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I'd say approaching 190-200whp you will need bigger injectors probably, and depending how big you go with those you may need a bigger rail, probably a better fuel pump too. It really depends on your setup though, a blanket question like that won't get you answers your looking for. If you just do normal bolt-ons then yeah you'll be fine with the stock fuel system.
its not like upgrading the fuel system is expensive anyway. 370cc injectors are around $120 used and a new fuel pump is like $100 new. I would assume if you are getting above 175whp NA on a DE you will have a piggyback or stand alone where you can alter the injector size.
If you have a high output DE, it wouldnt be a bad idea to upgrade the injectors to 370's. With proper tuning, you can run higher horsepower at a lower duty cycle.
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its not like upgrading the fuel system is expensive anyway. 370cc injectors are around $120 used and a new fuel pump is like $100 new. I would assume if you are getting above 175whp NA on a DE you will have a piggyback or stand alone where you can alter the injector size.
Not asking for monetary reasons, but I think I have a ballpark answer now. Thanks.
I used this online fuel injector calculator thingy. It estimates about 195hp @ 100% duty cycle, 175hp@90%, 160hp@80%. I'd guess it has an error of about 0 to -10whp.
__________________
Khiem
'96 SE-R.... boost, brakes, suspension, etc... sold
'05 Evo
'05 CBR 600RR
I used this online fuel injector calculator thingy. It estimates about 195hp @ 100% duty cycle, 175hp@90%, 160hp@80%. I'd guess it has an error of about 0 to -10whp.
Khiem,
Found this link on RC Eng's site. If anyone knows it would be them. I think by bhp, they are referring to crank hp. I'm pretty sure the calculator you used needs crank power to work out right.
Gosh, according to this formula the stock injectors would be past 80% duty cycle at a mere 140 whp. That doesn't seem right. What gives?
I suppose if you bump the acceptable duty cycle to 90% and lower the BSFC a tad bit, you end up with a respectable number, but I guess I expected a lil more.
RCEng page is as close to facts-based truth as you can get.
The usual "suspect" parameter in those calculations is the actual BSFC of the engine which can only be guessed within the ball-park ranges given in this page.
Still, how did you get to the 80% IDC for 140 BHP? (<-- probably 140 wasa typo because I've seen you mentioned 160 elsewhere).
For the stock SR20DE 259cc injectors, with .8 (80%) duty cycle, 4 injectors, 0.50 BSFC (the "worst" suggested for N/A engines, i.e. the one in need of larger injectors), 43.5 PSIG fuel pressure, I get 157 BHP.
And yes, they are at the CRANK.
As for the 80% "limit", it is supposed to be for all-out or racing applications. For street or dual purpose cars, it is a bit conservative. How many times do street cars redline 3rd, 4th or 5th gear and hold it there? In most cases we go to a very brief visit and change gear or back up.
90% IDC is still a very safe limit for street/dual cars. For "blips" even 95% is OK. And if we do use the most favorite #s in the formula (.45 BSFC and still a safe .90 IDC) it gives 197 BHP. This would be at the limits of N/A DEs excluding S5/C6M experiments by you-know-who and who. VEs are a different story but, then again, they do come with a minimum Injector size of 333 cc/min.
RCEng page is as close to facts-based truth as you can get.
The usual "suspect" parameter in those calculations is the actual BSFC of the engine which can only be guessed within the ball-park ranges given in this page.
Still, how did you get to the 80% IDC for 140 BHP? (<-- probably 140 wasa typo because I've seen you mentioned 160 elsewhere).
For the stock SR20DE 259cc injectors, with .8 (80%) duty cycle, 4 injectors, 0.50 BSFC (the "worst" suggested for N/A engines, i.e. the one in need of larger injectors), 43.5 PSIG fuel pressure, I get 157 BHP.
And yes, they are at the CRANK.
As for the 80% "limit", it is supposed to be for all-out or racing applications. For street or dual purpose cars, it is a bit conservative. How many times do street cars redline 3rd, 4th or 5th gear and hold it there? In most cases we go to a very brief visit and change gear or back up.
