At what HP are the stock Injectors maxed out. I plan on adding a better fuel pump because this seems to be the fuel systems first week link. Please dont guess at the HP #. I would like to get to 340WHP(400HP at the crank), and would like to know if the stock injectors can handle the load.
Thanks

 

You are definiately going to need bigger injectors for that kind of power, even with a better fuel pump. At around 300WHP over 7K I see the duty cycle hitting mid 90's (not good), the general rule is to keep the duty cycle in the 80's at max load/RPM.
I have similiar power goals and am looking at some 680/660cc injectors, you also do not want to go with a bigger injector than you really need either.

 

So I what you are saying is just step up the injectors one notch for my power goal??? are 660's the next size up?
Thanks

 

340whp will definitely require a fuel system upgrade. i know a bunch of guys running UR's 785cc's and walbro fuel pump. injector duty cycles in the lovely 70% ranges.

 

340 whp does not require a fuel injector upgrade!

We made 360 whp on the completely STOCK fuel system!! The 380 whp we made could have been reached also if it had not been for fuel cut, that is the only reason we changed to the 680 cc.

With an ECU reflash to avoid the fuel cut the stock injectors and pump will handle atleast 380 whp. I made 446 whp in my old AWD on 550 cc injectors and an upgraded fuel pump. I have made over 600 whp on a 660 cc injector.

David Buschur
www.buschurracing.com

 

Well how about the EVO fuel pump??? Will that be able to take 340WHP?

 

David,

I think he was saying 340WHP as measured from an AWD Dyno jet, if I am not mistaken your results are measured with a 2WD system? If this is true would 340 AWD dyno values be around 360-370WHP on a 2WD? Do any of your customers with these staged mods have AWD Dyno Jet test results for comparison?

What sort of A/F ratio is used for this sort of power? Can we run these levels reliably day to day with questionable quality pump gas?
What injector duty cycle do you think is consistent and reliable to run with for sustained periods?

Keep in mind that people like myself who like to spend a lot of time on road courses, will also spend an awfull lot of time at these sustained high load levels. Do you honestly believe I can safely and reliably maintain 340WHP*(360-370), with questionable pump gas, nearly maxing out the fuel system for sustianed periods?

 

Yes, what I want is 400 HP at the crank which I think would come out to around 340WHP on a 4WD dyno. Here are the exact mods that i will be running: Buschur 3" turbo back with high flow cat, BR MAF pipe, BR intake, BR I/C pipe(with mini battery), HKS cams, cam gears, and the XEDE to piggy back(oops almost forgot, a ground kit). I would also like to run around 20.5 psi peak tapering off to around 19psi. I also have 93 octane down here.

 

i would upgrade injectors just to be safe....the most important thing for an engine is fuel...and you wanna make sure you can get plenty of it. plus overworking the injectors like that is not a good idea...eventually one will lock up.

 

LOL, just rolling my eyes at typical East coast small injector stuff.

I am wondering why Buschur is thinking of fuel cut as occuring unessicarily early. Since these cars are capable of laying down 340 whp at 20 psi on 91 octane, I cannot imagine fuel cot as being set far to conserveatively, so it seems to me Buschur upgraded his injectors because he needed more fuel then they could safely provide, not because fuel cut was preventing them from performing as they should.

 

It seems to me that with just a piggyback at the time, he reached those numbers. Correct me if im wrong. If he could not get the CFM he needed to make that power then his thoery of the fuel cut could be valid. From what i understand he needed to increase the boost so he can take advantage of the additional fuel that was available. If boost cut prevented that then i see his point. If tuned properly i dont see any problem at all with those numbers.
But you state that the evo can produce 340WHP at 20psi on 91 octane?
do you have a link to who did this?
Also was this info from corrected dyno numbers?
I know that usually you can go MUCH leaner on the dyno to pinch out MAX power. Something i wouldnt trust for the street.
No offense i just cant understand why he would state that if it wasnt true. David has a good reputation, i cant see what advantage he would have from hiding something like that.

 

I cannot even stumble through what you just wrote, its a load of gibberish. It really makes no sense...

"Correct me if im wrong. If he could not get the CFM he needed to make that power then his thoery of the fuel cut could be valid. From what i understand he needed to increase the boost so he can take advantage of the additional fuel that was available. If boost cut prevented that then i see his point. "

Huh? Boos cut? WTF does that mean?

RNR made that power, uncorrected, on a Dynamic Dyno.

Im not accusing Dave of hiding anything. Simply

A) I do not understand how fuel cut UNFAIRLY prevented him from making more power on stock injectors

B) The injector szing arguement for these engines goes back alot longer then the EVO scene. BR and east coast guys always liked smaller injectors and higher fuel pressure then RRE and us west coast guys.

 

Lets me see if i can help you clarify my statement.
If sufficient fuel is present, with the stock injectors, then the increase in BOOST pressure (AKA added CFM of air) is what he needed to make it to that HP level.
IF HE HIT fuel cut with just a piggyback then he could not reach his goal.

Maybe the guys here on the "east coast" seem to write a little better too

It also seems to me that by dumping in ALOT more fuel (or should i say **** water for you ""west coast guys"") then you MAY achieve this. BUT i believe that in real world testing they wouldnt get that without getting a little more boost pressure. IMO.
I could be wrong.
Stock 560cc injectors should have no problem getting 340WHP on the evo.
As far as 380 they are coming pretty close to 90% duty cycle.
This assumption is based soley on the stock fuel system incorporating stock rail pressure rather than 1:1 increase with boost. I am not sure if the control solenoid allows this increase on the evo.
If however we were to bypass the fuel pressure solenoid all together then we can keep those duty cycle times a little lower. I would think; in theory.
Let me know if you need any more help with my post.

 

Nope, I still don't think that makes sense. It still is gibberish.

"If sufficient fuel is present, with the stock injectors, then the increase in BOOST pressure (AKA added CFM of air) is what he needed to make it to that HP level.
IF HE HIT fuel cut with just a piggyback then he could not reach his goal."

That reeks of illiteracy to me, I don't think you have any room to manuever when it comes to saying east coaster's write better.

If I understand that **** you just wrote, what your trying to say is that...No, I don't really understand yet. Do you know what fuel cut is based off of? Try to explain that again, this time in a way that will make sense to other people and not just in your head. Don't get me wrong, I can tune EMS's and work at a shop, Im certainly no idiot, I just can't understand Dutch translated into English by a Korean rice husker.

 

Its not really worth commenting on your ignorance. It is a shame that someone who has alot to offer to this forum would react so negatively. You act like you dont understand what im saying?
Ignorance really is blissful for you Huh?
Some simple mathematical calculations should help you, since you doubt it can be possible to achieve that power from the stock injectors. AAhh **** it.your just a fool.