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Author Topic:   Nitrous questions.
JoeD
Journeyman

Posts: 50
From:
Registered: Feb 2003

posted 03-10-2003 12:26 PM     Click Here to See the Profile for JoeD     Edit/Delete Message   Reply w/Quote
I haven't raced yet but I am thinking down the road about nitrous.
My car is a 65 Mustang. 289 with stock/ported heads 1.90 & 1.60. TRW flat-tops. 282S cam. Stock rods with ARP bolts. Stock crank. Performer RPM with Carter 625. Hooker headers through two and one quarter I.D. pipes and glass-packs out the side. 3.89 Detroit Locker. Carb and rear gearing is going to change. I may have a problem with my top-loader as it is close-ratio. I am willing to go to 4.56 gears if it will make the tall first gear be workable. I will use slicks.
Now my nitrous questions. I don't see any sense in having horsepower that only will be used occasionally for racing. Will my engine handle nitrous as it is set-up now? The engine is solid. How much is needed to get my car down around 12 seconds? Is it hard to use with a manual trans.? How do you use it? How much does it cost per run and what systems are any good? How hard is it on the engine if just getting near 12 seconds?
It sure sounds more practical than driving around with 400 plus horsepower, all the time, for no real purpose.
ANY advice is appreciated...pro or con.

Joe

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65_289
Gearhead

Posts: 761
From:
Registered: Jul 2001

posted 03-10-2003 12:44 PM     Click Here to See the Profile for 65_289   Click Here to Email 65_289     Edit/Delete Message   Reply w/Quote
With some sticky tires, a 100 shot should put you well into the 12's. You can probably get away with 93 octane on a 100 shot if you retard the timing properly.

As far as kits, I have heard good things about Edelbrock and Nitrous Express

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rockafellz
Gearhead

Posts: 1426
From: San Lorenzo, CA, USA
Registered: Aug 2001

posted 03-10-2003 12:44 PM     Click Here to See the Profile for rockafellz   Click Here to Email rockafellz     Edit/Delete Message   Reply w/Quote
Good questions!!

Hopefully n2oMike will be replying soon. He has a wealth of knowledge on this subject and isn't afraid to share it.

You may also want to do a search in this forum for "nitrous".

Erik

------------------
1966 Ford Mustang 2+2
Mine - Restomod in Progress

1966 Ford Mustang Coupe
Dad's - Original Unrestored

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Tea'sGrabber
Gearhead

Posts: 276
From: Seattle, Wash.
Registered: Feb 2003

posted 03-10-2003 12:50 PM     Click Here to See the Profile for Tea'sGrabber   Click Here to Email Tea'sGrabber     Edit/Delete Message   Reply w/Quote
Will your motor handle it?? Nitrous won't hurt it as long as you follow the directions!!Carb you have will have to go,Manifold is questionable..You don't mention what you're running for ignition, or fuel system. I ran a 302 for 3 seasons simular to yours that ran 13.60's. 12.20's with 125hp Super Power Shot system. Never hurt anything.Sold the motor to a friend and it still runs mid 13's in a 65 coupe.

------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.

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JoeD
Journeyman

Posts: 50
From:
Registered: Feb 2003

posted 03-10-2003 02:02 PM     Click Here to See the Profile for JoeD     Edit/Delete Message   Reply w/Quote
Guys,

My ignition is a Unilite with a Mallory high output coil. I just installed it but it is okay if it needs to go. I just have a Holley mechanical fuel pump, not anything special.

Joe

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sick66
Journeyman

Posts: 31
From:
Registered: Nov 2002

posted 03-10-2003 03:30 PM     Click Here to See the Profile for sick66   Click Here to Email sick66     Edit/Delete Message   Reply w/Quote
first off, i run a 100 shot from edelbrock...i think this system offers the best of everything......easy set up, nice painted brackets etc.
second i think Tea'sGrabber is wrong about the carb and manifold suggestion....i run a performer rpm intake and an 600 cfm edelbrock performer carb in my 66.
Definately go with a high volume electic fuel pump that is over 7psi or you will have some problems. I went with a holley.
As for gears i don't think you will have to go that high for 12's. i run 13.5-13.2's with a open 2.80. the rear end set up you have sounds solid. before you mess with nitrous race without it first. you set up sound like it can do some damage without it.good luck...you will run into people that think nitrous is not the thing to do but there is no bigger rush then pushin that button.
p.s. can i get dibbs on that third member if you get rid of it?

