High Boosting Questions ??

[Faheemo]

Ive just fitted an Auto gauge Boost Gauge to my 96 S2 and i'm getting up to 1.4 bar reading in 3rd gear upward.
1st and 2nd getting 0.8bar .

According to the guy i bought my car from it's supposed to be standard. No chip.
I havent opened up the ECU Box as yet but i suspect that it's been chipped.
Is ther any other reason the car is boosting so high ??
Is it safe to run such high boost with standard injectors etc ...
What should i do ?
The boost seems very high should i be worried ?

The car has a standard Exhaust decatted and everything else seems standard !

[mastermind]

Hi Faheemo

Your car should boost to 1bar in 1st, 2nd or 3rd, I used to get 1.1bar in 4th or 5th.
Autoguage is also not the most acurate guage on the market, but its still showing a huge difference between gears.
1.4 sounds like it may be chipped. How does the car run at 1,4bar boost, is it smooth, do you have a surging problem. whats the feul consumption like. There are some very bad chips/tuners floating around in SA which you should be weary of.

Send me a PM and I will put in touch with the rest of the S2/RS2 nuts in SA.

[Jamo]

Ive just fitted an Auto gauge Boost Gauge to my 96 S2 and i'm getting up to 1.4 bar reading in 3rd gear upward.
1st and 2nd getting 0.8bar .

According to the guy i bought my car from it's supposed to be standard. No chip.
I havent opened up the ECU Box as yet but i suspect that it's been chipped.
Is ther any other reason the car is boosting so high ??
Is it safe to run such high boost with standard injectors etc ...
What should i do ?
The boost seems very high should i be worried ?

The car has a standard Exhaust decatted and everything else seems standard !

I'd say thats normal if your car has a homefry chip from S2Central.
Your getting 1.4 bar as the ECU goes into overboost mode for overtaking in high gears.

Drop S2Central a PM if you have a concern.

[GandalfS6]

@Faheemo, AutoGauge is not that accurate but 1.4 bar is too much too be an inaccurate boost gauge. 1.4 bar is perfect for a chipped S2, so i would not worry about it. It is pretty clear that the car is chipped. Can you check this with the previous owner(s)?

[Faheemo]

Previous owner doesnt have a clue, and claims the car is standard.
But he was the 2nd owner, me the 3rd, so i gonna open up the comp box and have a peek.
Havent managed to borrow another gauge as yet.
She does boost to 1bar in 1st & 2nd.

[Faheemo]

Got Friedling Racing to check out my ride, and guess what it was chipped.
Question now is why does it return to standard boost (1.1 - 1.0 bar boost ) now and again ?
Making me scratch my bloody head !

[dan_b]

What grade of petrol are you using? Also, what altitude are you driving at, and how hot is it? The ECU has all sorts of protection systems to prevent engine damage caused by low grade petrol, high altitude, high temperatures etc. Also, as mentioned above, the boost is limited in lower gears to save the gearbox (I presume?), but you get more maximum allowed boost in higher gears.
If you're getting hesitation or jerky acceleration and random dropping boost though it could be a dreaded boost leak?

Enjoy the chipped performance!

[kwlw]

What grade of petrol are you using? Also, what altitude are you driving at, and how hot is it? The ECU has all sorts of protection systems to prevent engine damage caused by low grade petrol, high altitude, high temperatures etc. Also, as mentioned above, the boost is limited in lower gears to save the gearbox (I presume?), but you get more maximum allowed boost in higher gears.
If you're getting hesitation or jerky acceleration and random dropping boost though it could be a dreaded boost leak?

Enjoy the chipped performance!

I'm not sure if ECU protects gearbox. I think, it's just the load on the engine is not enough (and the amount of fuel burned) to make turbo spin on the full power. I've not seen gear indicator on the S2 manual gearbox. Correct me if I wrong.

On high altitute, Motronic can make more boost to correct loss of power.

Sau

[S2central.net]

Only Mihnea has the definitive answer on this, but the ECU *could* work out what gear the car is in because it has inputs for road speed and engine speed.

Sau is right that highest load cannot be generated inlow gears. For one thing in stock chips, you only reliably get into overboost in 4th or higher.

But Sau's comment about higher boost at altitude is misleading... there is a limit to that of course because turbo's don't like thin air. Anyway the ceiling is provided by the 2.5bar ABSOLUTE pressure limit in the MAP sensor.

Dan is right about elaborate protection routines for poor fuel, knock, temperature, sensor failure and boost leaks in the depths of Motronic programming.

Paul

[dan_b]

Sorry - my musing about lower boost in lower gears was me thinking "out loud" as to why that would be engineered to be the case, I have no knowlege of whether that's true or not. My working theory was that not allowing full boost in low gears would be a way of protecting the transmission a bit?

[S2central.net]

Its a perfectly good theory Dan - I just dunno if its actually implemented by the code.

I DO know there is a funky routine in the RS2 ECU which limits boost when you have hooked up a trailer to the factory fitted tow-hitch - which is clever !


Paul

[Billman]

@s2central
That happens through disconnecting (cutting the signal)of the altitude sensor! So the ECU limits the boost!\

@dan
the Celica GT4 Carlos Sainz that i had once had lower boost in the first and second gears t oprotect the gearbox!

[Faheemo]

Shucks !!
I have a tow hitch on my car, but nutting hitched to it.( this is no RS2 aswell)
Living at sea Level.
Using 95 Octane at present.
97 only available in Leaded here.
Boost leak may be a possibility. ( have to do a pressure test ther )

@PAUL ! I've got my chip tuner to look at my files and he says that the chip is def not standard. MAP sensor also has being changed.
He also says he cannot recognise it to be from any of the South African chip tuners.
My guess it's probably your's or Minhea's. Ruled out MTM as well.
Is ther any way he can identify your chip ?
He did mention something about ther being a 8bit checksum not quite the same as his checksum.
( he also said he cannot improve anything on this chip !)
Got any records of chips sold to southafricans with a green s2 ?
Could it be that the octane rating is too low for the chiped version is this written into the chip ?

[S2central.net]

Think Mihnea supplied a set or two into SA, but I haven't yet...

That checksum is actually a 16-bit number - my chips actually have unique checksums so I can trace them if they turn up somewhere. If your ECU isn't one of Mihnea's then I can look into for you. If it is one of his, then you'll be well looked after.

Why has the MAP sensor been changed - what does it say on it 200, 250 or 300kPa ?

Stock chips have a preference for proper fuel - like 98RON - chipped cars are no different in this regard. Less than optimal performance is to be had with 95RON fuel.

Have you checked fuel pressure is OK ?


Paul

[mastermind]

Afaik I am the only 1 running Mihnea's RS2 set up in SA.
Paul, 2 or 3 of my buds in Cape Town have bought your 280HP chip sets for their S2s.

Faheemo, use 97 leaded with an octane booster or 102racing fuel, all S2s were able to run leaded in SA, we use a unquire lamba as well, clean the lamda often.

There were some S2s with a Unichip(whatever that is). Audi SA did the MTM chip on some S4s and maybe an S2 as well.