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-   -   How much boost? (https://www.scoobynet.com/general-technical-10/26280-how-much-boost.html)

Col 30 September 2000 03:54 PM

Just finished fitting a boost gauge to my scooby my94 uk model.
What psi should it be running?just had it out for a blast and it was running about 13psi,is this about right?

cheers

sunilp 01 October 2000 09:43 AM

A RB5 will run a different boost to a 94WRX as they have different turbos etc.

try a browse through

Al Harcombe 01 October 2000 12:20 PM

Col
Smack bang in the middle of the playing field. While talking to Subaru field engineer about my RB5 with the surging/lumpy fuel problem at 2500-3000 rev`s.I asked what the boost should be. He and the mechanic both stated 12-14psi. Fitted a boost gauge from Scoobymania (top service by the way) last month and went for a simular blast. Achieved a maximum boost of 14psi.
Al


GRANT 01 October 2000 05:43 PM

Col,
Have an MY00 and was getting 14.5/15 Psi on full throttle in 5th gear.
Now get 17.5 psi after mods.Only used for very short bursts.

Grant

[This message has been edited by GRANT (edited 04 October 2000).]

Richard Gledhill 01 October 2000 10:46 PM

What mods have you got on your MY00? I get 14.5psi, or occasionally 15psi (after track day http://bbs.scoobynet.co.uk/smile.gif) with a better air filter and intercooler splitter...

Richard

GRANT 01 October 2000 11:31 PM

Richard look up my e-mail on profile and will give more details.

Grant

sunilp 02 October 2000 07:32 PM

Blimey, the guy has got a std MY94 UK and you lot are giving him irrelevant details.

Just to add my irrelevant fact, my car runs 1.21bar held with no overboost to 6700rpm http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

GRANT 02 October 2000 08:08 PM

Don't take it so seriously Sunil.

We are not all as clever as you http://bbs.scoobynet.co.uk/smile.gif

Grant

sunilp 03 October 2000 07:54 PM

i am not - see the winky faces, but the poor bloke is probably tearing his hair out. Wish you lot would learn to read http://bbs.scoobynet.co.uk/wink.gif

Blackscooby 03 October 2000 08:14 PM

The UK motors (UK 94) where meant to run about 13 PSI I think.

I'm sure mine held something like this. On my boost gauge the engine cut out came in with brute force at 17PSI. (Overboost protection).

Modifications meant that I could hold 23 PSI, peak of about 27PSI. DON'T DO IT !!! You'll bust a piston like I did http://bbs.scoobynet.co.uk/frown.gif

Now I have a hold of 18PSI, with no peak thanks to a Apexi Boost regulator. No damaging peaks. Apperently its the peaks which caused the damage. Mine ended up pinking its nuts off apparently when the engine was investigated.

It addition the intercooler becomes very inefficient at sustained high boost, causing in high inlet temps and reducing power.

I think approx 13/14PSI (1 bar) is good for a standard UK engine.

Thanks

Mark.

R19KET 03 October 2000 08:56 PM

Mark,

Just what mod's did you do to hold 23psi/peak 27psi, and why did the piston go if the mod's were ok to hold that boost,

Mark.

Blackscooby 03 October 2000 09:14 PM

Basically it couldn't take it.
The pistons weren't forged items just the standard Subaru ones. I'd had alsorts done over time. Group A head gaskets, modified ECU, free flow filter, SS exhaust.

On the Hillclimb event when I ran the boost it blew the IC off its mountings http://bbs.scoobynet.co.uk/biggrin.gif
and blew the IC pipes off.

3 of us could not get it to move when we reseated it ~ but it did it again. Now thats of lot of PSI going into the inlet.

I've got the video from the event and you can see where the piston went & and you hear it go !!! http://bbs.scoobynet.co.uk/frown.gif

The power was scarey ~ just like a playstation game. Would spin all 4 out of bends in the dry in second easily.

The guy who preps the car for me is a basically a nutter (no offense intended Alex if you're out there). We just over did it.

Its now running Cosworth pistons along with a small Type R turbo (so its lost its high end power), but gained lower down the rev range.

18PSI is the most I can take it to as the IC can not cool the inlet temp enough so it starts to pink again anything over 19PSI.

To get more out of it I'd either need Water injection (direct inlet type) which isn't allowed under the FIA Hillclimb regs, or a front mounted IC which would so I'm told allow me to run about 1.5bar or 22 PSI again http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

But they're serious money http://bbs.scoobynet.co.uk/frown.gif

Maybe next season !!!

Cheers

Pete Croney 04 October 2000 04:18 PM

Blackscooby...

That sort of boost is pushing the intercooler off with 160lbs of force. No wonder it came loose 8)

R19KET 04 October 2000 07:28 PM

Pete,

Where does 160lbs of force come from http://bbs.scoobynet.co.uk/confused.gif

Mark,

I guess it's down to what gives you more power (and no det'), less boost, and more advance, of more boost, and less advance.