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Tea'sGrabber
Gearhead

Posts: 276
From: Seattle, Wash.
Registered: Feb 2003

posted 03-10-2003 04:17 PM     Click Here to See the Profile for Tea'sGrabber   Click Here to Email Tea'sGrabber     Edit/Delete Message   Reply w/Quote
My reference to the RPM manifold was that open plenum manifolds don't interfere with the spray bar..... The carter has to go!!!

------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.

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jdsgallops
Gearhead

Posts: 326
From: Naples, FL
Registered: Feb 2001

posted 03-10-2003 04:44 PM     Click Here to See the Profile for jdsgallops   Click Here to Email jdsgallops     Edit/Delete Message   Reply w/Quote
First off keep the gears you have. Nitrous makes your engine rev quicker so you don't need as much gear. Secondly any properly tuned kit will be safe. Edelbrock and NX seem to be the hot ticket right now. Third, All you need to do to use it is put it on your car. When installed you will have an arming switch and a momentary switch. Hit the arming switch and then when you are ready to use the N2O hit activate the momentray switch. Simple as that. From there you just need to hang on. Good luck and have fun.

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 03-11-2003 06:21 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
Before you start, make sure to have a bottle heater and pressure
gauge, along with a fuel pressure gauge and regulator for the nitrous
enrichment. A good ignition system is also mandatory... one that
doesn't keep advancing the timing to the moon as the engine revs.
It should STOP at around 36 degrees total. (with the nitrous off)
Check it!!!!!! Wild advance KILLS nitroused engines...
Factory distributors are really bad about this.

Mostly geared to a carb system, but applies to all.... Here Goes!!!

------------------------------------------------------------------------------

Now that we've got the juice, how do we have fun with it?

Well first off, you don't want to get anxious and hurt your
engine... Once the system is properly installed, check to
be sure its fuel enrichment is working properly. Turn the
nitrous bottle off, arm the system, and with the revs around
3000 rpm, tap the button. The engine should fall on it's
face. It should be about like hitting a kill button.

Now that we know it works (the engine is getting enrichment fuel).
Let's see what other items are necessary...

-COLDER spark plugs! Do NOT use Split Fires! For the street,
use the coldest non racing plug you can find... especially
if you might have to use the system with pump gas.

-A bottle heater and pressure gauge! You MUST know what your
bottle pressure is to get consistent results! The gauge tells
you the pressure, the heater allows you to control it. Keep it
around 900 psi for best performance.

-Fuel... Use the BEST you can find! Detonation on nitrous can
lead to some VERY un-pretty things! Straight pump gas should
not be used on systems over 125hp on a 302. These engines with
their 10 7/16" head bolts are prime game for blown head gaskets
if everything isn't right. A little detonation goes a loong way
on these motors...

Make sure you have a good ignition system with good wires.

**** Now that you are set up, how is it tuned???????? ****

First is timing. The timing NEEDS to be retarded about 3
degrees for every 50hp of nitrous boost. If you don't, it's
bye-bye head gaskets, or worse! You need to go with the upper
end of this scale when pump gas is used (even if you add octane
booster). Just DO IT!!!!! I use MSD's Multi-Step Retard to
do this automatically anytime the nitrous is engaged.
If you are in the market for an ignition system, The MSD Digital 6 Plus
costs $279, has a timing retard, a two step rev limiter, plus
is adjusted by little dials. (instead of chips)

******** FUEL SYSTEM ********

To start, make SURE your fuel system is able to maintain
full fuel pressure at full throttle high rpm with the
nitrous engaged! It's better to be safe than sorry here.
I've seen cars break into the 10's with a single Mallory
140 or Holley Blue pump, but wouldn't really recommend it.
I use two Mallory 140's on my car. One for the engine, the
other for the nitrous.

******** FUEL PRESSURE ********

If the fuel pressure is too high, the car will exhale a bunch
of black smoke out the exhaust, and will not run anywhere near
its potential. It will feel very lazy (well, for nitrous).
We want to lean it out, just not toooo far.
My buddy's 2V 351C Mach I went from 9.00 to 8.50 in the 1/8,
just from lowering the fuel pressure!

