z28boysteve

iTrader: (9)

well as I've posted I got the Z28 to run 11.33 @ 118 N/A finally, and at 3,300 lbs, that takes about 400RWHP to do.... well shy of what it should make.. power seems to fall off, even though the engine still revvvs smooth at 6,000 + rpms, and my cam is made for 6,500 peak power and shifting at 6,800
Desktop dyno 2003 said the motor is supposed to make 497 at the flywheel, Im in the neighborhood of 460 flywheel is my guess.
If all my estimations and assumptions are correct will my stock injectors support this kind of horsepower? what about at 60PSI? (28lbs/hr)

METALBEAST

iTrader: (1)

Well when I run the numbers, rounding up to 500 FWHP:

IS = (500*0.5)/(8*0.9)

IS = 34.7 lb/hr injectors. Rounding that up to the next available size, looks like you need some 36 lb/hr injectors. I would at least get some 30 lb/hrs for your setup.

z28boysteve

iTrader: (9)

how much HP do MAXXXXED out 24lbers provide, meaning 100% duty cycle
(edit) never mind you posted the math in front of my face lol
Well using a BSFC of .42 (A lean N/A motor) and 100% duty cycle that means a max hp of 460, exactly my estimate...

If raise the Fuel pressure to 60PSI they put out 28lbs/hr I can support 500HP if it can make it at a BSFC of .45 and 100% Duty cycle (open at all times)
so I MAY just barely get by with the stock injectors at 60psi, but after that they are done. I should probably just go ahead and get some 36lbers

z28boysteve

iTrader: (9)

Racetronix sells a set of 37lb/hr injectors at a good price too through thunder racing.. $333, guess what I need to buy :-( Im going to dyno my car in early january, if the wideband shows a good fuel mixture at 60PSI ill just stick with stock, but if its leaning out up top like I feel like it is. ill go with the Racetronix injectors, but hey, I maybe might pick up 40HP for $333 wouldnt that be a good gain power/dollar lol, and pretty much guarentee me about a 10.90 @ 122 N/A then I can finally give the nos a squeeze, which of course I will also dyno first to make sure the A/FR looks good on that too.

infinitebird

iTrader: (11)

I haven't had my car dynoed yet so I don't know what my power level is but with the (relatively modest) mods in my sig, my stock injectors dc was at 86% at 6000 rpm. Now I think I might be running a little rich, but even if I am, that doesn't seem like much room for adding more serious power mods.

I don't think there's any way the stock injectors will support that power level.

GIZMO

iTrader: (8)

Steve,

I'm currently running 10.50's at 3200 lbs with the stock injectors at 50 psi. I have tried running 30 lb injectors, but found that they hurt performance at my level. Of course my set-up is race only with DFI, so your results might be different.

Good Luck,

Daren

Alvin

iTrader: (2)

Why are 30's hurting you, you might hae to start your tune over but it wouldn't be that bad.

I've been able to get as much as high 360'rwhp out of stock injectors and as low as 340ish. RPM is really what limits your injector because you have less avaiable time to open per intake stroke.

GIZMO

iTrader: (8)

I did a bunch of track testing with injectors a few years back. I purchased 30 lb injectors thinking that the 24's might be holding me back. The only way that they would come close to working was to lean them way out so that they were pumping the same amount of fuel as the 24's. At that point the car was slower at all points down the track, but especially on the short end. I have talked this over with Woodro Josey and Jeff Warren and they both agree that in our application the injectors work better if they are pretty much static. The injectors that are in my Camaro are over ten years old and have never given a problem.

Daren

GIZMO

iTrader: (8)

Woodro was running 9.8's at Rockingham a couple of years back with 24 lb injectors! (LT4 @ 2900 lbs).

Jeff was in the 10.3's at Rockingham this year with 24 lb injectors! (LT1 @ 3200 lbs).

z28boysteve

iTrader: (9)

All Hail NHRA Stock Eliminator!!! Finally someone who REALLY knows what near stock cube N/A stock headed LT1s are capable of, Ive long had interest in running stock eliminator but my motor is far from legal except for the bottom end
Does it look likely that the stock injectors at stock fuel pressure are a factor holding me back?

what trap speeds can you get on 24lbers at Stock PSI
would you mind pming me I have a boatload of more injector questions

GIZMO

iTrader: (8)

The absolute best thing that you can do is to put your car on a dyno and log the o2 readings. DFI makes tuning a bunch easier, but I am sure that you can get the same results with the factory PCM if you work at it. I wonder what your timing map looks like? I am at 42 deg on the bottom end and taper down to 36-38 deg by the traps (100-110 octane race gas).
When you say that you shift at 6800 rpm, are you pulling the lever at that speed or is that the speed that the shift hits at? If you are pulling the lever at 6800 rpm the actual shift point could be 300-500rpm higher. Again, the dyno will help. I find that I am quicker if I short-shift the 1-2 shift.
I noticed a lot of body roll in your pictures. You will probably gain some sixty foot if you run an air bag. Don't worry if you don't lift the front tires by much. I have had some 1.35 sixty foot times where I only lift the tires about 2".
What PSI are you running your Hoosiers at? I never run less than 18 psi and will go as high as 22 psi if the track is good.
The turbo 400 is probably killing you by as much as 2 tenths N/A.
If you want to hit the tens with your combination it will take a bunch of little adjustments to get there. You need to analize every little thing.
In answer to your original question, 120 mph trap speeds are possible with stock injectors at 45 psi. If your injectors are in excellent condition, they are not your problem. I would take a hard look at the tune. Ed can probably help you a bunch with your factory PCM.

