JC, how can you tell if you have a late type? Mine is a factory fitted '86.Quote:
Originally Posted by justinc
Cheers.
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JC, how can you tell if you have a late type? Mine is a factory fitted '86.Quote:
Originally Posted by justinc
Cheers.
Not too big a deal. I have a turbo rocker cover now and still have a crossover pipe going over it and the standard bonnet.Quote:
Originally Posted by rovercare
Your cross over pipe is a fair bit smaller in diameter than a water/air intercooler;)Quote:
Originally Posted by isuzurover
lamb - finally on the road, I bet your pleased. Gonna be home around the 4th. Has it rained up there yet? Ordered a mad man but wont arrive till late Jan....
Got any pics of the exhaust, from the turbo?
geck
hi mate, very happy, I just turned the fuel up, it is now 2 turns from stock and more boost :twisted: 13 14psi, so much better and no change to cruise egt.Quote:
Originally Posted by geckos
it has rained but not much. So you trying to keep up with the speced up county now with the mad man :p
Hello Lambrover,
First post as a new member so i hope it works.
I worked with a couple of diesel mechanics and asked them what they thought about turbo charging the n/a 4bd1 in my stage 1, and they covered the usual stuff about lubrication, turning up the pump, intercooling etc that i needed to look at.
One subject they seemed to dwell on was the amount of mechanical advance the injection pump has and to ensure it wasn't to much for the amount of boost i wanted to run. The idea being that as the boost increases, the amount of advance needs to be reduced.
I've had a look in the manual for these engines and the 4bd1t runs about 6 degrees less advance than the n/a engine. Maybe this will explain the high EGT no's.
I'm not a diesel guru but maybe a new thread comparing boost pressure and exhaust temp on turbo'd n/a engines compared to factory turbo engines might help.
These guys had some experience with racing trucks but some of the experts on this forum may know more about it.
Welcome Sparkie,Quote:
Originally Posted by Sparkie
I can't add any tech. on timing advance with boost pressure. Perhaps it is retarded because the air in the cylinder will have a higher pressure (more air compressed to same volume) and hotter temp. at the start of injection.
But generally, if you are injecting much more fuel, the timing needs to be advanced.
The information I have for the NA and turbo versions of the 4BD1 give different timing advance for both versions depending on year model - the camshaft/valve timing also changed at the same time.
Also remember these values are the static timing and the automatic timing advance unit on the turbo engine is different.
Up to 1988: 13* for 4BD1, 10* for 4BD1T (from my manual).
1989 on: 16* for 4BD1, 15* for 4BD1T (posted by Isuzurover).
Some USA spec engines I have seen info on:
1980, 10* for 4BD1
1985, 14* for 4BD1T
1989, 13* for 4BD1T
Quite correct, higher boost, higher temps/ cylinder pressure faster initial burn and to a point faster complete burn. then add just a bit more fuel and you get a slower total burn but there is more to burnQuote:
Originally Posted by Sparkie
so has anyone changed there pump timing?
I think my pump was played with prier to me owning it and adding a turbo the lock wire had been cut.
When I took the car for its first run with the turbo I left the fuel alone I was only getting 6 to 7 psi very late so I couldn't leave it like that so wound it up some, but some of you guys have wound the pump up heaps, most of you have intercoolers as well don't you, that is probably the biggest differance.
Clean32,
That agrees with what i was told, but are you saying if you add a little more fuel it can counteract the extra advance by slowing the burn.
Did a bit of research a while ago on common rail and one article (i'll see if i can find it), stated that at the start of the injection event in a mechanical injected engine, the fuel will not start to burn until a small amount is already in the cylinder, not as soon as injection starts. The time and amount of fuel is related to combustion chamber temp and therefore boost pressure. The higher the temp, the quicker it starts burning.
Common rail engines inject a small amount early, so the main injection event burns almost immediately it is injected. I think they call it "pre injection" or similar.
Bush65,
Should have been a little clearer about the advance numbers.
4BD1 13' static(crank) + 5' mechanical(pump) = 13 + (5*2) = 23' at 3000 rpm
4BD1T 10' static(crank) + 3.5' mechanical(pump) = 10 + (3.5*2) = 17' at 3000 rpm
Not sure how much difference 6 degrees would make or how much different the mechanical advance is on later engines. Would be interesting to find out.
Sparkie.