Shame you can't use the Aquamist system though, it works very well on my car http://bbs.scoobynet.co.uk/biggrin.gif

I just need to go internal......

Mark.


Danny Fisher 04 October 2000 09:38 PM

Mark, thats enough about you needing to talk about your internal systems thank you


Dan

Pete Croney 05 October 2000 08:54 AM

Mark

160lb of force comes from a cross sectional area of 6 squares inches(3849mm2 actually), at the junction between intercooler and inlet manifold, and a pressure of 27lb/sq inch.

Blackscooby 05 October 2000 12:03 PM

Mark,

Regarding your internals....yeah its a shame I can't use the aquamist system. I looked into it, then read the regs. An intercooler is not exactly effecient, and water increases density of the air by a massive proportion.

R19KET ~ its a bit of a balancing act between what can be done safely and how much power do you want. Previously I was biased towards power, but get it wrong as I did and its bl00dy expensive.

I got a Motorsport place to set it all up, so I've no idea what advance or anything is set. It seems to work well though.

Cheers

Mark.

R19KET 05 October 2000 12:36 PM

Mark,

I changed to the MRT top mount, and it works very well. Compared to the standard IC (with water injection) my temps dropped by about 25deg' (still using the WI).

What I meant about boost/advance, in my previous post, is have you tested to see what map (either more boost, and less advance, or less boost, and more advance) gives the most power.

Mark (R19KET)

Blackscooby 05 October 2000 04:53 PM

Pete,

Yep it must have been a heck of a lot of force to manage to do what it did...The force broke two of the bolts which hold it on http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

160lbs...**WOW**

Don't use that much boost anymore... I'll only end up with a bag of bits again http://bbs.scoobynet.co.uk/frown.gif

Mark,

No I haven't played around with the settings interms of advance and boost to see which gives most power. I ran scared when it came to setting up the Fuel controller / boost mapping. Left it to someone who (hopefully) knows what they doing.

MRT top mount ~ whats all that about then ?

What is it / how does it work ?

Cheers chaps.

MarkW.

sunilp 05 October 2000 08:23 PM

Pah, i knew that Pete http://bbs.scoobynet.co.uk/wink.gif

R19KET 05 October 2000 08:52 PM

Pete,

I'm confused......if it's 160lb across the inlet to the throttle body, how much is it through the 3mm pipe to my boost gauge, and why does it still read 19psi.

If you put a 1lb weight on a 1 sq inch piece of wood, you'd get 1psi of force, if you then took a 6 sq inch piece of wood, and placed the lb weight on it, would the force be 6lbs.

Mark.

Mark.

jwhitton 06 October 2000 08:29 AM

BlackScooby,

Cant you run a Motec or other 3D management system to ensure it has a inlet temperature input which the ECU can modify the ignition and goost to? I know Ahmed Bayjoo does this on his Cosworth ECU replacements. I have also seen Skylines with inlet temperature meters and mods done.

Do Pace sell a charge cooler for the Scooby or why not try STi like water spray on the intercooler.

Or better still just buy a Yellow EVO like Richard Hargreaves and beat him at his own game. Last time I ran against him even in a sprint even modded STis where 1 second or more behind at Three Sisters.

jon

Pete Croney 06 October 2000 08:38 AM

Er...

pounds per square inch. I think it means what it says.

Although your boost guage pipe is only 3mm, it is still full of air that is at the same pressure as the intercooler and inlet manifold. The 3mm pipe may slow down the speed of the air as it flows to equalise pressure between the manifold and guage bellows but, given time to equalise, the pressure on every square inch of what is containing the pressurised air will be the same. If you use a 10mm pipe, would you expect to see more boost?

No, but your boost guage may react more quickly.

If you have 27 pounds pressing against every square inch and you have something with an area of 6 square inches, you will see 27x6=162lbs of force.

Oh... and if move your 1lb weight onto a piece of wood 6"sq, it will press down onto the carpet with a force of...

(I know the suspense is killing you http://bbs.scoobynet.co.uk/wink.gif )...

0.167lbs

Hope that helps and no running in the corridors http://bbs.scoobynet.co.uk/wink.gif http://bbs.scoobynet.co.uk/wink.gif


Blackscooby 06 October 2000 05:43 PM

John,

Yellow Evo....aaggrrrrr yep I know it well. Robbed me of Harewood trophies (him and Malcom Pinder) every time they turn up !!!

What were you in the other Sunday at 3 Sisters. I was there as a spectator cos I couldnt get an entry...(boo hoo)

Myself and Malcolm have had some fantastic battles at Harewood.

Should have bought Jon Mounseys Sapphire (?) Cossie....Now that machine was something else. B4 anyone says anything..yes I know it was a Ford Cos...but My goodness what a machine http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

Engine managements...hmmmmm its tempting.....

Regards

Mark


jwhitton 10 October 2000 08:30 AM

BlackScooby,

Yes I also know Malcolm Pinder.

The story goes that I ran my 200bhp RS Turbo in the plus 2 litre class last year. I was outclassed by the 4WD machines but it is the competing that counts :-) !

