General performance figures for>

[J333EVO]

Bugger I didn't mean that to come across like I thought you were having a go at me, if you know what i mean, I'll put it down to lack of sleep & being pissed that the TV repair/insurance person hasn't turned up yet & I have to stay indoors till 530 till he does, sorry.

(I only kid on that I know things )

 

[alexGS]

It'd be interesting to hear if anyone has damaged their Uno Turbo engine through fitting a bleed valve. I found that even if I wound the thing right open, the boost never got any higher than 'moderate', about 0.8bar according to the dashboard gauge which is apparently inaccurate. This was on a hot day at a track. Basically the standard turbo is carefully chosen to be really small and efficient, and it doesn't seem to produce much more boost than standard even when you have a big exhaust and the wastegate basically 'open'.

Bear in mind of course that the fuelling DOES increase even if the wastegate is being 'tricked', because the airflow meter registers more airflow. The computer is indeed mapped to 1 bar. I presume, after that, the fuelling cannot increase further. But like I say, I don't think the standard turbo can get up to 1 bar. Has anyone found otherwise?

-Alex

 

[J333EVO]

I think you'll find that increasing boost does not increase air flow as you yourself have the stated the reason for this. You have quoted boost in BAR, BAR is the AIR PRESSURE this has nothing to do with air flow which is measured in cfl (I think), which are 2 very different things, therefore the ECU has to be reprogrammed to accommodate the increase (OK on the UNO it can go to 1BAR without reprogramming), otherwise you get fuel starvation & possible detonation which can lead to at worst pistons melting. This is why you can run a bigger turbo with less boost but get the same results as it is flowing more air due to having bigger impellers. Any tuner who knows their onions will not fit one, it was a popular mod on turbo cars in the 80's early 90's when there wasn't the depth of knowledge that there is today, & this is why turbo cars got such a bad name for reliability, I'm not saying that bleed valves are all bad ,all I'm saying is they're crude, they lower the lifespan of the turbo's & head gaskets etc if not used properly i.e. turned up to indefinable levels & there are better more reliable ways of getting higher boost levels

You see a turbo does not produce more boost when you fit a bleed valve etc, it still spins at the same speed as before flowingh the same amount of air, because it runs off the exhaust gases, all you are doing is increasing the pressure in the system that is normally controlled through use of the waste gate letting excess pressure out. You wouldn't want your waste gate open as you would then get no boost, thats why you fit an uprated wastegate because when you up the boost, you can get whet is know as wastegate flutter, which is when its opening a closing ever so slightly but rapidly as it doesn't have the pressure in the spring to hold the boost in. On the integrale the waste gate is computer controlled rather than spring controlled, which means it opens & closes to produce diff boost levels dependent on gear selected, 1st 2nd gear 0.6, 3rd 0.9 4th 5th 1.1BAR but thats a smart system that would be expensive to replicate in a car without it.


Aaron.

 

[alexGS]

Aaron,
Yes I do agree with everything you've written - I've had a ride in an Uno in South Africa that was running a very large turbo, low boost pressure indicated but you could tell that there was a large amount of airflow...

I guess all I was saying, then, is that I think the standard turbo on an Uno is not capable of flowing any 'dangerous' amount of air vs. what the standard ECU can provide fuelling for - and this happens to correspond with indicated boost pressures up to but not exceeding (in my experience) 1 bar. Therefore, I found with the bleed valve wide open that the boost pressure would not rise above about 0.8bar and so, I'm suggesting that the standard turbo is unlikely to cause engine damage when running with the standard ECU. It seems like everything has been carefully engineered to fit together (as I'm sure it was).

I can see your point that if a bigger turbo was fitted, the ECU would not necessarily meter the fuel correctly for the additional airflow, even if the boost pressure was less than 1 bar. And so in that sense, boost pressure and airflow are not related. But I maintain that for the standard turbo, there was a known relationship programmed-in to the ECU (because there is a limit to what the standard turbo can flow).

As for the electronic wastegate on a Delta Integrale (and also the 'overboost' feature of Croma turbos) I get the impression that such mods as restricting boost in low gears would be for reducing torque steer (or for the Integrale, ensuring the life of the transmission?)

