NITROUS OXIDE ( nos / n2o ) advice forum

The MGB has been stuck at 9.6 seconds on the 1/4 mile now for a while. One of the problems has been the old torque converter. Its been on the car since the old days in 2006 when the car was only making 200-300 hp. The converter is rated for 350hp. But these days the engine is putting out 600hp + and the converter is slipping now. The old converter is a 2800-3200 stall model. Back in the day the engine made peak torque at 2700 rpm. But the latest Rover V8 makes peak torque now at 4800 rpm. We had one last go at going better than 9.6 on the strip by trying to hit it hard off the line. But the end result was a monster wheelie which ended up with the car launching hard and the body roll saw the nearside rear wheel off the ground for a second or so The 60 foot time was good, but as we shifted to 2nd gear it let go No 2nd gear at all ?? So a second or so of wondering what went wrong saw the shifter being banged to 3rd gear which was actually there !

The run was a lame 10.1 pass.

So we have thrown the old gearbox out, fitted a new TH350 with race clutches and a transbrake. And a new 800hp converter with a stall speed of 4200-4500 rpm.

I will be back out on 14th September learning how to drive the MGB all over again with a transbrake. I'm hoping to find my 9.5 second pass before the end of the year

Sounds like a good move Perry, although I've never been keen on wasting torque with high stall converters when using nitrous but the best of luck in achieving a sub 9.6 run on the 14th.

Thanks Trev

Hi Folks !
Prepare yourselves for a bit of a ramble from an excited racer

The initial testing on the new transmission has been very good so far. The downside is that I had trouble teaching myself to shift gear correctly. The old tranny was a normal forward shift pattern. The new gearbox is reverse pattern. This should have been no problem, or so I thought ? After 10 years of pushing the ratchet shifter forwards, getting my body to pull it backwards became an issue which was the cause of much piss taking from the boys in the pits Even as I drifted into stage I was shouting at myself "pull it back, pull it back" But as soon as the lights changed I let the transbrake button go, and as the shift light came on and I pushed the stick forwards into neutral DOH!! I did 5 test passes in total. Passes 1 and 2 were 1st to N with the rev limiter working overtime. Pass 3 was a clean shift to 2nd and then the tyres let go so I was drifting on the limiter for a while before I aborted the run. Passes 4 and 5 saw me growing a pair and actually bringing the launch rpm up to 4000 on part throttle, then letting the button go and planting my foot. But again on these two passes I shifted from 1st to N ?? Rev limiter came in so I kept my foot in and pulled the stick back twice to find 2nd gear. and then 3rd gear to finish the runs. These were all non nitrous passes (as I guessed I would cock it up) and despite the missed gear shifts on the last 2 passes I did run 1.4 and 1.5 in the 60 foot and both runs were 10.9's. On the old setup I would hold the revs at 2000 on the foot brake (anymore than this and the brakes would creep me into a cherry) and just plant my foot as I let the foot brake go. I did several non nitrous pulls like this on the old setup and the car ran 60 foots of 1.5 with ET's of 10.8's to 10.9's !!

So I have already equalled my old non nitrous PB data with missed gear shifts. If I can get out next Saturday and do a clean non nitrous pass with no gear shift cock up's I'm hoping to run around 10.8 or better with a 1.4 60 foot or better. I know that the above ramble may make no sense to some folk, but I'm getting very excited right now. I have already decided uprate my Mallory 6Al to an MSD digital 7 controller as this will give me the option to use a 2 step rev limiter so I can go full pedal in stage with a launch rev limiter holding the engine back at 4000rpm until I let the button go. The MSD isnt cheap so it will have to wait until after Xmas to see how the funds go. If I get some time I intend to add another relay to run piggy back with the transbrake button. This relay will provide a series contact for the throttle microswitch on the carb. So in theory I could push my foot to the floor on the transbrake to see where the revs settle as the converter winds up. This would see the throttle micro switch closed, but with the circuit still held open on the aux relay. Then when I let the button go I can let FRED do whatever I have programmed him to do. I'm thinking to leave him with his current settings, but add in a 1 second start delay so the car can get rolling for a second before he chucks in a 100 of nitrous with the other 75 shot coming in over 0.8 of a second which is what my old foot brake launch setting is?? OH MY!! This is so exciting now If I can get my shit together and bring myself to go with more pedal on the transbrake I may actually make a new non nitrous PB next weekend ? If I can do this and make proper gear shifts I'll chuck a bottle in the MGB and see what happens. I think FRED is over 20 years old now and he's still going strong

At this point I will say sorry for all this blurb ! But I'm on the point of another breakthrough with the old Rover V8 on the 1/4 mile. I did say that when I broke the 10's I would retire the car and build something else with a Chevy engine. But I had run the 10's for a good while and then with a few tweaks we not only broke into the 9's, we sort of smashed it with regular 9.6 passes. There were 17 back to back 9.6 passes over several visits to the track. The last 9.6 was straight off the trailer at the Mopar Nats at Santapod. This raised a few eyebows when the folk on site saw that I had a rover 3.9 under the bonnet.

