ETEC Turbo trouble

[heffa]

Hi guys.
I´m running a 13 XM 800 etec with my own custom turbo kit. I´m a novice when it come to turbos, but I´m closing in on something now. But I have these problems ;
- Can´t get more then 3 psi boost no matter what spring I put in the waste gate.
- Using a dobeck gen 3.5 fuel box. Can not get the AF ratio lower then 15 on max boost. Using Deka 85 injectors.
- Sled runs strong up to 7500 rpm´s, but then stops pulling.

The sled runs much better when the engine is cold.
Have checked and rechecked the charge tube and can't find any leaks.
Is it possible that the BOV is to soft and opening to soon?

Any other obvious ting I´m missing here?

Really hoping some of the turbo gurus here on the forum can point me in the right direction

Best regards, Håvard.

 

[turbo800]

If you can't get more than 3 psi boost, you either have a exhaust leak or your leaking boost somewhere between the compressor and the motor. Mine was leaking at the intercooler when I could only make 3 psi. The elbow had started to worked its way off. I was surprised it even made what it did!

Some people use PVC pipe fittings with a rubber fernco (coupler) to the end of charge tube, to test for leaks with compressed air and soapy water. Yes its possible your BOV is opening too soon. That would be a good place to start looking.

You didn't mention what turbo your running. Also not familiar with the Deka injectors. If its a large turbo, it's possible your not getting enough exhaust volume to build boost. Are you sure the Deka injectors are firing?

Double check the wastegate linkage and make sure its fully closing the flapper to make a seal. Also to eliminate the wastegate and spring possibility, just take the hose off the actuator for testing purposes.

 

[Backcountrypro]

First off you will need to find out why you are only building 3 lbs of boost. Your fueling issues are more than likely caused because you are building such a small amount of boost. Does the blue light come on when the boost starts to build?

On my Gen 3.5 box the green blue mode is the switch point for when the fuel turns on when sensing boost. The lower the setting the sooner the fuel starts to come on-on mine setting #1 starts the fueling at 2/3 psi and turning it all the way up to #8 delays the fueling until boost builds to 3.5 psi. Depending on what you have your green blue set at the fuel might not be turning on soon enough. Either way fix your low boost problem first and I almost bet the rest of your problems will become easier to fix.

Now I don't know for certain on this but I imagine the amount of fuel added is directly related to how much boost you are building. If you are only producing 3 lbs of boost the control box will only give X amount of fuel for that psi.

On mine when I max out my red mode and my red/blue mode and hit the throttle it will give so much fuel it will flood the engine.

Like I said get the low boost problem fixed first. Check all the boost lines going to wastegate, boost gauge, and fuel control box. Look for any leaks in the charge tubes and airbox. Possible the exhaust has a major leak at the y-pipe or where the exhaust enters the turbo? Maybe pull the heat shield off the pipe and look for any cracks.

Let us know what you find....

 

[Wheel House Motorsports]

as for the controller, where did you get it, do you know what the modes are set to do?

Dont want to steer you wrong with what to adjust, but i worked there for a while and know my way around the controllers better then most people on here, just need to know what modes are doing what.

As for the kit, first, some pics would be good, to see if there is anything glaring wrong thats hurting you. Second, some specs of parts would be nice, again, to confirm what you having going on.

3rd... but first on the to do list, pressure test things. so many problems can be solved by doing that. you would be amazed what little leaks you will find.

And as for only getting 15 afr wide open, with 85# injectors genaric dobeck etec code is enough fuel to make over 300 horse... so you would know if that was your limit right now... lol

 

[heffa]

Thank you guys for all your help. The specs for the kit :

- D&D ported cylinders with billet head 11,5:1 comp
- Comp 3071 oilless turbo with Tial .86 housing
- Aerocharger snow to air intercooler
- Tial 38mm wastegate w/ Turbosmart boost tee controller
- Turbosmart BOV

Drove the sled with just the D&D cylinders before the turbo mount, engine was super snappy and responsive despite the lowered comp.

I´m offshore at work my self, but I will get someone to check if any of the screws that plug the extra air holes on the waste gate has unscrewed and felt out. That would explain something I guess.

The fuel parameters on the Dobeck is as follows ;

Controller Functionality :

Mode 1 - Green: Bottom End Fuel 5000 rpms to around 6250 rpms 0.5 = 0 or 0 milliseconds
8 = 10 % or .8 milliseconds

Mode 2 - Yellow: Mid Range Fuel 6250rpms to 7200 rpms 0.5 = 0 or 0 milliseconds
8 = 10 % or .8 milliseconds

Mode 3 - Red: Main Jet Trim Fuel. 0.5 = 0 or 0 milliseconds
8 = 30 % or 2.4 milliseconds

Mode 4 - Green/Blue: Boost Fuel at initial Turn on Point. 0.5 = 0 or 0 milliseconds
8 = 30 % or 2.4 milliseconds

Mode 5 - Yellow/Blue: Max Boost Fuel. 0.5 = 30 or 2.4 milliseconds
8 = 80 % or 6.4 milliseconds

Mode 6 - Red/Blue: Boost fuel turn on point. 0.5 = .5 psi
8 = 2 psi


I measure the boost on the engine side on the throttle body, was aiming for 6 psi running 100 % AvGas.

But how do I ensure that the BOV is not opening to soon? And how do I adjust it correctly?

Best regards, Håvard.

 

[gus bohne]

there is no need for a bov on any throttle body sled. you could lock it closed or remove it to determine if that is your leak. turbo sizing is fine.

If the port timing was raised or if the exhaust port was raised or widened your fighting a loosing battle. any time those 2 things are done on a turbo you loose so much of the low to mid transitional torque that fueling gets really rich and tuneabilty suffers.

 

[heffa]

Well, I now know why I´m not getting boost. One of the plug screws on the lower half of the waste gate was gone, so the vent hole was wide open. Will have to fix that when I´m home from work and see what happens.

Gus, we are running the same ported cylinders on an other turbo kit, and it rips. We are driving from sea level to 3000 feet here, so that may have something to do with the fact that the porting is working good here on turbo applications.
The only difference from mine kit versus the other, is that I have lowered the comp to 11,5:1. The engine ripped with this comp without the turbo, and since I´ve been struggling with some other issues after the turbo came on, I haven´t been able to verify how the lowered comp is working with the turbo. I lowered the comp because I wanted to be able to run some more boost safely

Thank you for all the good input, it really helps a novice turbo tuner

Best regards, Håvard

 

[manlye]

Your not building boost because your turbo is waaaaaay to big.


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