RE: Citroen AX at the 'ring: Time For Tea?
Discussion
xu5 said:
mhr1294 said:
Holy mother of thread revivals, but it's related so it's okay.
Back on topic of PSA diesel engines, the iron block version of that engine is far better.
If you know anything about these engines, you might find this interesting!
This is a 1.5D engine with a Lucas DPC fuel pump.
the hp figure doesn't concern me, but 2 other factors do.
How did they get it to make power up to 6,000 rpm? From fuel pump tweaking alone?Back on topic of PSA diesel engines, the iron block version of that engine is far better.
If you know anything about these engines, you might find this interesting!
This is a 1.5D engine with a Lucas DPC fuel pump.
the hp figure doesn't concern me, but 2 other factors do.
They only cross over at 5252rpm if it's lbft and bhp, and on the same axis (which they are, in this case).
Admittedly having a graph with bhp and Nm seems odd, but there you go. Most old PSA engines equal or better their book power figures on a rolling road, so it doesn't take much to make good numbers
Admittedly having a graph with bhp and Nm seems odd, but there you go. Most old PSA engines equal or better their book power figures on a rolling road, so it doesn't take much to make good numbers
xu5 said:
How did they get it to make power up to 6,000 rpm? From fuel pump tweaking alone?
So the Lucas pump is drive by target rpm style on the throttle lever. So that allows it to rev harder with more throttle position. So yes.Also the fuel screw is turned 300 degrees in from standard, the injection timing is advanced and the camshaft isn't in the standard position.
Bosch pumps drive by fuel quantity and the max engine speed is set by a spring governer with a calibrated K value, so the max speed can't exceed 5500rpm unloaded. You can feel them pulling fuel at about 4800, so they're pretty useless for power - albeit very reliable.
Only other modifications were a custom exhaust (1.5") manifold back, which I deliberately left long, and drove it for hours testing, and gradually cut bits off the end until it sounded right at high rpm.
Same for the inlet, 4 individual inlet tracts, port matched, unfiltered.
Yes the graph is in metric HP and Nm. they graph would cross (I think) 7020rpm if possible.
What's odd about it is where the peak torque occurs. I've 3 of my previous engines (all bosch VE pumps) made peak torque about 1800-2300rpm.
I'm sure a turbocharger will sort it, it certainly fixed my last engine and I've still got the rod and piston to remind me of my previous mistakes
So this is your engine? It's pretty interesting stuff. I wish I realised it had some tuning potential when I had one! I wondered how well a positive displacement supercharger with uprated fuel pump would work, but then I sold it and got another Rallye!
mhr1294 said:
So the Lucas pump is drive by target rpm style on the throttle lever. So that allows it to rev harder with more throttle position. So yes.
Also the fuel screw is turned 300 degrees in from standard, the injection timing is advanced and the camshaft isn't in the standard position.
Bosch pumps drive by fuel quantity and the max engine speed is set by a spring governer with a calibrated K value, so the max speed can't exceed 5500rpm unloaded. You can feel them pulling fuel at about 4800, so they're pretty useless for power - albeit very reliable.
Only other modifications were a custom exhaust (1.5") manifold back, which I deliberately left long, and drove it for hours testing, and gradually cut bits off the end until it sounded right at high rpm.
Same for the inlet, 4 individual inlet tracts, port matched, unfiltered.
Yes the graph is in metric HP and Nm. they graph would cross (I think) 7020rpm if possible.
What's odd about it is where the peak torque occurs. I've 3 of my previous engines (all bosch VE pumps) made peak torque about 1800-2300rpm.
I'm sure a turbocharger will sort it, it certainly fixed my last engine and I've still got the rod and piston to remind me of my previous mistakes
Also the fuel screw is turned 300 degrees in from standard, the injection timing is advanced and the camshaft isn't in the standard position.
Bosch pumps drive by fuel quantity and the max engine speed is set by a spring governer with a calibrated K value, so the max speed can't exceed 5500rpm unloaded. You can feel them pulling fuel at about 4800, so they're pretty useless for power - albeit very reliable.
Only other modifications were a custom exhaust (1.5") manifold back, which I deliberately left long, and drove it for hours testing, and gradually cut bits off the end until it sounded right at high rpm.
Same for the inlet, 4 individual inlet tracts, port matched, unfiltered.
Yes the graph is in metric HP and Nm. they graph would cross (I think) 7020rpm if possible.
What's odd about it is where the peak torque occurs. I've 3 of my previous engines (all bosch VE pumps) made peak torque about 1800-2300rpm.
I'm sure a turbocharger will sort it, it certainly fixed my last engine and I've still got the rod and piston to remind me of my previous mistakes
xu5 said:
I'll be turbocharging it again, I'll be doing it properly this time though. head studs etc. had issues cooking the oil and lifting the head with a GT15 and no wastegate!
So, someone I know had a non intercooled and no wastegate GT15, 9mm Bosch VE made 135hp. Internals can take that, and the Helix clutch was slipping (190ft.lb of torque) - mine threw a rod before I got that far with it.
I'll probably go bigger than a GT15 for a more progressive power curve. GT2052 most likely - that's a job for into next year though.
I too have a Rallye, I've got an S1 106 that's in the last 95% stage of completion, and it seems to be taking an age hahah!
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