NITROUS OXIDE ( nos / n2o ) advice forum

Soooo close!!
I ran a 9.62 today straight off the trailer. Sadly as I crossed the finish line I was engulfed in petrol fumes which stank the car out.
The seal on the filler cap of the race tank has failed and I ended up with about a cup full of petrol in the boot floor.
Unable to fix on site so that was it for today.

All I did was drop 5% off the start power and drop the build time from 0.9 down to 0.7 of a second.

60 foot dropped to 1.39 seconds as well.

Here's a slo mo. Should have a real time vid on Monday when my mate gets home to upload to youtube

https://www.youtube.com/watch?v=Xs-elD0 ... GyG4tfRrjw

Real time vid is online:)

https://www.youtube.com/watch?feature=p ... _yCCMlQ7ME

Hi Pel

Nice run...

Why no wheelie bars ? there is easily at least one tenth (maybe two) wasted lifting the front wheels, maybe more ?

We had a saying in Top Fuel.... "one wheel up, ok, two wheels up, sort out your wheelie bars"

All the best Brett

They are on the Winter list Brett

I'm about as maxxed out as I can get now on leaf spring suspension and slapper bars

Time to add some more tubes I think ??

Pel

Hi Pel

Wheelie bars are a definite at this stage..... time spent going upwards is time added......

All the best Brett

You are spot on mate!!

This was where I was on the old engine 2 years ago. We tweaked and tightened and kept the front wheel down to about 2" of lift for the 10.2's..... Then i made the new engine and now we are worse off than we were before with both wheels now well airborn, but also running strong 9's

Wheelie bars alone could gain me a tenth or more for next year I reckon??

The car stuff is going on the back burner for a while as on Sunday I became a Grandad for the first time

My new Grand Daughter "Faith" will be taking up some of my garage time I think

ok i will be the first....awwwwwwwwwwwwwwwwwwwwwwwww

Cheers Ted!!
She's a little cutie ..... I'm happy

CREDIT WHERE IT'S DUE - THAT'S SERIOUSLY IMPRESSIVE!!!!

Anyone who isn't impressed by you running those numbers has no idea about anything.

Even without adding wheelie bars there is certainly a 9.5 in it, as it's still LAZY immediately off the line.

OUTSTANDING!!!!

Hi Pel

I am IMPRESSED.... which takes some doing...lol

But forget the 9.5.... you should be concentrating on the 8 .... then the 9.5 will be easy...

All the best Brett

Thanks Trev!
Your comments are worth a lot to me mate

Hi Brett!
I'm taking the softly softly approach for the time being
I would like to see if I can find a 9.5 ticket on the last few RWYB's of this year. So I need to find 300th's of a second to do it.
The season end is close, my slicks only have about 2mm left on them and the holiday, the new Grandchild and a new heating boiler have wiped the racing budget out now

It may happen, it may not. I'm more than happy with what I've achieved since rolling out the new engine for shakedowns just over 3 months back. The car now run in the 9's all day long, and I am looking for a timing ticket with 8.99 written on it for next year. So I need to find nearly 3/4 of a second to do it.
That number sounds so, so small doesnt it? 3/4's of a SECOND !!

And a lot of my non racing mates find it somewhat amusing that I'm going to be doing a lot of mods over the winter to find that extra time. One of the funny comments was "cant you just put your foot down a bit harder?"

The wheelie bars will help the launch. My 60 foots are now in the 1.3's, but she still struggles after the 1/8th mile marker. 6 seconds to 114mph in the 1/8th, and then the power tapers off giving me just another 23mph in 3.6 seconds to the finish line.
This has been how all my Rover V8's have performed. Fast first half followed by a lame second half.
So I may be tinkering with cam changes over the winter after getting info from the dyno next month. I've not had the car on the rollers yet. I dont even know what my best shift rpm is? Its all been guess work so far by trying to feel how the car pulls.

I'm hoping to get the dyno stuff done before the last RWYB in October. That would be good as I will then have an idea of where my peak torque is in the rpm range so I can adjust my gear shift point so I can make use of peak torque on the shifts from 1st to 2nd and 2nd to top gear. This may give me a slight increase ?

So the goal is actually an 8 second timing ticket. And as we work towards that I'm hoping to go sub 9.5 regularly

I will just bide my time and do small adjustments on the way to the 8.99 second attempt.

