TT2 RR Results (not good)
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The basics of it are that it made less power (130 compared to 140) at a higher RPM (7200 compared to 6000) with less torque (110 compared to 134). It also made boost only slighty earlier in the rev range

And to cap it all the head gasket blew, not sure why.

I'm going to fit the old head later, but stick with the T2 for the time being.

Bugger, bugger and bugger again.

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

damn, possible problems?

what have you changed since last year wil?

Team Racing

The IC is deffo big enough.

As the power is so much further up the rev range I think it's the head, bigger valves and bigger ports will always do this.

I just thing that the ports and valves are too big.

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

I'm not sure all is lost. I would like to see the plots of power and torque overlaid from the old engine before I come to a conclusion.

Look at it like this. If we have 110lb (ish) from 4000 - 7000 insted of 135lb from 4500 to 6000, even though the peak figures are down the spread is better and could work on track. I would like more and it is always a development so I am thinking stick with it for now.

http://www.twin-turbo.co.uk
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As if by magic. That is pretty rubbish in my book

Edited by wil_h on 2nd May, 2006.

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

Will, I have to ask.
What boost were you winding it up to?


Are we talking about a bog-standard R5GT turbocharger?

doh, but disapointment is all part of the fun!

As far as I know it is a standard R5 T2, running at 15psi

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

I'll do an overlay of the Metro T3 and R5GT compressor maps tonight and see if there is anything obvious.

Seems like it's down on bananas everywhere though?

cheers dave.

Head gasket failure was between No.1 cylindeer and a water jacket hole at around 1 O'clock, Fire ring totally gone. Never had one fail there before. Nothing obvious on block and head.

Wil

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

A few things surprise me - that you say the 998 with the stock R5GT turbocharger revs higher than the T3???
And you say that the boost seems to come in only a little earlier now?

I think you need to check a few things. I'm immediately thinking cam timing.
I know that the 0.35turbine R5GT T2 in mine fell flat on its face at 6200rpm.

It's been a long time ago, but my experience of the T3 is that it certainly revs longer (more rpm potential). I am assuming you had the metro T3 with the 0.25 turbine (is this the turbine you used last year?)...

You seem to be the other way round though - in that your T2 revs longer?

Were the HC's giving anything strange or were you just tuning it with the Lambda?

Cam timing is easy to visually check inside of a minute by looking at the toothed crank wheel vs the full lift on #1.
I'd also give your turbo's a once over.
Check the A/R of your turbine on the T3's and also measure the diameter of the bore at the entry to your T3 turbine. Maybe you've had a modified turbo all these years?

Also check the T2 the same way and report back.

D

Arse biscuits :( :( :(

Just goes to show that theory is all well and good but sometimes things just don't work out as you think they will.

wil ,was this the same dyno that created the other figures? is there any chanve of a dyno mis calibration for yuor rpm ? also ,from the blown hg ,poss detonation ,is the timing at all experimental ?all usual q i m sure yuov thuoght of ,fuel octane ,compression ratio, mixture etc , what cam duration do yuo have in it ,and whats it timed in at ? hope this helps good luck ,chin up chap .regards robert.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Sorry to here that wil, keep us posted on what you find, your right bigger ports and valves can not be good, I was down on power for a while this year as i opened the ex ports up like every one said about, NO good and i wish i hadn't! metal filler here we come!

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

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I think the thing you need to understand about the reving is before we had a standard (opened out combustion chamber) MG metro head which was the restriction. Now we have a well flowed head. I was expecting it to rev longer purely because of the head. It looks like the head could be causing problems low down because the ports might be too big, hence the T2 looks slow to spool up.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

ben ,what are the diffs in the engine between the dyno runs ?? regards robert.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Took mine to Dave Walkers last week, it was doing 127.2 bhp, 140lbft torque @ 4790, 16 psi.
Got a fancy new electronic boost valve now as well, From an Audi TT I think. (£50 off Dave) It controls the boost is conjunction with throttle position. It should make the car easier to drive, instead of the boost coming in with a bang, it's much more progressive.
It could of handled a bit more boost, but the injectors were running out of pulse width,raising the fuel pressure obviously helped, but there is a limit.
Think I might have to revise my diff ratio's to.
I have to say,I think the 998cc motor, makes a fab Turbo unit.

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

I am suprised the T2 has no A/R markings, sometimes they are hard to spot but they are usually there somewhere or other.

usually on the inside of the snail on a T2, or atleast the ones i have here are, just near where the acuator is plumbed in.

It does have one Wil.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

How about uploading some pics of it so we can take a nosey?

That said - the R5GT is the smallest unit. I'm just wondering if you have tried a slivia one or something by error...

Compressor is 0.48 (inside the 'snail'. Where is the turbine marked.

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

ah, that ain't a R5GT unit then, and I think that is your problem...
You find 0.48's on 1600's and above - the earlier S13 nissans has 0.48's I believe. The Rover 2litre turbo has a 0.49 for example. That said - you also find 0.63 on the majority of 1800's nissans and other similarly sized engines...

Put simply - I suspect your turbine is way too large for a 998 - it'd be like trying to spool the T3 with a 0.35 turbine off the escort.
It won't be spinning the compressor anything like fast enough - and who-knows what the spec of that is....

Thing is - what to do next?

Well - start by finding out what you have compressor wise - which means whipping the turbo off, removing the compressor housing and measuring!
And whilst it's off, also measure the turbine trim.

We can then work backwards from there and get this sorted

Chances are, your compressor might be ideal for building a 'big boost' hybrid... For an immediate answer though - you need an R5GT unit just like Jim sold on ebay for £75 only a week ago...

OR stick the T3 back on... You can see how well matched it is to the small 998 like yours from the diagram peter put up...

Edited by turbodave16v on 2nd May, 2006.