I am thinking of a little squeeze on my car. I can borrow my friends NX systems wet, single nozzle system.

motor:
12.5 JE's, eagle h-beams, sleeved 84mm

What safety precautions do i need to take?
Whats the largest shot safe on that setup with stock fuel pump, 310cc injetors?

tia

 

I wouldnt go more than 65 on the stock fuel pump. Also when you run nitrous get some colder plugs and retard the timing.

 

bump for this guy... i have a similar setup

 

thats some pretty high compression, i dont know how big of a shot you wanna go with that.

 

A friend of mine had a ls motor built with eagle rods, srp pistons at about 11.5:1 compression. He ran a 125 shot, BUT had an upgraded fuel pump and it was a direct port kit.

I had a low compression built motor i ran a 200 shot direct port setup on..

In your case, I would keep it round 50 and work your way up slowly. Check plugs after every run and don't tune below 1/2 full tank of the juice.

 

why didn't you up grade fuel pump when you got the rc's

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by t04ecvc &raquo;</TD></TR><TR><TD CLASS="quote">
I had a low compression built motor i ran a 200 shot direct port setup on..
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200 shot??

what 1/4mile times were you running?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b18c-93 &raquo;</TD></TR><TR><TD CLASS="quote">why didn't you up grade fuel pump when you got the rc's</TD></TR></TABLE>

stock dohc pump is fine for a pretty much all motor can make..pretty mcuh.

so if i upgrade fuel system and use a single fogger, only a 65 shot? i was hgoping for more.

 

get boost

 

wont work with 12.5:1

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2dark2bslow &raquo;</TD></TR><TR><TD CLASS="quote">wont work with 12.5:1 </TD></TR></TABLE>

Sure it will, you just have to tune well, lots of fuel, not too much timing. You will make massive power...

Just a quick explanation for the reason why this is true:

There are TWO kinds of compression. There is what is called static compression, and then there is what is called dynamic compression. The static compression is the number we always here about, ie 9:1, 10:1, or in this case, 12.5:1.

Now, the dynamic compression is the "effective" compression, and it describes how the motor 'sees' the air inside and what is happening with it, when it is actually running. The dynamic compression depends on the efficiency of the motor's head, intake system, and it's ability to charge the cylindar with air. Lets say your IM is resonance tuned for a specific rpm, sort of a 'mini turbocharger effect.' At this point, the dynamic compression is higher than 12.5:1, because the air is being forced in the cylinder under pressure.

If you take two different motors, lets say one with 8.5:1 compression, and one with 12:1 compression, and turbo them both... And say, your goal is to get 300hp even out of each motor at a specific rpm, lets say, 6000rpm's.

Obviously, these two motors are going to take different amounts of boost to reach the goal of 300hp @ 6000rpms, namely, the low compression motor will take more. This is because of the lower static compression.

When you acheive your goal, and lets say boost 15psi on the 8.5:1 motor, and it makes 300hp @ 6000, and you boost 10psi on the 12:1 motor, and it also makes your goal of 300hp @ 6000rpms. When the power is equal, your DYNAMIC compression is equal, IE the required level of boost + the static compression add up together to give BOTH MOTORS exactly the same dynamic compression, hence they both make the same power at that rpm. In a boosted motor, the dynamic compression is much higher than the static compression anytime the motor is under boost.

Therefore, if you set a reasonable hp goal for yourself, and you get a good tuning ecu, possibly the ems or the like, and a good tuner, you can definately make reliable power. If you make the same peak power as a 9:1 motor, lets say, both 400hp, your car will be much faster. You will have more area under the curve. Your high static compression will promote a better low end and a faster spool, and you will beat the **** out of a low compression motor of the same hp.

Good luck, with whatever you choose in the end, and I hope this shed's some light on the subject.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">200 shot??

what 1/4mile times were you running?

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Never made it to the 1/4. I was always battling issues with the car and never wanted to make the long drive. Best 1/8 was 8.56 @ 94mph with 2.1 60ft.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2dark2bslow &raquo;</TD></TR><TR><TD CLASS="quote">wont work with 12.5:1 </TD></TR></TABLE>

i was talking about boost...i thought high compression loved bottle....i was replying to him.

so what do you think is a resonable limit?