Start with the smallest hp jets, with the fuel pressure turned
up extra high. This will ensure an extra margin of safety.
With the tranny in neutral (park), bring the revs up to 3000
and tap the button. The revs should jump up a bit. Probably
not super crisp or fast... just kind of a 'VROOOOM'. Do this
with the bottle pressure at its operating range. (850-950 psi)

If it hits EXTRA hard, like BAM! You are probably a bit lean,
and need to increase the fuel pressure.

We can now start to decrease the fuel pressure....
Do this with the car in neutral. Starting with the pressure
high, we are going to be tapping the button at 3000 rpm as we
gradually decrease the fuel pressure.

As the fuel pressure is lowered, the engine will start to respond with
increasing aggressiveness. The VROOOOOM will start to turn into
a BANG! When it BEGINS to get pretty crisp, it's time for a road test!

At full throttle around 3500 rpm, hit the button and hold it
for 3-4 seconds. The car should respond in a positive manner. :-)
As you let off the button, kill the engine, coast to a stop,
and check the plugs. They should look clean, but have NO specks
on the porcelain. If they do, it's aluminum from the pistons,
and the fuel pressure needs to be increased. Chances are, at
this point it will still be a little rich, and you will find no specks.

Decrease the fuel pressure a little at a time while making the
above test. As soon as you begin to see ANY specks on the plugs,
raise the fuel pressure a half pound or so, and you should be
close to optimum for that hp level. If you want to try other
jets, you need to go through this same testing procedure again.
Start rich, and work your way down.

You will be **AMAZED** at how much better a nitrous system works
once the fuel pressure has been optimized!

**** Other things that help optimize a nitrous equipped car ****

- A good exhaust. BIGGER is BETTER! 3" pipe and mandrel
bends rule in nitrous applications!

- Proper camshaft. A lobe separation around 110 deg is a
good compromise on a carbed street engine.
Some extra exhaust duration is also a plus.
8-12 extra degrees is good. To maximize
nitrous performance, go to 112. 114 on an
EFI car.

- Compression. Low compression makes tuning a lot more
forgiving. Make the same mistake with both
a high and low compression engine, and your
chances of living through it are MUCH better
with the lower compression.

If an engine is a little low on compression
anyway, (5.0 with a cam for example) nitrous
can bring in a SERIOUS wake-up call!


Good Luck, and HAVE FUN!!!!!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

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Red65
Gearhead

Posts: 115
From: Northglenn, CO, USA
Registered: Jul 2002

posted 03-11-2003 07:11 PM     Click Here to See the Profile for Red65   Click Here to Email Red65     Edit/Delete Message   Reply w/Quote
The mention of the bottle heater reminds me of a website I saw a couple years ago. This guy's bottle heater malfunctioned, and turned his NOS bottle into a trunk bomb!


http://www.enhancedhealth.com/NOS2.htm

------------------
'65 Fastback

[This message has been edited by Red65 (edited 03-11-2003).]

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JoeD1860
Journeyman

Posts: 48
From: Arizona
Registered: Mar 2003

posted 03-11-2003 09:27 PM     Click Here to See the Profile for JoeD1860     Edit/Delete Message   Reply w/Quote
Mike,

Wiyh a 100 HP shot, what is the cost per race?
Do you use the nitrous all the way down the strip from start to finish?

Joe

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 03-11-2003 10:49 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
Nitrous bottles have safety valves that 'blow' at 3000psi. I believe I read that fellow stacked TWO of the blow-off disks on top of one another, and THEN left his heater on... with an overfilled bottle. It's hard to say what psi the sucker reached!

Some folks are just plum ate up with dumbass!

Set on 100hp, you'll get around 100 seconds worth of 'fun' out of a bottle.

Yes, I engage the nitrous at the starting line. It makes the 60fts drop from from mid 1'6's off the bottle, to a best of 1.43 on it!

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

[This message has been edited by n2oMike (edited 03-11-2003).]

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65_289
Gearhead

Posts: 761
From:
Registered: Jul 2001

posted 03-11-2003 10:53 PM     Click Here to See the Profile for 65_289   Click Here to Email 65_289     Edit/Delete Message   Reply w/Quote
So are you bouncing off the rev limiter with the nitrous on? Does that hurt the engine?

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 03-11-2003 11:31 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by 65_289:
So are you bouncing off the rev limiter with the nitrous on? Does that hurt the engine?

