I e-mailed Jeff directly on this , nut I know he is a busy person , so I will ask everyone.I am looking for a moderately priced heat shield for my stock turbo, for my 1990 Turbo Grand Prix.I previously used the universal wrap from Thermo-Tec but I prefer not too keep the heat in.I did wrap the manifolds and down pipe which should help as far as melting stuff in the eng. bay.But a heatshield would be great for the turbo durability and would make great use of the vent on the hood . I saw one on the web for $79.00 for a T3 or T4 turbo , would this work? It looks like it has 2 mounting holes that should line up by the down pipe flange. I just layed the rebuilt motor and tranny in this afternoon.I ordered a blow off valve and am hoping I can get a heat shield before the end of the week. I'm also interested in a turbo timer , any advice on this? The only one I could find was a univeral type w/o a harness/connector.
Welcome to the site BTW, this is a very good thread . Personally I haven't got that far, I've just rebuilt my 5 speed and will be installing it in next weekend :peace:. But soon after this, I will be looking into that. defintely the turbo timer. I followed up on a thread in here and someone installed a security system that already had the turbo timer included, you should check into this.
http://cgi.ebay.com/VIPER-DEI-REMOTE-START-AND-ALARM-791XV-2-way-paging_W0QQitemZ300067757910QQihZ020QQcategoryZ94832QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Why don't you want to hold the heat in the turbo?
Because if you dont let the metal surfaces cool down befor the engine shuts down it will burn the oil causing early turbo bearing failure. Since you need the engine running to flow the oil....
Quote from: pontiac6ksteawd on January 06, 2007, 10:29:06 PM
Because if you dont let the metal surfaces cool down befor the engine shuts down it will burn the oil causing early turbo bearing failure. Since you need the engine running to flow the oil....
turbo timer +1
Quote from: pontiac6ksteawd on January 06, 2007, 10:29:06 PM
Because if you dont let the metal surfaces cool down befor the engine shuts down it will burn the oil causing early turbo bearing failure. Since you need the engine running to flow the oil....
If you use synthetic oil you NEVER have to worry about coking and seal failure. Also if you are not in the boost a few minutes before you shut down you don't have to worry about coking with dino oil. If you allow the exhaust gases to cool before it enters the downpipe you will lose performance. The longer you can hold the heat in the exhaust the greater the velocity of the gases leaving the engine. Give it a place to cool and condense and you will lose the velocity.
Now look at the fact that the T25 is nothing more than a bottle neck at the turbine wheel. If you allow the gases to cool and condense at the bottle neck and you lost a good portion of the velocity on a system that is too small to begin with.
Lastly we have an oil cooled and water cooled center cartridge. The water cooling will wick the heat out of the cartridge LONG before air cooling just because the turbine housing is not insulated.
To each his own on this one but I have seen way to many loses from not insulating the turbine housing rather than wrapping it up or ceramic coating it along with the piping before the turbo. I have said it before and I will say it again...BTUs are a part of power production and the longer the heat (BTUs) stays in the exhaust the better you are.
Even with sunthetic oils, I would imagine that it would still be a good idea because the oil could cook the seals around the compressor. Also with the motor running, it allows the bearings to cool off at the same pace, and evenly.
I dont know, I let my car cool down for 1 minute befor i shut it down. For 2 reasons, I always drive it like I stole it, and that little sticker on my sun visor tells me so.
Quote from: pontiac6ksteawd on January 07, 2007, 10:16:40 AM
I dont know, I let my car cool down for 1 minute befor i shut it down. For 2 reasons, I always drive it like I stole it, and that little sticker on my sun visor tells me so.
x2 MUST OBEY THE STICKER!!! :laugh:
Like I said to each his own on this. Was Synthetic oil used in these cars in 1989-1990?
