13 replies to this topic

[Soren]

Although I have already done 6000km I’m still quite new to my Opel Speedster Turbo (<6 month).

As the distance covered indicates, I’m using it for my daily commute (and what a change from an old, but still newer than the Opel, Mercedes E class diesel). What a thrill in comparison!

 

However, mine is slightly tuned (I guess a stage 1 or so), and that, despite the slightly increased power, is root cause of some annoyance, especially when getting on the freeway.

Induction noise (I guess that’s the name) is very, very much present as the car is mounted with an open air filter, and while providing great short term fun, it also gets a bit tiring in the long run (at least for me) to have that rather loud hiss directly behind my neck.

 

So, I am planning to revert back to a closed air filter, the filter box seems to be easily available on eBay, but that leads to a few questions:

1. I guess I need to have the ECU remapped back to original setting, assuming it has been mapped using the open filter? Also it seems like remapping is usually done with high octane fuel (99-100), but I would prefer if I can just use 95 octane, which also counts for going back to original.
2. Is it a no brainer to map the to original settings, I don’t have the experience myself, but if not too complicated, I would like to ask which tools to use, where to get the binary, and perhaps if someone has a guide (preferable where I can read/store the current code in case I want to switch back some day)? An option would of cause be to have a shop do it (I guess it is a pretty standard job).
3. Will the torque curve change significantly when going back to original setting (haven't had any luck searching for Speedster/VX220 Turbo torque curves)? Currently I appreciate the rather high torque at moderate RPMs (attached), which make daily, non-racing, driving fairly relaxed, -and still having the ability to make big smiles when driving a bit harder.
4. Mounting the air filter box seems to be a pain if done from above, -I can just reach the current air filter, but seems to be a pain to refit anything in this location. Will it be easier to do if removing the left wheel arch and work from below? Can anyone post/send a picture or two showing how the closed air filter box is originally mounted?

Thanks in advance!

Søren

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[martinroger]

I don't have a tubby, but I can confirm that usually the original air boxes are easier to fit through the wheel arch. No idea on torque curves, but I'm not sure you'll feel the difference in daily driving. I guess the experts will confirm this or not

[Nev]

You won't need a remap for just switching the air filter. The ECU has sensors and algorithms to adapt to small changes.

 

You should ask/ring up the company that mapped your car and ask if you can use 95 octane. It's quite likely to be safe to do so I think, but best to check.

 

Just re-install the OEM airbox in the OEM location, it very cramped, but can be done by removing the passenger side ear. That will eliminate induction noise, as the OEM box has a couple of tuned trumpets in it to specifically do that.

 

GL.

[Soren]

Thanks for the answers!

 

Unfortunately I don't have any history regarding the mapping of the car apart from previous owner that took it to a dyno, so I don't know which company did the mapping.

 

Regarding being safe to run 95 octane, -I must admit I have done so for most of my ownership due to availability along my daily route. I have not experienced any "knocking", but sometimes when accelerating hard i 3rd the engine can cuff around 3-4k RPM. Could that be a symptom of too low octane? I have checked the softness of the air intake tubes, they don't feel that soft when engine is warm, but not too hard either, so I don't know if I should mistake the fuel or the tubes to partially collapse/deform. It feels/sounds like cuffing/loosing power, and then coming back with a severe "kick", and acceleration is smooth and almost breathtaking all the way from there.

 

[Nev]

A simple way to check if the OEM rubber inlet pipe to the turbo is collapsing is to wrap duct tape around it tightly, that will give it more strength. Then test drive it. Or alternately, install a small video camera in the engine bay. I use a cheap £5 Chinese one and it's identified quite a few useful things for me in the past.

Edited by Nev, 31 July 2019 - 06:01 PM.

[Ormes]

OEM Map has a bit of a flat spot built into the curve, probably to get over some emissions regulation or something... Are you sure it has been mapped?... where is the red line?

[Soren]

Honestly I am not sure it has been mapped, but since the measured 216bhp is a good notch higher than the factory spec of 200, I was just assuming. Don't know what realistic numbers to expect compared the factory spec, but perhaps my job to do may just be the air filter box, and a good check of the air hoses.

 

I have no number for the red line except that from the rev. counter.

[coldel]

My turbo had just a miltek exhaust fitted and standard air box and hit 225bhp when remapped (done by previous owner with rabbid remaps) - maybe your map is actually as standard and gained some hp through minor mods?

[SteveA]

Thanks for the answers!

 

Unfortunately I don't have any history regarding the mapping of the car apart from previous owner that took it to a dyno, so I don't know which company did the mapping.

 

Regarding being safe to run 95 octane, -I must admit I have done so for most of my ownership due to availability along my daily route. I have not experienced any "knocking", but sometimes when accelerating hard i 3rd the engine can cuff around 3-4k RPM. Could that be a symptom of too low octane? I have checked the softness of the air intake tubes, they don't feel that soft when engine is warm, but not too hard either, so I don't know if I should mistake the fuel or the tubes to partially collapse/deform. It feels/sounds like cuffing/loosing power, and then coming back with a severe "kick", and acceleration is smooth and almost breathtaking all the way from there.

 

Have you checked the vac and recirc hoses? The symptoms sound like one might have fallen off.

[Ormes]

My turbo had just a miltek exhaust fitted and standard air box and hit 225bhp when remapped (done by previous owner with rabbid remaps) - maybe your map is actually as standard and gained some hp through minor mods?

 

Or maybe the dyno was 'generous'

[Soren]

I have checked all hoses I could find, -all seems to sit right and I found none cracked.

The only mod to the car I have documents for is a timing belt kit from Regelin, which should provide a "less bended" path for the belt, but I doubt that should impact performance too much.

 

I think I will try to go for mounting the closed air filter box and see how it behaves/sounds then.

 

Thanks for all inputs!

Søren

[SteveA]

Did you check the small 2mm plastic hoses?

[Ormes]

I have checked all hoses I could find, -all seems to sit right and I found none cracked.

The only mod to the car I have documents for is a timing belt kit from Regelin, which should provide a "less bended" path for the belt, but I doubt that should impact performance too much.

 

I think I will try to go for mounting the closed air filter box and see how it behaves/sounds then.

 

Thanks for all inputs!

Søren

 

I suspect it will be for the Aux belt and not the timing belt.
 

[scw02102]

The fact you have a flat spot between 3-4K they indicates a standard map or a not optimised stage 1.

When I mapped mine from standard the stage 1 remap got rid of that flat spot as it was noticeable.
All dyno through out different readings so 216bhp on a friendly rolling road is possible