Which plug for N/A dyno pulls

[lekid]

My engine always sees nitrous on every pass at the track.

We are getting ready to head to the engine dyno to break the engine in and make a few pulls N/A (I don't spray nitrous on the dyno).

I run an NGK -10 plug with my 350-400hp jets. I obviously do not want to run those plugs on the dyno. Last time on the dyno, I run NGK -7 (non-projected cause I can't run projected with my pistons) since I had a set at the shop. I need to buy some this time and wondering is -7 is still the proper choice or if I should go to -8?

Engine is SBC 400ci 23deg heads 13.0:1cr with a big nitrous cam and a 4150 carb.

[In-Tech]

The engine dyno is much more forgiving than the track although you can still hit preignition on the dyno with too hot a plug. You haven't stated the NA hp level. Also, why not use the nitrous on the dyno?

[lekid]

Around 700hp (at least that is what we made last time and hoping for a little more).

We don't use nitrous on the dyno because we found out from previous nitrous dyno sessions that a tune on the engine dyno with nitrous does not translate to a proper tune at the track. Same with the chassis dyno. We have a few engines/cars from friend and I where we have tests that prove to us that it was useless to dyno on nitrous.

Also, Steve Johnson from Induction Solutions (who we pretty much all use) has always told us to get the motor happy on the dyno N/A and keep the nitrous for the track, and it would be foolish to not listen to him in our opinion.

It has worked for us (5-6 guys) to do it that way: Engine and/or Chassis Dyno the engine N/A and only run the nitrous at the track and our tunes have been pretty close to perfect from the get-go with Steve's numbers when flowing our systems.

[Tuner]

NGK # 9 heat range

[Walter R. Malik]

I have seen different type spark plugs, ( extended reach - short reach - cut back, half gap - fine wire - surface gap - multiple electrode, etc.), even of the same brand and heat range, exhibit differences in the character of how the engine runs and the power output.

[GARY C]

My engine always sees nitrous on every pass at the track.

We are getting ready to head to the engine dyno to break the engine in and make a few pulls N/A (I don't spray nitrous on the dyno).

I run an NGK -10 plug with my 350-400hp jets. I obviously do not want to run those plugs on the dyno. Last time on the dyno, I run NGK -7 (non-projected cause I can't run projected with my pistons) since I had a set at the shop. I need to buy some this time and wondering is -7 is still the proper choice or if I should go to -8?

Engine is SBC 400ci 23deg heads 13.0:1cr with a big nitrous cam and a 4150 carb.

I had a similar 377 build, we ran -8 straight motor and -9 on nitrous 300hp. Engine ran on C12 and separate cell with C16 for nitrous.

Same on a 357 with Phillips B33 fuel for both engine and nitrous.

[lekid]

We run Renegade Pro120 Nitrous for both motor & nitrous. Probably gonna dyno on 110 or 112 since I only have 3-4 gallons of Pro120N left and no orders are placed until May around here.

[GARY C]

We run Renegade Pro120 Nitrous for both motor & nitrous. Probably gonna dyno on 110 or 112 since I only have 3-4 gallons of Pro120N left and no orders are placed until May around here.

I would think the 112 with a 7 or 8 should be fine NA.

[steve316]

With tuner on #9 ngk it is what I use

[F-BIRD'88]

You can probably use the -9 plugs for both N/A and nitrous.
It is cold enough for nitrous.. A plug that is too cold is more pain than gain.
Dial in the gap and ground strap shape/length.

[MELWAY]

Care to discuss how the nitrous tune up changed from dyno to racetrack?

I would of thought it would be safer to rough in and collect data on nitrous tune up on dyno. Than burn it down on racetrack

[lekid]

The air/fuel and timing was completely different.

Steve believes that the rate of acceleration going down the track through the gears is different than a constant rate of acceleration on the dyno. Since our nitrous system works with pressures (fuel and nitrous), the nitrous/fuel flows at a steady pace regardless what the engine rpm is, and the rate of those rpm climbing will be different on a dyno vs the track, and that will have a direct affect on the timing for that given tune-up, therefore the tune-up will be different.

I have not seen the need to tune the nitrous system on the dyno. If your motor is where it should be for fuel and timing, you should be able to get a baseline that is pretty close when using a system that was flowed.

[In-Tech]

The air/fuel and timing was completely different.

Steve believes that the rate of acceleration going down the track through the gears is different than a constant rate of acceleration on the dyno. Since our nitrous system works with pressures (fuel and nitrous), the nitrous/fuel flows at a steady pace regardless what the engine rpm is, and the rate of those rpm climbing will be different on a dyno vs the track, and that will have a direct affect on the timing for that given tune-up, therefore the tune-up will be different.

I have not seen the need to tune the nitrous system on the dyno. If your motor is where it should be for fuel and timing, you should be able to get a baseline that is pretty close when using a system that was flowed.

I disagree with your statement of constant flow, there will be a surge of nitrous at the beginning and it drops off from there and low pressure fuel systems it is the opposite for fuel. These are things you can monitor on the dyno and tune accordingly. You are correct however, it is imperative that the engine tune must be correct or you will chase that bad tune. A datalogger is your best friend.

And as to your original question, a ngk -7 if fine for NA at your power level, a -9 or -10 would be appropriate with that amount of power adder.

[lekid]

The air/fuel and timing was completely different.

Steve believes that the rate of acceleration going down the track through the gears is different than a constant rate of acceleration on the dyno. Since our nitrous system works with pressures (fuel and nitrous), the nitrous/fuel flows at a steady pace regardless what the engine rpm is, and the rate of those rpm climbing will be different on a dyno vs the track, and that will have a direct affect on the timing for that given tune-up, therefore the tune-up will be different.

I have not seen the need to tune the nitrous system on the dyno. If your motor is where it should be for fuel and timing, you should be able to get a baseline that is pretty close when using a system that was flowed.

I disagree with your statement of constant flow, there will be a surge of nitrous at the beginning and it drops off from there and low pressure fuel systems it is the opposite for fuel. These are things you can monitor on the dyno and tune accordingly. You are correct however, it is imperative that the engine tune must be correct or you will chase that bad tune. A datalogger is your best friend.

And as to your original question, a ngk -7 if fine for NA at your power level, a -9 or -10 would be appropriate with that amount of power adder.

Thanks.

We do have a datalogger and we have decided years ago that if we are gonna spend money using Induction Solutions systems, that we would tune the way that Steve recommends it. There is always numerous ways to do everything, and this way is worked for us.