Decat STI - Boost Spike Fix Idea - Feedback?
08 April 2002, 10:05 PM
#93
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Pooder
No, but only used it once to test it!
You really need an intake temperature gauge to check it out.
Again, probably no performance increase (it would make the car quicker if you emptied the dirty great water tank in the boot LOL
), but it would guard against detonation by lowering the inlet charge temperatures.
This would not be an issue with a standard road car, but would be beneficial on track, particularly on hot days, and again particularly if the car was running more boost.
No, but only used it once to test it!
You really need an intake temperature gauge to check it out.
Again, probably no performance increase (it would make the car quicker if you emptied the dirty great water tank in the boot LOL
), but it would guard against detonation by lowering the inlet charge temperatures.This would not be an issue with a standard road car, but would be beneficial on track, particularly on hot days, and again particularly if the car was running more boost.
08 April 2002, 10:18 PM
#94
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Dave T-S
We used to use water injection on the spey engine on the BAC I-11 in order to restor power at high temps. Pumped 350 gallons of de-min water through the engines during the take off roll using a turbine pump. Added about 1000bhp per engine above 28C
Steve
We used to use water injection on the spey engine on the BAC I-11 in order to restor power at high temps. Pumped 350 gallons of de-min water through the engines during the take off roll using a turbine pump. Added about 1000bhp per engine above 28C
Steve
08 April 2002, 10:25 PM
#95
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Pooder
BAC 1-11
We live under the landing flightpath for Stansted and British World were still flying theirs until recently!
Glad to say Stansted has just banned the noisy Chapter 2 aircraft and I don't think theirs were hushkitted, so that's probably the end of them
Water injection to lower the intake temperature pretty much works on any engine I think. Some internal combustion engines do it by injecting water directly into the air inlet, or the Subaru (and other) method just on to the intercooler to cool the charge down.
BAC 1-11
We live under the landing flightpath for Stansted and British World were still flying theirs until recently!
Glad to say Stansted has just banned the noisy Chapter 2 aircraft and I don't think theirs were hushkitted, so that's probably the end of them
Water injection to lower the intake temperature pretty much works on any engine I think. Some internal combustion engines do it by injecting water directly into the air inlet, or the Subaru (and other) method just on to the intercooler to cool the charge down.
08 April 2002, 10:30 PM
#96
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Yes I was a Captain with them up until 3 years ago now flying the quiet 737-800 out of Gatwick.My point was that perhaps the best place to inject the water would be into the turbo since it is like a jet enjine
Steve
Steve
08 April 2002, 11:27 PM
#97
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Thanks Dave, will be interested on your thoughts on the gasket - will pick up the mail at work tomorrow. Hoping that the dealer will replace it FOC as they supplied the gaskets and fitted it for me. Sounded promising when I spoke to them today.
09 April 2002, 11:51 PM
#100
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Please help me : do you think it is possible to fix on my STI7 a Blitz Nur Spec Variable Chamber Exhaust without any overboost problem ? This exhaust is not a decat system, since I understand it keeps the first cat. If my understanding is correct, you have 2 cats and I understand that the overboost problem is linked to the first cat. Could you also explain what do you mean by up pipe and down pipe ?
Thank you for your precious help vis à vis an ignorant little french.
Thank you for your precious help vis à vis an ignorant little french.
10 April 2002, 05:07 AM
#101
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No word from Pete yet...
As far as I know it is likely to be a restrictor.
As to whether it is the uppipe or the downpipe - they both have the same result - faster spool up of the turbo leading to rapidly increasing boost and the factory boost controller doesn't respond fast enough to "catch" the boost level before it overshoots.
A larger restrictor (in theory) should allow the boost control to react more quickly and catch the boost spike earlier.
Another possibility is to lengthen the actuator arm a bit by unscrewing the adjuster, which would have a similar effect because the factory boost control solenoid would be working at a lower duty cycle for a given wastegate opening.
Note that I personally haven't tried either approach. My car is in getting the decat fitted - the company here in NZ has a fix that they have used on two previous STi's with good results. Unfortunately they are not talking as to what it is!
