i’m going to install a nitrous plate on my 340 duster going to hit it with 100 shot my rings are gapped at 0.020 top and 0.018 second car ran a best of 11.8 seconds at 113 in the 1/4 first question do you think the ring gap is OK for 100 shot? Second question how many tents will I shave?
nitrous
- Thread starter F21
- Start date
-
Maybe @Jeremiah (jd) can help answer that
33IMP
Well-Known Member
This comment is pure guesswork, and makes lots of assumptions!
I think you should be okay with a hundred shot. I hope you have forged pistons, I consider them mandatory for squeeze.
If your weight with driver is around 3500 lbs, Wallace says you have around 415-420 horsepower. ASSUMING you hit the nitrous off the line, and assuming it will hook in that case, THEORETICALLY 11.ohs are possible
I think that is optimistic.
Frankly, I'd hit the juice in second and third only, and hope for/expect 11.40-11.50.
My opinion only.
I have seen one second plus from a hundred shot on a car that was built from ground up to use nitrous.
I think you should be okay with a hundred shot. I hope you have forged pistons, I consider them mandatory for squeeze.
If your weight with driver is around 3500 lbs, Wallace says you have around 415-420 horsepower. ASSUMING you hit the nitrous off the line, and assuming it will hook in that case, THEORETICALLY 11.ohs are possible
I think that is optimistic.
Frankly, I'd hit the juice in second and third only, and hope for/expect 11.40-11.50.
My opinion only.
I have seen one second plus from a hundred shot on a car that was built from ground up to use nitrous.
Number one I don't think I would do a full pull with that ring Gap. Heat continues to build the longer the system is engaged. I would think with a third fourth gear or second third if you have an automatic would probably be fine. And I would expect three to four tenths off your time.jmo
That's not so wide at .005-.007 an inch per bore.
Ring gaps variance, so close together (.005 or less) will not make much difference in overall output.
IIRC there was a test where an engine (450hp) had around .030, tightened up the gaps to .018. Engine made about 7 more HP. That's on a delta of .012 gap, 60-70% more spacing than the .018. .004 is going to be 2-3 at best.
JMO, wider is better, safer and allows for other stuff to be stacked on an engine. Give up 5-8hp for an extra 100+, all day,every day!
Class racing where every .0001 matters, do it different. Same as people that complain about putting 3-5# of wire in a car to be exponentially safer... but 5#... OK
Gap the second ring wider...
For the OP, depends on the piston. I'll guess not hypers as the recommended top gap is short of recommended on street/NA (.026 @ 4.04) Hypers, maybe ok, maybe not. Hypers would want in the .028-.034 area IIRC
IIRC there was a test where an engine (450hp) had around .030, tightened up the gaps to .018. Engine made about 7 more HP. That's on a delta of .012 gap, 60-70% more spacing than the .018. .004 is going to be 2-3 at best.
JMO, wider is better, safer and allows for other stuff to be stacked on an engine. Give up 5-8hp for an extra 100+, all day,every day!
Class racing where every .0001 matters, do it different. Same as people that complain about putting 3-5# of wire in a car to be exponentially safer... but 5#... OK
Gap the second ring wider...
For the OP, depends on the piston. I'll guess not hypers as the recommended top gap is short of recommended on street/NA (.026 @ 4.04) Hypers, maybe ok, maybe not. Hypers would want in the .028-.034 area IIRC
Last edited:
TT5.9mag
Two atmospheres are better than one
I’ve seen 100 shots blow up engines. I’ve also seen engines with 100 shots last years and lots of passes. Your ring gap is tight but with a good tune up can live a long damn time. Start conservative on timing and make sure fuel pressure is rock solid ALWAYS and you won’t have a problem. Read plugs. Always read plugs. Start by pulling 2-3 degrees of total timing out and look at the ground strap. You may find that you can run the same timing as NA if you have low static compression. But pull it out to start and read plugs. Have I said read plugs enough yet?
33IMP
Well-Known Member
And pay attention to your gear ratio.
If you're geared properly for the mph you have now, you might find too much rpm at the finish line with a nitrous shot.
Especially if you use it in 2nd and 3rd, the mph increase will be more dramatic that the ET improvement.
If you're geared properly for the mph you have now, you might find too much rpm at the finish line with a nitrous shot.
