Supercharged imp
Turbo Mini Forums

I love this project,

mainly because its all done diy, with saws files and glue! :)

The charger is an Eaton off a Merc. Probably an early M45.

Interestingly, the charger pulley has been swapped fo a much smaller one than previously used.

If it is an M45 then I would have thought that it was going to be running a bit fast for the Imp.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Yep, should make around 5psi at idle if I want, although I am going to have to tune my way round the det at low rpm!

It should not take much more power to drive than a normal set up, as on light throttles the boost is being bled off, reducing the parasitic losses.

On 2nd May, 2010 blown_imp said:
Yep, should make around 5psi at idle if I want, although I am going to have to tune my way round the det at low rpm!

It should not take much more power to drive than a normal set up, as on light throttles the boost is being bled off, reducing the parasitic losses.

Yes i moved to the darkside

Instagram @jdm_brett

ARG ! The pics arent working anymore . . . . .is it just me ?

"So wat we gonna do tonight Brain?"
"Same thing we do evernight Pinky!"
"Try to take over the world!"

love it nice had it on the road yet?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

uhoh, it would appear that I have blown up my photobucket account!

lol. I was looking forward to seeing it too!

Update time!

Well, after many years of trying, I finally managed to blow up the imp due to too much boost! ;D

The engine has been slightly pressurising the coolant system for a while and I knew that the head gasket was on it way out, so the aim was to up the boost to 10psi (the engine should have a compression ratio of 10.5:1) and see what she would do.

Well I can say that she sure does boogie on 10psi! It was damp here and it was lighting up the tires in second :o :o
There was a bit of detonation due to the ignition being too advanced for the onslaught on boost at low rpm.

I noticed that the temperature was straying toward 95 degrees, when it usually goes nowhere over 80. Pulled over and sure enough it had lost a lot of water. Fortunately I was only 5 min from home, so I let it cool a bit, topped it up and trundled back, happy in the knowlege that the HG was toast!

This was the result -

Mayo -


Something is not quite right here -


Is this not meant to be round?


The det has pushed the fire ring outwards on No.3 then burned straight past it! It was also on it's way on No.2 aswell

So this gives me the excuse I need to home port the head!

Once the head was pulled I measured the combustion chambers and with a handy calculator provided by Eric (the man with the turbo clan), the compression ratio was pinned down to between 12 - 12.5:1, mental! No wonder the HG didn't last long, the combustion pressures must have been through the roof :o :o

A couple of weeks passed due to other fun but non car related commitments, with only the odd hour here and there to dedicate to the imp. Now anyone who has done any porting at home will know how slow the progress can be, very frustrating but in a sadistic way, satisfying too

The only tools available were a clarke rotary tool -



and a single carbide burr, with a flame shape, less than ideal, but the budget does not stretch to a full set of burrs right now, so it will have to do!!

so with vibration white finger, ringing ears, and ingraned dirt the result (95% of the way there) is as follows -











Now I have aimed for a D shaped area around the valve stem bowl and valve seat, and ports are smoothed, a little larger and all reshaped. The combustion chambers are taken out as far as I dare, I have no idea how thick the casting is

Now I know it is not perfect, but it will be a million times better than the stock ports, and the compression ratio should be down significantly.

Left to do -

smoothing all the cutting marks
CC'ing the chambers
polishing the chambers and exhaust ports
reassembly!

I'll keep you updated, and if it works how I think it will, i'll put even more boost into it

Hugs

J

It's always good when blowing your engine up is fun

More boost is always the answer!

Knowledge is directly proportional to the number of items broken!

OMG What a car!!!! Well done!

1399cc, Eaton M45 supercharger, N2O system, compression ratio 9.23:1, boost pressure 0,8bar/11.6psi.

http://www.garaget.org/?car=176816

Really?

at this rate i'll be God pmsl

don't polish any of your grindings , fine surface grinding is it

You should be using wills rings on an Imp, not an old fashoined head gasket.

I learnt the hard way on a Normally Aspirated 998 in my youth (when I left Minis for the Dark Side).

I still have it (the 998 engine with Wills rings) just in case I get back into Imps again.

Seriously though, forget a traditional gasket and get the head machined for the Wills rings.

Schrödinger's cat - so which one am I ???

what Rod says....

also its common to tig some material into the chamber on imps to get a good flowing shape, however in your case as your removing more material i think you can achive similar without the tigging.

it's a 930 block, so the cast in liners do not really allow for the wills rings, and machining for wet liners is out of my budget!

I have got a source for a considerably more stout gasket, and see how that goes. If more problems arise then the next option will probably involve getting the head wire rung to pinch the fire rings.

Schrödinger's cat - so which one am I ???

Don't get me wrong, they do work, my last engine was a will wrung 998 and they were good. Unfortunately that engine was let down by a batch of inferior outer water gaskets, so all the water got out anyway!

wow thats mental

Eric still uses a head gasket, but they fail in a similar way a couple of times a season.

Interestingly that failure looks more like a failure caused by an undertightened head than det.

See here http://www.mlcmotorfactors.co.uk/Trouble%2...rs/GasketTT.pdf

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

http://www.moulson.co.uk/se/currentprojects.html

Hi guys, just a quick one, CC'd the combustion chambers, got it to within 0,3cc just by eye!! Tidied them up and now within 0.15cc, and that is within my measurement error tolerance

So they have gone from 17.5cc to 22cc, that brings my compression ratio (by my calcs) to 9.7:1, down from a minimum 11.75:1. Should be good for a bar now at least!

Edited by blown_imp on 10th Jun, 2010.

Awesome ! I really want an Imp now !

"So wat we gonna do tonight Brain?"
"Same thing we do evernight Pinky!"
"Try to take over the world!"