cygnusx1 Posted July 12, 2004 Share Posted July 12, 2004 I wrapped my exhaust turbine with thermotec wrap designed for this purpose. I wanted to reduce engine bay temps and run the turbine more efficiently. Tonight, I got back from a hard highway run and even after a five minute easy cool down ride, I could see orange glow from under the wrap. Any thoughts on this. Is the wrap a bad idea and is a glowing turbo a bad sign? Quote Link to comment Share on other sites More sharing options...
Jersey Posted July 12, 2004 Share Posted July 12, 2004 I would think after a 5 minute easy cool down, the glow should be gone. If i press my T3 for a good run, she'll glow but it'll go away after a minute or so while idling. I dont know too much about the thermotec wrap your using but it sounds like your exhaust temps are a bit high. Do you know if your running lean on top? Could be the cause. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 12, 2004 Author Share Posted July 12, 2004 Well, I dont know what temps Im running and I dont know what % Im running. I know I'm playing with fire but I tried to set everything up fairly conservatively. I have the AFM tuned to just a tick leaner than where the heavy black soot stops from the tailpipe during WOT. I dont have tons of tuning experience with a turbo. I do know that lean will run high EGT but doesnt excessive rich also cause high turbine temps? BTW the FMU brings fuel 55psi at 13boost. Quote Link to comment Share on other sites More sharing options...
Jersey Posted July 12, 2004 Share Posted July 12, 2004 Hows your exhaust? I see in your signature - 2.5" SS Exhaust/DP - mandral bent? running a cat? which muffler? 2.5" all the way back? Just wondering if there's any restriction. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 13, 2004 Author Share Posted July 13, 2004 Nice glow in that photo! I am running SS 45 degree downpipe 2.5" and it is 2.5" all the way back with no cat. The only thing in my exhaust is the 2.5" Magnaflow Muffler at the tail pipe. The muffler is WIDE open with a straight through flow. Looking through it makes me wonder why I even put it there. I also dont drive it much over 5200 rpms ever--well sometimes I do like the other night Just a good habit I guess. I wish I had a EGT or wideband AF meter to let me know if I was in the ballpark. I thought it was running great but when I saw the turbine glow, I thought again; maybe sumtings rong. Regardless of the glow, it does run good. Quote Link to comment Share on other sites More sharing options...
Clifton Posted July 13, 2004 Share Posted July 13, 2004 I used header wrap on my trucks turbo and a stainless heat shield, can't see if this one glows. It's so tight in there it was starting to warp my plastic valve cover with out the wrap/sheild. I had a D21 Nissan pickup with the Z24 and a turbo. It would glow just from driving, without even boosting. I didn't have a heat shield or wrap on that one though. Quote Link to comment Share on other sites More sharing options...
Sean73 Posted July 13, 2004 Share Posted July 13, 2004 If the turbo is running red hot, it's still going to run red hot with the wrap. All the wrap does is help heat retention (which aids flow) and reduce underhood temps. It won't reduce turbine temps, and due to the blanketing effect it probably will make the turbine remain hotter for longer after you shut down. Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 13, 2004 Share Posted July 13, 2004 Your timing maybe be retarted. A late firing ignition causes a lot of unburnt fuel to be pushed out the exhaust valve and then it finishes burning in the exhaust manifold. That is how they make those pretty glowing photos. A rich mixture and majorly retarding timing. My V8 Z will make the headers glow cherry red unless I use at least 20 degrees of initial timing. Try advancing the timing. If it pings then you should reduce the amount the distributor can advance so more initial timing can be used. Or get a boost timing retard I welded up my distributor advance slot in my 76 turbo Z so it advances only 8 more degrees after idle (stock is about 18 degrees more mechanical advance). Then, I set the initial timing at 20 and it advances to 28 by 3500 rpm. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 13, 2004 Author Share Posted July 13, 2004 SO let me get this straight. Lean wil cause high exhaust gas temps and rich will cause high exhaust temps also. So a perfect mixture and burn should yield the lowest turbine temp given all other conditions the same. -improper timing mimicks a lean or rich condition by either burning too hot (ping) or ejecting unburned fuel; both leading to high egt's. Correct? BTW I run stock ZXT base timing 21 or 22 degrees. Quote Link to comment Share on other sites More sharing options...
