Tdiclubers hate mtdi!!

[TylerDurden]

IIRC, turbos get hotter... more fuel + more air = more fire. Never heard of anyone needing a pyrometer on a NA.

[One_punchmachinegun]

Yeah, I'm no expert. Just kinda a theory. I feel like if there is any over fueling with a diesel it make a hotter environment. With a turbo diesel at least you have the extra air flow, I'm sure it has it cons. Really I feel that it would vary with the type of setups. turbo, intercooler, exhaust size etc. I mean at turbo would create a harsher environment, but hotter? Idk.

[theman53]

I know a guy killed an na dropping precup. I think one tiny shot of ether was involved.

[TylerDurden]

Yeah, I'm no expert. Just kinda a theory. I feel like if there is any over fueling with a diesel it make a hotter environment. With a turbo diesel at least you have the extra air flow, I'm sure it has it cons. Really I feel that it would vary with the type of setups. turbo, intercooler, exhaust size etc. I mean at turbo would create a harsher environment, but hotter? Idk.

I liken it to an oxy-acetylene torch: you can light-off just the fuel and crank open the valve, get a big sooty flame and not much heat... add a bit of O2 and things get hot.

I can def see a precup blowing out with ether.

[theman53]

When mine ate the precup my TD pump was with Giles and I was running as an ECO...turbo but no fuel for it.

[One_punchmachinegun]

With diesel fuel and how it burns doesn't require a flame, which I'm sure you know. Now, diesel engine get hot from over fueling and gassers get hot from under fueling. So if a diesel is putting fuel into the chamber to be burnt for energy, and there isn't quite enough air to completely burn that off it will cause the fuel to slightly burn and become a sooty mess. This is was causes the higher EGTs.. So for a diesel I don't quite is air being the issue, fuel quantity seem to play the role of higher EGTs. Another way to look at it is "how to lower EGTs?" From what I've gathered it get more air in the chamber to burn it all. By adding a good intercooler to the mix you cool the air making it more dense, resulting it be more concentrate so to speak. When that cool air hits the combustion chamber it expands from the heat, making more air to burn the fuel. Cleaning up the exhaust and lowering the EGTs. But that's just one way to slightly lower EGTs. Not that your wrong, that's just my spin on it. I'm no expert.
Why does the unburnt fuel cause the high EGTs, maybe something to do with flow? Idk.. but a turbo I could see speed up the process, since most times you have to fuel more to create the boost you want.

[jboogie13]

With diesel fuel and how it burns doesn't require a flame, which I'm sure you know. Now, diesel engine get hot from over fueling and gassers get hot from under fueling. So if a diesel is putting fuel into the chamber to be burnt for energy, and there isn't quite enough air to completely burn that off it will cause the fuel to slightly burn and become a sooty mess. This is was causes the higher EGTs.. So for a diesel I don't quite is air being the issue, fuel quantity seem to play the role of higher EGTs. Another way to look at it is "how to lower EGTs?" From what I've gathered it get more air in the chamber to burn it all. By adding a good intercooler to the mix you cool the air making it more dense, resulting it be more concentrate so to speak. When that cool air hits the combustion chamber it expands from the heat, making more air to burn the fuel. Cleaning up the exhaust and lowering the EGTs. But that's just one way to slightly lower EGTs. Not that your wrong, that's just my spin on it. I'm no expert.
Why does the unburnt fuel cause the high EGTs, maybe something to do with flow? Idk.. but a turbo I could see speed up the process, since most times you have to fuel more to create the boost you want.

More fuel creates higher egt's because its not completely burned by the time the exhaust valve opens, meaning that it is still burning as it passes through the valve(s) and turbo, thus over temping the turbine, and coking the oil in the bearing.

[vanbcguy]

With diesel fuel and how it burns doesn't require a flame, which I'm sure you know. Now, diesel engine get hot from over fueling and gassers get hot from under fueling. So if a diesel is putting fuel into the chamber to be burnt for energy, and there isn't quite enough air to completely burn that off it will cause the fuel to slightly burn and become a sooty mess. This is was causes the higher EGTs.. So for a diesel I don't quite is air being the issue, fuel quantity seem to play the role of higher EGTs. Another way to look at it is "how to lower EGTs?" From what I've gathered it get more air in the chamber to burn it all. By adding a good intercooler to the mix you cool the air making it more dense, resulting it be more concentrate so to speak. When that cool air hits the combustion chamber it expands from the heat, making more air to burn the fuel. Cleaning up the exhaust and lowering the EGTs. But that's just one way to slightly lower EGTs. Not that your wrong, that's just my spin on it. I'm no expert.
Why does the unburnt fuel cause the high EGTs, maybe something to do with flow? Idk.. but a turbo I could see speed up the process, since most times you have to fuel more to create the boost you want.

