The Triumph Dolomite Club - Discussion Forum

Wouldnt the injectors be at 100% if you were running out of fuel delivery?

Tony

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Membership 2014047

I think the Durametric gubbins logs what the ecu requests, with our original 9e30 tune the ecu requested 130% duty cycle at 4k revs, that pointed out quite nicely that even after increasing the fpr to 5 bar (standard 3. the injectors (40lb) were fully open.

So, we dropped the fpr back to 3.8 and installed 60lb injectors, the injector duty cycle dropped back to sensible levels (less than 100%).

We're now running 80lb injectors, both bank 1 and 2 mixture are stable but after building boost and increasing speed bank two starts going ever so slightly lean, that could be a duff O2 sensor on bank 2, but when boost drops off the mixture is back fine, hmmmm.

Increase the boost a bit more and bank 2 goes ever so slightly more lean - I could change the O2 sensors on bank 2 or do as a few people have said (are you still running a standard fuel pump with double the size injectors - hmmm, yes) slap a better fuel system on and try again.

I'm going with what others have seen as they increase the power on these things, there are plenty of really fast cars out there, our's is a mere pup.

Ok maybe swap sensors left to right to see if the lean condition changes too? At least the sensor is (relatively) easy and cheap to replace rather than the whole system. Is this 6 cylinder? Do you know the cc's of the injectors? Im not familiar with the lbs rating of injectors

Tony

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Membership 2014047

Also, what was the fuel pressure at vmax?

Tony

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Membership 2014047

Yes Tony - a 911 is a flat 6, I'm not sure on the CC's - all the gubbins we have, the injectors are rated in lb's. A quick google shows 80lb injectors at 840cc/min.

New pump going in on Friday, when I start to think about how much the pump has to do, at 192 you're travelling at over 3 miles per min, under 20 seconds = 1 mile, at roughly <5 mpg (on most track days we get around 6-8 mpg) the pump is probably flat out so that's the best bet at the mo and the pump is probably cheaper than trying to swap things around and the pump is a recognised weak point.
50 miles is about the max we get out of a tank on a track day - it's got a silly tank where it straddles the front drive shafts (they have been removed) - so the float don't work below 1/4 - and it's a small tank anyway, 14 gallons brimmed.

TBH I didn't check the fuel line pressure, I will on the next run in July.

You really can't check this on the road, even in Germany you'd need some clear space, the track day map is for mid range grunt and we've never had an issue, apart from the thirst, a new set of rear tyres per track day is the norm (Michelin 295/30's) as are brake discs and pads (not every track day, but if you have a couple of days at Spa you'd best book tyres, discs and pads) - the discs are bigger than my dollys wheels, and it's a lardy old girl).

Off boost she returns 30mpg - which is great for a long distance trip, and very comfy, hoon it and you're back to single figures.

Fastest lady again http://www.terminalvelocityuk.co.uk/results.html