Direct Injection = Carbon Buildup?
07-18-2013, 08:54 PM
#81
If you think rocking a car back and forth as described in the thread above is common/smart practice you are being primitive. There is no reason one would rock the driveline of a car in FIRST gear forward/backward on any of these big dollar engines.
Breaker bar in one direction, well yeah duh. The above thread was referring to the crank being hard to get to, so rocking it back and forth in first is the best solution. Haha, not the same as bumping a starter pal.
I would like to see someone do that on a Valvetronic motor on one of these forums without the valves at min. lift. I'm sure theres already a thread for that too LOL
I agree not many people will want to be running meth on an N/A V8. We just got a couple new GMCs in. I havent seen one in the shop yet so I still haven't seen how they set the PCV up.
Breaker bar in one direction, well yeah duh. The above thread was referring to the crank being hard to get to, so rocking it back and forth in first is the best solution. Haha, not the same as bumping a starter pal.
I would like to see someone do that on a Valvetronic motor on one of these forums without the valves at min. lift. I'm sure theres already a thread for that too LOL
I agree not many people will want to be running meth on an N/A V8. We just got a couple new GMCs in. I havent seen one in the shop yet so I still haven't seen how they set the PCV up.
07-19-2013, 07:20 AM
#82
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Another thing not being considered is how the meth system is setup. Maybe those who havent had good results have it set to turn on at wot only and need to refill there tank once a month.
The meth ingredients arent that cheap anymore and it wouldnt be hard to believe those experts on the bmw forums you referenced might be cheap on the spray.
It was pretty common we were hosing the motor down to the point we needed refill meth twice a tank. including lots of mexico high speed rallys. that could be the difference youre looking for.
The meth ingredients arent that cheap anymore and it wouldnt be hard to believe those experts on the bmw forums you referenced might be cheap on the spray.
It was pretty common we were hosing the motor down to the point we needed refill meth twice a tank. including lots of mexico high speed rallys. that could be the difference youre looking for.
07-19-2013, 09:26 PM
#83
Why don't you explain how it is any different to turn the engine by the flywheel with a starter, than by the flywheel with the trans???
While your at it, you can add what being an interference engine makes a difference. The starter wont save a valve from being bent, hell most starters have enough *** to bend a rod if there is too much fluid in the chamber
by that logic, pop starting a car would destroy the engine...
The engine doesn't know the difference, it only knows its being turned...
07-23-2013, 12:37 PM
#84
FWIW IMHO when you are doing valves, its easier to bump the car back and forth, or use a breaker bar to turn the engine, as you can always stop the crank exactly where you want it.
Why don't you explain how it is any different to turn the engine by the flywheel with a starter, than by the flywheel with the trans???
While your at it, you can add what being an interference engine makes a difference. The starter wont save a valve from being bent, hell most starters have enough *** to bend a rod if there is too much fluid in the chamber
by that logic, pop starting a car would destroy the engine...
The engine doesn't know the difference, it only knows its being turned..
Why don't you explain how it is any different to turn the engine by the flywheel with a starter, than by the flywheel with the trans???
While your at it, you can add what being an interference engine makes a difference. The starter wont save a valve from being bent, hell most starters have enough *** to bend a rod if there is too much fluid in the chamber
by that logic, pop starting a car would destroy the engine...
The engine doesn't know the difference, it only knows its being turned..
Theres more than one way to skin a cat in this instance
07-23-2013, 12:42 PM
#85
Another thing not being considered is how the meth system is setup. Maybe those who havent had good results have it set to turn on at wot only and need to refill there tank once a month.
The meth ingredients arent that cheap anymore and it wouldnt be hard to believe those experts on the bmw forums you referenced might be cheap on the spray.
It was pretty common we were hosing the motor down to the point we needed refill meth twice a tank. including lots of mexico high speed rallys. that could be the difference youre looking for.
The meth ingredients arent that cheap anymore and it wouldnt be hard to believe those experts on the bmw forums you referenced might be cheap on the spray.
It was pretty common we were hosing the motor down to the point we needed refill meth twice a tank. including lots of mexico high speed rallys. that could be the difference youre looking for.
07-24-2013, 02:32 PM
#86
I'll put my 2cents in on this subject as a reformed Audi B7 RS4 owner I'm more than familiar with intake valve build up on direct injected gasoline fueled engines. Making a motor work is a study in physics, electronics, and CHEMISTRY! I say there is a MASSIVE FAIL on the part of Direct Injected gasoline fueled motors. The build up isn't only oil from PCV system but also tars, and parrafins from the fuel being injected into the cylinder. The fuel air mixture in most high performance motors will have a tendency to reverse flow at certain RPM levels, that tendency has to do with lots of aspects but, in a high performance motor with lots of intake to exhaust overlap on cam timing (much less overlap in the C7 than in an RS4) reversion is always present during some period of motor operation (in old Detroit muscle the reversion most evident at idle the "lopey cam" sound.) During this time of reversion, the fuel mix hits the backside of an intake valve which is no longer being cooled by a fuel mixture crossing its backside while entering the combustion chamber. This hotter valve causes the mixture to boil and leave heavy deposits of tar/paraffin that are present in even the best "Top Tier" fuels. This build up will be present on all DI motors, the VW 2.0 4 cylinder, the DI Lexus motors, Mercedes, Audis, the GM 3.6 V6, even Porsche DI motors are showing problems. If you don't want build up run your C7 on E85 and enjoy the 18MPG fuel mileage.
No easy solution to this one!
No easy solution to this one!
07-25-2013, 03:05 PM
#87
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I can confirm this is an issue for us N54 guys. I have walnut blasted 4 N54 cars now including my own 2x in the past 60k. Every 20-30k the idle will get pretty rough and the DME will kick in a bump the idle rpms from 650 to 900rpm to smooth it out. It take about 3 hours start to finish. The only items that have to come off the car are the intakes filters and the intake manifold. From that point on its just TDC the piston and blast away then vacuum the debris out. Runs like butter afterwards.
07-25-2013, 05:08 PM
#88
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I'll put my 2cents in on this subject as a reformed Audi B7 RS4 owner I'm more than familiar with intake valve build up on direct injected gasoline fueled engines. Making a motor work is a study in physics, electronics, and CHEMISTRY! I say there is a MASSIVE FAIL on the part of Direct Injected gasoline fueled motors. The build up isn't only oil from PCV system but also tars, and parrafins from the fuel being injected into the cylinder. The fuel air mixture in most high performance motors will have a tendency to reverse flow at certain RPM levels, that tendency has to do with lots of aspects but, in a high performance motor with lots of intake to exhaust overlap on cam timing (much less overlap in the C7 than in an RS4) reversion is always present during some period of motor operation (in old Detroit muscle the reversion most evident at idle the "lopey cam" sound.) During this time of reversion, the fuel mix hits the backside of an intake valve which is no longer being cooled by a fuel mixture crossing its backside while entering the combustion chamber. This hotter valve causes the mixture to boil and leave heavy deposits of tar/paraffin that are present in even the best "Top Tier" fuels. This build up will be present on all DI motors, the VW 2.0 4 cylinder, the DI Lexus motors, Mercedes, Audis, the GM 3.6 V6, even Porsche DI motors are showing problems. If you don't want build up run your C7 on E85 and enjoy the 18MPG fuel mileage.
No easy solution to this one!
No easy solution to this one!
On the new LT1, the cam phaser does not allow independent adjustment of either the intake or exhaust valves. The overlap is fixed. So that bodes well for keeping intake deposits down.