I agree with you as far as velocity , but I would sacrifice a little velocity for cooler air(=denser air=more horse power) I had one of those laser thermometers (point and shoot) and checked different temperatures at different locations at idle and after a hard blast ,and I really didn't write it down but they were ridiculously high at both.Off the top of my head it was a good 600 dg F at the turbo and 450-500 dg F at the manifolds while giving it throttle , and I'd say about 250-260 going into the throttle body/upper plenum pipe.While I do agree that volumetric efficiency is important , so is thermal efficiency.There has to be a good balance between the 2 to maximize performance, and, fuel economy while we're at it.I mean is it me or has anybody else noticed that you actually use more fuel in the hot summer air the on a nice 60 dg day , because the computer has to add a lot more fuel to cool the mixture to prevent it from pinging ,and at the temps. I mentioned above that ECU is adding a lot of fuel at mid to wide open throttle.I did wrap the pipe to the throttle body and the turbo and these temperatures dropped by about 100-200 dgs, which definitely helped insulate the air going into the throttle body from the intercooler and give me a little more "umf".I will say this , I'm no expert, but I have recently purchased a really good book from S and K speed that really went into detail about turbo's and superchargers and it was really informative.(I can't find it right now or I'd tell you the name of it :-( ) One thing that was mentioned that I found interesting was that the turbo out performs the supercharger as far has creating horsepower is concerned , the one draw back is the heat exchanged from the turbine housing to the compressor housing, and based on everything else I read in there (they all these crazy formulas and graphs-really nice pics too) I feel it is important to cool everything you can because there is plenty of heat being generated from that exhaust ,and if your getting on it the way I am getting on it your probably going to have too much heat.Next time you see a fairly new Mack truck or a Case ,Dae woo FEL try to sneak a peak at the size of there intercooler , it is gigantic , or even a new Ford F550-F750 - Gigantic , They want to keep these things cool for durability and max performance , I cant afford a bigger intercooler right now ,but I will be getting one in the future,right now , I just hope some one can tell me where I can get a heat shield at a decent price.Anyone???
Very good, turnawrench :thumb:
Very good if it made sense.
Folks are talking about removing the heat blanket from the turbine side of the turbo to reduce temps in the intake stream. How can you reduce temps under hood and radiating from the turbine housing if you have removed the blanket?
There is no way the intake is at 600*F at idle or full throttle. The IAT would melt right out of the intake plenum. You could light a cigarette off the intake! The under plenum vacuum lines would be melted as well. ;) The temp off the exhaust manifolds right out of the port maybe...but not the intake piping or plenum.
What you are saying about the ECU making it richer under higher temps is completely false. This is nothing more than cause and effect. If the intake air is less dense because it is hot, it takes less fuel than what is being injected by the ECU. If it was a cold day and it could burn all of the excess fuel you would be at a better mix rate. If you do not burn all the fuel you will be rich. These ECUs are direct programming for fuel. Set the fuel table and you are there. I can run my car on the dyno today at 40*F outside and then do it on a 100*F day and the fueling is EXACTLY the same. I may be 20 HP difference and a half a point different on my A/F on those two days...but the fueling is the same. The only thing this ECU controls is boost and timing to reduce knock (ping). The Coolant temp is a direct link to whether or not the ECU decides to fatten the mixture and that is only during idle to fatten the mix during warm-up. The ECU in our cars could not care less if it is hot outside or cold. If it is cold outside you get more power because the charge air is more dense. More power because it is COLD not because the ECU says...ok it is 20*F outside and we can use this special fuel and spark table to give this guy a ride! ;)
If you are on a Jeff M generic tune or stock tune (same fuel tables) then YES it fattens up ridiculously during mid and full throttle. It is programmed that way from the factory (unchanged by Jeff M generic tune) that as soon as it sees the boost breakover it richens up to cool the cylinders during boost. Problem is it is SUB 10.0:1 A/F mix and you are LOSING power just because the cylinders are being quenched with too much fuel. I have proven a 30 HP increase just by removing fuel that is not needed under boost conditions and getting in at 11.2:1 for a safe tune. I run 12.5:1 on my personal cars and see a considerable power increase without playing with timing...that is where the extended power comes from.
