akshay67

Whats the best way to improve this acceleration (on a MY99 UK)? It pulls to a 100 very nicely, but takes years to get to 140mph on the autobahn...

Gareth Allan

big turbo, has me reaching for an imaginary 6th gear everytime...

john banks

Heard of yet another car letting go at sustained high speed the other day. Just be a bit cautious trying to keep up with the big capacity normally aspirated German stuff - I personally would keep it below 130 mph if I was on an Autobahn except for short periods of time. I don't think anyone truly knows why this happens but various points about oil and airflow have been made.

ustolemyname??stevieturbo

iTrader: (1)

more horsepower generally helps acceleration!!!!!!!!

Katana

John, I think thats when front mounted intercoolers come to play. If you see the shape of our cars you can imagine how the streamline would look like. There would probably a vacuum above the intercooler scoop which basically means that hardly any air would go into the intercooler as you go faster and faster.

What I'm thinking of doing is to direct air from the front of the car near radiator via a hose or something. Should work out cheaper than a Front Mounted intercooler eh? Hmm, I guess its a good summer's project for me then.

john banks

I know what you mean Katana, however, my intake temperatures are not hot at high speed - they are nice and cool. There was some dispute over the airflow thing, but I am sure my scoop is scooping fine.

Iain P

If you are worried about inlet temperatures during high-speed runs get a temp probe. I bought one from Autospeed.com in Australia. Cost about £19 including postage! It doesn't react particularly quickly but is fine for cruising and low speed (in traffic, for example). I have been told to avoid high engine loads with more than 55 degC. Highest I have seen is about 65C in traffic but soon drops when the speed rises. I fitted mine in the intercooler-out pipe with a banjo fixing.

Katana

Ahh, but at what speeds and how long was it held for. I think a few people has blown their engines up at around 150 mph.

sammyh

iTrader: (1)

Buy a Porsche

john banks

At 6000 RPM (private road I have a very big one ) it still had 17 PSI (7 more than standard) and was pulling well. 24.88/1000RPM. I could see the temperatures were not increasing - the thermocouple acts very quickly. I can get much more impressive intake temperatures at lower speeds where things are working very hard and there is less airflow. I really don't think this is the answer personally. On the track as speeds increase towards the end of a straight (but this is only 110 mph so not relevant arguably) things actually cool quite nicely - I realised not to go slow on the straights to try to cool things down. However, until there are more answers I keep my 147 mph speed limiter and a self imposed on should I ever go to an Autobahn. In fact I know I should set it to 130 mph if I am planning it then I won't be able to misbehave.

[Edited by john banks - 5/20/2002 7:37:18 PM]

Iain P

I think an oil cooler and oil temp gauge would be a good investment for track or high-speed useage. I agree, John, the temps do rise after you slow down which is where things probably go pear-shaped.

mike_s14

I think a Skyline would be better.......

john banks

Skyline group buy ?

sammyh

iTrader: (1)

R34 hmmmmmmmmmmmmmmmmmmmmmmm

mike_s14

Lets do it..

Right if we all chip in and split the days of the year buy how many people join in we'll be sorted.

I fancy a R34 V Spec, god better get some people....

Sieze

Goodbuy no. 3 big end , hello big bill! I can personally reccomend not holding sustained high revs in a scooby.

Sheepsplitter

Sieze: Can you give a little more detail.
Like how many revs, for how long, in what conditions etc.
Thanks in anticipation,
someone who wants to minimize the risk to his engine ;-)

Hoppy

Katana, I know what you mean about air flow to the scoop at high speeds, but JB has some hard evidence that inlet temps are okay (although there will obviously be huge mechanical stresses going on).

Maybe the problem is not airflow so much as the position of the TMIC - ie above the engine and right next to the turbo which is red hot. On slowing down the heat-soak to the inter-cooler is going to be huge so when you boot it again you're in trouble.

Which means that ducting more air from the front won't help

Just another theory.

Richard.

john banks

Anecdotally it is when people lift off that things go pear shaped?

wrxeat

simple don't lift off.........

Adam M

Gareth,

how is the turbo?

happy? I do hope so.

I am not convinced by this air flow crap, as I have heard the japs also suffer from it and theres dont go above 112mph.

I also know of several big end bearing failures (not just no. 3) that have occured on cars with fmics, and after sustaining a low speed cruise.

Floyd

iTrader: (9)

Adam

The thing is we don't know what the driving style/history was before they let go. Long sustained low speed cruise, but previously thrashed the nutts off for 1000miles, who knows???

It could be that there is a fatal combination of wrong fuel/oil, oil level, high speed/poor cooling and harsh backing off of throttle which causes this?

I do concur that the 112mph Jap thing doesn't fit though, but then again they've had delimited cars over there for blasts through certain tunnels....

I'd like to check what goes on with i/c temps, at 130mph and beyond, so will any volunteers queue here please?

F

john banks

You got a private road for me to play on ? What are the maximum speeds you can get on some of the bigger English tracks? Knockhill seems to be easily under 120mph unless you have a monster.

Katana

If we can get the guys who unfortunately had big end failures post here and tell us exactly how it happened, what were they doing, turbo pressure, mods, etc, we could come up with a hypothesis on how this happens exactly.

Adam M

what a good idea!

cant believe no one thought of doing that before......

oh, thats right, they did. and the answer???


inconclusive, only a pattern of similarity.

slowing down after sustained high speed cruising (over 100) although some failed after cruising at 70, and an oil change within the last few 100 miles.

also a mixture of cars with and without fmics.


Bob rawle collated all the data, but i think the result was so random that there were no answers worth reporting on.

I am sure if you ask nicely bob will repost the results.

Katana

But did they posted everything? like the colour of their alloys and such?

john banks

Correlation with gold wheels? Sorry this should not be muppetised. Come in Mr Lewis...

Leeroy

The fact of the matter is Impreza's aren't designed for sustained high speed running. My previous 24V Gsi Carlton would embarass most Imprezas on the dual carriage way, certainly above 130, which I had countless experiences of!!

Trout...

The only thing more embarrassing than being embarrassed in a Scoob by a Carlton - is driving one!

Unless it is a Lotus Carlton

Mind you the Carlton couldn't catch me

Trout

PS Full details of car - tuned by idiots (me) thrashed for over 30k miles - still working fine! After three years there is finally a real fault - the power steering pump is noisy!

Cosie Convert

Power steering is for girls Get yourself a lightweight Scoob and you will not need it. You need to drain all the oil though or the steering is still heavy.
So much more feel through the steering, just like a Westfield which is nice