Inliners International
Posted By: wdschell Nitrous on My Modded 250? - 08/08/14 11:48 AM
So I have read some posts about turboing, supercharging and nitrous. I dont think i have the skill to install a turbo or a super so that leaves me with nitrous. I also didnt put forged parts in and i know that matters, but I also know you can run low level boost on a stock engine. Just wanted some other opinions.

You guys helped me out a lot when I was doing my build so I figured I would ask the question here

Chevy 250 .040 over
comp cams 260h cam (w/Valve spring kit etc)
Head lump ported, polished
Offy intake
Holley 390
Flowtech Headers (also a turbo problem)
Posted By: CNC-Dude #5585 Re: Nitrous on My Modded 250? - 08/08/14 02:49 PM
You can run lower levels of nitrous with cast pistons with no problem. You generally need to get an upgraded high volume fuel pump, and I don't think anyone makes then for these engines any longer in a mechanical version, so electric may be an alternative.
Posted By: wdschell Re: Nitrous on My Modded 250? - 08/08/14 02:59 PM
What exactly is lower levels? Like 50-75 shot? Thats fine I was probably going to change my fuel pump soon anyway. Also I read that I need to use fogger nozzles since the intake doesnt sit on top of the engine?
Posted By: CNC-Dude #5585 Re: Nitrous on My Modded 250? - 08/08/14 03:26 PM
Yes, a 50-75 HP shot is what I am meaning. I think you will get better fuel and nitrous mixing with a plate though because of the siamese ports configuration having a tendency to have fuel robbing characteristics. I know some race guys that have used fogger nozzles without much issue, but that's just my preference in this case.
Posted By: wdschell Re: Nitrous on My Modded 250? - 08/08/14 05:14 PM
Alright I appreciate the info!!
Posted By: Twisted6 Re: Nitrous on My Modded 250? - 08/08/14 07:54 PM
Ask Mighty6 he used to run nitrous Before he went the turbo route.
I used to run a Cheater NOS system on my 250.
http://www.jegs.com/p/NOS/NOS-Cheater-Ni...CFYZaMgodr1IAKA
Crazy fast I might add, w/the smallest jets the kit came with. crazy
150-175 HP for smallest jets the kit came with.

Minimum cubic inch is supposed to be 350 C.I., I was just shy of 100 C.I..

I just used smaller jets than what the kit came with.

I would not recommend this kit for you especially if you have cast pistons.
Use a dedicated fuel system for your Nitrous.


MBHD
Posted By: wdschell Re: Nitrous on My Modded 250? - 08/09/14 04:04 PM
What was the biggest shot you ran with that kit? What do you mean by dedicated fuel system? Stupid question probably
Posted By: wdschell Re: Nitrous on My Modded 250? - 08/09/14 04:28 PM
Just saw the *not* before recommend. Dang small screen only phone
I used the smallest jets the kit had which was 150-175 HP jets.

Those were too big & the engine detonated like crazy, but it was by far the fastest my Camaro ever felt (even with the detonation). eek

When purging the nitrous before getting ready to use.
The engine would rev so quick when just purging.(150-175 HP jets)
It was like having no fly wheel or torque converter on the engine.

I later down sized the jetting to approx. 75 hp.

A dedicated fuel system, having two fuel lines, one for the engine, one for the Nitrous system.
One fuel pump for the engine, one for the Nitrous system.

Running a small shot of 25-50 or so HP increase, I do not think it is entirely necessary to have a dedicated Nitrous system, but it is safer to run two separate systems.

MBHD
Posted By: wdschell Re: Nitrous on My Modded 250? - 08/09/14 06:02 PM
Ok thanks. I appreciate the info.
© Inliners International Bulletin Board