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Author Topic:   nitrous
streetstang67
Gearhead

Posts: 305
From: SC, USA
Registered: Nov 2002

posted 01-01-2003 01:49 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
How much nitrous can an internally stock 289 (bored .030 over) handle? I've heard things about 302's being stronger and that some 5.0's came stock with forged pistons and crank....so where does that leave the early 289? How stong of a motor is it? and what can it handle?

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n2oMike
Gearhead

Posts: 1547
From: Spencer, WV
Registered: Jan 2001

posted 01-01-2003 03:30 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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streetstang67
Gearhead

Posts: 305
From: SC, USA
Registered: Nov 2002

posted 01-01-2003 03:36 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
Sounds like a lot of things could go wrong if it isn't set up perfect...I was thinking about one of the Edelbrock kits. But still, what "shot" can my motor handle? 50hp,75hp,100hp,125hp.....?

Thanks a lot

[This message has been edited by streetstang67 (edited 01-01-2003).]

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itlbrnmoff
Gearhead

Posts: 746
From: Indianapolis,IN.USA
Registered: Nov 2002

posted 01-01-2003 09:17 PM     Click Here to See the Profile for itlbrnmoff   Click Here to Email itlbrnmoff     Edit/Delete Message   Reply w/Quote
Damn Mike...I haven't considered nitrous on any backyard bomb that I have, but I was really impressed with your knowledge on the subject...
If I ever build a SERIOUS engine, I would'nt be afraid to try it though, based on what I've just read here.It's good to have access to information that one might not have been looking for...so...I want to say Thanks also...

------------------
Mustang Lover...
Blue Oval Bleeder...
I've got the scars to prove it...
Society's whipping post...
Low Dollar 1983 Mustang GT W/T-tops...
306 4bbl. T-5 3.45 trac-loc...it'll burn 'em off
1988 Lincoln LSC
5.0 auto full power

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streetstang67
Gearhead

Posts: 305
From: SC, USA
Registered: Nov 2002

posted 01-03-2003 10:26 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
After reading "Fastymz" post about low 14's, and 75 shot is ok on an older motor....Then what would be good on my motor that has less than 3,000 miles on it?

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n2oMike
Gearhead

Posts: 1547
From: Spencer, WV
Registered: Jan 2001

posted 01-03-2003 11:46 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
The weak link with 289/302's is the fact that they only have 10 measly 7/16" head bolts.

351W's have 10 beefy 1/2" bolts, so they hold very tightly. SBC's have seventeen 7/16" bolts.

If you plan on very much nitrous at all, you'll need to be sure the engine has top quality gaskets and ARP bolts or studs. It will also need to have good fuel and the timing will have to be kept in check, or you'll be changing head gaskets.

To be safe, I wouldn't be using more than 100hp without all the above. Any above that, and you'd better have race gas in the tank as well.

Many people get away with more, but their systems are running extra rich and aren't tuned to make max power.

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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2BAD6568s
Gearhead

Posts: 109
From: South Point, Ohio, USA
Registered: Feb 2002

posted 01-04-2003 10:03 AM     Click Here to See the Profile for 2BAD6568s   Click Here to Email 2BAD6568s     Edit/Delete Message   Reply w/Quote
What fuel pump and regulator would you suggest? I am buying the 6 plus ignition, so should I buy a msd billet dist? I am only 15 and my dad knows a lot about cars but nothing about nitrous. My motor is still in the machine shop but here is what I have. Its a 65 289 40 over with a factory crank, eagle i beam rods, bullet camshaft with 280/290 duration with .510 lift. trw forged flattop pistons, Ford gt40y aluminum heads with arp head studs, and a ford motorsport billet main stud girdle. the intake is an old style torker with a 600 dp. How much spray can my motor take and what system would you suggest?

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n2oMike
Gearhead

Posts: 1547
From: Spencer, WV
Registered: Jan 2001

posted 01-04-2003 01:33 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by 2BAD6568s:
What fuel pump and regulator would you suggest? I am buying the 6 plus ignition, so should I buy a msd billet dist? I am only 15 and my dad knows a lot about cars but nothing about nitrous. My motor is still in the machine shop but here is what I have. Its a 65 289 40 over with a factory crank, eagle i beam rods, bullet camshaft with 280/290 duration with .510 lift. trw forged flattop pistons, Ford gt40y aluminum heads with arp head studs, and a ford motorsport billet main stud girdle. the intake is an old style torker with a 600 dp. How much spray can my motor take and what system would you suggest?

The safest bet is to use two pumps. A high performance mechanical can be used to feed the engine, then an electric one can be used for the nitrous enrichment. I like the Mallory 140, but it's fairly expensive now. A holley blue should also work.

The billet distributer is an EXCELLENT investment. It will keep that wild advance under control. It comes with really heavy springs installed from the factory, so those will have to be changed to the lighter one for about any application.

I like the new Edelbrock kits. They are very good quality. 100hp is a good limit to stick with. That 100hp will feel really strong. You won't feel that much difference stepping it up to 150 from there. Don't forget to pull 3 degrees out for every 50hp. You'll want to start around 36 degrees total (with the engine revved up) then retard it to 30 with a 100hp shot.

Nitrous follows the rule of diminishing returns... You get a LOT more out of that first 100hp than the next 100. Don't get greedy... unless you enjoy changing head gaskets.

When using an electric fuel pump for the nitrous enrichment, it's a good idea to wire it up to the 'arming' switch. This way, anytime the system is armed, the fuel pump gets turned on automatically. (forgetting to turn the pump on is a bad thing.

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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streetstang67
Gearhead

Posts: 305
From: SC, USA
Registered: Nov 2002

posted 01-05-2003 02:23 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
I'm not wanting to run my car with a 250 shot of nitrous or anything near that big, I just want a little boost of power every once in a while. Without getting a better fuel pump and ignition system(is there a way to change my stock ignition where it doesn't keep advancing the timing?) and all that stuff, would 50,75,or 100 be best. Of course I know that a 50 shot would cause less wear or damage than a 100 shot, but with mostly stock components, what could SAFELY be put to this engine? Eventually, I'll add an ignition box with a rev limiter and mabye even a high flow fuel pump, but as of right now, what could be put to the engine with no extra wear or damage...remember, I want this engine to last. You seem to know a lot about nitrous and everything to do with it. Thanks a lot for your help, you have given me much helpful advice!

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n2oMike
Gearhead

Posts: 1547
From: Spencer, WV
Registered: Jan 2001

posted 01-05-2003 03:16 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by streetstang67:
Without getting a better fuel pump and ignition system(is there a way to change my stock ignition where it doesn't keep advancing the timing?) and all that stuff, would 50,75,or 100 be best.

You can take the distributer apart and make a 'stop' that will keep it from advancing past a certain point, but a MSD distributer @ around $160 is a really good buy. A good fuel system is a good investment as well. Messing with the stock unit involves a lot of trial and error...

I would recommend using your nitrous money to buy these items, get the engine tuned in and running well... then invest in a nitrous system. Haste makes waste. Do it right the first time, or you'll just end up having to do it again.

You might get by with a 50-75hp shot as it sits (except for at least a high performance fuel pump teed off to the nitrous solonoid) but my advice is to wait and do it right. You NEED to be able to control the fuel pressure and timing. If you do go forward anyway, be sure to retard the timing by turning the distributer before any nitrous blasts.

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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streetstang67
Gearhead

Posts: 305
From: SC, USA
Registered: Nov 2002

posted 01-06-2003 04:07 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
What fuel pump do you suggest? My engine is already tuned. Also, If I got the MSD distributor, and a pertronix or something like that, is that all I need?

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