It has been a while since I last posted a question on here. I have had an MY96 now for about 3 years and have, at last, decided to go ahead with a modification to an otherwise standard car. I can only afford one mod at the moment as my wedding is imminent and the cash is a bit short.

The one mod that seems the best to go for initially (to get the best results for the least outlay) is to decat the downpipe. For about £170 it is not that expensive and apparently makes the car more driveable with the turbo spinning up quicker. However, before going for it I wondered if anyone could advise me if I am likely to see any problems with overboost. I seem to remember quite a while ago, on an ongoing thread, that someone said that they had had problems following a downpipe change and were seeing overboost.

I know the other issue here is passing the MOT, but with the middle CAT still in place I seem to remember that passing is not a problem as long as it is nice and hot.

Is there anything else I should be aware of?

Any advice gratefully received.

Mark.

[Edited by Spatch - 5/27/2003 9:53:58 PM]

 

What type are you looking for ?

Closed neck, Open neck or Twin dump ????

I am led to believe that Twin dump and Open neck are the prefered downpipes as they give more torque and are less restrictive.

My MY98 has a twin dump and I have had no problems with Overboost.

If you are strapped for cash how about a Dawes device to raise the boost a few PSI, £40 for device and a bit more for a boost gage and easy to fit.

Hope this helps

Neal

 

Neal,

Thanks for the response. I wasn't aware there were that many varieties of down pipe! What is the difference between the three? What have the results been with yours then? is the difference between stock d/p and twin dump noticeable? Have your MOT's been ok?

I will look at the Dawes option, thanks.

Another question I have, which may or may not be related with overboost. If I floor the throttle in 1st from about 2000 rpm, it accelerates until the point at which the turbo normally kicks in, then it seems to hesitate slightly before it really takes off. The hesitation is enough to push me forward in the seat until the point when the power comes back in and I am thrown back again. This does not occur (or is not noticeable) in other gears where the power delivery is smoother. I have read that overboost, if detected, will cause the car to hesitate until the boost drops. Is it possible I could be seeing this or is this a trait of the earlier cars? I have tried resetting the ECU but this makes no difference.

Thanks
Mark.

 

My mate's has those very symtoms (MY94).

 

AFAIK boost is higher in high gears, as such, if it overboosts in first, it will do it in all other gears

 

Brun

Has your mate done anything about it?

Mark

 

Mark

I think this is correct for the downpipes! I am sure someone will post if its incorrect



Concerning the overboost, I used to have it on my MY98 between 3500 and 4000 revs usually first felt in 5th gear due to oil contaminating the boost controller sensor. Once the oil was removed from the sensor with brake cleaner and the oil level taken to no more than halfway on the dipstick I havent had a problem. Though I dont know how relevent this is for your MY.

Cheers

Neal

[Edited by NM - 5/29/2003 10:31:09 AM]

[Edited by NM - 5/29/2003 10:34:16 AM]

 

Bloody picture is tiny !!!

I have emailed it to you !!!

Neal

 

The first and best modification I and most people make is to replace that bloody restrictive backbox.

If I had to start all over again it is where I would begin.

Drrrrrrrrrrrrr

 

Do the downpipe ... I have a Scoobysport DP, OE centre and have swapped from OE BB -> SS BB -> OE BB -> Scorpion BB and there is very little difference performance wise in any of them.

Noise wise yes, performance wise no.

Do the downpipe, big difference, earlier spool up .. nice mid range increase.

Hamish.

 

Thanks guys for all the info.

Neal, I will have a look at the picture when I get home. Cheers.

Going back to the problem with the hesitant spot I see in first gear, I assume that I can rule out overboost then. From what people are saying it looks as though I would see overboost in higher gears first, not in first gear first.... If this is the case, has anybody any idea why I have this hesitant spot and is there anything I can do about it.

Mark.