Hi all,

A friend and I are having problems with a D Reg Cosworth. The car drives spot on other than having boost problems. We installed a boost gauge today to see what kind of pressures we are getting.

When driving in any gear at say 1500 rpm, then foot flat to the floor, I would expect the boost to start rising around 2-2.5k revs then hit peak boost somewhere between 3-4k revs but the car just doesnt boost. A peak boost of around 0.5bar is acheived at somewhere between 5-6k revs with not much below that.

We have gradually wound the actuator rod in little by little, and is currently set on its shortest setting, but this hasnt made any difference what so ever.

We disconnected the AMAL valve and had the actuator running directly from the compressor housing on its shortest setting and it still wouldnt hit peak boost (0.5 bar) till around 5 revs.

Other than this the car drives ok with no smoke, bangs etc.

It feels as thought the engine isnt detecting any load on the engine, if that makes sense. Its feels like its boosting far too late in the rev range and the boost levels seem a little low. The ECU has been labelled up as 'stage 1' also.

Could this be a faulty AMAL Valve??

Any advice would be greatly appreciated as its driving us nuts.

 

how new is the actuator? these do need replacing after a period of time

have you checked for vac leaks?

what's the spec?

has this just started happening or has this always been a problem since you owned it?

 

Thanks for the reply.

He has just bought the car around 2 months ago. It has 36k miles from new and we thought it was standard with just stainless exhaust. We have had a look at the ECU and it is labelled as 'Stage 1' but performs a little weak at the minute.

The actuator look pretty new, but we have tried a second one which made no difference. Cant see/find any vacuum leaks, and the car has ran like this since he bought it. Looking through the receipts, there is some their for the actuator, one for a MAP sensor etc which suggests that a previous owner has had similar problems.

Checked the DV and that seems ok, and cant seems to think anywhere else that could be leaking boost other than Actuator or DV.

Its as if the engine isnt detecting enough load to provide low boost. Could it be earthing problem??

Starting to anoy the hell out of us.

 

I would firstly look at the ignition side of things to rule this out, if you are getting spark out under boost, it won't develope boost as not enough fuel is being burnt to spin turbine fast enough, but it will just feel flat, so decent plugs gapped at 0.6mm, I would suggest AGPR12PP8 on stage 1, next check the fuel pressure, should be 3 bar with vac on, and rise to around 3.6 with vac off and plugged.
The dump valve if leaking can be tested by using a bit of wood dowel/broom handle cut down in place of dv temporarily to see if this is leaking.
I would do the cheap free things first, it's likely to be something very basic.
tabetha

 

Penny washer not sealing in the turbo ?

I had this on a saph i had and it drove exactly how you have discribed it.

Steve.

 

Well, thats freaky

Just got back from looking at it. I have been racking my brains thinking about it and decided it must be something faulty with the wastegate. Took the down pipe off, and there it was. The washer was sitting too high and catching on the housing causing it to sit open. So cut the top off the arm and re-welded it in a lower position which made the wastegate seal properly.

Over the moon. It was then missing under boost, so checked the plug gaps and they were set to standard 0.8 so adjusted them to 0.6 and problem solved.

One last thing to sort out, I have set the actuator to the standard setting. The car peak boosts to around 1.1-1.2 bar then settles back to 0.7-0.8bar. With the car being 'Stage 1', what should the boost settle at? I was thinking that I would need to adjust the wastegate to hold around 0.9-1.0 bar, does this sound about right for stage 1? or does it sound like the car is still running standard boost??

Nearly there,

 

I was right

I would not want it holding anymore than 1 bar boost. Better off getting the fueling checked as thats cheaper than a engine rebuild.

Steve

 

I like your style

I would imagine with it being chipped to stage 1, it will be running rich at 0.7 bar would it not?? I just need to know what pressure to set the actuator at. Its going to go for a full setup on the rollers soon anyway.

Cheers for all the help.

 

For stage 1, boost should be set to 1 bar, which is for the sake of argument, 14.5psi. Much above that, and the standard 2 bar MAP sensor simply 'lies' to the ECU about manifold pressure, ie tells it there's less air in there than there actually is.

With the amal valve connected (provided it works!), the ECU will control the boost as best it can, and according to the boost values written to the chip by the author. As long as you've got the actuator set in just about the right position, the ECU can take over from there. To lower boost, lengthen the rod by half a turn for each 0.02 bar (0.3psi) less. To increase boost, shorten the rod by half a turn for each 0.3psi extra.

Having it setup is a great idea - as for setting the fuel pressure yourself, you'll need (obviously) an accurate fuel pressure gauge, and the recommended fuel pressure setting from the chaps that wrote the chip. As Tabetha said above, normally this is 3 bar with the vacuum pipe connected to the pressure regulator, but sometimes it's set slightly higher.

 

If your penny washer, and wear is this bad, I wouldn't leave it too long before a recon one, they normally wear in the actual housing, the crack in the seat as there always is doesn't normally cause a problem, but new turbine housings are £150, if not already done so a 360 bearing needs to be in there with any rebuild at stage 1.
As said 1 bar is the norm for stage 1, or 14.5038 psi!!
tabetha

 

Thanks for all the excellent advice. The penny washer was sitting high, ie was sitting bout 4-5mm high and wasnt sealing the hole properly. Think the sleeve must have moved. Anyway problem solved now and seals nicely.

I set the actuator by taking the arm off the wastegate then pressurised the actuator to 0.5bar and at that point extended the arm so that it fitted straight onto the closed wastegate arm. I read somewhere that this was how to set it to factory settings. But by doing so, the stage 1 chip initially boosts to just over 1 bar, then i assume the AMAL valve is releasing pressure to the actuator, causing the boost to drop to a factory 0.7bar (10psi?). So am i right in thinking that by shortening the actuator arm this will cause the boost to hold at 1 bar once the AMAL valve releases pressure to the actuator??

Looking at the actuator arm, to shorten it enough to give a further 0.3 bar, i will probably have to turn it approx 7 full turns? which looks as if it will use most, if not all the threads. (must be a standard actuator).

This is my first experience with a cosworth, I have come from Honda Type R's and subaru's, and so far.. i likey

 

the boost pressure should be set to the parameters of the chip inside the ecu; as said, normally 1 bar for stage 1

i full turn normally equates to just under 1 psi, so be careful!

cossie's are the simplest & easiest engine to work on...maybe part of the reason why they have such a cult following!

assuming the engine is in good order; you may as well go straight for stage 3; you'll get bored at stage 1 very quickly

always a good move to get the fueling checked; especially if the chip origins are unknown

get some pics up of the 3 door

 

Cheers.

As said originally, its my mates car, just been helping him out getting it running properly. Hopefully looking to pick up a nice sapphire cosworth after the winter.

Heres my mates. It has 38k miles i think. Nice and clean.

 

looks very clean!! theres a few guys on here fron newcastle way

good luck with it all

 

nice,

whats the black round thing near the header tank,power steering tank,and washer bottle?

 

Think the first owner had a/c fitted as a dealer option. something to do with that i think.

 

ahh!

 

very nice i likee

 

Jees that is tidy, got a lucky buy there!!
tabetha