So I have my APS kit running on a built motor at 10 psi. The motor is 8.5:1 compression. I will have actuators to increase the boost around mid next week, and I was planning on running 16-18 psi of boost.

A couple issues have come up while running 10 psi of boost however.

1) I have a "true dual" APS exhaust, and I am having a little bit of smoke come out of my exhaust when I let off the throttle out of one side of the exhaust. The right side has the issue, so I assume the problem is ethier one of the cylinders on the driver's side, or the turbo on the driver's side. I am guessing that the smoke is oil at this point but I don't know for sure. I am going to pull the motor to change the actuators I think, so I may just build another motor and put it in, instead. I have only run the motor at 10 psi, and I am pulling 6.5 degrees of timing, and the fuel curve is around 12:1 AFR.

2) I am having a cooling issue after doing about two or three runs in the car, and then parking it after letting it idle after a short time (to cool the turbos). The coolant will start to boil inside the block, and therefore increase water pressure. Soon enough the overflow tank fills up and shoot coolant out like a fountain. This is when the car is off for about 3-4 minutes. When you turn the car on, it immediately sucks the coolant back in to the radiator, and the problem goes away.

I have all stock cooling components at this point. I would be curious to hear what people think about different cooling mods effecting this issue. I imagine it will only get worse at 16-18 psi

Chris

 

Me as well as quite a few others w/ the APS TT are having smoke issues from the left drivers side turbo... Mine's been at the shop for quite a while now trying to remedy the issue. APS has been great about it so far trying to help me.

Your cooling issue is most likely due to bubbles in your cooling system, it's quite a pain to burp it all out. Eventually I gave up and took it to Infiniti to do it for me, had it done in 20 minutes.

 

Wow, so you don't think my motor is done? hah hah That's actually pretty awesome news. What does APS think the issue is? It seems to puff some smoke out after I rev it, and it comes down. The last time I saw that was on an S2000 motor with some scoring on the sleeves.... At idle there is no smoking at all. Does this match your description of the issue?

Chris

 

How much oil did you put in? The "add" line is now your full line, should be about 5 quarts (slightly more).

Since it's only one side you probably just need to adjust the oil drain.

 

Yeah, well my drain hose has been adjusted quite a few times by authorized dealers/installers. I had a complete leakdown/compression test and I'm good in that area. It always seems to be w/ the left driver side turbo. We'll see I guess... Maybe Garrett forgot to put the oil restrictor in the turbo oil inlet and it's receiving too much pressure? Who knows...

I've never heard of this issue with the Greddy TT kit. That may attribute to them using hard oil return lines vs. rubber hoses for interoperability between LHS and RHS cars.

We'll see... hopefully yours is just a hose that needs to be trimmed. Good luck!

 

APS will tell you it is either your oil returns being partially restricted/not trimmed properly or your oil level is not correct.

What you are seeing is EXACTLY what I am seeing on my setup (stock motor). I don't get smoking all the time, but maybe 1/3 of the time.

When I go for a drive, I get into boost pretty hard, slow down to a stop, give the car a quick little rev to maybe 2500 rpms, and a few puffs of smoke as the rpms come down.

 

Chris, this is definately a 100% sign that you have air in your cooling system. It is very common, as the VQ motor is notorious difficult to purge of air bubbles. The process can take 2 hours easily..with two people. Have the system rebled again, and this problem will go away. Now you have me worried that the overheating/boil over...may have caused some heat related damage such as head gasket weakness...resulting in some white smoke.

 

Sharif is exactly correct, as always, lol. I got very tired of the airlock that the stock cooling system created. One of the ways I made the system easier to bleed and it is cooling better is by capping off the two lines for the throttle body. This is actually the highest point for air to get to and I dare to say that this is causing alot of the overheating problems. No matter how good I bled the system it was nearly impossible to get these two lines totally clear. I capped these lines off where they come off the coolant lines and totally eliminated these lines. It made a world of difference. These engines were not made to produce this much heat and this becomes evident anytime you start running high boost on a built motor. I know that it will take longer to heat up the intake tract during the winter but in Florida this is not a real concern of mine. What do you think Sharif?

 

I never ran into the difficulties some have had when filling the coolant. Once I fixed my water leak, it was really easy. Just pour it in super slow (takes about 10 min), start it, run it around 3000rpms for a few sec, shut it off and let it cool down, top off, and repeat the process, making sure you fill it SLOW to get the air bubbles out. It took me 3 times to get it to where the coolant level no longer dropped, and it ran just fine all the way up until I dropped it off at GRD, 1000 miles later.

 

I think these problems are more apparent with built motors. You are still running the stock motor right. I had no problems until I started getting past 11psi with repeated full throttle runs. I have had almost all of the air out and it still bubbles and gets in the highest point(throttle body). No comment on my previous Sharif?

 

I trimmed the oil lines today. When I removed the drain lines, oil came out the top of the fitting in the oil pan. I trimmed off about 2 inches from the LHS turbo, and about an inch and a half from the RHS turbo. I have a very difficult time reading the drip stock, as it seems to have oil all over it when I pull it out. I stock the dip stick in to another motor and it seems that the "low" line on the drip stick is around the bottom most 'rib' on the upper oil pan. So I pulled off the drain lines to trim it, and the oil drained up to just below that bottom rib (top of oil return fitting) and then I added a little bit of oil.

I already have the oil lines to the throttle body capped off. In fact, one of the caps to the throttle body spung a pin hole leak today and I had to replace it. It caused quite a mess as it was spraying coolant in a fine mist all over the engine....

We'll see if the smoking starts to go away, it doesn't bother me that much at this point. My shop buddy is coming back on Tuesday so I will have to wait to do the coolant bleeding. I will just take it easy on the car until then.

Thanks for the help.

Chris

 

Capping off the cooling lines going to the TB will likely not hurt. Many of the aftermarket plenums, such as the SpeedForce Racing manifold, simply bridge the lines. I assume that is what you mean, as you can't physically plug the line, but you can bridge the two lines to maintain continuity of flow. I really havent tried this technique.

IMHO, the main area for air bubbles is the heater core, since you will notice your heat does not operate properly until the heater core is filled with water, and the majority of the bubbles are gone.

As you mentioned, the incidence of overheating usually becomes evident under high boost high load conditions. If there are minor air bubbles in the cooling system, you may not experience overheating/boil-over at moderate boost levels. But as the heat and pressure increase, the water reaches it's thermal capacity...as the air pockets have greately reduced the coolant's effectiveness as a heat transfer medium. Anothe sign of air bubbles, is to monitor your coolant temps. Under boost/load/dyno...the coolant temp will rise, but once you idle back down, the coolant temp should quickly return to the sub 200F range. If it stays at aroun 210-220F, then you know you have more air bubbles to work out of the system. Also note that the stock temp gauge is incredibly lazy, and doesnt budge from abour 170F to 225F.

CJ, forget about trying to read the dipstick with the APS kit Simply drain the oil, change your filter, and add precisely 5 qts of oil. This is about 1/2 qt more than OEM. After you are certain there is no more smoke, you can gradually add 1/4 qt at a time...and repeat the same observation process, but never add more than 5.5qts total. Good luck!