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[Dave Eastwood (Gadgetman)]

On 22/06/2025 at 12:01, Flying Carrot Steve said:

 

I've never seen a roll hoop with that extra extension on top before! For a tall driver I guess? Or if wearing a helmet maybe? Seems like an excellent idea to me. 

 

You used to see a few similar mods to the old RAC roll bar, back in the day. Not seen it done since the rule changes brought about the MSA roll bar, so i guess it was no longer compliant?

[joolz]

Been doing some quick cam timing tests, results in my development thread 

 

[Dan Hook]

Took my car to Northampton Motorsport last week for some attention to the cold starts and a map check.

 

Unless the car had been sitting in the garage on only the hottest of days, it would start fine but run a bit lumpy until — I can only guess — the coolant reached around 30°C or so. Easily resolved with a bit of gas or just starting to drive, but I wanted it checked over having previously replaced a duff CHT sensor.

 

Troy spent a morning running it up and down on the dyno, changing some of the ECU (OMEX) base settings and tweaking all the low RPM fuelling maps. As far as I know, it was as out the box by Westfield beforehand. Apparently, it had been configured to look for 9000 RPM, and by reducing it to a more realistic 7500 RPM, it gained a load of “resolution” in the map — fuelling is now more discrete and precise across the RPM range. The idle control values were also set poorly in the ECU and needed doubling to their maximum.

 

Anyway, it now starts and idles great, but I’ll need to wait for it to be truly “cold” to see how it behaves.

The dyno work did manage to kill the exhaust bobbin — too hot in low or no airflow — but it’s easy enough to replace.

 

The whole team there were really helpful and deserve the good reputation they get on the forum. 

[Flying Carrot Steve]

3 hours ago, Dan Hook said:

Took my car to Northampton Motorsport last week for some attention to the cold starts and a map check.

 

Unless the car had been sitting in the garage on only the hottest of days, it would start fine but run a bit lumpy until — I can only guess — the coolant reached around 30°C or so. Easily resolved with a bit of gas or just starting to drive, but I wanted it checked over having previously replaced a duff CHT sensor.

 

Troy spent a morning running it up and down on the dyno, changing some of the ECU (OMEX) base settings and tweaking all the low RPM fuelling maps. As far as I know, it was as out the box by Westfield beforehand. Apparently, it had been configured to look for 9000 RPM, and by reducing it to a more realistic 7500 RPM, it gained a load of “resolution” in the map — fuelling is now more discrete and precise across the RPM range. The idle control values were also set poorly in the ECU and needed doubling to their maximum.

 

Anyway, it now starts and idles great, but I’ll need to wait for it to be truly “cold” to see how it behaves.

The dyno work did manage to kill the exhaust bobbin — too hot in low or no airflow — but it’s easy enough to replace.

 

The whole team there were really helpful and deserve the good reputation they get on the forum. 

 

 

Gotta get mine there sometime, it's not had a full dyno session since Troy did it in 2019

[dvd8n]

Just done my annual O2 sensor replacement. 

 

 

I swear, I've put more O2 sensors in than spark plugs 🤬

 

[Naranja_Al]

4 hours ago, dvd8n said:

Just done my annual O2 sensor replacement. 

 

 

I swear, I've put more O2 sensors in than spark plugs 🤬

 

It looks from the photo that your sensor is mounted at 90 deg from the horizontal line of your exhaust or perhaps even lower. This will encourage condensation in the exhaust to damage the sensor. It might be worth looking to relocate the boss more in line with the below detail. I had to do this on my car to reduce the number of times the sensor needed changing.

 

 

 

 

 

 

[GaryH]

@dvd8n@Naranja_Al

 

The O2 sensor on my factory Sigma car is in similar position to that on dvd8ns car. Interesting given the orientation suggested above.

 

David, what sensor are you using as a replacement?

 

Gary

[dvd8n]

4 hours ago, Naranja_Al said:

It looks from the photo that your sensor is mounted at 90 deg from the horizontal line of your exhaust or perhaps even lower. This will encourage condensation in the exhaust to damage the sensor. It might be worth looking to relocate the boss more in line with the below detail.

 

Yes, I am intending to replace the whole ECU in the autumn, and was already considering getting the boss repositioned at the same time.  You can see in the photo that the orientation is indeed lower than level and could only have been worse if it was positioned vertically up.  But, annoyingly, the sensor started playing up this week and not replacing it would just have been cutting off my nose to spite my face.  You'd think that people making exhausts would know this stuff.  Oh, well 🤷

 

4 hours ago, GaryH said:

David, what sensor are you using as a replacement?

 

Well, in the past, I have just ordered a replacement from the Weber website and received a genuine Bosch 0 258 006 731 at a competitive price.  But this time not only had the price doubled but annoyingly I got a generic no name one instead.  

 

If I need another alpha compatible one in future then I think that I will either just get a shonkey pattern one from eBay much cheaper or go to a local parts house and get a genuine Bosch one for my money 😞

 

David

 

[GaryH]

Hi David

 

Thank you. I've been pricing CAT and O2 sensor replacements, my local parts guys can get genuine Bosch 731, or generic matched parts. They do a great job on parts for all our family cars, so I'll see what they can come up with.

 

I'm still running the alpha pro4 ecu, I'm still dithering about replacing it, as I've used one before I might go megasquirt.

 

At my last MOT, the tester reckoned that as the lambda/fuel air ratio was spot on through the rev range, it was more likely that the CAT was failing to make testing borderline. This links to a point that @Dave Eastwood (Gadgetman) made in another emissions/MOT related post.

 

Thanks again.

 

Gary