View Full Version : "Blips" in turbo power delivery.
Greetings people - what a fab board you have.
I have recently become the proud owner of a shiny blue, coupe turbo. :D
All is fine apart from when I give it some stick, when there appears to be a couple of slight 'blips' during the power delivery. Nothing heavy, just little blips. This doesn't occur if I'm being gentle, which makes me think it might be something to do with the turbo.
Anybody got any ideas on this - could it be something simple like some cra*py fuel?
Cheers
Jimbob
lotus astra
12-09-2003, 19:43
2 things I can think of off the top of my head!
Firstly, I would use Shell Optimax, and get get regal or coutenay to tell your software that this is all your car is gonna accept from this day forth!
The standard ECU will accomodate, but not properly, if its forced to run 99.5 RON it will run better!
Some people say Optimax is a con, I beg to differ, these people have not had their ECU forced to run on Optimax, if they did, they would notice the difference after about 5 full tankfulls, if they then went back to even super plus, the car would load in 3rd gear, causing lag between 3 and 5000 rpm.
Secondly, have you got either a relief valve or BOV, these are essential for any Turbo engine, as it stops the turbo baldes from stalling.
The back pressure caused by lifting off the throttle can cause the compressor of the turbo to stall. In extreme cases, the compressor can actually shatter.
After a dump valve is fitted, you will notice an immediate change in feel to the car, especially after changing gear. This is because the turbo is kept spinning during closed-throttle conditions and is therefore able to provide full-boost quicker, if you are nailing everywhere, this symptom will be shown in gear changes, but if you let the turbo spool softly (driving normally) this will be less noticable!
Oh, and thirdly, welcome to the Site!
HTH
8) :wink:
aaaaaaannnnnnnnnddddddddd breathe!! lol
Good info that Lotus! I've got a quick Q for ya mate why'll were on the subject.Can Vaux use the Tech 2 to tell the car that's is runnin on Optimax?? :?
lotus astra
13-09-2003, 16:30
I believe so....
I think it would be worth getting any software updates available for your ecu, like BIOS flashes for a computer.
Oh, also, you can get Vaux (nice dealers) or Regal / Courtenay to swap the standard Coupe Turbo ECU software with that of a GSi turbo, as there is 8 bhp difference between the two software apps.
:wink:
Lotus Astra,
Thanks v much for the advice.
My car is totally as standard. I was under the impression that this engine has a dump-valve fitted? If not, I'll have to get one I guess :)
Good idea on the software upgrade too. So it would be better to get the GSI software rather than upgrade to the latest coupe version?
Cheers again
Jimbob
LordNikon
13-09-2003, 19:54
Welcome to the site !
The Vauxhall dealers are not allowed to flash the ROM with a different models vairation. IF you are however friendly with them they will do it but just hope you don't need warranty work in the future, the first place they go is TECH2 !
However Regals or Courtenay will flash the ROM for a cost ! :) - the standard turbo has a wastegate and bleed valve, but not a dump valve. I have never experienced your symptoms with my Turbo, but I only had the car for 2hours before the dump valve going on ! :)
Welcome to the site !
the standard turbo has a wastegate and bleed valve, but not a dump valve. I have never experienced your symptoms with my Turbo, but I only had the car for 2hours before the dump valve going on ! :)
What's the difference between a wastegate & bleed valve compared to a dump valve? Also, would fitting a dump valve increase insurance premium? (generally) What kind of price range am I looking at for a moderate dump valve. I'm keen on the type that makes a nice whooosh sound on the a gear change. Thanks
Dont get a cheapo valve, the baileys piston valve is the best looking and makes the nicest sound
LordNikon
14-09-2003, 20:47
The Dump Valve should be mounted as close to the throttle body as possible. It stops the back pressure when you change gear stalling the turbo and making it re-spool. Thus keeps the turbo spinning ready for the next power delivery !
All dump valves that are atmospheric will make the whooosh sound. I have a Bailey one on mine, look at www.regal-shop.co.uk for one. You will need a fitting kit aswell.