90% IDC is still a very safe limit for street/dual cars. For "blips" even 95% is OK. And if we do use the most favorite #s in the formula (.45 BSFC and still a safe .90 IDC) it gives 197 BHP. This would be at the limits of N/A DEs excluding S5/C6M experiments by you-know-who and who. VEs are a different story but, then again, they do come with a minimum Injector size of 333 cc/min.
My calculation DOES come out the same as yours, Chris. I said 140 whp if you look above, NOT bhp. As far as street car versus racecar, my application is race, so this is probably even more important. If an injector goes semi-static, that could cause bad det as things lean out, right? The question is what is the safe whp limit under race conditions. I'm going to now say no more than 160 whp. If anyone agrees or disagrees, do let me know.
OK, IMHO, for your case you should be OK with stock injectors and a good fuel pump. Not to go into the crankHP vs. WHP argument again here, with a 90% IDC for safety the "max" crank HP is between 177 (BSFC .5) and 196 (BSFC .45).
Using my "well documented" crank-to-whp formula from PumaRacing.co.uk, 177chp is ~ 150whp. 196 chp is ~ 165whp. Of course, 160whp is 40whp than a stock SR20DE...
Well I guess with these calculations this makes my chart so wrong. I will not try and defend my chart but I will say this. You guys need to look at fuel mixture example how rich or lean a car runs.
Next using real world comparisons is a great idea. There have beem many people on this forum that have made well over 160 WHP on stock injs, some have made 170-175 WHP on stock injs.
Here are some turbo facts for you just about everyone here with 370cc injs make 250 WHP at stock FP and this is with no problem or harm to the motor.
The quote below is from SE-Rawkus. He was running 4 bar, Z32 MAF with Tomei Yellow 601 cc injs, please note the WHP of 433 WHP and the car was still not running lean ( Please note on my chart I have these injs good for 457 wHP at 4 bar )
Quote:
Originally Posted by SE-Rawkus
Well...I made 433 whp w/ a stock bottom end Avernir motor @ 20psi.
Major mods:
O2 Induction Manifold
Comp Springs w/ Crower Retainers
Lets look at Mike K's post about Sarah Forest car. She is at 3 bar with 72 lb injs with Cobra MAF and she is at 448 WHP with no lean conditions.
Now below is a quote from Mike K saying he put a larger turbo on Sarah Forests car and she is now up to 473 WHP, yet again 3 bar 72 lb injs cobra MAF. ( Please note on my chart I have these injs good for 520 WHP at 3 bar )
Quote:
Originally Posted by choaderboy2
473 whp now with my turbo, she's beating you rockwood. We quit, clutch is starting to slip and don't want to hurt the tranny.
Please read the post, look at your calculations and come up with new calculations
This is a response to someone saying my calculations are wrong. From looking around on this froum and from examples listed above you tell me what you think. I say to that person please recheck your findings and see where you went wrong. As you can see I have my findings backed up solid.
23 cc = 16 WHP
46 cc = 31 WHP
93 cc = 63 WHP
139 cc = 94 WHP
185 cc = 125 WHP * Pink
231 cc = 156 WHP
259 cc = 175 WHP * Red
278 cc = 187 WHP
324 cc = 218 WHP
333 cc = 226 WHP * Grey
---------------------------------------------333 cc @ 4 bar = 261 WHP
370 cc = 250 WHP * Purple
---------------------------------------------370 cc @ 4 bar = 290 WHP
416 cc = 281 WHP
444 cc = 299 WHP * Brick Brown
---------------------------------------------444 cc @ 4 bar = 345 WHP
462 cc = 312 WHP
509 cc = 342 WHP
555 cc = 373 WHP * Yellow
---------------------------------------------555 cc @ 4 bar = 423 WHP
601 cc = 405 WHP * Yellow Tomei
---------------------------------------------601 cc @ 4 bar = 457 WHP
647 cc = 436 WHP
692 cc = 468 WHP
740 cc = 500 WHP * Red
---------------------------------------------740 cc @ 4 bar = 580 WHP
850 cc = 570 WHP SARD
---------------------------------------------850 cc @ 4 bar = 660 WHP
