E30 Rb25 Setup Issues

[Candyman69]

haltech plugins run off all the factory sensor's included MAF (mass air flow sensor) unless the volume of air entering through the air flow meter exceeds its measurement capacity. Which is when you disregard the afm and opt for a MAP sensor (manifold absolute pressure).so I'm guessing you will have a map. (vacuum hose from the manifold directly to your ecu) I'm just wondering if you don't have an air temp sensor you wouldn't get the most accurate tune would u?

yes it could be boost spike so you need to see what your boostin at 3000rpm

being a gt30/76 i wouldn't think it would be at full boost 3000rpm on an rb25det unless you have a very small turbine housing

i may be wrong

what boost control do you have? i would check/replace vacuum hose to waste gate as it sounds like it could have a leak.

or actuator could be buggerd. is it internal or external waste gate?

[Timcgt]

How do I turn the boost down? Ecu manager won't let me change anything, and what would cause it to spike?

[Candyman69]

over boost! leaking vacuum hose to wastegate.. or fuct wastegate. if its just spiking then going back to a lower boost level and holding steady could be your boost control. when boost comes on hard at such a fast rate it can spike before the boost control system can correct it. what boost control do you have?

[Timcgt]

I disconnected the actuator and the wg flap moves freely and the actuator has plenty of pull. Is there any way I can test the little boost control solenoid? The vac lines are pretty much new, but I will replace them anyway

[scotty nm35]

Take the solenoid from the system and see if it holds actuator pressure first.

The Mac valve has a bung in the outlet, is it a bleed filter? Make sure nothing is blocked by blowing through it. Usually the outlet is left open but if its a filter you should be fine.

You should be able to test the whole system using a compressor with the reg turned down to target the boost level. Also the Haltech should have a frequency signal you can pump down the solenoid output to simulate its operation, not sure how to do it but I have seen it done many times when setting up the systems.

Sometimes if the highflow is too large for the rear housing the wastegate hole needs to be opened right up, otherwise it will overboost continually.

[Candyman69]

still need to know if its just boost spike or constant over boost? are your ports to solenoid configured correctly? where are you getting your vacuum feed from to port 3 (middle port) should be as close to the turbo as possible for accurate readings. i know some gt3076 have nipples directly on the turbo but some don't. If you are getting it from the intake manifold i would recommend tapping a nipple as close to the turbo as possible as your solenoid will be getting a delayed reading. Also can get a big pressure drop through intercooler. could be causing the spike in boost pressure

[Timcgt]

Yeah there is a filter on the other side of that valve, I'll pull it out and see if it's blocked. Also the signal for boost is just after the turbo in the cooler pipe. How does it work? Map sensor tells the ecu manifold press, then sends the signal to that valve which switches and uses the boost pressure to open the wg?

[Timcgt]

How will I find out what actuator pressure is? Just join the lines and go for a spin?

[scotty nm35]

As long as there are no leaks, yep.

[Candyman69]

ecu gets reading from map sensor. boost level is set through duty cycle/gain on boost map, solenoid will bleed off air until set psi is reached then will divert air to actuator opening waste gate. to test actuator spring pressure you will need a compressor or air pump with a regulator and a gauge. fit to actuator line and pump up until actuator opens then get the reading from the gauge.

[scotty nm35]

to test actuator spring pressure you will need a compressor or air pump with a regulator and a gauge. fit to actuator line and pump up until actuator opens then get the reading from the gauge.

Won't work, you failed to take manifold pressure into account.

[Timcgt]

Won't work, you failed to take manifold pressure into account.

Just to test wg actuator? I woulda thought it will work. If I try and test the whole system with the solenoid still connected I need manifold pressure

[scotty nm35]

The actuator will crack at a much higher pressure with the compressor, as in the car it will have manifold pressure helping push the puck open. The best way to find out the actuator pressure/boost level is to drive it.

[Timcgt]

I took it for a spin with the vac line connected directly to the wg actuator and it opens at 15 psi (so i guess its a 1 bar actuator)

What if i just go for a new boost control soleniod? the mac valve if i can find one

Now it is just a constant overboost with full throttle and it used to be every now and then. So something has been faulty and now is buggered?

That is the only thing that can really cause these symptoms from what i can tell?

[scotty nm35]

Perhaps the engine is flowing more air now with the colder air temps and the wastegate can't keep up anymore? It sounded like it was on its limits.

Do you have a die grinder?

[Timcgt]

Perhaps the engine is flowing more air now with the colder air temps and the wastegate can't keep up anymore? It sounded like it was on its limits.

Do you have a die grinder?

Haha if you can find me a step by step guide I'll have a crack. If the turbo has to come off I'll be replacing it with something a bit more responsive.

I might try and drop the boost to 1bar and see if that changes anything, if it keeps hitting boost cut then I'll get serious. For now I'll swap the valve as they're only 50 bucks. Have a skid day coming up at tailem bend motorsport park so want it going hard for that

[Candyman69]

actuator won't crack thats why you have a regulator to cut pressure at set psi

die grinder?? what you want him to grind out his waste gate port.? would prob delay initial boost build up as exhaust gases will leak even when waste gates closed.

if it boosts fine without solenoid connected theres the obvious problem

could be a wiring faulty to the solenoid or the solenoid itself. (solenoid is bleeding all the air out instead of feeding it to the actuator)

what was you psi setting before this hapend (max boost)

[Timcgt]

18psi

It has slowly gotten worse. It did it once on the drive back from Brisbane and once on the dyno run. But now its constant boost cut with full throttle. I have another actuator coming so I'll try that

[Timcgt]

New actuator didnt fix the problem. Constant boost cut on full throttle. I think scotty nm35 is onto something. Its cold as hell down here atm. And when i picked the car up from brisbane it was fine but that was summer time in qld, no overboost issues, now its winter time in lower SA....

How can i drop my boost level in ecu manager so i can test the actuator? If i go down to 14.7psi, and even if it is opening slow or not flowing enough it should still stop boost rising once its fully open?

I cant seem to alter or even find my max boost setting in haltech ecu manager. i can alter boost cut and restore but cant find anything else.

I have a track day next weekend. Will i do it harm if i just plumb vac line direct from fmic pipe just after turbo to the wg so it opens at 14.7? will it just run rich? or is there a chance it'll lean out?

Also, do you guys recommend running 6 litres of oil if im slidng it to try and prevent oil starvation in a internally stock rb25

[KiwiRS4T]

Mac valves are very reliable so probably not the problem. Ideally a good tuner will stick it on a dyno and pinpoint your problem.

And yes overfill to kink in the dipstick for a little extra insurance.