But it would still be interesting to hear if someone has managed to melt their Uno turbo engine using a standard turbo...

-Alex

 

[jamie86]

My mate damaged his engine using an uno turbo......oh sorry that was on a Y10( and a hybrid turbo. )
Sorry bit off topic!

 

[J333EVO]

Hi alex, you'll probably find that the reason that the standard turbo doesn't show anymore than 1BAR boost is because the waste gate spring is probably pre loaded to open at that point to ensure engine safety, but the turbo itself will probably be boosting more than that, I could be wrong.

You are correct with the integrale (which has over boost as well) limits the boost in lower gears to safegaurd the drive trian as the car its self has an amazing amount of mechanical grip & huge amounts of low doen torque, 220lbs/ft at only 2800rpm. Some of the early tuners just lifted the safety limit in lower gears to make the car feel faster but did the cars no good. Now of days the chips you get are fantastic they still limit the boost in lower gears but now by as much and over boost safely to 1.4BAR which in the grale is an extra 40/60bhp (dependent on exhaust) taking it up to 260/280 which makes it fun!

 

[uno_jens.]

here is a videoclip from inside my uno..
I only hade a bigger turbo,injectors and of course a bleedvalve.



http://www.turbom.wz.cz/uno at 1[1].5 bar.wmv

 

[The Negotiator]

Bit like my 999cc

 

[uno_jens.]

he he

This is also from inside my uno, but the quality is a bit low..
It´s very dark..but the sound

the bleedvalve is set to 1.8 bar and there is no traction in 2:nd gear...

http://www.turbom.wz.cz/uno at 1[1].8 bar.wmv

 

[alexGS]

Uno_jens, that's amazing, I get the idea that the engine was hardly even trying! And the way you back off after a few seconds, I wonder what speed you got up to!

For a bit of comedy I should make a video of the same thing in my Uno 60. The start would be pretty much a complete stall. I think my foot would be on the floor for at least 2 minutes before I felt like backing off... plus of course the video would be a bit taxing on everyone's bandwidth.

-Alex

 

[Dunc Uno Turbo]

nice

loving the 2nd clip with NO traction hehe. what 1/4 mile times are you running at 1.8 bar and what bhp? also what engine mods have you done?

got any pictures of your uno and engine bay?

Dunc

 

[uno_jens.]

These clips are old.. I had maybe 180-190 hp at that time.. nothing special done to the engine.
It is a 1301cc in a mk2 body.

I have no clips from last year with 244 hp.. The old clips are kinda slow compared to now.

 

[J333EVO]

Cricky with an extra 50bhp I hope you've sorted out the traction problems as it was a total none event in the vids.

I know a friend of mine had major problems like this about 7/8 years back when he did the first in the UK 6speed 2L turbo Nova, it ran 300bhp but was slower than my at the time 180bhp Renault 5 over the 1/4 mile (just) as he had such problems with traction, once up to speed in was an awsome car, from 50 to 140mph it was devastating. He decided to junk the Nova & transplanted all engine & box over into a MK3 Astra GSi got bespoke Bilstein suspension made by them to match the requirements of the car, which although heavier was so much faster due to the vastly improved traction off the line, like mid 12's fast and 160mph+

I know that the fastest 5 turbo i've seen over the 1/4 11.9secs (disregarding the twin engined one) was running 260bhp but had a great suspension set up, whereas I've seen some monster 330bhp 5's have a little trouble off the line.

I also found when using my 5 on the track it was often faster to turn the boost down to enable me to get the power on earlier out the bends to counteract the massive torque steer, although once I got in car adjustable boost you could turn it up on the straights just like in the old turbo days of F1. he he

Keep up the good work & get some new vids of the car now

 

[uno_jens.]

I have a aftermarket ecu now, and can set the boost to groundspeed..
Maybe I will use traction controll next year..
I did only drive one time the 1/4 mile and got only 13.0 sec.. It was on regular tires..
The front suspension is 14 years old, and there will be som e changes..

I have not driven the car since July and there is some upgrades to do over the winter..