Seems as though the only people that know the answer are those in the trade and they would rather make money out of it than share the info?
(PS - can someone pleeeease tell me how to do the smiley thingies?)
As far as I know it is likely to be a restrictor.
As to whether it is the uppipe or the downpipe - they both have the same result - faster spool up of the turbo leading to rapidly increasing boost and the factory boost controller doesn't respond fast enough to "catch" the boost level before it overshoots.
A larger restrictor (in theory) should allow the boost control to react more quickly and catch the boost spike earlier.
Another possibility is to lengthen the actuator arm a bit by unscrewing the adjuster, which would have a similar effect because the factory boost control solenoid would be working at a lower duty cycle for a given wastegate opening.
Note that I personally haven't tried either approach. My car is in getting the decat fitted - the company here in NZ has a fix that they have used on two previous STi's with good results. Unfortunately they are not talking as to what it is!
Seems as though the only people that know the answer are those in the trade and they would rather make money out of it than share the info?
(PS - can someone pleeeease tell me how to do the smiley thingies?)
10 April 2002, 07:48 AM
#102
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Frenchie (great name by the way 
),
The up-pipe is the pipe that goes from the exhaust headers to the Turbo and the Downpipe goes from the Turbo down to the mid-section.
It's looking like the problem is the up-pipe but that hasn't been confirmed yet.....
Matt
),The up-pipe is the pipe that goes from the exhaust headers to the Turbo and the Downpipe goes from the Turbo down to the mid-section.
It's looking like the problem is the up-pipe but that hasn't been confirmed yet.....
Matt
10 April 2002, 08:55 AM
#103
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Bretman
Some people in the trade claim to have already fixed the overboost problem.
Other people in the trade claim they have a fix but haven't actually tried it yet.
There is far too much of a grey area surrounding this issue and we will not commit our cars to be part of anyone's development programme.
I think Mike Wood at Prodrive summed it up - they could sign the PPP off now, or they can sign it off when they are happy it works properly and safely. If for some reason it doesn't, your warranty in the UK will cover any outcome.
Personally, I like Prodrive's approach best.
Some people in the trade claim to have already fixed the overboost problem.
Other people in the trade claim they have a fix but haven't actually tried it yet.
There is far too much of a grey area surrounding this issue and we will not commit our cars to be part of anyone's development programme.
I think Mike Wood at Prodrive summed it up - they could sign the PPP off now, or they can sign it off when they are happy it works properly and safely. If for some reason it doesn't, your warranty in the UK will cover any outcome.
Personally, I like Prodrive's approach best.
11 April 2002, 09:43 AM
#105
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Quite understand your position, Dave, and fair enough too!
In NZ we don't have the luxury of a PPP, so I will have to persist with third party alternatives!
I will be going out tomorrow to check the result of the work on my car (with the Select Monitor in operation), so I'll let you know what happens...
In NZ we don't have the luxury of a PPP, so I will have to persist with third party alternatives!
I will be going out tomorrow to check the result of the work on my car (with the Select Monitor in operation), so I'll let you know what happens...
12 April 2002, 03:31 AM
#107
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Yep, but they still haven't sorted the variable valve timing part of the Link. (and I'll need more money to get one - all of mine is going on 98 Octane!!)...
Maybe as the next upgrade... ;-)
Maybe as the next upgrade... ;-)
12 April 2002, 06:58 AM
#108
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YEHAAAAAAA!!!
Full decat with Scoobysport downpipe fitted and working... spikes limited to only 1.3 bar maximum, verified on the Select Monitor.
The bad news is that there must be some difference in spec between the New Zealand model and the UK and JDM ones (apart from the 206 versus 195 KW), because before any modifications (with the exhaust system fitted) the maximum spike was only 1.43 Bar.
This could be due to the Scoobysport being an open mouth downpipe?
Again, the installers are being cagey about what they did, but I understand that it is nothing more than what was discussed previously in the thread.
