924Board.org

[Fasteddie313]

I see from some 911 forums that some injectors will flow a small amount more than others given them being in the same same fuel distributor, but I’m pretty sure that if their is enough fuel distributor flow it will just blast right through the injectors, like the GTS does..

Maybe it’s that some injectors are slightly more restrictive than others, but I think they can all just flow basically whatever is pushed through them, +- a few % of eachother..

“””

injector C2 3.3 turbo : bosch 0437 502 017 Porsche 931 110 225 00
Flowed qty per 60 sec : 270 gr

injector C2 3.6 turbo : Bosch 0437 502 057 / Porsche 964 110 235 20
Flowed qty per 60 sec : 285 gr ( at least)

.....

The specific gravity of gasoline @ 60°F is 0.739 so your flow would be:
-017 injectors @ 270g = 365.4 ml/min
-057 injectors @ 285g = 385.6 ml/min
About a 5.5% increas in fow for the -057 over the -017 if standard deviation is very low.
“””

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/621594-wrong-fuel-injectors-my-car.html


On some 911 fuel distributor..

But small variances between injector flow on the same fuel distributor I don’t think sets a limit on what the injector would flow if supplied more fuel from a different distributor..

I.e. The GTS can slam more fuel through the same OEM 931 injectors (017) by just supplying them more fuel..
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80 Turbo - Slightly Modified

[Cedric]

[safe]

I'm very sceptical that the stock fuel distributor will support 300hp, not without modifications. I would also think that the fuel pump is getting very near its limit too.

Any dyno sheets to support this statement?
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/Magnus, Stockholm Sweden
=======================
Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe

[Cedric]

I think there might be some values that are a bit of here, 0.5 BSFC is around 300g/kWh according to the convertor (im lazy). I can guarantee you that our old overfueling knock sensitive engines are not close to that on full power. So will most likely affect the predictions quite a bit. Would be fun if someone tried it though to see what it could deliver, actual HP will depend alot on other stuff though, like turbo matching and ignition timing etc.
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1980 924 Turbo
www.instagram.com/garagecedric/

[Fasteddie313]

Might not be so overfueling and knock sensitive if you run a good IC and are able to tune your AFRs so you aren’t running pig-rich..

I think this engine is a tank.. Supposed to hold the cylinder pressures/torque of a diesel..
I suppose you wouldn’t think that going off the experience of non-intercooler engines, untunable CIS that is doing who knows what, the time before widebands, etc..


That’s what it’ll flow, whatever power that would make would have to be tested/measured..
Probably will never be tested because nobody will ever do it..

I’ve never measured the power I’m making either, have no idea, I know it pulls very hard though and makes my M3 feel like a turtle..

I’d like to dyno some time.. Might get around to it, but I just use big hills and sometimes my brakes to street tune.. I can even have someone else drive and say “hold 4000 RPM and 13psi, now 4500, now 5000, now slow down and do the same thing at 17psi”.. Can do static tuning all day long that way on long straightaways usually in 4th gear and make it do whatever I want..

Don’t really need to dyno for anything, and whatever numbers it would give would be “dynos are inconsistent” anyway..


Cedric I’d definitely try one but who knows when..
I’ll be lucky to find time to just install my new injectors and see what that does.. Might need some slight retuning..

Might use black RTV and just glue that lower charge tube connection instead of relying on just a gasket..
I’m not sure if I’d even notice a little boost leak there though because I’d just end up tuning around it.. Unless it was big enough to notice I’d probably never even know..


I’m sure track conditions are harder on thermal management.. Probably should see if you get any cooling issues.. You might..

Yeah just tach signal.. It can tell RPM that way but not crank position..
Doesn’t matter “constant injection”..
Would need a real signal for ignition..
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80 Turbo - Slightly Modified

[Carrera RSR]

Get it dyno’d....... .

From my experience your butt cannot tell the difference between 200 and 250rwhp. Both feels quick in a 924.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[safe]

I dont doubt that it is a stout engine or the tuning you can do on the streets. I doubt that the kjet can deliver the required fuel.
Remove an injector and meassure what it can deliver at maximum plate lift.
_________________
/Magnus, Stockholm Sweden
=======================
Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe

[Fasteddie313]

[safe]

[Fasteddie313]

[safe]

Cant decipher who wrote what.
438 cc meassured?
Then 300 is possible in theory, but has boost preassure been detracted from the fuel preassure?
_________________
/Magnus, Stockholm Sweden
=======================
Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe

[Fasteddie313]

Well, reducing fuel pressure by about 14%/14psi only reduced fuel flow by about 2.8%..

Sooo.. Could it be assumed that the inverse is also true?


Also, stock fuel pump seems adequate to quite a bit more than what I expect a stock FD to do..
_________________
80 Turbo - Slightly Modified

[Carrera RSR]

All guess work until its proven on the dyno.......... which I did and hit 268bhp estimated to crank, limiting to 6000rpm, 1.1bar, and fuel delivery of circa 360cc/min. Probably could have gotten more if rev'd out further, more boost etc. etc, but this a safe place for AFR's and detonation for my car and end use.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Fasteddie313]

In any case, aside from theoretical maximum limits, I believe we can all agree that adding an intercooler greatly increases reliability/durability against any possible tuning mishaps, and then adding boost on a decent tune will make HP #s become larger..

I live out in the middle of nowhere and when I contacted the closest dyno shop they wanted nothing to do with my contraption and recommended that I just street tune it.. So I have..

Their is one other place relatively close with a dyno but they specialize in diesel pickup trucks.. Deisel freaks..
Maybe I could use their dyno just to get some numbers but I don’t find it extremely important..

I have been in my home state for about 17 days total this year.. I am going to take some time off soon but I’m looking to book a sailing charter on Lake Superior.. (To somewhat advance another one of my pipe dreams)
Like I said.. If I even get around to installing my new injectors and doing some testing after that, I’ll be lucky as far as Porsche time goes..

For now, I have time for reading, writing, and parts accumulating..
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80 Turbo - Slightly Modified

[Carrera RSR]

Shouldn't matter what vehicles the dyno shop specialise in, you just want an hour of their time to strap your car down and run 2-3 pulls.......get some data + a bhp/torque print out and then get outta to the shop smiling with big numbers

As for importance.......apart from bar room bragging and willy waving on forums , its just really good to confirm the time and money invested is getting you near or over your goals.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252