Fredysan

Hi:

I'm runinng a TD05FE but sadly there is some surge problems... These are my mods:

- TD05FE polished
- Polished Stock headers
- Custom Upipe
- Air filter HKS Super Mega Flow
- Walbro GSS342 Fuel pump
- Fuel pressure regulator @ 46 psi (at idle with the vacuum line off)
- Greddy ProfecB boost controller
- Stock Bypass valve

The greddy has two settings low: 15 psi, high: 20 psi. These are the symtoms:

- At the morning, 5° celsius, in low mode the boost raises to 17 psi and have severe hesitation in boost in second and third gear. I hadn't did the test in high mode with this T°'s

- At nigh, 12°, in low mode, boost is the normal 15 psi, without surge problems, but in high mode there is surge but ONLY in third gear....

It seems the surge have its origin in some restrictions in the intake track, but if this is true, the problem should be at all gears... Tell me if I'm wrong...

Does anyone had have similar problems?

Thanks in advance

AndrewC

What RPM is this happening at?

I have some surge between in 4th/5th, boost gets to 1.35-1.38bar at 3100 in 5th, 3300 in 4th and then holds until around 3700/3800 and then boost jumps to 1.45bar which is its target. In 3rd and lower I don't get 1.35bar until around 3600/3700 and there is no noticeable problem.

During this time boost is oscillating quite rapidly +- 0.1bar and a fluttering sound can be heard.

I put it down to my UK engine not being able to flow that much cold air until nearly 4000RPM.

Andrew...

PS. Spec of my car is UK98/fe TD05/Hybrid FMIC/Gruppe-S headers/H&S uppipe/3" exhaust/custom 2.5" inlet pipe/MBC at 1.45bar.

Delboy2

I have a similar setup on a UK96 and haven't noticed any surge problems. Recently I did a wideband plot along with boost and found the pressure was very stable but below target(1.85psig) mainly due to me not adjusting the Boost controller's compensation since the FMIC was fitted this became apparent when on the rollers. With the boost target now 1.4bar and the Boost controller 're-tuned' the pressure appears to be very stable - I am going to do another 'plot' shortly to confirm.
My boost control at present is an HKS EVC IV

Cheers

AndrewC

Delboy,

I would be interested in seeing your WB plot.

Andrew...

Fredysan

AndrewC:

I haven't see exactilty at what RPM this does happen but it's about 3500 to 4500. My target is about 1.38 bar (20 psi) and I had played with the balance **** of the greddy. The manual say if you have "hunching" boost you may turn the balance **** to the mild side, I already have it at the mild side, the problem decreases but it still having surge...

The oscilation is similar yours (about 0.1 bar). Also I have some WB plots.
I forgot say you, but my car is also a MY98 Turbo.

Any idea in order to solve this? I replaced every hose by silicone hoses, checked if they have some leaking and also changed the Blow off by the stock one.

At the other hand, 1.45 bar is quite high... have you tested your A/F's?

Regards from Chile

AndrewC

I have a Link ECU and tune with Wideband/EGT/Det Cans, AFRs are fine

Here is an extract from a Link log showing the problem on my car (although the boost oscillation isn't clear, you can see that the boost stops rising about 3200-3300 and then jumps around 3600) The link obviously shows average MAP (in kPa, divide by 100 for bar) but in the range 3200-3600 the boost gauge needle is vibrating

AlanG

Is it a mechanical gauge? in which case it may be needing dampened to reduce the oscillations.

Can't remember now, but does the Link not log at a rate of approximately 4 times per second, in which case it would show up any boost variation?

AndrewC

4.25Hz on mine

Yes it is a mechanical gauge, I could put a restrictor in it to damp out the oscillation, but I can hear a pss pss pss pss noise when it happens, I need to log it with the WB to get a higher sample rate to see if it is genuinely oscillating.

Perhaps I need a BOCD?

Andrew...

Fredysan

Mmmmm

I also have a mechanical gauge and heard that pss pss sound... I think it could be:

1.- Something in the boost control system
2.- Something in the intake track

Tha sad thing is I don't know what kind of testing should I do in order to know what is happening...

By the way What is a BOCD?

AndrewC

Mine only started when I fitted a custom inlet pipe, the effect of the pipe was that boost came in much faster once it had started spooling, previously it took longer to get from 1bar to 1.4bar and I didn't get the noise which is why I presumed it was simply too much airflow for the engine. I need to try a larger/different airfilter just to eliminate it, but I don't think it is that as can be seen from the table below once past 3600-3700 it happily runs just under 1.5bar until the TD05 starts to run out of puff and it tails off to 1.3 by 7000:

Andrew...

KLR16V

iTrader: (2)

Just for interest what injectors are you running on ?

Mark

Fredysan

I have the stock injectores: 380 cc