2871R Estimates for Diesel Des

[diesel des]

Yea Jamo thats what i thought! It was driving the LPG kit mad at 6-7K rpm as it lost its trigger signal. Hence the need for the bigger injectors i have in now and the remap. Still some tweekin to do to petrol ecu, but it drives GREAT now on gas all the way to 7.5K limmit. Getting it for 40p/l too...

[Jamo]

Ah yes it now clicks, I remember you saying about 100 % duty cycle in that thread.

Is the new map going to be gas or petrol? interesting article in PPC magazine this month saying to get the best out of LPG you can advance the ignition more than when it's running with petrol.

[S2central.net]

Tis a good point about even more advance running LPG as the RON is so high... Tis amazing stuff. When I get the pure petrol mapping finished, I'll look at a variant with a mode switch so it can run more aggressive timing when the gas is on... But thats jumping ahead a bit.

[diesel des]

Yea im suscribed to PPC. Would be good to have a twin map setup. But its getting it sorted on petrol thats important now so the gas ecu has something good as a base point. I can tweek the AFR with the gas ecu etc.

[Rusty]

All sounds very interesting! What is the boost threshold in the real world? Does it feel a bit flat after 6500?

[S2central.net]

Flat ?

Yeah right - flat out more like

1.6bar up there no problem - its mental I tell thee...

From WOT in 6th at 2000rpm it hits 1bar circa 2700rpm and has 1.5bar at 3000. Boost builds to peak of 1.7bar circa 4.5k. Can't remember where the actual threshold is but its low...
On paper the 2871R should surge with that boost profile, but it just doesn't... Its a monster !!!!

Its also an unfinished monster - binary fog descending on me with some niggles to sort and Des being very patient until I get the real-time setup on the air.

[Rusty]

'Flat' was a comparative term to the mid range performance, a bit like the k24 drops off over 6500k relative to the mid range

What EM? RS2 or standard?

I've always wanted a 2871 and if you can get away with minimal engine alterrations and simply turbo / injectors / map then that's an interesting prospect compared to a full-blown bottom end rebuild for the same money...

[S2central.net]

Pretty sure its RS2 EM...

Stock AAN cams & timing
Stock bottom end
Stock head & IM (AAN)
Stock fuel pump & FPR
3" DP (can't remember if CATs are fitted)
BIG intercooler mind you and an uprated clutch (required for Desmonds launch tactics - and a neckbrace required for his passengers)...

Mid range torque levels are in remapped RS2 territory - its the upper revs where this thing hauls ***... Yet it remains tractable off boost...

[Rusty]

Damn this forum and its witchcraft

[GazzaG60]

think the standard fuel pump is the reason for the 100% DC of the injectors.

the k24 drops off well before 6500 id say andy. id say 5500 relative to mid range. torque is well on its way down by then.

sounds like a good road turbo the 2871 there. maybe a bit small for my likings but sounds like it would dust me mid range.

[S2central.net]

Re injectors... yes the other way to go was with very high fuel pressure (and suitable Tarzan spec fuel pump) on smaller injectors... Upgrading the fuel pump is a major PITA though...

[S2central.net]

Gotta realise we are damn close to limit of stock AAN fuel pump here though... Manual says to expect 650cc on a 15s burst - thats 2600cc per minute - which is about what we need at 5.6bar fuel pressure. Thats actually a bit close for comfort.

If we relay the power to fuel pump for ~14V with engine running then we are into 3400cc per minute territory - some headroom I think.

Oh and a 21 minute WOT run on the Autobahn would empty a full tank of petrol - LOL !

[GazzaG60]

at the same place myself paul.

basically with my setup im runnig 650cc with the standard pump. i can see the DC rising all the way and 100% by around the 5500 mark. with factory injectors (s2) i saw 100% at 4krpm.

still running ok but im gonna put a pump in over christmas. im going to run a Holley FI pump inline after the factory in-tank. should do the trick. i hope.

[Rusty]

think the standard fuel pump is the reason for the 100% DC of the injectors.

the k24 drops off well before 6500 id say andy. id say 5500 relative to mid range. torque is well on its way down by then.

sounds like a good road turbo the 2871 there. maybe a bit small for my likings but sounds like it would dust me mid range.

Yeah I agree as you can see it on a dyno graph, however, on my car with some tweaks it holds on a little longer before your butt dyno starts to complian that it's getting a rest, for me that's at about 6500rpm in the lower gears.

[GazzaG60]

im not trying to say you are wrong andy by the way. just going from my experience and opinion.

how do you get such a small turbo to hang on. ported exhaust side?

having had a few experiences of big turbo conversions what i tend to find myself and others is that they think that their smaller turbo was holding on to say 6k until they try a bigger variant and then instantly change their mind.

turbos are about compromise after all.

so what do you think the 2871 is capable of Paul?