Stock injectors good to 300Hp, true or false?
#16
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If you look at eg the following injector calculation site
#17
It is correct physics that a relation exists between fuel consumption and HP.
The "trick" would be in the assumption of how much fuel is used to produce 1 HP,
For our cars a value of 0.5 concurs with my own measured values:
- Almost maxed out at 290HP(crank) on stock injectors at 43,5 psi
- 80% duty cycle at 350HP (crank) on 55lbs/h injectors at 43,5 psi
The "trick" would be in the assumption of how much fuel is used to produce 1 HP,
B.S.F.C is brake specific fuel consumption - How much fuel you are using per horsepower per hour
- Almost maxed out at 290HP(crank) on stock injectors at 43,5 psi
- 80% duty cycle at 350HP (crank) on 55lbs/h injectors at 43,5 psi
#20
I am curious as well. I have a AFM, K27/6, 3 inch test pipe and catback, 3 bar regulator, I would like to run 16 psi of boost. I plan to use for the track, until I finish my project. I like the idea of stock injectors since I use as daily driver and want to get the best gas milage. Any one noticed drop in milage going from stock to 55lb injectors?????
I am about to start tuning the Vitesse chips with the Piggy Back, I am sure I will learn more from this.
Steve
I am about to start tuning the Vitesse chips with the Piggy Back, I am sure I will learn more from this.
Steve
#21
Race Car
everybody needs to remember to add the boost pressure to the equation ie; 43.2 + 15 psi or whatever. Imo the stockers are maxxed just at 300hp running a little higher FP.
I have also heard that the stock injectors are more like 42# ers. I tend to believe this a little b/c I have ran 36# ford injectors in my car and have had to turn down the FP to get the same AFR when going back to the 951 units.
I have also heard that the stock injectors are more like 42# ers. I tend to believe this a little b/c I have ran 36# ford injectors in my car and have had to turn down the FP to get the same AFR when going back to the 951 units.
#22
If you're willing to run risky AFR's, high duty cycles, and ridiculous fuel pressure, they can support 300hp. RKD managed 400rwhp with 48lbs. I personally couldn't get anywhere near that out of mine though, but my fuel pump had seen better days so that's not a fair measure.
#23
Rainman
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this is very good, very good to know. thanks for the information so far.
sid, once again (as always) you prove to be an invaluable resource of information...is there anything about 944s that you DONT know? lol.
is there any way we can settle once and for all how much stock 951 injectors really flow? any method of testing?
sid, once again (as always) you prove to be an invaluable resource of information...is there anything about 944s that you DONT know? lol.
is there any way we can settle once and for all how much stock 951 injectors really flow? any method of testing?
#24
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I am curious as well. I have a AFM, K27/6, 3 inch test pipe and catback, 3 bar regulator, I would like to run 16 psi of boost. I plan to use for the track, until I finish my project. I like the idea of stock injectors since I use as daily driver and want to get the best gas milage. Any one noticed drop in milage going from stock to 55lb injectors?????
I am about to start tuning the Vitesse chips with the Piggy Back, I am sure I will learn more from this.
Steve
I am about to start tuning the Vitesse chips with the Piggy Back, I am sure I will learn more from this.
Steve
#25
Rennlist Member
this is very good, very good to know. thanks for the information so far.
sid, once again (as always) you prove to be an invaluable resource of information...is there anything about 944s that you DONT know? lol.
is there any way we can settle once and for all how much stock 951 injectors really flow? any method of testing?
sid, once again (as always) you prove to be an invaluable resource of information...is there anything about 944s that you DONT know? lol.
is there any way we can settle once and for all how much stock 951 injectors really flow? any method of testing?
btw Sid, we have ordered a set of those new injs. 1650ccs *****. Hope they do the trick! Looks like all going well, it's on the dyno next week.
#26
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Is this question purely for a theoretical value or do you plan on maxing out stockers? If that's the case wouldn't it just be worth the few dollars to buy a bigger set than risk blowing your motor? Not trying to be a ********, but seems like it's not worth the risk.
btw Sid, we have ordered a set of those new injs. 1650ccs *****. Hope they do the trick! Looks like all going well, it's on the dyno next week.
btw Sid, we have ordered a set of those new injs. 1650ccs *****. Hope they do the trick! Looks like all going well, it's on the dyno next week.
#27
Rainman
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Is this question purely for a theoretical value or do you plan on maxing out stockers? If that's the case wouldn't it just be worth the few dollars to buy a bigger set than risk blowing your motor? Not trying to be a ********, but seems like it's not worth the risk.
btw Sid, we have ordered a set of those new injs. 1650ccs *****. Hope they do the trick! Looks like all going well, it's on the dyno next week.
btw Sid, we have ordered a set of those new injs. 1650ccs *****. Hope they do the trick! Looks like all going well, it's on the dyno next week.
im gathering all the necessary information for my (very long-awaited) upcoming project...this includes fuel injector sizing..
a big box labeled 'eaton' will be at my door on tuesday...
#28
Rennlist Member
Waqqas I was hoping to be on the dyno a week or two ago but one thing and another gets in the way and creates delays. As for goals, well it depends on what fuel type you're talking...but this is not my thread so I'll leave it to another day when I have some numbers.
Sorry for the OT.
Sorry for the OT.
#29
Rennlist Member
definitely hoping not to max out the stockers just yet...951 injectors should be perfect (read, more than enough) for the power levels i would like to achieve..
im gathering all the necessary information for my (very long-awaited) upcoming project...this includes fuel injector sizing..
a big box labeled 'eaton' will be at my door on tuesday...
im gathering all the necessary information for my (very long-awaited) upcoming project...this includes fuel injector sizing..
a big box labeled 'eaton' will be at my door on tuesday...
#30
Three Wheelin'
With boosted cars, the fuel pressure will be higher with boost but this is offseted by the same boost in the intake and that means the fuel injector flow rate remains the same.
At 3 bar, stock 951 injectors are good for around 280-300 flywheel hp and that is a stretch. I wouldn't use them anywhere else than street car. 951 engine with 8v head doesn't have very good BSFC, 16v is much better (more efficient).
For example: on my turbocharged euro 924 I had 440cc injectors (same as 951 ones at 3 bar) and at 250 flywheel hp (1 bar of boost, talk about crappy flowing head, huh) , injecors were at 70% duty. Lambda was 0.83-0.84.
At 3 bar, stock 951 injectors are good for around 280-300 flywheel hp and that is a stretch. I wouldn't use them anywhere else than street car. 951 engine with 8v head doesn't have very good BSFC, 16v is much better (more efficient).
For example: on my turbocharged euro 924 I had 440cc injectors (same as 951 ones at 3 bar) and at 250 flywheel hp (1 bar of boost, talk about crappy flowing head, huh) , injecors were at 70% duty. Lambda was 0.83-0.84.