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Discussion Starter #1
ok so ive been trying to do calculations, and by the looks of rc's website http://www.rceng.com/technical.htm i am going to need like 400cc injectors just to get 225 crank hp.

so all you turbo guys around the 180-225 crank power levels let me knwo what injectors youre using. if stock tib injectors rated at 195cc can make 130hp stock with room to grow, then i dont see why 290's cant supply need for 200hp at the crank.

just trying to select some injectors. i am really aiming for 225crank hp but 200 will suffice. not sure how much power i will be able to make before the boost limiter on teh scoupe cuts me off but i think 200 should be about right.

are 290's good enough for 200hp? i dont want to have to invest in a rrfpr but if need be i will. i just dont want to be dumping raw fuel out at idle and before boost, and standalone is out of the questoin.
 

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Stock accent injectors are 195cc. Tib injectors are 240cc you should be alright. At least I was pretty sure those were the ratings.....
 

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450cc rx7 injectors
 

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im running 240cc injectors at not much under 300 crank hp in the 1.6l alpha with no sigh of knock. yes i am running high fuel pressure, but a good pump can handle it...

thus imo 400cc/min for 200hp is WAY overkill and it will idle like a dog.

tibby injectors (240cc/min) will be fine for 200hp.

never trust calculations, they dont take everything into account. ask somone who has already done it. practical expirience wins any day.

[Edited by T-WING on Oct 11, 2005 5:50 AM]
 

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Discussion Starter #6
yeah but i dont want to change my fuel pressure regulator. from what i understand, the scoupe turbo is a 1:1. so if i max at 14psi that should net me about 53-55psi at the rail. i am looking to buy some 290's i think that should be sufficient for my goals correct?
 

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Your stock fuel pressure (at 0 vacuum) should be 43 psi. At 43 psi fuel pressure, you'll need 440cc injectors to make 225 crank HP. With a 1:1 rrfpr, at 14psi of boost, your fuel pressure will be 57 psi. At 57 psi, you'll need 400cc injectors. Get the 440's to be safe. When you use the RC calculator, use a BSFC of .65 for turbo cars and a max duty cycle of .85.
 

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Discussion Starter #8
t-wing: what is your pressure at the rail for your setup at full boost?
 

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i have a rising rate fuel pressure reg. im running about 60psi (no not the best idea i know, but it cirtainly works)

for 200 crank hp i wopuld have thought 240cc/min injectors would be fine, but then i thougth you had an ajustable rising rate fuel pressure reg (imo you should get one anyway, its another way to tune the a/f ratios if you need it)

BUT if you have stock fuel pressure i would think you would definatly need to go bigger.

so in this case i will bow before the supreme experience of i8acobra.
 

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Discussion Starter #11
well these views seem quite conflicting. i kind of do want to use a new rrfpr, but as aaron already said, with the scoupe's 1:1 i should be over 55psi anyway. if i dont need it then i wont get it. you say you are running 240's at 60psi to make about 275 at the crank (give or take). i would be running injectors with about 17% more flow and under 9% less fuel pressure. if you are absolutely sure that youre running 240's then i should have no problem pushing 225 max. for the time being (this winter) i will only be running about 10psi and maybe 175 crank at best. i think i am going to run 290's and see how far they will go with the stock regulator and pump, and upgrade from there.

im not looking for anything blistering fast, if youve been following my FI posts at all youll see that i just want something quick to spool, with decent power and very driveable. the GT22 in 60 trim 52mm is balls to the wall max at 250hp and should be very driveable on teh street. after i find a good way to adjust timing and fuel my final mod will be 8.5 or 9.0 cr pistons. hopefully with some good tuning i can make it cruise the highway at 35mpg or close to it. anything is better than what it is currently, i am only getting about 210 miles to the tank without driving it hard (about 50/50 highway/city).
 

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With 290's, you can make about 215 crank HP (at 57 psi), but your injectors will be at 110% duty cycle. This is basically wide open all the time. It will work, but the injectors will eventually fail.

Get the RC 440's. They're only $84/ea. here:
http://www.importparts.com/shop/product_info.php?cPath=800_802&products_id=2762
 

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"You will give 110%."
"That's impossible. No one can give more than 100%. By definition, that is the most anyone can give."
 

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rather go bigger than smaller.. I run 550cc on my 1800 and the car is drivable in town, open road or race... from 1000 to 3000 rpm, the car is normal especially under light foot... but put foot down under load then obviously due to tuning the injectors will open to what ever duty cycle they have been tuned for .... like I said .. the injectors duty cycle can be set to your driving style depending on the managment setup. Obviously too big and it will idle too crappy and also be more difficult to tune on a smaller engine..

on a 1500 motor, up to 400cc should be more than ample to get what you need and more...

Grant
 

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Originally posted by XericRally
[body]
"You will give 110%."
"That's impossible. No one can give more than 100%. By definition, that is the most anyone can give."

[/body]
Fuel injector flow rates are measured at a certain frequency at 43.5 psi. This frequency is "100% duty cycle". However, if you can open and close the injector faster than the frequency it's rated at, you going faster than 100% duty cycle. Most injectors will go to 110% duty cycle before going static (always open).
 

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The mechanic said that my 5th injector will be a 500cc! Is that reasonable or not? The 1.3 uses the 190cc injectors.
 

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Discussion Starter #18
well thats a bit much but so long as your stock injectors will be controlling idle and off boost you wont have any problems with idle. with a 5th injector its more of a concern as to how its controlled and the device you use to control it accurately.
 

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[body]Stock accent injectors are 195cc. Tib injectors are 240cc you should be alright. At least I was pretty sure those were the ratings.....

[/body]
Accent injectors are 165cc's... not that it matters...
 
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