Yes...Insulate your intake charge pipe. Yes insulate or Jet-Hot your turbine housing and insulate your downpipe. Yes insulate or Jet-Hot your manifolds and cross-over. HOLD IN ALL THE HEAT YOU CAN until it gets to your tailpipe. The cooler it is under your hood the better. The longer the heat stays in the exhaust the better. But to remove the heat-blanket on the turbine housing so things cool better makes ZERO sense to me. Now when you do some research on our T25 you will see there is a HUGE heat issue just because it has no where to go after it leaves the cylinder. If you open up the turbine wheel to reduce the IMMENSE backpressure the T25 has you will see a large HP increase as well as reduced underhood temps because it is not holding exhaust gases in the exhaust manifolds, cross-over, and turbine housing.
As far as your heat shield...I do not know where to send you for that. Reason I have not explored a heat shield for our application is it does nothing for us if you properly insulate everything. ;)
:confused: :confused: :thinking: :thinking: :leaving:
Am I seeing double. Two Jeff post in one thread. :laugh: Good points both of you. :thumb:
Kinda miss some of thoes old long winded threads. :icon_sad:
Jud
I've gotta say though, some of the things turnawrench said are not true. I tune motorcycle engines and it is DEFINITELY not true about a richer mixture on hot days- It is the opposite. Hotter air temps will not cause detonation, but when the engine is under a load, it will. Hot air at say 90* requires LESS fuel to run than say 60* air. You can adjust the timing to remedy detonation, not add fuel. That is what KR is/does in cars. /end hijack
Thats correct. And a prime example of this is during the winter, your car will get worse fuel milage. Maybe not much, but it will. Where as in the summer, it will get better fuel milage. My truck for example will get 7.2 MPG in the summer, and 6.4 in the winter. The density of the air directly affects fuel milage. And density is a direct affect of temps.
EXACTLY. The air is more oxygen concentrated in the winter cold, therefore, there needs to be a richer fuel mixture to remedy this. The air is less oxygen concentrated in the summer, so a leaner fuel mixture is required in the summer. Generally, the hotter the temps, the less fuel is required, therefore you will get better gas mileage in the summer, and in the winter- vice versa.
I'm not picking a fight or an argument ,but for the record , I never said it was 600 dg at the intake , that would be crazy as was stated , and as far as my theory on fuel consumption , I could be wrong , my motor was extremely tired (177,000 mi) when I started noticing this so that could have a lot to do with it , but ar we 100% sure that all the knock sensor adjust is timing and boost control? What if that is not enough to cool down the cylinders?How much can it really back off the timing without taking away too much power? Is the ECU really just relying on the CTS for input or do several other sensors come into play , including the knock sensor? I believe they all come into play.The knock sensor is smarter then you think ,it not only controls timing it also shortens the injector pulse width and increases the duration.Think about it for a second , if it has to cool the top of the pistons, the intake and exhaust valves , and the combustion chamber , can it really cool it down enough just by retarding the timing and lowering the boost? I strongly believe that too much heat is not a good thing.Also for the record I did not compare winter fuel economy to summer.It was more of a spring to hot humid NY summer comparison.Once again I'm not trying to be insulting ,I just want to voice my opinion and here yours so we can all learn from each other.I have a lot of respect for this thread , the info supplied from it , and the work I've seen some of you guys to these rare breeds.I've seen the pics and it has inspired me.That is why I decide to keep her and rebuild her , I think she is worth it and I just want the best for her LOL.
You are not making anyone mad or not showing respect...I just have an abrasive sound when people read what I type because I stick to the facts. Do not take it personal...just most on here have learned that about me and do not take what they read from me to them to heart.
Now as far as the ECU telling the injectors to fatten the mixture when it senses knock. Please tell me what line in the code for the LG5 says that?