I've done a lot of searching and reading and I'm still confused.

I'm running a fully built block and head, 10:5:1 comp pistons,
sfmu stock injectors t3/t4 turbo(internal gate 3" exhaust and so on.

Right now its set at 8psi and everything seems to be fine. I hit fuel cut at about 5500rpm so from what I've read I need to change out a few sensors as there on their last legs I assume?

Anyway I'm tired of this and need more power.
I'm preparing for msns, mbc, and bigger injectors.
Now the thing is what size should I go with? Most of what I've read is about the standard comp piston engines and what not.
If I run 880's should that be enough? thats around what 500hp?
Whats the largest injector the ms can tune?
Also are all injectors the same? Or do I have to buy ones specific to the 420a?

Thanks for any help.

You need high impedance injectors. With msns I dont think you have any problem which size you choose, the only think I would worry is your ratio 10.5 and lot of boost. You can get 440CC easy and these can put down 18psi...

Originally posted by ChloRure
You need high impedance injectors. With msns I dont think you have any problem which size you choose, the only think I would worry is your ratio 10.5 and lot of boost. You can get 440CC easy and these can put down 18psi...

MS can handle both high impedance (saturated) and low impedance (peak and hold) injectors.

Not all injectors are the same, but the 420A uses a domestic style, O-ringed injector. Injectors from cars like Mustangs should fit perfectly. Injectors from most imports (i.e. the 4G63), or companies like Denso could work, but they might need a little modification for them to fit into the stock rail and injector bosses.

Look here:
http://www.2gnt.com/www/corbin/chooseinj.html

and here for information on injector flow rates:
http://www.megamanual.com/v22manual/minj.htm

10.5:1 compression ratio might give you some problems once you turn up the boost. Expect to retard timing and/or use water/alcohol injection to suppress knock.


-http://www.symtechlabs.com/-

I have 780cc's on a big T3T4 (SC61) with 10.5 comp running 17lbs and have been for 3 years on MS. Im not retarding timing or any kind of injection. The only prob I ever had was a faulty HG and it burned up a piston.

Just pay attention to what you do and listen to your motor.......and watch your WBO2, cuz Im assuming you have one with wanting more hp's, lol.

Good luck

Thanks for all the help guys. Its much appreciated!
dj420, what kind of power are you making at 18psi?
Why haven't you turned up the boost? Or whats holding you back?
I'd like to get as much hp as possible while keeping it a streetable car.
Any suggestions on a headgasket that would be able to stand up better?

I had it to 20 before but it was acting funky(ignition). Ive never dynoed it, dont wanna be let down, lol. Havent turned up the boost cuz of the ignition. Suggestions on the HG are, dont cheap out on the HG and def get studs.

jw why your running a high compression piston instead of low...?

Better low end torque. Its really nice when you have a bigger turbo that doesnt spool right away, cuz then "intown" driving doesnt suck.

Hey dj420,
what type of IDC were you running at 20psi or if you dont have that then at 18psi? Just wondering if you were close to maxing out those 780's.
780's should apparently be good for 430hp at 90%IDC I'm wondering though what kind of psi would need to be run in order to use that much fuel.
If anyone else has an idea feel free.
Thanks.