End result - sounds great - goes like s**t off a shovel and the boost is within factory boundaries, verified with Subaru diagnostics....
**GRIN***
Full decat with Scoobysport downpipe fitted and working... spikes limited to only 1.3 bar maximum, verified on the Select Monitor.
The bad news is that there must be some difference in spec between the New Zealand model and the UK and JDM ones (apart from the 206 versus 195 KW), because before any modifications (with the exhaust system fitted) the maximum spike was only 1.43 Bar.
This could be due to the Scoobysport being an open mouth downpipe?
Again, the installers are being cagey about what they did, but I understand that it is nothing more than what was discussed previously in the thread.
End result - sounds great - goes like s**t off a shovel and the boost is within factory boundaries, verified with Subaru diagnostics....
**GRIN***
12 April 2002, 09:14 AM
#111
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Bretman
Well done!!
re max peak boost, have you got a replacement up pipe on?
Decat from turbo back = 1.5 (ish) bar spikes, include up pipe takes it to 1.7 bar.
Well done!!
re max peak boost, have you got a replacement up pipe on?
Decat from turbo back = 1.5 (ish) bar spikes, include up pipe takes it to 1.7 bar.
12 April 2002, 08:56 PM
#112
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I will stick with the factory uppipe... I don't have a cat in the uppipe, so I'm not too concerned about swapping that out. The sleeving in my opinion won't have too much of a negative effect.
13 April 2002, 10:34 AM
#115
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Boxer
The Subaru LaMco gauge fits in a little pod on the top left of the steering column, and doesn't obscure anything - works well.
I fitted mine in about 40 minutes.
The Subaru LaMco gauge fits in a little pod on the top left of the steering column, and doesn't obscure anything - works well.
I fitted mine in about 40 minutes.
16 April 2002, 01:51 PM
#116
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Dave T-S.... I've got the subaru lamco 3 gauge pod that sits where the little clock was... my problem is that I don't think the boast gauge is working properly, or I've got a serious prob with my car, the lamco gauge, MPa, hovers @ about 0 then peaks to about 0.05 ???????, now on my calcs it should be holding about 0.1 and peaking to about 0.15, to be honest the cars pulling strongly so I don' think its the car.... what does your show on the gauge in MPa...
Cheers,
Gary
Cheers,
Gary
16 April 2002, 09:52 PM
#117
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GSti
You are right - my LaMco gauge peaks at about 0.135 Mpa and holds around 0.1 to 0.115.
Where did you take the gauge inlet pipe from - tee'd into the pipe off the dump valve?
[Edited by Dave T-S - 4/17/2002 9:09:00 AM]
You are right - my LaMco gauge peaks at about 0.135 Mpa and holds around 0.1 to 0.115.
Where did you take the gauge inlet pipe from - tee'd into the pipe off the dump valve?
[Edited by Dave T-S - 4/17/2002 9:09:00 AM]
07 May 2002, 02:03 PM
#119
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Pete,
Dave has said it all really Except for the fact that we weren't looking specifically at boost spiking but how the cars behaved in general. These were drags from standstill up to whatever speed we could achieve by the end of the road Pretty much redline in 1st-4th and 6000 in 5th. We did some other runs as well and when we get the time, we'll re-visit the road and do some more specific tests (I did mention that we were gonna do some more runs didn't I Dave? )
Matt
P.S. I only got my STi Wednesday night so it will be a while before I'm doing any kind of testing in mine
[Edited by mutant_matt - 7/5/2002 2:04:27 PM]
Dave has said it all really
Except for the fact that we weren't looking specifically at boost spiking but how the cars behaved in general. These were drags from standstill up to whatever speed we could achieve by the end of the road Pretty much redline in 1st-4th and 6000 in 5th. We did some other runs as well and when we get the time, we'll re-visit the road and do some more specific tests (I did mention that we were gonna do some more runs didn't I Dave? )Matt
P.S. I only got my STi Wednesday night so it will be a while before I'm doing any kind of testing in mine
[Edited by mutant_matt - 7/5/2002 2:04:27 PM]
