help on loss of power
Turbo Mini Forums

a 1293 engine with gt20 ph2 and a good head should produce way more than 90 bhp on 14 psi so somthing is massivly wrong !
I can check plug gaps etc and remove the air filter if needed but if the air filter was restricting it would it pull the same boost right through the revs and acctualy climb slightly at the top end.

On the road it just dies at 5k and allthough you can make it rev past it kind of slows down as if theres no boost there

Could this be pre ignition ?
I would change the plugs for a set one grade harder as an easy way to check.

My guess is the inner two cilinders leaking combustion pressure due to head gasket and or cracked head.

Best be methodical about this; I'd start with leakdown test, then cam timing check / trigger wheel position after that.

what cr and what max timing ?

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

7.5:1

Don't no the answer to that next question I'm afraid robert ! Does 20- 22 sound some where !!
Running megajolt with machined pulley

Edited by cossierick on 7th Jun, 2017.

What Ignition system are you running ?? Have you confirmed the Advance at 5000rpm as i've had broken springs in my dizzy causing all kinds of trouble in the past.
Could your exhaust be to restrictive I.e. Broken baffles in the muffler.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

It's running very rich. Given the potential for uneven fuel distribution you could be losing a cylinder over 5k.

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."

7.5 is very low CR,

i dont knw the dynamic comressions of hand but could it have droped going to the ph2, thus losing power?

discuss:

Too complicated for me im afraid joe but yes please discuss !

Denis , yes power wasnt massive but given the compression and low boost i thought it was ok ! That 110hp is atw !

I suppose that could be possible paul but wouldnt it give other symptoms ?

Pauls got a better handle on this than me, but Ive just had a quick look, and it seems that the 266 closes the valve at 56deg ATDC vs the ph2 at 62deg... which drops the already low compression more 6.12 vs 6.36:1.

Is that a big enough drop to stop it from producing power then Joe !
I need to get some checks done first now I think

that is very rich..

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

rick, going back to our messages, and touching on what Joe says, both me and craig was running higher cr, mine was around 8.3:1
and i remember craig went for a cr around 9:1 maybe 9.2:1


craig had more ccs, larger valves, larger ports, higher compression
but i out spooled him by nearly 1000rpm, however he made more power on same boost
i needed around 20psi to keep up with his 15, his turbo didnt last much past that and he sold up

mine would hit a wall around 6200rpm, rev through it but not much point.
im struggling to find data logs but iirc i had 15psi by 3000rpm

Yes i moved to the darkside

Instagram @jdm_brett

"Close the barn door"........ MD274.....

Fit a bigger turbo?................

this a good choice?

Yes i moved to the darkside

Instagram @jdm_brett

I agree, 7.5 is too low. Is that even possible to achieve. I've never been below 8.3:1 and above 8.5:1 now.

A combination of low CR and 'bigger' cam seems likely.

Race cams just won't work with a low CR. Look at old cars with low CR they has nearly zero overlap on the cam.

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

Sounds a bit of a odd problem you have there Rick.

I can't help much. I'm at 7.9 with a gt17 and phase 2 no issues pulling the CR. doesn't drive to bad off boost either.

That's encouraging though I think

Wil , it's an old school build motor , it was done in 2001 !!!
It was never bad off boost either but I was running a 3.7 fd !

JB Weld the piston crowns to bring the CR up?

Anyone want to but a gt20 and phase 2 😩😩

Is the gt20 really the weak link here? Thought some were running up to 8k with k heads and this turbo?

If so mine may well be out too!

Edited by minimole23 on 7th Jun, 2017.