I ran in April 99 at Three Sisters and about a month later needed to get the engine rebuilt. This was done by Ahmed Bayjoo, the high Priest of Ford tuning, and took longer than expected. Hence I had to cancel Aintree and Curborough. I then ran at Three Sisters again in October 99 in the pis**ng rain.

I locked all the wheels of the car at the end of the straight coming of the hill where the go karts start is. I then ploughed into the tyre wall at about 30-40mph.
It was an expensive day - bumper, wing, light, indicator, wash bottle etc etc.

Both the bloke with the grey Skyline and Richard Hargreaves both called it a day after seeing me do this in the first timed run.

I still have the RS which is as quick as most UK spec Scoobies, I am sure many can confirm this at RSOC at Silverstone this year. I am also the owner now of a MY00 Scooby which wont be going near a track.

I know that Malcolm Pinder has a Graham Goode exhaust and ECU on his STi, phase V I think.

If you have a look in Hargreaves car it is right on the regulations, no carpet, light seats, lots of interior bits removed. I think it has also been breathed on in the ECU and turbo department. Have you noticed it spits flames as he starts down the straight!

The only chance you have of beating that thing is to join him and buy a later EVO Extreme or Tommi special!

I am not sure if I am going to spint again due to the cost versus track time ratio. Much prefer track days for value for money, also I am a sour puss since really the RS should be in Alan Tewlars group. hargreaves would be worried if Alan got an EVO !

jon

Blackscooby 10 October 2000 09:03 AM

Jon,

The Yellow Peril machine of Richard's is fantistic. It is on the edge of the regs, but as far as I'm aware it is within them. Under that bonnet is the cleanest engine you will ever find. I've no idea what boost it runs but the gauge goes to 40 PSI http://bbs.scoobynet.co.uk/biggrin.gif

The main work on that car I think is in the suspension and as you say in the turbo and turbo management department. Around 3 Sisters in the dry there was no understeer at all, compaired to a Subaru which had cronic understeer.

One key difference is that Richard doesn't use it day in day out like both myself and Malcolm P. Therefore its easier to get away with no carpets and the noise really isn't that important inside the car.

Sprinting is an expensive form of motorsport in terms of track time ~ but I think its the cheapest form I'm likely to see. (Being diabetic means I can only hold a none race licence).

Next year I'm changing from the Subaru to a Pug 205 which has already been heavily breathed on my LAD Motorsport. It just a sprint motor to be used in Modified production cars...ie same as Bobby Friers's Clio.

I know that I'll never beat Richard as I can't spend that much money on cars. I would also have to learn how to drive "properly" to have a chance.

Sorry to hear of your incidents in the RS. I agree that anyone in the class against EVO's and Impreza's in a 2WD turbo car is at a disadvantage as in my opinion (humble) there should be a separtate class for these type of motors. Its unfair to pitch 2WD turbo's against 4WD machines which have fancy trick technology distributing power, and active yaw control etc....(specifically EVO's !!!)

The Pug should be cheaper to compete in, every time I broke the Impreza the costs were crippling http://bbs.scoobynet.co.uk/frown.gif

Cheers

Mark.

sammyh 10 October 2000 09:17 AM

Blackscooby be very carefull who modifies your pug I had six of them in various states of tuning and I do consider myself to be a bit of an expert. I'm not going to abuse tuners on this board, but if you want some advice e-mail me and i'll contact you this evening. My last 205 was a bit of a monster - six speed and 240bhp = very fast (bit scary sometimes). Unfortunatly its dead now!

Blackscooby 10 October 2000 10:10 AM

Sammyh,

You (will) have mail.

Thanks

Mark.


jwhitton 13 October 2000 08:40 AM

BlackScooby,

Yes I agree with your comments on Mr Hargreaves EVO it is mega. It is taxed but I have only ever seen it trailered to the course, would love a road trip in it. I assume it must be similar to say an EVO extreme due to the power hikes it has had.

There is a guy in the Group B car club who runs a very very fast 205, I think he is also on the commitee. Yes Bobby's Clio is a nice bit of kit, he was having problems in October 99 with water getting in his engine management. This was before I stuff mine.

Malcolm Pinder manages less understeer since he has the STI with the variable diff. Any UK spec car will have a problem keeping up.

Is the car able to run in under 2 litre road going? You could "compete" against Alan Tewlar!

You never know I may run the RS again next year!

jon

Blackscooby 13 October 2000 10:36 AM

Before Mr Pinder had the front mounted IC fit I was 2 tenths of a second behind at the Harewood Hillclimb. We had fantastic battles. Loved it http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

I beat him on 1 event, but then I blew my engine http://bbs.scoobynet.co.uk/frown.gif ~ subsequently turned it down a bit

Not bad for a 1994 UK motor !

My Pug would be in the Road Going modified's under 2L.

Never seen the Yellow Peril (RH's EVO) acutally on the road. (I'm often up that neck of the woods)

Mark


[This message has been edited by Blackscooby (edited 13 October 2000).]


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