Boost Reading

[bilko0795]

What should my boost gauge be reading on a stock Ecu, my gauge is in Bar what would that equate to in psi. also what would the reading be on a Homefry ecu.

thanks.

[Rusty]

Stock S2 ABY?

You need to do a pull from 1k5 RPM in 3rd or 4th and press the accelerator hard down. Should jump up to around 1.0 Bar and then drop off to 0.6. If you don't satisfy the criteria for overboost, then it'll see around 0.8 Bar.

On a Homefries, you should see 1.4 Bar, dropping to around 0.8, unless you have a big IC / it's cold outside / you're in the Alps... Here's boost profile from a dyno pull (/14 to get Bar).



If you don't do the run in the higher gears, you'll not see full boost as the revs rise too quickly and the desired boost changes from the peak values above.

What are you seeing?

[bilko0795]

I have only done it the once and it was done in second and hard down on the pedal through each gear didn't quite reach 1.0 bar though, it got around to 0.7/8 bar, will check again when i go to work later now i know what gear to be in this is the gauge i have is it one of yours i got it of Pete (Acidburn )

[Rusty]

That's not mine, it's from the HPMuirt group buy but that shouldn't make a difference.

WOT in 2nd will rarely see 1.0 bar. Need to be in 3rd upwards, ideally 4th and press the throttle down fairly swiftly IIRC.

[bilko0795]

Done the test boosted to 1bar when it cold but only 0.9 when engine was up to temp.

[Rusty]

You tired Vag com to see what the altitude sensor is measuring? Is the boost gauge sitting at 0 when at rest? What's the homefries ECU running?

[bilko0795]

When you look at the gauge I have the needle is on the bottom on one of the little screws
Before the 0.5 then when you drive in hovers in between the 0.5 and 0 then when you floor it it rises to the 0.8/9 and them drops back to 0.5 again. Not tried the home fry yet as I sent it back to spink as it was playing up. I will check the sensor with vagcom.

[UrS4boy]

When you look at the gauge I have the needle is on the bottom on one of the little screws .

Post a photo of the gauge, at rest with the engine off and a second one, at warm idle.

[AndyP]

Looking at the gauge you have it only reads to 0.5bar vacuum ( not technically correct I know ) , mine reads 0.7 at warm idle, so saying the needle is round by the screws makes sense.

I thought overboost on an ABY was 1.1bar?

[Rusty]

It changes with temperature and altitude but a temperate climate in a mild summer will see around 1.0 Have a look on s2central.

[UrS4boy]

...I thought overboost on an ABY was 1.1bar?

This is the absolute pressure graph. Overboost is about 2.1 Bar absolute (= 1.086 Bar at 14.5 psig/Bar and 14.7 psig (1.014 Bar, 1014 mm) atmospheric pressure). So yes, about 1.1 Bar.

[gadget6970]

Ive just put an up rated waste gate spring in and screwed adjuster right out and is hitting 1.8 bar on my homefry usually running 1.4 bar is it safe to run this figure on s2 aby ?

[Rusty]

No. Put the stock spring back in or get it remapped. It'll run like crap when coming on boost, as the desired boost and actual boost will be quite far apart, so the fuelling and timing won't be correct. Not a good idea.

Speak to Automark, MRC or prj on here about a live map.

Cheers matey. I shall take it out and look into remap at a later date.got some braking issues at mo front brembo calipers dragging a bit and getting hot