The nitrous is hooked up so it can be activated by either a throttle switch, or a button on the shifter. At the track, I use the throttle switch... so anytime the throttle hits the floor, the nitrous is activated!

When getting ready to launch, I'll bring the engine up on the 2-step around 6000 rpm at 3/4 throttle. (nitrous not on) When the light turns green, the clutch is released and the throttle gets buried. (nitrous turns on) After that, sh*t happens pretty quick! So the answer is, no, I don't have the nitrous activated with the car on the rev-limiter getting ready to take off.

But, from experience on the street with radials... (often go up in smoke, and let the engine free-rev on the bottle) Hitting the rev-limiter with the nitrous on can result in some MAJOR backfires! BAAAM! These are muffler busting SOB's! I blew apart two perfectly good stainless steel Edelbrock mufflers once like that. (these were the RPM mufflers that weren't fully welded. They were replaced with the fully welded 'race' series #5525, and no problems since) Of course there haven't been any major backfires since, either.

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

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JoeD1860
Journeyman

Posts: 48
From: Arizona
Registered: Mar 2003

posted 03-12-2003 10:29 AM     Click Here to See the Profile for JoeD1860     Edit/Delete Message   Reply w/Quote
Mike and friends,

That answers most of my questions and gives me a good idea of the nitrous "game."
I think it is a good way to go for what I plan on doing...AFTER I get some racing experience.

Joe

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Tea'sGrabber
Gearhead

Posts: 276
From: Seattle, Wash.
Registered: Feb 2003

posted 03-12-2003 10:57 AM     Click Here to See the Profile for Tea'sGrabber   Click Here to Email Tea'sGrabber     Edit/Delete Message   Reply w/Quote
n2o's reply is right on the money..... Nitrous is a great horespower enhancer, if used properly. Getting some seat of the pants experience @ the race track is a good idea!!!!! But there's no reason you can't install a kit and start playing with it... It takes a while to get use to it. I started off just using in 3rd gear as a top end charge. Tried different activation methods just to see what I like. GO RACE!!!!!!

------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.

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65_289
Gearhead

Posts: 761
From:
Registered: Jul 2001

posted 03-12-2003 02:12 PM     Click Here to See the Profile for 65_289   Click Here to Email 65_289     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by n2oMike:
But, from experience on the street with radials... (often go up in smoke, and let the engine free-rev on the bottle) Hitting the rev-limiter with the nitrous on can result in some MAJOR backfires! [b]BAAAM! These are muffler busting SOB's! I blew apart two perfectly good stainless steel Edelbrock mufflers once like that. (these were the RPM mufflers that weren't fully welded. They were replaced with the fully welded 'race' series #5525, and no problems since) Of course there haven't been any major backfires since, either.

Good Luck!

[/B]


I've heard about nitrous backfires. Scary stuff.

What about setting your rev limiter at say 6000, and setting the nitrous on a window switch to come on at 6200? That way, you could launch with the throttle buried, and not have to worry about the accelerator pump setup, and not worry about a nitrous backfire? The time it takes for the engine to go up 200 rpm would probably be no more than it takes to go WOT from 3/4, right?

[This message has been edited by 65_289 (edited 03-12-2003).]

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 03-12-2003 07:07 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
The engine falls below 6k rpm on the shifts... so the nitrous would turn off. WE CAN'T HAVE THAT!

I've got a way using two different relays to launch 100% wide open if I want.

It works fine for the time being.

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

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65_289
Gearhead

Posts: 761
From:
Registered: Jul 2001

posted 03-12-2003 08:25 PM     Click Here to See the Profile for 65_289   Click Here to Email 65_289     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by n2oMike:
The engine falls below 6k rpm on the shifts... so the nitrous would turn off. WE CAN'T HAVE THAT!

I've got a way using two different relays to launch 100% wide open if I want.

It works fine for the time being.


That's a good point. I forgot about the rpm drop on shifting.

But if you were running a slush box that launched at say 3000, then a 3200 window switch would be ok, since you never drop below that in a run. Right? Off-base?

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 03-12-2003 09:27 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by 65_289:
That's a good point. I forgot about the rpm drop on shifting.

But if you were running a slush box that launched at say 3000, then a 3200 window switch would be ok, since you never drop below that in a run. Right? Off-base?


Sure

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

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