Nigel Posted July 14, 2004 Share Posted July 14, 2004 Hmm... Well, highest exhaust gas temps occur at stoiciometric (14.7 to 1). So, it depends what side you start off on. If the engine is running lean, say at 16 to 1 and you make the mixture richer, EGT's will go up. If the engine is running rich at say 12 to 1 and you make the mixture leaner, again, EGT's will go up. So the trick is to know which side you're on. If it was puffing black on acceleration, then I think it would be pretty safe to say you're on the rich side. However, I'm thinking that a lot of unburnt gas (really rich or timing issue?) may light off in the turbo causing it to glow like Pyro stated. Nigel Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 14, 2004 Share Posted July 14, 2004 Well, if you are running 21 degrees base timing then i would think you are just running super rich. I don't think a lean mixture will not make a manifold glow red. How is your gas milage? How does you car idle? smooth or a little rough? Have you done a compression test lately? A stuck open exhaust valve could do that. What is your fuel pressure at idle? Are you using turbo injectors with a Non-turbo ecu then a FMU to raise the fuel pressure? If so, the turbo injectors will make your car run very rich at idle. A non-turbo ecu can use turbo injectors if you lower the pressure to 15-20 psi at idle. Also, a bad water temp sensor or a bad connection at the water temp sensor will cause a very rich condition. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 17, 2004 Author Share Posted July 17, 2004 Thanks for the tips.. Sorry but this is a bit wordy: Well I use a stock 83 turbo motor and stock 83 turbo ECCS and stock turbo injectors. I am not sure there is a water temp sensor in this sytem, It uses head temp which is working fine. Funny you mention idle. I can get a super smooth idle by adding some fuel mixture at idle by using the AFM wheel/spring to dial it in. Once I get a perfect idle, I think she runs rich at anything above idle. The reason I say this is because after setting it rich enough to get a rock steady idle, she will puff smoke when I rev after idle. If I lean it back out (AFM spring) to get a rough idle, the puff of smoke will not come out when I rev it off idle. All this seemed to scream, "INTAKE LEAK" but I have not found any yet. I realize the FMU is a potential source of richness and since I cannot watch the fuel pressure gauge while driving. I am going to disable the FMU and see what happens. Based on tests I did, the FMU will build fuel pressure to a of 55psi at 13psi boost or so. Maybe the richening curve of the FMU is too early. I may try my "patentpending" idea of putting a grainger-valve in the FMU boost sense line to keep the FMU from doing anything until 13psi. Anyhow, based on what you guys are saying, I do think the turbo is heating up from unburned fuel. The fact that the car smells rich and that I do see puffs of black smoke off-idle and sometimes while getting into boost spells rich also. After all that......the car runs pretty good overall and I was only a bit concerned with the glowing turbo so I hear it's fairly normal to light up a turbo anyhow. Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 19, 2004 Share Posted July 19, 2004 Since you are using all the turbo efi electronics then I would say the FMU is set way too high. Try ramping to only 45 psi at 13 psi. Yep, could be a vacuum leak. Z's will lose vacuum from just about everywhere. I have heard of vacuum leaks caused by bad rear main seals! Does your engine die when you remove the oil cap? It should if the vacuum system is working correctly. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 20, 2004 Author Share Posted July 20, 2004 Hehe, I started thinking about that FMU also and decided to tweak it down a bit last weekend. I turned it down, set up the AFM wheel a little richer to get that sweet idle, and then opened the plug gaps a little bit. I had them gapped tight but I find it to run a little smoother during daily driving gapped just a touch under factory spec. It was running really nice after all that. I guess you were correct that the FMU was doing too much. I am not sure about the vacuum leaks. I can't find any. Idle does drop about 200rpms when opening the oil cap or the dipstick but it does not stall. Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 20, 2004 Share Posted July 20, 2004 That is good news. The last thing you need to do is connect the tube from the valve cover to the intake tube between the AFM and turbo. You might need to lean it out after that. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 20, 2004 Author Share Posted July 20, 2004 Oh, that tube is already connected. In the photos it does not look connected but it is. I made a copper pipe "offset" that connects the lower end of the gray tube off the valve cover to the rubber intake boot just downstream of the AFM. The copper pipe allows it to go under the throttle body without kinking that gray hose. I also have the BOV vented into a 1.5" bulkhead fitting in the same rubber intake boot after the AFM. It's a pity that I can't hear the BOV at all since it's recirculated. I plan on taking some detail photos and possibly a driving movie soon. Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 20, 2004 Share Posted July 20, 2004 Is that a straight T4 or a T3/T4? What compressor wheel are you using? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 21, 2004 Author Share Posted July 21, 2004 The turbo in the photos is the old stock T3 but I am currently using a T04B Compressor side... its a reman turbo from "zcarsmakemyheadhurt", a forum member. He said it was a Super V trim wheel. I am not sure what numbers that equates to but I know it has more lag than stock and pulls REAL hard the faster I go. It is definately a high flow turbo. I managed to use the stock AFM-Turbo boot even though the TO4B compressor intake is about 3". At first, the turbo suction collapsed my cold air intake tube so I replaced that with a tougher tube then the ZX AFM-Turbo rubber boot was collapsing so I put the metal spring back into it. Ooops forgot to answer your question. The turbine is a T3. Quote Link to comment Share on other sites More sharing options...
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