More fuel creates higher egt's because its not completely burned by the time the exhaust valve opens, meaning that it is still burning as it passes through the valve(s) and turbo, thus over temping the turbine, and coking the oil in the bearing.

Some of that comes down to injection duration though... Small injectors with a small pump means to get a given fuel quantity in the cylinder the injection duration becomes longer - so even though you started injecting before TDC you are continuing to inject long after in order to get the volume of fuel you need in to the engine since the orifice you are pushing the fuel through is small and the pressure you have available to push it is low.

The result is the same as retarded timing - high EGTs because the fuel is continuing to burn as it exits the exhaust valve.  That's why a larger pump and larger injector nozzles work out so well on the DI engines - they can get the quantity of fuel needed in to the cylinder in a short period of time, allowing it to burn completely at the right time provided there is sufficient air in the cylinder for the volume of fuel being burned.

So the "when" is just as important as the "how much" when it comes to fuel, especially with DI engines where the combustion chamber only exists at TDC.

Naturally firing off a massive slug of fuel over a very short window will cause a significant jump in peak cylinder pressure - too much fuel too fast can be quite destructive even if there is sufficient air to burn it.  At some point you hit the physical limits of the pistons / head or possibly even the block in terms of actually containing the expansion of gasses from burning diesel.

[Smoker]

So the guy asked Giles how much power to expect out of a mechanical pump, and he said 'about the same'...    guy then assumes that he means that the MAX output of tdi-m would be about the same as a STOCK tdi-e?  A little common sense would go a long way.

[One_punchmachinegun]

Haha

[CRSMP5]

thats his true opinion sadly...

look at it like this... his m pumps are combo of other pumps....

8v played that game... finally slapped a rover pump on and it came to life.....

so i honestly think he needs to play with a few real tdi-m pumps... then see his opinion change...

[JessaBug]

I will say after toying around with my girlfriends mk4 ALH this past week doing the tbelt and messing with vag com I've come to more appreciate the electronic system. my problem with the people on TDI club however is they do not want to think outside their box whatsoever anything against the status quo over there gets your head cut off. I'm considering going electronic on my Passat just for something to do this winter. I still plan on keeping my mechanical pump so when the Chinese start blasting us with EMP.

thats what i don't like, they're all stuck in a box doing all the same mods, making all these posts like they're engineers and half of what they say is irrelevant or exaggerated or wrong.

This.This.This. I do read a lot over there, since we do have a TDI now, but some of the regurgitated false information just frustrates me. Its a whole clan of sheeple over there for the most part. Diesel is the best ever. And those old IDI diesels are scarrrrrry. A lot of times I look for people posting about IDIs just so I can direct them here. There are a few people over there who know a bit about IDIs but not many.

I will say that I do appreciate the electronics in the TDI. It is nice to hook up VAG-COM and get information on problems. But there are some problems that don't throw a code, and when that happens, it can really suck to track down. We've had a cold starting problem off and on in my husband's TDI that we can't track down. Its been fine lately, but we'll see once it gets colder this fall if it comes back. We have our '84 TD and an '01 TDI. They both have their pros and cons. But the mk1 is definitely much more fun. We'll be getting rid of the mk4 long before that mk1 goes anywhere

[CRSMP5]

vnt system is great check engine code issue with no real way to watch via vag-com... need a boost gauge and a vacume gauge rigged in to watch the system work.. and will show you sticky vnt vains.. or sticky valves or a crimped/damaged/plugged vac line... took me a year to figure out the test and if i owned any vnt car id run those 2 gauges just so i can spot when it starts to screws up... took me under 60 seconds to see the vains stick on my project.. and resolved guys over boost issue when his return vac line from the purge valves was blocked up and did not dump the vac off fast enough... spider eggs.. gotta love them...

[libbydiesel]

The electronics only assist in diagnosing issues that occur with the electronic engine management.  None of those issues can ever occur on a mechanically controlled diesel.  I suppose that it is nice to have the easy diagnosis of the slew of issues that you'd never have with an mTDI, but I'd rather just not have those issues and not need to diagnose them...

[RabbitJockey]

The electronics only assist in diagnosing issues that occur with the electronic engine management.  None of those issues can ever occur on a mechanically controlled diesel.  I suppose that it is nice to have the easy diagnosis of the slew of issues that you'd never have with an mTDI, but I'd rather just not have those issues and not need to diagnose them...

aint