boosting issues

[Limbo]

Hi guys
Just wanna see if anyone can give me some ideas with my car.
Currently its boosting but only around 6PSI, it spikes at 7PSI but drops to 6PSI.

Was working fine before, i changed the intercooler.
I've changed to a smaller cooler for better airflow around the car.

I've chcked for air leaks but found none, changed the BOV just in case.
checked the eboost lines, but nothing coming up with anything.

Anyone with any ideas?

Was working fine before i changed intercoolers.

[mugen_ctr]

did u get a larger cooler? usually this is why it happens, larger volume of air, requiring more air to fill it to get it above positive air pressure....

1psi spike is nothing, if ur spiking to 12psi than id b worried! since the set limit was on 6psi

If u got money to blow, electronic boost controller ftw! they can hold the boost at 6psi much better than any bleed valve through the whole RPM's

[Limbo]

i changed to a smaller cooler & i'm running eboost2

[mooshie]

How much of a size difference are we talking and what boost have you got it set to?

[DLO01]

And where is E boost plumbed in to? Before intercooler or after? I'd say you have it before interecooler?

What was the boost with the old intercooler?

[Limbo]

plumbed into intake manifold for reading
boost on older cooler was 10PSI.
Can feel the difference when i drive it also, doesn't have the punch it use to after 4.5krpm

[B16]

Have you checked the wastegate? There could be a problem there, stuck or something similar. If you have no leaks and the boost source point is at the IM, it would not be different from the previous setup.

I had a fubar wastegate that was leaking and causing boost creep, could be a similar problem but reversed.

[TODA AU]

Your problem is simple, easily explained & rectified with what you already have.
Steady 10psi - no problem,
Your real problem is that you probably can't do this yourself & deep down, you know you're going to have to pay someone to sort it out for you. Lol...
You can try do it yourself...
But at your own peril... lol

Your issue in a nutshell...
You have an increased pressure drop across the cooler core.
You have not compensated for this in your ebc settings.
Dropping the gate pressure will solve the perceived spike.
Increasing the rate will up the boost.

[Slaz]

lol at some of the posts, but Adrian has pointed out the problem.

[B16]

Please explain. I don't understand how that can be correct. If the eboost is measuring and regulating pressure at the intake manifold, it doesn't matter two hoots what the pressure drop across the intercooler is as the EBC should just keep the wastegate closed longer untill the pre determined pressure is reached at the measuring/regulating point, in this case the intake manifold....

[DLO01]

^^^ thats how I understand too Matty. Its measuring boost for wastegate at intake manifold.

[Limbo]

Please explain. I don't understand how that can be correct. If the eboost is measuring and regulating pressure at the intake manifold, it doesn't matter two hoots what the pressure drop across the intercooler is as the EBC should just keep the wastegate closed longer untill the pre determined pressure is reached at the measuring/regulating point, in this case the intake manifold....

yeah that's what i thought too. By decreasing the cooler size i would have thought the boost would increase. it actually boosts up quicker. Eboost is set to 12PSI, the max readin i've been getting is only 7.4 PSI.
Will be changing some of the vacumm hoses first and see if that solves it

i just don't have the ability to drop the car off at the moment.
Will get it sorted when it goes in for its water-to-air additional cooling

[TODA AU]

Guys... The E-Boost is set to a rate, not a boost pressure.
Think about it.;)

[RandyRhydah]

Care to explain?

[TODA AU]

Care to explain?
Short answer – LOL... Oh FFS, just read the instructions…
Long answer - Boost pressure is adjusted by changing the “set point” value
This is a value the is between 0 & 99… It adjusts the duty cycle of the solenoid.
The higher the number the higher the boost. So there is no confusion, there is no actual boost adjustment setting in the menu,
But if you adjust the “set point” on the fly; ie: under boost, the boost pressure will be shown rather than the set point value so you can see what you get. But you're setting the "set point" value, not a boost target value.
Gate pressure is to get the spool up right & prevent overshoot.
Sensitivity is self-explanatory.
Anyway, enough typing…
Go here: http://www.turbosmartonline.com/index.php?s=file_download&id=350

In reference to Hao's issue...
The current set point values do not take into account the pressure drop accross the core because the set point is just that...
A set point, not a boost target.
This needs to be adjusted & the issue will be solved.
Hope that's clearer

[RandyRhydah]

Good read, cheers

[Limbo]

Thanks Adrian, i've adjusted it and its upped the boost, just taking it up slowly now, previously was set to 20 but i've upped it to 45 and it hits 9.2 PSI.
Will adjust until it gets a nice smooth boost.


Just another question thought, i thought a smaller core has less drop?

[TODA AU]

Thanks Adrian, i've adjusted it and its upped the boost, just taking it up slowly now, previously was set to 20 but i've upped it to 45 and it hits 9.2 PSI.
Will adjust until it gets a nice smooth boost.


Just another question thought, i thought a smaller core has less drop?

Too easy, smaller flowpath equals greater pressure drop.
Bigger intercoolers work better.

[DLO01]

And by going to a smaller intercooler, your increasing the velocity of the air passing though it. So effectively the air to air cooling won't be as good a the larger cooler, taking that they are of similar construction.

[Limbo]

And by going to a smaller intercooler, your increasing the velocity of the air passing though it. So effectively the air to air cooling won't be as good a the larger cooler, taking that they are of similar construction.

Yeah that bit i knew, i guess i've confused pressure drop with lag.
Had to go smaller intercooler to get air to my a/c, so i could get better a/c cooling. That's why i am getting another water to air cooler also

[nigs]

Wait....were you concern about a drop of 1 (ONE) PSI in boost pressure?
LOL, so funny.

Good info from Adrian, you guys are lucky to have him on this board.

That shit is EBC 101.
Don't forget to factor in boost gain if the E-Boost supports that.