If we go sub 9.5 and dont make the 8.99 I'll still be more than happy mate. Its a stock bodied 38 year old MGB. It has all stock front and rear suspension and steering. The only fibre glass part on the body is the bonnet. The fibre glass rear wings are bolted over the steel ones to cover the tyres. The rear axle is the stock diff with copy shafts made by Moser. It has full glass and a full interior apart from racing seats, it still has a Rover V8 fitted and it runs strong 9's. Who wouldnt be happy with that ??

Everything from the recent 9.62 run forward is a bonus for the car from now on I think. It would be nice if I could find a new PB for next July at the Retro Show at the Pod as thats my fave event of the year when my MG buddies come for the weekend.

Pel

Your maths isn't as good as whatever you've done to reach a low 9.5, as you ONLY need JUST A LITTLE OVER HALF a second to run an 8.99 Perry.

The likely reason for your 2nd half fading is falling bottle pressure, so the easiest way to sort that is to add one of our NITROGEN PUSH systems and even with EVERYTHING left as it is now, you'd see a GOOD improvement in the 2nd half in particular but generally the whole run will be improved.

Ha Ha!!
Thats me being old school Trev and rounding stuff up. Yes its 0.63 of a second!!
I'm starting with approx 900 psi and the bottle is dropping to approx 800psi on a run.
And I made a mistake on my nitrous settings. I've been running and tweaking a 175 shot and not a 150 shot
But its all good eh? 10.00, 9.96, 9.81, 9.69 and now 9.62 all by adjusting start power and build time on the same shot of gas. And I'm still only hitting with 60% off the line with the build at 0.7 of a second.

This Saturday if we can get on track I'll just fiddle with the settings some more to see how much I can squeeze out of it?

Thanks for your support.

Perry

I'd say just go MAD with the settings. what's the worst that can happen?

Ha Ha!!
To be honest Neil. The engine feels like it could take the whole 175 shot as a fixed hit. Its taking over a 100hp off the line with the other 70hp coming in over 0.7 of a second as it is. The boost is only 4psi off the line with the other 10psi coming in over another second or so? FYI! This is the time of year that I tend to try and answer those "I wonder what would happen if " questions as I have until March April to repair any damage

Hopefully the weather and wind will be kind to us on Saturday??

BUGGER!!!

Couldnt race yesterday because my pre race checks showed a wobbly crank pulley. This was making the blower drive belt flap around. The crank pulley has split comletely along the sleeve where it goes over the crankshaft nose. I guess the resistance from the blower drive for the 9 second runs is proving too much for the 30 year old Rover V8 pulley's?

Time to rethink the pulley setup?? I have a spare pulley which i may just chuck on for the last RWYB in a few weeks? Then I can think about improving the blower drive for next year.

Perry

Hi Pel

Unfortunately that sort of thing happens , when you start doing really good times and stressing parts that were not designed for that sort of stress

In Top Fuel , we blew a LOT of blower belts (and a few blowers) ...

The crank pulley and the blower pulley MUST be both strong and absolutely directly in line with each other.... otherwise you will either lose a belt (if you are lucky) or it will take out the blower and possibly the engine if you are unlucky.....

Th pulleys/belts are absolutely crucial on any blower engine and although you may not have thought much about them in the past, its now time to have a think and get them right .....

All the best Brett

Good news from todays inspection

The crank nose is ok and the woodruff key is intact. But it looks like the woodruff key may have been the wrong one as it has some room between its top and the top of the grooves in the pulley and cam cog. This allowed the key to rock in the groove so one end was more proud than the other. This meant that the crank pulley only had contact with the key for approx 30% of its length. and this was towards the rear of the pulley sleeve. That will explain why the crack is wider at the rear of the crank pulley sleeve.

The pulley is knacked as is the front oil seal and oil thrower ring. But I have a large collection of spares so I'll dig them out tomorrow and get the engine back together over the next 2 weeks. I have to start night work on Wed for 6 days so I'll be back on the engine next week.

I want to put the car on the dyno if I can before the last RWYB on 19th October.

I'm taking bets on the dyno figures now

Here are the stats I have so far:
First build of the engine gave 402hp with 500 ft/lbs of torque with 6psi of boost.
This was with the old TRW pistons running 10:1 CR and this setup ran 10.9 on the 1/4 mile.

The new build has Omega pistons running 7.5:1 CR and I'm running 14psi of boost + a 175 shot of nitrous to run 9.6 on the 1/4 mile.

I'm hoping to see around 500hp on the dyno.

I havent got a clue but I'm looking forward to finding out soon. I cant run my slicks on the dyno because they get too hot, so I'm going to fit some spare 6" rims with my Toyo's fitted. Hopefully they will hold on just enough?

The car weighs 2600lbs with me in it. ??