HKS 740cc injectors

[Nicksemianiw]

I was wondering if they are any good. I found a good deal on some. And also will they slide into my stock fuel rail? Also would it be a good idea to get a nismo FPR?

[ca18det_boy]

I was wondering if they are any good. I found a good deal on some. And also will they slide into my stock fuel rail? Also would it be a good idea to get a nismo FPR?

yes, yes, and yes......the thing you want to keep in mind is how much power are you shooting for? You need to keep the duty cycle low, but not too low. I have a T04b90 turbo laying down 400rwhp 740ccs with an 85% duty cycle. If you want give me a turbo map of what you have and a hp you want to shoot for and we'll find out.

[Nicksemianiw]

I am shooting for 360-380 and in the future with a bottom end build up between 420-450 whp and that would be it but for now 360-380 and i dont have a map for my turbo yet its a HKS GT30 if that helps you at all. I will have to get it so untill i can take my turbo off i wont be able to tell you exactly unless you already know the map for the HKS GT30

[ca18det_boy]

stock bore and stroke? I also need the compression ratio that your running.

[Nicksemianiw]

Yes stock bore and stroke and i am running the stock 8:5:1

[ca18det_boy]

On hksusa.com they have like gt 3037 and other turbos like that. Since I can't find a map for that turbo we'll use one with similar sizing....I'll be back in 3 min

[ca18det_boy]

wow good choice on the turbo at 15psi you'll be 73% eff. That will also put you at roughly 362.1hp. Now lets see what you'll be doing at 22psi. At 22psi you'll be pushing 34.91lbs/min and roughly at 448hp. Your getting out of peak eff at 72% but your pretty close to the 73% island. In order to support 448hp you need appx 760cc or higher injector to maintain the 85% duty cycle. So for the 400 mark 740s are the best choice. If your doing standalone and plan to up the boost later on get some 800s or so. Peace

oh and you don't have to worry I found a gt30 map so those numbers are accurate.

[Nicksemianiw]

Thanks a lot man! It is incredible how efficient the HKS GT30 turbo is it is not that big and still works off a T25 flange! Just goes to show how impressive HKS is.

Nick

[ca18det_boy]

np man let me know if you have anymore questions. My door is always open. BTW I have silvia parts for sale if you want/need any. Email me if your interested.

[Nicksemianiw]

Because i dont have a Stock T25 turbo and a HKS GT30 turbo, is it safe for me to be running 12-13 PSI daily? Because 12-14 PSI is max on the T25 and i know i run a lot more CFM. So wouldent my motor be knocking? And if so how do i tell?

[ca18det_boy]

nope don't do it with the stock 370's you need bare min 550cc to run 12psi. !4psi and your getting towards 90+% duty cycle which is bad. If you get the 740's then yeah you can run at 13-15psi and be good to go. As for the knocking or pinging...are you running standalone? If not I can tell you how to make a datalogger for your SR for around $25 and 30min of your time.

[Nicksemianiw]

I'm not going to be running 4 PSI! I dont have any type of fuel tuning, i am geting a Apex'i S-AFC II. And that is good for my 360 whp with a rom tune. Also i have been running 12-13 PSI for a while now and nothing has happend although my motor heats up VERY easy it takes 4 min of driving and its a smige over half on the temp gauge. Could that just be my thermostat?Or is it because my FMIC is blocking my stock sr20det rad? And nothing bad has happend so far so why wouldent i be able to run 10 PSI? Or is it the CFM that limits me. And do you think i should not run the car at all untill i do my upgrades? Check my cardomain on page3.
Modified by Nicksemianiw at 9:12 PM 6/16/2005

[ca18det_boy]

no sorry I guess I got fat fingers on the lappy. I meant 14psi. As for the safc+rom.....bah I wouldn't bother with it. The purpose of a rom tune is so that you don't have to mess with it. The only reason I would do it would be to smooth out the idle since your venting externally. For the heating issue, your driving a turbo'd motor with a small radiator. The intercooler blocking it doesn't really help the issue either.

As for boost.....its not PSI its lbs/min. So lets say that your stocker T25 pushes 18lbs/min @9psi. Now lets say your gt30 pushes 18lbs/min at 3psi. You have to do some math to make sure you don't blow stuff up. I would keep driving it if you want. Make sure that you don't crank up the boost too much because the stock injectors don't really handle that much. If you decide to run the safc doesn't matter if you have the rom tune or not just make sure that you have some kind of datalogger. I really don't like piggy backs but if thats all you have its better than nothing. Remember good tuning makes that difference between a bus pass and a speeding ticket.

[Nicksemianiw]

Ok so what about 10-12 PSI daily. And how do i make a data logger? But oh well this will all be sorted out when i get my parts LOL.

[ca18det_boy]

on stock injectors...no way you'll blow that up with the quickness. As for the datalogger....have you ever made a board before? If you haven't then you can paypal me $30 and I can make you one you'll have to be in charge of putting it on your ECU but at least you'll have one.

[Teamsprock]

Hey CA18DET_boy I like the math on the flow of the GT30, I have that turbo currently and I went with Nismo 740's. I was wondering if you could do the math and tell me what that turbo should do at only .6bar, I dyno'd mine at that boost and would like to see how your numbers compare to actual numbers, I hope your numbers are correct because I am uping the boost to 1 bar tonight and I am hoping to see a signifigant HP gain as I was a little disappointed with the first dyno, but also I am assuimng it was low because the turbo is out of its efficency at that boost! I hope I don't seem like I am disagreeing just curious to see how the math vs. real world looks! I have stock stroke, increased bore of 86.5 and 8.5:1 compression ratio. This will be fun to see how close you are! I can't wait for one bar tonight.
Modified by Teamsprock at 2:58 PM 6/17/2005

[ca18det_boy]

eh it does seem like your disagreeing with me but that aside at .6 bar that should put you at 6.12psi. At 6.12psi your pushing 20.34lbs/min. Since your at 86.5mm bore and nissan sets up the displacement in increments of 50 technically your a 2.1L but barely. You should be around 261hp and since you have 740cc injectors your running a 51% duty cycle.

So how close am I? You should post your dyno sheet.

oh and at .6 bar even though thats really low your still running at 72% eff.

[Nicksemianiw]

So 8 or 8.5 PSI and i am set right? And i will be making the same power as a guy with a T25 at 12 PSI HEHE

[ca18det_boy]

AH NO!!!!! At. 8.5psi you'd be maxing out your injectors at 110%duty cycle....thats a sure fire way to mess somethin up....

[Nicksemianiw]

I cant go below the stock 7 PSI

[ca18det_boy]

then don't run that turbo till you get injectors, at 7 psi your running 105%DC. If you do, then you won't have a bottom end anymore.

[Nicksemianiw]

Ok