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Andrew Carr
14th March 2004, 22:28
I was going to title this 'Interesting result...' but it's not, I'm just a little confused :D

After fitting my Gruppe-S headers on Friday (took less time to fit than to wrap :eek: ) I did some logging today expecting to have to add fuel to my top row, however, I found that my held boost level had fallen by approx 0.1bar (1.4 to 1.3) and that it was now too rich (11:1 to 10:1), I use a MBC and if anything I was expecting the held boost to increase a little with the better breathing of the headers. Inlet temp was about the same and EGT has fallen about 50C

Datalog lab power graphs show the same torque and about a 5% drop in power which is good given the drop in boost and AFR.

At first I suspected a leak but there's no sign of anything blowing and boost threshold has only increased about 100RPM: 1bar @ 2800 in 5th/3000 in 4th/3400 in 3rd.

I didn't have time to tweak the MBC and map to put things right today but I will do that and expect to see a healthy increase in Torque and Power.

I'm still :confused: as to why this should happen though?

Andrew...

Bob Rawle
14th March 2004, 22:47
Add some timing, you need to take advantage of what should be improved VE. Headers can change the characteristic dramatically. You should have to add fuel though, unless the turbo is too restrictive to take advantage or the intake the same.

bob

Andrew Carr
14th March 2004, 23:00
Thanks Bob,

More timing sounds good, I already added 2-3 degrees after fitting the FMIC!

I wouldn't have thought that the TD05 would be too restrictive at this boost level, std intake pipe maybe, although I have that in hand. I was going to measure the intake pressure drop this week anyway before fitting new intake pipe.

Andrew...

Bob Rawle
14th March 2004, 23:04
With a TD05 it "should" have needed fuel, see what the timing can do, suprising how much extra is sometimes needed. Intake could be influencing.

bob

nom
14th March 2004, 23:45
Was the up-pipe changed as well?

Andrew Carr
15th March 2004, 07:19
I already had a 2" H&S uppipe which I have kept as the TD05 exhaust housing was ported to match this uppipe.

I was going to double up on gaskets at the bottom of the uppipe but when I tightened up the headers the joint closed up nicely so I just used the 1.

The car does feel stronger, smoother and quieter from about 4000RPM but the logs seem to suggest that the peaks are not as high. If I'm not busy I'll sneak out for an hour at lunchtime and do some more logging.

1 problem might be the tension on my wg actuator, I had previously loosened it a little to ensure that boost dropped of a little at the top end.

Not sure about adding more timing, already using 14@4000 - 17@7000 'Link' degrees which I though was quite a lot for a UK car, 1.4bar and straight optimax.

Andrew...

[ 15. March 2004, 07:26 AM: Message edited by: AndrewC ]

jim.....
15th March 2004, 07:45
The snowball has started rolling! here comes 20g.


Jim

Andrew Carr
15th March 2004, 08:20
Oh no it doesn't!

Need to speak to you regarding inlet pipework again!

Andrew...

jim.....
15th March 2004, 08:30
No problem, still got drawings, and welder if needed as back in work tomorrow.


Jim

Andrew Carr
16th March 2004, 09:47
1/2 a turn on the MBC restored boost but still not sure why that should be needed?

Fuelling is a mixture of things, not least me changing the map before adding the headers and the IAT compensation - must move the sensor to the throttle body!

Seem to have developed some lift-off noise now, not sure it's det as I can't hear anything in the det cans and no flicker on the knock link but the ECU records a couple of big numbers when I lift off in 2nd/3rd above 6000RPM - probably my gearbox about to pop!

Andrew...

Simon_
16th March 2004, 10:15
Gearbox! :eek:

Heres hoping it is a little rich at that point and just popping on lift off... ;)

Simon

[ 16. March 2004, 10:20 AM: Message edited by: Jolly Green Monster ]

nom
16th March 2004, 10:34
The Dawes would probably need to be reset simply 'cos the flow characteristics will be different - pressure at the wastegate, etc. From the turbo's point of view, it's running with a different engine now smile.gif

Andrew Carr
16th March 2004, 11:21
Who said Dawes :D

I expected to have to adjust the MBC, I was just expecting to be turning the pressure at the compressor outlet down, not up - if you see what I mean.

It is still overrich at the topend which I am hoping is causing the 'noise'.

I am having fun with it now all the mods are finally coming together, even my new injectors are on there way so I don't have to run 4bar fuel pressure anymore :eek:

Andrew...

nom
16th March 2004, 12:21
Oops - just too used to all MBCs being Dawes :D

Iain Atkins
17th March 2004, 15:27
Sounds encouraging Andrew smile.gif

Andrew Carr
17th March 2004, 15:47
Something is still wierd. Took about 2% fuel out of my top row, fuelling looks a lot better but still a tad rich at the topend.

With the midrange boost back to just shy of 1.4bar, torque has increased by approx 20lb/ft and peaks 200RPM earlier in 3rd.

Power is still down a bit, but boost is dropping off quicker, previously it was falling to 1.25bar@6000RPM, 1.15@7000. Now it's more like 1.15 at 6000?

As I said previously I suspect I need to put some tension back into the wg actuator rod as I suspect it's blowing open more easily.

Andrew...

[ 17. March 2004, 03:59 PM: Message edited by: AndrewC ]

Andrew Carr
23rd March 2004, 10:07
Well I tightened the actuator 2.5 turns on Sunday (when I took it off there was no preload at all) and it feels much better, haven't logged it yet but peak boost in 3rd/4th has gone from 1.37/1.39 to 1.45/1.48 with no adjustment to the MBC and the boost gauge doesn't 'creep' the last couple of PSI. Car feels a bit more brutal between 3.5-4K but haven't really explored the top end yet.

Will try to sneak out at lunch to set the MBC back to 1.4peak and log what's happening above 6K.

Got some PFR7s to try this week as well as the inlet pipe.

Andrew...

Simon_
23rd March 2004, 10:09
Well done.. weird that it was fine on standard headers though..

Andrew Carr
23rd March 2004, 10:29
Not sure if I mentioned it previously but the headers have affected loads of things, it took me a while to get it idling again properly and it's still not right when warming up (above 70C).

Clutch didn't like 1.48bar in 4th! Going to book it into Prosport as I don't have time (can't be arsed) to do it myself!

Andrew...

Andrew Carr
23rd March 2004, 13:52
OK now holds ~1.4bar in 3rd and 4th all the way to about 5800 where it starts to fall off 1.25 at 6500, 1.15 at 7000, which is exactly what I want for now.

Clutch is really unhappy with this tho'.