questions for anyone who knows about nitrous - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MITCH1914 · 09-09-2002, 08:21 AM

i bouught a powershot 125 hp nitrous system this weekend. my engine has hypereutectic 9.75 to 1 pistons. everyone i talked to said that a 125 shot would be safe. got a couple of questins?

can a stock hei support a 125 hit? if not what shoud i do to get a better spark?

what kind of fuel pump do you guys reccomend mechanical or electrical?

i know about retarding the timming, having 5 psi of fuel and dont run lean, and colder plugs what are other ways to protect my engine and make the nitrous work.

thanks

68 with 350 TPI · 09-09-2002, 10:52 AM

Well let me start by saying that you would be better off with forged pistons and a set of good rods with ARP bolts.

But I have ran a 100 shot on a stock engine quite a few times so it can be done. A 125 shot may be pushing it just a bit unless you engine is tuned really good.

You will need to retard the timming 2 deg for every 50 HP increase with a wet shot.(fuel and nitrous solenoids).
You will need to go down 1 heat range for every 50 hp increase.

Only use nitrous at full throttle and dont ever hit a rev limiter with it on!
Never use AV fuel with nitrous!!!
make sure its good auto fuel at least 91-93 octane (whatever is avalible where you live).

You can get a fuel safty cutoff switch for extra safty.
I also think a RPM activated window switch is a good idea to turn it on and off at a pre set RPM.

I use a throttle activated switch so I dont have to worry about holding down a button.
I just open my bottle and arm my system purge and hit the gas

I would run a eletric pump like a holly blue with a regulator if you could as they dont tend to surge as much as some of the mechanical ones.
But some of the better brand mechanical pumps will work fine.

And before you try the kit out make sure the solenoids are working.
DO NOT JUST LISTEN FOR A CLICK!
Take a line loose and test it to see if there is nitrous flow and then do the same for the fuel solenoid.

BTW to get the most out of nitrous you should look into a bottle warmer.
Nitrous works best between 950-1200 PSI to get the most out of a shot and I like mine at 1100PSI.

MITCH1914 · 09-10-2002, 08:16 AM

thanks for the feedback. couple more questions, what timming does a 400 sb usually need for a 100 to 125 shot and can my stock hei ingniton handle as much as 125. if it is not a good idea to stay with the stock ingniton how much is safe on a stock hei and what do you think i should step up to so that it can handle a 100 to 125 shot

also i am thinking about going with an adjustable plate so that i can start out at 50 hp and go up to 125.

thanks

68 with 350 TPI · 09-10-2002, 09:17 AM

well there is not a specific timming to run.
The best thing to do is find where you motor runs the best and then back it off from there.
Just remeber the rule of 2 deg retard for every 50 hp of power adder and also a heat range cooler plug.

A HEI will work but it would be better if you got a MSD 6A or MSD 6AL box to work with it for a little extra spark.

A ajustable plate is a good idea.
Its nice to have various jet sizes to work with and really tune it.

After a run at full throttle with the nitrous go back and pull all the plugs and look for little specks or for them to turn a white color.
If you see any of that back the nitrous down a bit.

If you need any help feel free to email me at Schulzautomotive@Hotmail.com

MITCH1914 · 09-10-2002, 01:07 PM

i appreciate your help. if i have any other questions i will e-mail you

thanks alot

68 with 350 TPI · 09-10-2002, 03:12 PM

sounds good.
Let me know how it goes and if you need help.
L8r.

09-09-2002, 08:21 AM	#1
MITCH1914 Registered User Join Date: Mar 2001 Location: indianapolis,indiana,usa Posts: 506	questions for anyone who knows about nitrous i bouught a powershot 125 hp nitrous system this weekend. my engine has hypereutectic 9.75 to 1 pistons. everyone i talked to said that a 125 shot would be safe. got a couple of questins? can a stock hei support a 125 hit? if not what shoud i do to get a better spark? what kind of fuel pump do you guys reccomend mechanical or electrical? i know about retarding the timming, having 5 psi of fuel and dont run lean, and colder plugs what are other ways to protect my engine and make the nitrous work. thanks

09-09-2002, 10:52 AM	#2
68 with 350 TPI Registered User Join Date: May 2002 Location: Wingate NC Posts: 456	Well let me start by saying that you would be better off with forged pistons and a set of good rods with ARP bolts. But I have ran a 100 shot on a stock engine quite a few times so it can be done. A 125 shot may be pushing it just a bit unless you engine is tuned really good. You will need to retard the timming 2 deg for every 50 HP increase with a wet shot.(fuel and nitrous solenoids). You will need to go down 1 heat range for every 50 hp increase. Only use nitrous at full throttle and dont ever hit a rev limiter with it on! Never use AV fuel with nitrous!!! make sure its good auto fuel at least 91-93 octane (whatever is avalible where you live). You can get a fuel safty cutoff switch for extra safty. I also think a RPM activated window switch is a good idea to turn it on and off at a pre set RPM. I use a throttle activated switch so I dont have to worry about holding down a button. I just open my bottle and arm my system purge and hit the gas I would run a eletric pump like a holly blue with a regulator if you could as they dont tend to surge as much as some of the mechanical ones. But some of the better brand mechanical pumps will work fine. And before you try the kit out make sure the solenoids are working. DO NOT JUST LISTEN FOR A CLICK! Take a line loose and test it to see if there is nitrous flow and then do the same for the fuel solenoid. BTW to get the most out of nitrous you should look into a bottle warmer. Nitrous works best between 950-1200 PSI to get the most out of a shot and I like mine at 1100PSI. __________________ Life is good with a 6-71 supercharged 355 in a 72 camaro

09-10-2002, 09:17 AM	#4
68 with 350 TPI Registered User Join Date: May 2002 Location: Wingate NC Posts: 456	well there is not a specific timming to run. The best thing to do is find where you motor runs the best and then back it off from there. Just remeber the rule of 2 deg retard for every 50 hp of power adder and also a heat range cooler plug. A HEI will work but it would be better if you got a MSD 6A or MSD 6AL box to work with it for a little extra spark. A ajustable plate is a good idea. Its nice to have various jet sizes to work with and really tune it. After a run at full throttle with the nitrous go back and pull all the plugs and look for little specks or for them to turn a white color. If you see any of that back the nitrous down a bit. If you need any help feel free to email me at Schulzautomotive@Hotmail.com __________________ Life is good with a 6-71 supercharged 355 in a 72 camaro

09-10-2002, 01:07 PM	#5
MITCH1914 Registered User Join Date: Mar 2001 Location: indianapolis,indiana,usa Posts: 506	thanks i appreciate your help. if i have any other questions i will e-mail you thanks alot

09-10-2002, 03:12 PM	#6
68 with 350 TPI Registered User Join Date: May 2002 Location: Wingate NC Posts: 456	sounds good. Let me know how it goes and if you need help. L8r. __________________ Life is good with a 6-71 supercharged 355 in a 72 camaro

09-10-2002, 08:16 AM	#3
MITCH1914 Registered User Join Date: Mar 2001 Location: indianapolis,indiana,usa Posts: 506	thanks for the feedback. couple more questions, what timming does a 400 sb usually need for a 100 to 125 shot and can my stock hei ingniton handle as much as 125. if it is not a good idea to stay with the stock ingniton how much is safe on a stock hei and what do you think i should step up to so that it can handle a 100 to 125 shot also i am thinking about going with an adjustable plate so that i can start out at 50 hp and go up to 125. thanks



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