Ok guys Ive been buying everythign for my turboed n/a and have had to reevaluate my fuel plans. Originally I wanted to go standalone with the megasquirt but if i go that route i wont be driving this for a very long time. how does this cheaper setup look? WIll it be effective and also safe for up to 12psi.

550 primaries
720 secondaries
safcII
tuned with wideband(not sure what kind yet)

 

do 4 of the same injectors. 720cc's... and def a standalone as soon as you can.. a walboro should be fine

 

You would have a real problem running 720s as primaries on the stock ECU. The car will tend to flood, and you'll have issues with running rich at idle. Stick to 550CC primary.

Your injector choices sound fine, but you will need a fuel pump upgrade.

 

you might want to consider an emanage. its a bit more expensive than the SAFC2, but you can control timing as well, with is VERY important on a high compression turbo motor. with the new emanage ultimate just coming out, the blue emanages are farily cheap. depending on how much boost your running, i think 550s and 720s are fine along with a walbro.

 

Not to thread jack, but I am running haltech and will be running the stock turbo at 12psi.
but around next april/may i will be upgrading to a larger turbo for hope of 350-370 whp.

First of all, can I use stock 550's on 12lbs (I dont think so)
And if I do need to change out my secondaries what would be an adaquate size, 1600's seem like overkill, and I dont like the large transition.

Or get the 720's for secondary now.......after turbo swap make them primary, and get 1000 cc secondaries???

 

Just 720 secondaries will be fine at 12 PSI. When you go with the large turbo, upgrade to 1600s or 1000s.

 

i don't understand how 1600cc's can be overkill for 250-300 horsepower, it only injects as much fuel as the computer tells it to. And if your using a standalone you tell the computer how much to tell the injectors to inject. Atleast 1600cc's give room for improvement in power later on.

 

I completely understand what you are saying. I have just hear of people having a hard time transitioning from the 550's to 1600's. I dont like how I have to modify the fuel rail, so I migth grab some 1200cc range injectors that drop right in.

I have built and tuned a good amount of cars but this is my first rotart, so the whole, primary-secondary injectors and leading and trailing ignition is different for me.

 

Cant i just retard the timing manually? Ill look into the emanage but last i check they cost as much as the MS.

AS far as the pump goes I already have a walbro here, just forgot to mention it.

 

You can, but you don't really have to. I ran up to 14psi with the timing at 7*, (2 degrees advanced over stock), leave it at stock and keep an eye on your AF/R's an EGT's and you shouldn't have too much trouble running low boost.

 

SO i should be safe in the 10psi range with the safcII and slight mnaual timign retard. right?

How do you read the exact degree of your timing retard?

 

OK... Lets do some fuel injector thinking here.....

1600's are WAY overkill for 300 HP.... WAY FRIGGIN OVERKILL......

Why? You got the right idea, BUT, the fuel injector doesnt inject as much fuel as the computer tells it to.... it opens the solenoid for as long as the computer tells it to each time it opens....... BIG DIFFERENCE between a 1600 opening for 2 milliseconds and a 750 opening for 2 milliseconds. Kinda like the difference between blipping the handle on your garden hose and blipping the nozzle on a fire hydrant. Get it?? THis is why tuning with bigger injectors and the stock ECU is a PITA. the Stock ECU doesn't know that there are different injectors in there and you can't adjust the maps, you have to alter the sensor signals to trick the computer into putting in fuel for a different amount of air and pressure.

People have got it down, but there is a limit to what you can do... Thats why you are seeing the re-programmed R-Tek ECU's, they actually adjust the fuel maps for the bigger injectors.

Also, the 1600's, because they are DESIGNED to dump in large amounts of fuel (most of the 1600's people are running were designed for LPG vehicles) they are not really good at injecting SMALL amounts of fuel, They tend to have minimum stable operation times around 2.5 Milliseconds... and, if you are only pushing 250 HP... thos 1600's aren't going to be running a hell of a lot more than that!!!

I ditched the 1600's in my car and went with 750 primaries and 1000 secondaries and the car is MUCH smoother... MUCH smoother especially at transition. That combo is good to about 450HP.. A number I doubt this car will ever see. Its mid 300's now, Maybe 400 next year with the mods I'm planning for the winter..... But I'm good for the time being.

That being said.. I'd loVe to run quad 1000's, It would make tuning the car a LOT simpler.. at the staging bar you divid the MS in half (well, give or take) but, I wouldn't suggest that with a Haltech... While the injectors would be stable down to the 1.25-1.5 milliseconds or so that it would be running at idle, the drivers on the Haltech aren't. The Autronic ECU, however.. it LOVES it, Zkeller had his **** PERFECT with quad 1000's and the autronic running them.

 

years of decay thank you very much for that response. I needed to find someone that was in the mid 300 range with a standalone. So I will go with the 720-750 range for my secondaries for now on the stock turbo. And then make the 720-750 my primary and get some 1000's for my secondary when I swap the turbo.

btw what was your targeted afr? I am shooting for 11.8's just to be safe, bad gas, heat, whatever. I would rather keep my engine for a while than pull an extra 10-15 hp out of it.

 

I was recently told that my stock primaries were not enough for the power I am putting out (295rwhp) and that instead of 550/750 I should be running 750/750.

Can anyone shed some light on this? I thought people only started beefing up the primaries once they started getting into the 350+ range?

 

If you have a standalone, it's irrevelant. You can tune the crossover period to match any setup. Nothing really wrong with larger primaries either in that case, but it can be slightly more annoying to make the car act proper with huge primaries.

If you are on the stock ECU, you may need to upgrade the primaries as there is a lean spot just before the switchover. Larger primaries will help prevent that but can make starting a problem (S-AFC has no effect during cranking).

 

Right now I am not running a standalone, but an Rtek 1.7 and an SAFC 2.

As I understand it, the Rtek brings the secondaries online earlier, at 3500 rpm, to minimize the lean spot at the crossover point.