The wastegate fitted on the standard Turbo stops it from overboosting and holds the pre-set boost pressure, as set by the ECU, around 9PSi I believe. I have made minor changes to mine and set it to 12Psi with a safety overboost of 14.5PSi or 1 bar.
OK, here's me! Creating controversy :D :D :D
Standard Engine? Don't waste your money on a dump valve, the car has a recirculating one, which does the job just fine, as it sits on the turbo.
The 'blips' don't coincide with the TC/ESP light flickering on the dash do they?
For more throttle response, bin the paper filter. Get a PVD (Pipercross) foam one. Rip out the air restrictors in the airbox and enjoy an improved performance off the throttle and a car that sounds rortier.
As for the Optimax, definitely run the car on it, mine runs much smoother BUT I have never heard of the ECU being 'told' to run it. Perhaps an ECU reset is what was done, nevertheless the ECU will retune to the better fuel after a week or so of regular driving
Maybe totally unrelated to this particular issue but I have a 2.0DTi 16v and at the moment am experiencing pretty much exactly the same thing with blips in the acceleration. Had turbo diesels before but the acceleration has always been smooth.
Any way, I intend to have it upto Vauxhall next week so they can take a look so I'll see what they come back with.
Roadrunner
15-09-2003, 17:06
Just reset the ECU, it makes a hugh differance, forcing the ECU to learn your driving style as opposed to slowly changing to it..
Standard Engine? Don't waste your money on a dump valve, the car has a recirculating one, which does the job just fine, as it sits on the turbo.
What is a recirculating dump valve? Is this fitted on the Astra Coupe Turbo as standard? Does this make the nice "whooosh" sound too?? Thanks
How long does it take to "adapt" to your driving style ??
I've had it about 3 weeks now...
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2.0 DTi 16v
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Standard Engine? Don't waste your money on a dump valve, the car has a recirculating one, which does the job just fine, as it sits on the turbo.
What is a recirculating dump valve? Is this fitted on the Astra Coupe Turbo as standard? Does this make the nice "whooosh" sound too?? Thanks
OK, to explain further, just about all modern turbocharged engines have a blow-off or dump valve fitted as standard. These work by opening when the throttle is lifted, relieving the pressure and preventing the compressor wheel stalling against the back pressure in the turbine housing, due to dead-heading the turbo.
On a 'standard' recirculating DV the air is fed back into the inlet side of the turbo, in theory this keeps the turbo spinning longer, but in practice it just reduces the noise. These are fine, but when a car has a higher than standard boost pressure, these original, smaller DVs cannot loose the pressure quick enough.
THEN you fit a higher performance dump valve, normally atmospheric, where the pressure is released out. This is the 'psshhht' you hear on a gearchange on a lot of modded turbo cars. They are also nice to fit to make a noise and let everyone know you have a blower under the bonnet, but they don't make power or performance on a standard engine. If you derestrict the airbox on the Z20LET and fit a performance foam air filter, like the PVD one, you will hear the blow off from the valve on each gear change and the wastegate can be heard more easily :D
Pssssssssttt @ 23psi :D hehe :D
Pssssssssttt @ 23psi :D hehe :D
No one likes a show off, Pete :D
I'll be able to afford your mods and catch up with you one day :( Either that or I'll be bringing a tool box to the next AS show and 'borrowing' things off the Coupe until it is returned to standard :wink:
Only Joking :D
I'll never afford all those mods :wink:
Just reset the ECU, it makes a hugh differance, forcing the ECU to learn your driving style as opposed to slowly changing to it..
and this is done by.....
Maybe totally unrelated to this particular issue but I have a 2.0DTi 16v and at the moment am experiencing pretty much exactly the same thing with blips in the acceleration. Had turbo diesels before but the acceleration has always been smooth.
It was totally unrelated... down to a "faulty brake light switch"... bizarre.
Sounds VX logical. My traction control stopped working and they replaced the mass air flow meter to fix it :?: :? :?
What next? Changing the wiper blades to cure a squeaking drivers seat?