Daren

z28boysteve

iTrader: (9)

Thats the plan on january second or so I plan on carting her over to horsepower engineerings mustang chassis dyno with wideband

Well I had to install an MSD crank trigger ign. the factory ignition has been letting me down, misfiring like crazy and I changed EVERYTHING in it, so I put a MSD flying magnet kit with an MSD 7AL3 in the car, no high speed retard is installed.
Im in the army so I dont get to spend as much time as I would like on the car so I installed the MSD, fudged on the timing with a good guesstimate, and raced it.
I dont have degree marks on the ballancer or a pointer and beleive I may have been too advanced because the car was hard cranking sometimes
next time im down ill lock and set the timing to exactly 36because of my smaller cam + I run pump gas.


I am hitting the shifter at 6,100 as the car sets now, It produced the best ET and MPH, but the cam is made to make its Horsepower at 6,500 so I should be shifting around 6,800 thats what led me to beleive I could possibly be running out of fuel, those injectors have 115,000 miles on them and have never been serviced.


Since alot of those pictures were taken I have installed a BMR eXtreme series anti-roll bar (a beefed up rear sway bar with adjustable spherical rod ends)
It now launches Exactly as you describe bolth wheels get up about 2-6"s and the car stays perfectly level. There is, on my website one picture from the rear of the car, in the dark at HRP showing what it launches like now

The one and only night I ran the car since it started running good again with the MSD I set the tires at 16PSI for a start point, they used to spin with my 3,000 stall at lower PSI, I probably wasnt hitting the tire hard enough and they were brand new and but sat for a long time, the new converter hits them really hard and they grip really hard, Im ready to play with the PSI next trip to the track in early january

I realize the TH400 isnt exactly a good transmission to go fast with a smallblock, but It will provide me Years of reliable service im sure and keep the running costs of my car down. a new race built reverse pattern manual TH400 only $800

I would have rather gone with a metric 200 or TH350 but I wasnt sure how they would hold up after a long time.


I figured they might be able to deliver that sort of performance, but I couldnt think of anything else that could kill my top end, Ive got a killer valve train and im sure its not floating.

also what are some cheap or free tweaks I can do to the car still
I figured I might as well TRY race gas, but my guess is the car will probably slow down

I posistively need to go to a wideband dyno, there is no telling how much power I could be throwing away on the bad tune.

I definitely need to set the timing, and maybe buy the Retard modules so I can build a curve with the crank trigger

Like you said I can also try raising the PSI in the slicks.

Where can I remove some more weight from the car? its 3,145 w/o me in it I know the first step is to probably not go to the track with a full tank of gas haha thats a start. I still need to install a roll cage, and that weight, even with chromoly will probably bring me to a hefty 3,200lbs

Thanks for all your time and knowledge - Steve

GIZMO

iTrader: (8)

1. If you are not already running synthetic oil, that would be worth quite a bit. The 0-20 mobile one works pretty well. Run four quarts.
2. Note that racing gas is not all about octane. You might want to try some VP C-11 or Torco 110. Both work very well.
3. The timing curve makes a bunch of difference. I think that your best bet is to buy a DFI (or similar). That way you can keep your crank trigger and have a programmable ignition. I can probably get you a used set-up for a good price. Note that LT1's love a lot of timing on the bottom end (even with the stock cam).
4. If you can't hook at 16 psi there is either something way off in your suspension or the tack is really bad.
5. The roll bar might actually help the car if it is installed properly.
6. My Camaro weighs approx. 2900 lbs empty. That's with both factory seats, all OEM interior trim (including the dash and headliner), rollbar, and an OEM SS hood. To get the weight down you pretty much have to grenade the whole car and then only put back what you need.

Daren

z28boysteve

iTrader: (9)

wow Im not exactly all about taking my whole car apart for weight savings lol..

But wideband tuning, the C11, the DFI, more tire pressure, setting the timing and a real timing curve, and synthetic oil all sound like they would make me pick up quite a bit,

does 4 qts include filling the filter?
how do you make the DFI work out a timing curve with crank trigger?

GIZMO

iTrader: (8)

You can fill a pick-up bed with all of the stuff that you don't need. If you do it right no one will ever know that you took the car apart!
Four quarts includes the filter. Don't worry, If you are using good quality light weight synthetic oil, you won't have an issue with starvation. I have all of the center oil returns plugged to stop oil hitting the cam, etc.
The crank trigger replaces the optical sensor on the opti-spark. The map is programmable for rpm and throttle position. The only thing that you have to do is to find TDC and use a timing light to verify that your crank trigger is positioned correctly.

Take Care,

Daren

z28boysteve

iTrader: (9)

Thanks again daren!