Especially if you use it in 2nd and 3rd, the mph increase will be more dramatic that the ET improvement.
OK, so going to give a little bit more info might be better help
1973 Plymouth duster if I remember correctly, 2250lbs with me in it
340 stock stroke rods are fitted with ARP bolts 30 over forged icon pistons
Brox B1 cylinder heads air gap intake 750 carb can’t remember the jetting
727 Trans 3200 stall need more stall eventually manual valve, buddy
8 3/4 391 gear 28 inch tire hi Flo edelbrock electric fuel pump an-8 to regulator -6 to bowls Car made 335 whp on the Dino with 32° of total I did have total timing set at 35° but picked up more horsepower when I dialed it to 32°
1973 Plymouth duster if I remember correctly, 2250lbs with me in it
340 stock stroke rods are fitted with ARP bolts 30 over forged icon pistons
Brox B1 cylinder heads air gap intake 750 carb can’t remember the jetting
727 Trans 3200 stall need more stall eventually manual valve, buddy
8 3/4 391 gear 28 inch tire hi Flo edelbrock electric fuel pump an-8 to regulator -6 to bowls Car made 335 whp on the Dino with 32° of total I did have total timing set at 35° but picked up more horsepower when I dialed it to 32°
That's tight.
I wouldn't spray it with ring gaps that tight.
Make sure it isn't lean and send it. Set the timing to 30 degrees and let her rip.
Jeremiah (jd)
Well-Known Member
Only direct experience should be considered when making your decision.
With an efficient closed chamber head like you have I'd pull 4 deg of timing to start. You'll likely end up pulling 2 deg once it's dialed in. I'd run a 7 or 8 heat range NGK non projected tip spark plug with 110 or 112 octane leaded Sunoco. 116 is overkill but that would suffice. Definitely use a WOT switch as well as a RPM window switch for safety. Flowimg fuel pressure w/ a .073 jet should be 5.5psi, bottle pressure 950ish (925-975)
I'dl ike to see the ringsa few thou looser. That said I sprayed my 4.375 bore/.024 gap 451 with a 175 shot on 110 Sunoco with heat range 7 plugs without issue. Make some 330 or 660 ft pulls and check everything before making a 1/4 mile hit.
With an efficient closed chamber head like you have I'd pull 4 deg of timing to start. You'll likely end up pulling 2 deg once it's dialed in. I'd run a 7 or 8 heat range NGK non projected tip spark plug with 110 or 112 octane leaded Sunoco. 116 is overkill but that would suffice. Definitely use a WOT switch as well as a RPM window switch for safety. Flowimg fuel pressure w/ a .073 jet should be 5.5psi, bottle pressure 950ish (925-975)
I'dl ike to see the ringsa few thou looser. That said I sprayed my 4.375 bore/.024 gap 451 with a 175 shot on 110 Sunoco with heat range 7 plugs without issue. Make some 330 or 660 ft pulls and check everything before making a 1/4 mile hit.
I was going to run 30° of timing to start
I am already running the NGKV power 8 and I run 30% 110 and 70% 93 octane also I am going to use a wide-open throttle switch with the progressive controller so will be introduced slowly my current fuel pressure is seven psi in the AFR is 11.9
I am already running the NGKV power 8 and I run 30% 110 and 70% 93 octane also I am going to use a wide-open throttle switch with the progressive controller so will be introduced slowly my current fuel pressure is seven psi in the AFR is 11.9
weedburner
Well-Known Member
Is that valve facing the rear of the car?
For those that don't know, from the factory the bottles typically have the dip tube intake in the bottom corner of the bottle, clocked in the same direction as the bottle discharge (opposite side from the label).
To make sure horizontal bottles discharge liquid as long as possible, mount them with valve in front. Also with the bottle discharge pointing down, which puts the dip tube feeding from the lowest/rearmost location possible. I have a couple bottles that I have replaced the valve in, the label doesn't always land in the same place when you replace a valve. With those, I always make sure the dip tube faces the same side as the discharge when I put it together, that way I know where it's at with the bottle assembled.
Grant
TT5.9mag
Two atmospheres are better than one
TT5.9mag
Two atmospheres are better than one
You should probably put a regulator on the nitrous’ fuel side. If not you need to jet the fuel side down from most of the charts. They’re built for 5.5psi of FLOWING (that’s very important) fuel pressure.
-
Similar threads
- Locked
