Injectors > max bhp output.
 

Although im currently Subaruless, I was for some strange reason thinking is there a logical bhp for each cc on injectors?

It appears there is the way I have worked it out, stand to be corrected of course :lol1:

78% of the CC is the Max output of BHP at 3.5bar pressure running full duty, does this seem right?

3.5 Bar
Attachment 55698

3.0 Bar
Attachment 55699

Remember im only asying there is a logical explanation for each table, im not saying this is the Power you will get from using the said injectors, also each table would mean that you would be running close to full duty.

Rob

PS Im ready for the stones to be thrown at me :)

so for 420 i didnt need to buy 650's then --- Doh!!!!!!

I was actually just searching for something like this :thumb:
I'm looking at getting 550s but heard they struggle to get to 400 bhp but looking at the chart its saying different :wonder:

hmm my 440`s were at 98% duty and could only manage 336bhp all other mods were more than capable,.,

Same mate, mine were maxed at 320bhp

I made 347 at 91% on 440's a while back but I did have a fuel reg fitted with 0.5 bar more fuel pressure.

This can be truth,but with FPR and parallel rails and depends on fuel used,boost etc.


Jura

I have a fpr so i should see what i want with about 0.5 bar pressure increase?

To be fair though i was running standard pressure when i had it mapped.
I would of probably seen more with 3.5 bar then

General rule of thumb is every 0.5 bar increase gives 10% flow so a 440 becomes 480ish cc.

Is there any disadvantage of increasing fuel pressure?? Why not just increase it as a matter of course when you map it?

It's a nice table but the bhp figures in reality are perhaps a little optimistic :)

As long as the fuel lines are all in good condition then no disadvantage at all.

I found this a while ago not sure if its correct tho
http://www.scoobypedia.co.uk/index.p...rFromInjectors

yes lets go with this cos it makes me feel better about buying 650's:lol1:

My RCM 550's were getting very close to their limit at 390. I now use a FPR to help them out a bit and currently set at 3.5 bar.
Don't think 432 would be achievable with 550's and no FPR to be honest.

That looks more realistic, 440s at what i acheived at 3 bar.
sorry just re read Robs 1st post and he does state 3.5bar so 346bhp is possible then

Guys I was only experimenting with the a simple formular :o

The % I was stating isnt duty cycle, its the % of the CC that creates seems to follow a pattern of bhp.

78% of 100cc works out at 78bhp
78% of 1000cc works out at 780bhp simples.

Im not syaing this is anywhere near right, but it does seem to be somewhere near after doing a little home work.

Also its worth pointng out that I know 440's will do 340bhp with a 3.5Bar FPR, also 550's will make well over 400bhp with a FPR. With this in mind the table although adventurous isnt a millions miles away.

I'll re-jig it for 3 bar :lol1:

Rob

I use the following as a rule of thumb.

(CCs / 5) x 4

I.e 565cc injectors in theory should give 565bhp in a 5cyl car at 100% inj duty at 3.0 bar.

Hence in a 4 cyl = 452. Run at about 80% duty for 361bhp.

Or you could use this

http://www.rceng.com/technical.aspx

Martyn

Can you up the fuel pressure without a map, or only when mapping?

Only when mapping as it will alter the mixture.

Martyn

cheers :)

On a newage STD injectors (550 pinks) running at 100 % duty will max out at 384 bhp

Andy

Maybe yes maybe no. All cars will vary, you can only offer a guide. Mine with a FPR got close to the stated on post1.

My car runs 740 injectors, it has 500bhp, there is still room for more power from 740's

Mine did that down there



<<

On standard fuel pressure and 380cc injectors.

Rule of thumb: 550cc x 4cyl = 2,200 / 5 = 440bhp (100% and 3BAR fuel pressure). Safe / 80% duty = 350bhp.