What injector size for my LT1??? Grumpy?

[80LS1T]

I have a 93 LT1/T56 that I am modifing to put in my 80' ZX. I want to know what size of injector I should run with these mods...

 

1. Port and Polish of Heads and Intake

2. 58mm Throttle Body

3. .030 bored over

4. Not sure on what pistons but compression will be in the high 10's

5. LT4 Hot camshaft kit

6. EGR system eliminated

7. 1.6 ratio roller rockers

8. Upgrade to newer style Opti spark

 

I was thinking 30lbs injectors???

 

Can someone give me a website or something that gives HP ratings for injectors? These are high impedence injectors.

 

Thanks

[Mudge]

I'd like 30#s, but even 24#s would be ok, but I like low duty cycle setups.

 

24# is good for "450 HP", and most ported heads/hotcam/headers cars hit 370 RWHP if the tuning is on.

 

Dont put much effort into the intake, especially with the TINYCAM, raise the runner IF the heads require it, which depends on the port job, and open it up for the 58mm TB, then leave the rest alone.

[grumpyvette]

you must burn a certain amount of fuel to make a given level of hp, engine size has far less to do with it than engine efficiency and peak hp output , use this calc to figure what you need, figure on an 80% duty cycle max and a .55 bfsc

 

http://www.z31.com/software/injector.pl

 

http://www.rceng.com/technical.htm#WORKSHEET

 

http://www.rbracing-rsr.com/fuelinjectors.htm

 

here read this also

http://www.grapeaperacing.com/GrapeApeRacing/tech/fuelinjectors.cfm

[Guest Zcarsmakemyheadhurt]

Sdsefi.com has a chart on its fact/Tec page but I would use a 42lb. injector if you have a programability on your fuel computer due to the compression.

[Tim240z]

Here is a good site for calculations:

Smokem up

Tim

[Mudge]

I considered 36# for my own setup, but 42#s I'm not so sure about. In high impedance form I hear complaints that idle is pig rich because 1ms is too much fuel for thier cars even at 1k RPM idle.

 

I would go for some used 30# SVOs, they will more than take care of you, I made 411 RWHP with an ignition miss with my 30# and I got them for under $200, low miles.

[v8dats]

hey mudge whats your setup for that 411 rwhp?

is that naturally aspirated?

some details on the idle,power through the rpm range?

just curious? any ecm mods?

thanks,

juan

[Mudge]

No ECM "mods", just reprogrammed with Tunercat.

 

Heads/cam/SLP shorties/K&N intake, basically just the 'basics', nothing fancy, it was a budget setup.

 

http://docmudge.tripod.com/dynorun030902/index.html

 

It was a daily driver, with stock 3.42 rear gears, so it was driveable yes, in a Z with 1200 less pounds, it would have been extremely driveable on the low end. I had to be conservative with low end timing due to the crappy gas in CA, otherwise it would have been a true low end beast, had it pulling very hard off idle but unfortunately found knock all too fast. I was in theory supposed to hit 20 more RWHP, peak was supposed to be ~6500 RPM about and I ended up flatlining after 5900.

[v8dats]

sorry to bring it up again but what cam did u use?

[Mudge]

I could make suggestions based on what you want out of the car, but my cam is proprietary and has to remain that way (I know, stupid, but thats how some people retain thier secrets and therefore think that it retains biz).