NITROUS OXIDE ( nos / n2o ) advice forum

The 840 is still in one piece
Additional maps being loaded tomorrow
The sun's gonna shine all day saturday
Hope to see some of you

I'll be there mate!
The MG is still in bits so I'll be pit bitch

wish i could come but my cars in bits too. but im going up on the 2nd octber rwyb thats the day befor the jap show final ver to watch that too, so im guessing rwyb mite be quite packed, is any 1 up there 2nd oct then

Wish I was not working, But I have booked off the 18th and 19th for the bmw show, Trust you will be there too.

Equalled my PB today, so bench mark is set for the BMW Show at the pod, which is my next big event.
Many thanks to Perry for yesterday, unfortunately only phone help today, including a call form Trev
I can only see this car ever achieving low 13's, but that would make me VERY happy
The other massive achiement was of course to have gone home in one piece, for a change
Everything is now crossed for the 18-19th

What jet sizes, timing and Max settings did you end up using, because you should have got a better result than that Richard.
How did the car pull at high rpm for the PB run?

Richards car left the line quite lazy on Saturdays Runs. But when the gas kicked in after 1 second it did squat hard off the line but had a good deal of black smoke from the pipes for most of the run.

We tried several combinations of fuel and nitrous but the sweet spot seems to be 150 nitrous jets with 60 fuel jets and low build times to see the 13.9's. Over this and it gets slower. Richard has 40 psi of fuel in the rail. I'm not sure that the stock fuel system can support more than a 150 shot. He may have 40 psi. But does he have the flow rate??
At least he now has a tune for the BMW show which should bag him a high 13 second pass.

If its smoking it has more than enough flow rate!!!!

He should have been getting the nitrous in on the launch and that explains why the improvement is so low. He'd be at least 0.5 secs quicker if he got the gas in off the line and I'd guessed it would be something along those lines, which is why I was asking about the Max settings.

Hi Trev, Here are the settings:

150 Nos 60 Fuel (in both pairs)
-3 degrees retard
50%-100% in 0.4 sec in every gear
rpm rev drop 1000
rpm windon 2000-6000

Launching at 2000rpm
Rev'd cleanly to the red line at 5700

If that's the case how come you were getting lazy launches as Perry describes?

If that's the case then you should have first gear set at 150 HP instantly (or whatever the car can handle) and just use the progressive to make the transitions between gears 'softer'.

Did you run out of time to try the bigger jets????

Unfortunately yes, I run my PB at 16:40 and the track closed at 17:00

I have an answer, Pel can be passenger next time to observe and watch the controller too.
The extra ballast should aid traction
Seriously Pel, your help yesterday was very much appreciated.
Doing everything today on my own has killed my back.

Hi Richard

Some thoughts on your lazy launch...

Your car has a kick down switch correct ?

Is it like mine which is attached to the bottom of the throttle pedal ? so you have to totally smash your pedal to the floor to activate it ?


If its the same type as mine as it was hard to be SURE i was pressing quite hard enough on the pedal , I put in a manual kick down switch on my dash...




(bottom right-blue toggle switch) with which I can manually flick the switch and then the Nitrous comes in on the rev window switch in the Maxx...

Its also extremely useful on the road (without nitrous) as say you know you are about to overtake and need a lower gear on the autobox or a bootful of power then I activate the switch and then the smallest amount of pedal pressure say 1/2 inch from top then causes the autobox to instantly kick down...

And more importantly it gives you instantaneous launches....

All the best Brett

Hi Brett, I'm at WOT just as the peddle hits the kickdown button (which I deativate on the 1/4 mile) as I want the engine to shift before the redline. I reakon there's a very fine line for this activation point, that needs further investigation

If you had a wooden leg like me you'd know your foot was on the floor, because there's nothing between off and on when you've no feeling or finesse of control.

I once drove a friends car and when I got back after the run he had to re-fabricate the throttle peddle and mounting because I'd mashed it all.

One of the reasons I make cars run quicker times than my customers is because I bend the throttle stops and bulkheads.

This is how you should be launching;

1) Kick-down switch ON for first gear (arrange it so you can switch it off for the 1st to 2nd switch), otherwise the launches are likely to remain lazy.

2) Left foot on the brake and right foot close to full throttle as you push the car against the brakes in to stage.

3) Lights go down mash the throttle and release the brake simultaneously and the instant you do that you should be adding as much nitrous as the tires can take at that point and then set the build time to deliver how ever much the tires can take during the entire of first gear.

The LAUNCH & FIRST GEAR are VITAL for ET's - if you don't optimise your technique for getting those 2 right and you don't maximise the benefits of nitrous during that period, you're wasting at least 0.5 to 1 sec. and that's where your 12 sec run is waiting to be discovered.

I have discussed pre loading with Richard and its something he will be doing in 2 weeks when we have our last test day before his event. I'll take the car for a spin and see how she feels.
Seeing the car launch from the start line is almost like seeing n2 delay activated as it pulls away quite sluggish and a bit smoky. But then all of a sudden its like he flicked a switch and activated the gas. But as far as I could see the n2 delay is off.
At least he has a good starting point for final testing now.
Perry

I totally agree with the comments on my launch, I need to get that right

Get me a list of the Max Extreme setting you have been using and I'll see if any are responsible for the delay.

I'll see if i can photo the screens.
Wish I'd thought of going through the settings while I was with you.

So have I got this right ,if you don't depress the gas peddle all the way down from stand still ,the default gear is 2nd,if this is the case can you not use one of the out puts from the max to select 1st so the gear box is ready to go on the green.


Austin

Hi Austin, I'm pretty certain it starts off in 1st gear, but I have NEVER had anyone test with me to confirm my settings.
But there is definitely a delay off the line of about half a second before the NOS kicks in

So is the kick down switch just for down shifting on the move , Iam just thinking this delay may be the ECU sorting out the gears ie -- torque modulating

The kick down switch is ONLY for on the move and makes the engine rev longer in the gears (when in auto).
I by pass it to enable manual shifting and when by-passed the auto box shifts earlier too.

screen shots sent to you

Hi Richard

Hmm to the above....

Your auto box sounds remarkably like mine which starts by DEFAULT in second gear (which could explain your slow launches) which is why I activate my kickdown switch manually, its the ONLY way I know to FORCE it to launch in first...

All the best Brett

Hi Brett, when I race, I use the manual option and the display says its in 1st.
I have counted the gear changes, so that is confirmed.
It definitely starts in 1st.