Nitrous question?

[68coronet]

I added a small 125 shot of nitrous. Question on numbers I'm getting. Car is a 68 coronet .030 over 440 ported and polished eddy heads roller valve train, flat top Pistons, 4 sp with 3.91 gear ratio making 425hp and 481 lb ft at the wheels. Added nitrous and getting 465 hp and 599 lb ft at the wheels. I am running atomic efi set up to control timing, separate pump running 6 psi for nitrous. Retarding timing 4 degrees when nos is activated, afr drops to 10.2-1 then comes back to 11.5-1 which is where I read it should be with the nitrous. I am not complaining about the torque numbers just wondering on the hp numbers of I'm missing something? This is my first round with nitrous.

 

[Budnicks]

Not knowing your kit/system details
I'll be just guessing without reading the plugs etc.
I'd probably just be guessing, without seeing & hearing it anyway

I'd say your fuel side of the N20 system is probably too fat

the efi is trying to compensate some maybe too

Rear wheel HP, seems 125hp kit isn't up to that # in crank HP either,
it seems because it wouldn't loose that much in the drive train usually...

are you sure you have the proper N20 & Fuel jets in the N20 system
Is it a plate kit under the TB ?
is it a kit in the intake tube or a dry kit ?
does it have nozzles in the cylinders ?
who's kit is it & what kind of N20 kit ?...

10:1 afr is fat/riche IMO, even 11.5 is fat,
maybe try a little less fuel pressure like 5.5psi

they way over advertise HP ratings allot too,
a slightly bigger N20 jet might work better on that solenoid only @ the same fuel settings,
it may show better #'s don't go too lean thou...

If it was on a chassis dyno,
the operator "should be able to tell you where the problem is"
big time change in Torque #'s that's good, maybe the dyno read out was wrong too...

I'm not going to be held responsible for any damage, just suggestions....LOL

sorry I can't be of more help

 

[ozymaxwedge]

Is it a single plane or dual plane ? single plane will show more power. Lobe separation ? A bit more like 112 will show more power.

- - - Updated - - -

I agree with Budnicks, would say it's too fat.

- - - Updated - - -

One more thing, You say you have it retarding 4deg, What is your total timing ?

 

[68coronet]

It is a N.O.S 125 powershot wet kit. It goes that rich when the nitrous kicks in then leans back out to 11.5 which is where the target afr is set on the atomic efi controller. It is set at 12.5 at wot without nos. total timing is 34 degrees, and the timing is being retarded 4 degrees when nos kicks in, but it says timing might not have to be retarded if racing fuel is used on the fuel side. But the guy at the dyno shop said better safe than sorry. I am using a self contained fuel system for the nos, pressure dead heads at 8 psi and drops to 6.5 when nos is activated. Plugs are good, no carbon, no detonation, just wondering why the nos kicks up the torque so high but not the hp. Not sure on cam specs just that the lift is .598 solid roller. I will look for paperwork tomorrow.

 

[dieseldazzle]

What fuel are you running?

 

[76mopar]

What jets are you running? You are mixing carb setup (Nitrous) and EFi for the motor. Sounds like the EFI might not seeing more/not enough fuel introduced when the nitrous hits. Have you called Holley to discuss this? I would say they have run into this problem before.