Will 30# injectors be enough for this setup? Need to know.

[astronut1885]

Hey guys. I want to get a blower in a month, and I obviously need to upgrade my fuel and air delivery systems to match. Here's my current engine combo:

GT40P heads-no porting, valve work has been done, and they have 1.96 intake and 1.54 exhaust valves, which are larger than stock P heads
Explorer GT40 intake- no porting
E303 Cam straight up install
1.72 roller rockers
FRPP headers, MAC prochamber, Mac Flowpath catback, all 2.5"
U/D pullies
A/C delete
MKVIII fan
Smog delete
MSD ignition
70mm TB/EGR (not now, but it will go on with the blower)
MAC cold air intake
stock 302 bottom end
255LPH fuel pump (Walbro)
Crane AFPR
SN95 fuel rails.

I want to add a Vortec A trim supercharger, pushing about 5psi max. I need to know if a Pro M 80mm TB and FRPP 30lb injectors will be able to support that setup. I think it should, but I am no expert. Thanks for the help guys!

 

[nito88stang]

It SHOULD be enough. That being said, the only way to make sure is to take it to the dyno to make sure.

 

[RydeOn]

30lb injectors start maxxing out around 370rwhp. It should be ok.

 

[astronut1885]

Cool. I am going to dyno again once the blower is on, so I can get a good handle on my A/F ratio. I will hopefully get a Tweecer and from there be able to really tune the hell out of it. How much should I expect from that combo? A friend has an A trim, 306 shortblock, home ported E7s, Explorer intake, 1.6 rockers, unknown midsize cam, MAC shorty headers, H pipe, and catback, and all the same small parts and bolt ons. He made 326 RWHP I believe.

 

[Grn92LX]

You'll NEED an fmu if you intend to keep those 30's. Why not 42's and no fmu?

 

[astronut1885]

Why will I need an FMU? The reason is because I have an oppertunity to score this setup for cheap, but before I do I want to make sure they'll be enough.

 

[RydeOn]

30s are tricky because they are a 'gray area' injector. You will not be certain that they will run your combo without a FMU. You probably will be able to run without one but youd want to find out on the dyno. 36 or 42 injectors are pretty much blower injectors and youll be gauranteed that you wont need an FMU.

 

[RydeOn]

BTW if you do need to keep the FMU you order the 4:1 calibration discs from Vortech and swap disks in your FMU.

 

[nito88stang]

30s are tricky because they are a 'gray area' injector. You will not be certain that they will run your combo without a FMU. You probably will be able to run without one but youd want to find out on the dyno. 36 or 42 injectors are pretty much blower injectors and youll be gauranteed that you wont need an FMU.

Rydeon is right, 30's are right in the middle. They're a bit too big for mild HCI combos and they're a bit too small for blower applications. They're more suited for tame 351 combos or 302 based strokers. In your case though you should be fine, now if you decide to step up your combo then they might not be up to the task.

 

[blown93feature]

I can tell ya that those 30#'s are good enough when used with an fmu for 80 to 88 horse per cylinder.I am going back to the dyno soon with the "S" trim bolted back up and should put down 500 to the ground through the auto that equals out to be around 600 at the flywheel.That last time I went to the dyno I had a converter issue,that since has been changed and a running real rich problem when I had a 6:1 disk so since then I changed a few things and haven't been back.I run twin 255 walbro's and the rest of the fuel system is stock including the fpr.I can tell ya right now that running an "A" trim with your parts, that you won't have an issue at all.

I can also tell ya that getting an a trim to produce 10 psi is just playing with fire you are on borrowed time.The only reason you will ever see 10 lbs is your over spinning the blower and doing nothing but pushing hot un usefull air down the motor.The second thing is your motor not running very effeciant and as a result your seeing higher boost numbers because of very restricted heads.

 

[Rick 91GT]

I'd go 36# and no FMU...the extra injector will not hurt.

We made 465RWHP @ 5600RPM with a 36# and no FMU, 38psi of fuel, 255lph Hi Pressure, ATI inline (T-rex). We saw 9.8psi of boost on the PMS and the blower was topped out, 93 Cobra,331ci, Extrude Honed Cobra intake, ported/polished stock cast iron GT-40's, 83mm Pro-M, AFM power pipes, 1.625" shorties, high flow CAT h-pipe, 2.5" exhaust, all emissions and A/C. Just upgraded to a DART block, AFR185's, 72# inj and a YS-TRIM....

The A-trim is being phased out, you'll want to get a SC trim. It will make more power, spin higher and last longer...

 

[astronut1885]

I don't want to make more than 5 psi to be honest, because right now I don't know what my motor can take. I have P heads, which are higher compression, so I'll have to really dial back timing, but my 130k mile shortblock might not like alot of boost. It runs really well now, and seems solid, but a blower can change all that. I think I'll go with 36 or 42 injectors and skip the FMU. As far as the blower, I'd love an SQ, but they are really expensive. A friend has an A trim, but wants an S, so we are going to go in together on an S trim kit, and then swap head units so I have the A and he has the S.