Exo

So I'm new to the forums and I just picked up a 1995 z28 camaro here about a month ago. The previous owner has some work done to it and I'm curious to of anyone has a idea of whp everyone thinks it puts down.

Lt1 with mid length headers, open Y pipe right now also have flow masters I can put back on, lt4 hot cam kit, bowl work on the heads, 54mm TB, ford motorsport 30# injectors.

The car also has a adjustable suspension and 275 nt05r on the back right now, T56 with hurts shifter, and I think that's all I'm sure I'm missing stuff.

Any ideas of power on this set up? And any ideas how much more these injectors can take? thinking about spraying it soon and curious if I need to upgrade injectors again.

Thanks in advance.

Chimera96

hot cam LT1 with head work likely makes around 325 RWHP

The injectors are good. Hot cam could be fine with the stock 24 lb

spray....not the best idea on a non forged bottom end

Exo

Car was bought like it sits so no 24lb injectors to go back in.

I have read a smaller shot 150 and under is fine on these motors as long as fuel is there.

Injuneer

150 on a stock motor (275 flywheel + 150 = 425 flywheel) is not the same as 150 on a heads and cam build (maybe 375 flywheel + 150 = 525 flywheel). I'm sure some have done it, but you are really pushing the limit. Spray at too low an RPM and you're going to break something.

Your actual HP is really anyone's guess with unknown head flows.

30 #/HR FMS injectors (@39.15 PSI) will flow 31.6 #/HR at the LT1's 43.5 PSI. Good for ~450 flywheel HP/390 rear wheel HP.

What type nitrous system are you looking at - wet or dry?

Exo

Nitrous outlet system most likely and dry shot into the air box. And it will be set up on a WOT switch and eventually window switch.

I think I'm going to get the car dynoed and figure out my WHP Numbers and get my AFR figured out to before I spray it.

Chimera96

the bottom end stock??..how many miles on it?

if answer is yes and over 100k mi...don't spray it

NOS is cheap and quick power adder....but a forged bottom end is what you want to put up with it for any period of time

Just about every stock bottom end H/C LT1 I know of that had spray, usually a 100-150 shot,....did not last long. #6&8 pistons especially....YMMV

Exo

Motor was rebuilt and has 30k miles on it, Previous owner told me it has stock rods but forged piston. Kind of strange how most places on the internet and few people in person say they spray 100-150 shot and never have problems on a H/C LT1.

Chimera96

NOS no doubt adds power. Your fueling system AND tune need to be spot on for any reasonable longevity for a "NOS use" motor..

Stock rods are good assuming they were sized and fitted with ARP fasteners. Forged pistons is good

can't emphasize the tune and fueling components enough for NOS applications

if you have a stock fuel pump you should consider a 255 lph pump for NOS use. Even just the NA H/C. Using a FP gauge taped to windshield and holding WOT on open road for at least 1/4 mi to confirm fuel pressure does not "start" to drop into the WOT run. Your 30 lb injectors are favorable vs the 24's

Injuneer

If you're running a dry setup, the 30 #/HR injectors may not be adequate unless you boost the fuel pressure when you spray. Also, appears you are planning to spray dry thru the MAF sensor, and the LT1 PCM does not respond fast enough. The LS1 worked fine spraying through the MAF, because is has a much faster processor.

I ran the NOS 5176-EO dry kit on my STOCK engine, and that got sprayed after the MAF sensor and used a pressure regulated slip stream off the main nitrous feed, applied to the fuel pressure regulator vacuum compensation port, to raise the fuel pressure to the 80-90 PSI range. That was with 24 #/HR injectors. But that required changing to a FMS/SVO pintle style injector. The factory Multec injectors will lock up at high pressure. Kit was difficult to tune, because they had a jet in the slipstream, attempting to control the flow, (and hence the fuel pressure) that split off through the vacuum compensation line.

If you have forged pistons you have eliminated one weak point in the stock LT1 rotating assembly. The only documented LT1 rod failures I have seen occurred at the 600 HP level. GM did a changeover from the traditional "pink" SBC rods, to a powder metal rod that was surprisingly strong. 95 should have the PM rods. The big risk with the rods and the crank bearings is detonation. The huge cylinder pressures generated by detonation hammer those components.

You definitely want to optimize your tune without the nitrous, then use external means for spark retard and fuel enrichment.

plattted

What year did G M start using powered metal rods instead of the pink rods?

What external means to control spark and fuel?

Injuneer

PM rods were phased in during 1994 model year. My 94 is very late production, and had the PM rods.

Spark retard can be implemented using an ignition box, like the MSD Digital-6 (many others available).

In a wet system, supplemental fuel for the N2O is supplied by spraying fuel into the N2O stream. The amount of fuel, relative to the amount of N2O, is controlled by inserting a "jet" (restriction orifice) into the fuel supply line. Change jet size (diameter) to adjust fuel.

In a dry system, the extra fuel is added through the injectors, either by changing fuel pressure (see NOS 5176 description, above) or through increasing injector pulse width. That requires an aftermarket ECU (like my MoTeC M48Pro). Some dry systems spray the N2O before the MAF sensor, and sometimes rely on O2 sensor feedback to fine tune. That works OK with the LS1 PCM, because of its speed and feedback capabilities. With the slower LT1 PCM, it seems to be hit or miss.... some have gotten away with it, others have not. The MAF sensor calibration is based on measuring the flow of air, knowing its temperature, density and specific heat. While N2O is still made up of nitrogen and oxygen, the density and specific heat are different than air because of the different % split between oxygen and nitrogen.