More boost Issues..

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12-10-09, 10:34
jimnielsen

More boost Issues..

More boost Issues..

Well, i drove the Q4 at Winton this weekend past, with a totally different electronic boost controller. I did not use the Pierburg valve system at all the whole day. The boost controller I was using is a self-learning system, where basically you drive the car for 14 brief episodes of full boost (ie lap one of a race..) and the system learns how to manage the wastegate. So it could hardly be more different. The funny thing is that the boost response and control of the system was damn near identical to the Pierburg system, except that I had set it to produce 1.45 bar - which it did - for a second or so - then it was back to the 1.25 bar boost (to 7100 RPM) that the original system produced.

I believe that the turbo can produce more boost, so I now need to look for other problems. Firstly I am going to try to use a wastegate actuator with a higher opening pressure (harder spring) and also i am concerned about the 'restrictors' that are in the line between the WG and the control valve.

1. has anybody else used a higher opening pressure actuator?

2. what is the purpose of the restrictors?

3. I have blown the exhaust manifold gasket (just a small breech - but I will have to pull apart a lot of stuff to fix it...) Is there an alternative to the standard exhaust manifold gasket that will last longer at 1.4 bar?

thanks.. jim~
12-10-09, 11:05
AlfaJack

I thought the bits between the two pipes from the actuator and WG were joiners - I wondered why it had them and your post clarifies my mis-understanding.

You could try this Spesso exhaust manifold gasket:
http://www.auto-integrale.co.uk/parts/gaskets.htm

I think they are pretty high quality parts.
12-10-09, 13:01
SteveNZ

Assuming the gasksts you are using are of reasonable quality I would suspect the flanges are warped leading the the gasket failure. Is it the head end or the turbo end that is the problem?

To prevent warping the flange you need to use washes as large and fat as physically possible. I got some made by an engineer once to prevent this

Wastegate actuator restrictors are used to reduce the volume of air bled off to achieve a the same boost. With a bleed valve system you can control boost 2 ways. Either bleed more or less air off (there is a maximum limit). Or increase/decrease the restrictor. An electronic boost controller may vary one or both. The tighter the restrictor the more sensitive the bleed valve will be. Too much restriction may cause inaccurate boost control while not enough may cause a narrow adjustment range.

Additional restrictors are generally not required with aftermarket electronic system as its all built into the solenoids.
12-10-09, 14:41
AlfaJack

When I changed to an MBC I think I left those restrictors in place - not certain but it may explain when my boost peters off like it does.
13-10-09, 02:34
SteveNZ

It won't affect a MBC.
13-10-09, 06:45
Evodelta

Check the manifold flanges for distortion, a few people have reported blown gaskets on these manifolds due to this problem (many were distorted from new). Also the supplied gasket whilst obviously compromised wasn't much good. Jack is right, the Spesso is a really good gasket.
13-10-09, 07:33
wrinx

Quote:

Originally Posted by Evodelta

...a few people have reported blown gaskets on these manifolds

Jim is running an ebay stainless manifold, do you mean that or the OE manifold?

One thing I noticed about the ebay version is that there is no separation between each pipe, like there is on the OE.

Wonder if it would be worth cutting between each one to reduce the possibility of warping?

wrinx
13-10-09, 10:47
jimnielsen

Ok, I have ordered a Spesso one. Thanks all.

jim ~
13-10-09, 19:03
AlfaJack

Is it possible to get the manifold "faced"?
13-10-09, 19:42
Evodelta

Quote:

Originally Posted by wrinx

Jim is running an ebay stainless manifold, do you mean that or the OE manifold?

One thing I noticed about the ebay version is that there is no separation between each pipe, like there is on the OE.

Wonder if it would be worth cutting between each one to reduce the possibility of warping?

wrinx

I mean the ones on Ebay, some were warped from the start and needed milling before fitting, maybe they warp some more on the car, I dunno. I'd put some money on it being the cause of the problem here.
Yes, I like the idea of the expansion slots too, letting something move when it wants will help prevent cracking and distortion.
13-10-09, 19:42
Evodelta

Yes it is Jack.
13-10-09, 20:39
jimnielsen

1 Attachment(s)

yes, i do have the 'ebay' manifold. I can tell you why the problems have occurred.

The face of the manifold is 'flat enough' - though not perfect, the real problem is that the gaskets that they supply for the block-to-gasket and turbo-to-gasket are worthless. My turbo-to-gasket one lasted one race!

But.. even these poor gaskets may have been ok except for the studs and nuts that they provide which are rubbish!. They break with heat, fall off and have threads too loose to be tightened properly.

If I was going to use this manifold again (and I would) - I would purchase better gaskets and use cone nuts to ensure that the thing stays bolted on - its the thing coming loose that destroys the gaskets.
13-10-09, 20:44
jimnielsen

1 Attachment(s)

Temperatures

... and another thing. I think its amazing how effectively intercoolers work!
13-10-09, 22:11
wrinx

Interesting, I've not noticed any problems with mine yet...but it's hardly been used compared to yours :lol:

Mine is using different nuts and allthread though...and it's double gasketed! :eek:

I've just bought some 6mm stainless sheet to fabricate a spacer to allow a bigger gap between the head and manifold.

Will bear your experience in mind when putting it back together.

wrinx
23-10-09, 01:43
jimnielsen

2 Attachment(s)

I have received the Spesso Exhaust Gasket that I purchased from Nyssa. It looks a LOT more substantial that the original one! Wish I'd used one in the first place!

jim!~
23-10-09, 06:34
1NRO

Rub a new / good condition oilstone over the manifold flange, that'll soon tell you how flat it is.
23-10-09, 07:22
wrinx

That looks much better...how much was it?

wrinx
23-10-09, 08:37
Brul(tm)

Quote:

Originally Posted by jimnielsen

I have received the Spesso Exhaust Gasket that I purchased from Nyssa. It looks a LOT more substantial that the original one!

That's odd :confused:
I ordered one original through a local Alfa romeo dealer and received the following gasget.
http://i115.photobucket.com/albums/n...s/IMG_8574.jpg
part number 7700579.

This looks a lot like the one from spesso.
Mine has the following inscription on it:
Alto Germany, the Lancia logo and an F7 marking with the number 12721-081. On the back it says 1047-081/1

Greetings,
Marc
23-10-09, 10:10
jimnielsen

The Spesso has two metal faces with some 'other' material in between. The metal faces are joined through the exhaust manifold holes. The gasket is 2.1mm thick. It was 60 UK pounds.
23-10-09, 10:37
Brul(tm)

The one I received has metal in between the "outside material" and joined metal faces like you disgribe. Only mine is just 1.6 mm thick. Don't remember the price, have to look that up.

Greetings,
Marc
23-10-09, 20:21
Evodelta

I don't see any similarity between yours and Jims? You realise there is the new and old gasket in his pics? The Spesso is SS on the outside......
25-10-09, 11:45
Brul(tm)

Quote:

Originally Posted by Evodelta

I don't see any similarity between yours and Jims? You realise there is the new and old gasket in his pics? The Spesso is SS on the outside......

All I am saying is that the original gasget I ordered trhough the dealership looks differant than the original in the picture.

The gasget I received, has similarities with the Spesso gasget. I never said they are the same or have the same quality.
Obviously the Spesso gasget is far more superior!

Greetings,
Marc