a BIG boost in performance at any given boost level, with much faster spooling. You can also map to run weaker, as manufacturers have to pour fuel in under high boost to stop the cat substrates from breaking down with the temps. 50 BHP can be gained on a stock VVTi with no cats and a PROPER re map, just by weakening the on boost mixture. Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 Part of the reason I got Chris to leave my first cat in was to evaluate what the EGTs will be, so I guess I've now established they really will be too high for the sort of boost I want going forward. I will now look at performing a full de-cat and making my exhaust quieter Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 4, 2008 Share Posted January 4, 2008 It would be hard to make it noisier... Tanabe Medallion Touring is what that car needs. Quote Link to comment Share on other sites More sharing options...
cheekymonkey Posted January 4, 2008 Author Share Posted January 4, 2008 It would be hard to make it noisier... Perhaps removing the first cat might do it Tanabe Medallion Touring is what that car needs. I must try and listen to a Supra with one of those. I like the idea of "discreet sports racing" - perhaps it comes with a brown envelope as well! Seriously though, I wish I could keep the same sort of exhaust sound but just make it quieter. I love the canal-boat style warbling at idle Quote Link to comment Share on other sites More sharing options...
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