I'm out next Saturday at the Pod for more test runs. I have been online to Sport and Soccer and ordered a new pair of balls which should be with my on Friday so I can use them on the start line next weekend

The next goal for the MGB was a 9.59 pass. I'm hoping that before the end of this season that the car may run in the 9.4's ??

Here is my last run from last weekend. I have the shift light set at 5700 rpm and the limiter is set at 6000 rpm. In the vid you cant hear the missed gear shift. It just sounds like I've run 1st gear out a bit longer than normal.

http://www.youtube.com/watch?v=8BXRnsAe ... GyG4tfRrjw

Crazy as it seems there MUST be an 8 in it Perry!!!!

BTW I found some semi-dismantled FRED's in my store room the other day and thought you might like to purchase one as spares for yours, just in case.

Thanks Trev!
I think that I could well run close to an 8 now ?

My next controller upgrade will be a max or similar I think. The FRED has done very well and may go onto my Sons Escort next season. I will be wanting to look at monitoring afr as a safety thing. I already have twin widebands on a logger which has an aux output for alarms. But I think with a better controller I could hook this in as well as fuel pressure safety, bottle contents etc. Hopefully I'll get my act together on Saturday if the weather holds out?

Regards
Perry

RWYB tomorrow and I'm stoked to say the least. Can my modified Rover 3.9 run a 9.5 or better ??

Holy Shit !!!

I now need to back off the WoN nitrous system ????

Trevs system has got my old MGB down to 9.6 seconds on the 1/4 mile as boost only could not make it. But I have been having to add more nitrous to compensate for my transmission issues. I have now fitted a new torque converter which is matched to the engines output.

So on Saturday I decided to see how the existing WoN nitrous setup would work with the new torque converter on a test run at Santa Pod.

I should really have thought a little more about what I have been doing on the car this last 12 months. And I should have realised that if I had a torque converter that would be better at getting power down, I should maybe have backed off the nitrous settings to soften the launch a little. But in my usual style I thought sod it. Lets just see what happens eh ?

And I found out in a big way very quickly

This first WoN test pass was mental..... In the last 2 years I have been using nitrous to compensate for the failings of my old transmission system. And now I have the transmission matched to the engine. I just was not expecting what happened ?? When you see the Video you will understand why I'm so happy at running a 10.1 second pass as opposed to my old 9.6 second passes If you subtract the 1+ seconds I had to come off the pedal to get straight again. And then take into account that the nitrous takes another 1 second to get back to full power after hitting WOT on this run against my mates Slingshot you will see why I'm so happy.

I'm actually thinking that this could have been a flat 9 second pass or better ?

I nearly shat my pants when I left the start line and all I could see was the sky ??


http://www.youtube.com/watch?v=nVscbPHg ... GyG4tfRrjw

Heres another vid from the other lane which gives a better impression of just how fast the MG left the line

https://www.youtube.com/watch?v=eg3avnsNKrc

I've nearly choked and died from laughing so much Perry!!!!!!!!!!!!!!!



THAT IS ONE HELL OF A LAUNCH & I'M AMAZED THAT YOU DIDN'T SHIT YOURSELF!!!!

I'm so pleased to see that after all these years, you're NOW getting the FULL benefit from the WON system, AT LAST.

It must now be IMPOSSIBLE 'NOT' to run an 8 second pass and that MUST rank among the MOST OUTSTANDING ACHIEVEMENTS, that any WON customer has ever managed, despite the fact that most people (with their monster V8s and much quicker times), will fail to appreciate why.

It may have taken many years to get here but EXCELLENT work none the less.

BTW I'm guessing that you shut off before the 60ft mark, which is unfortunate, as although it would have been clocked by your rear wheels it would probably still have been your quickest time.

OMG perry that looked so violent i nearly shit myself just watching it
i wanna do that with my mx5 going to tesco i'm so jealous

You might like to see what's being said about your escapades on my facebook page Perry.

Ha Ha Trev!
I've watched that vid so many times now. And I have re lived the action inside the car as well. Even in my sleep I backed right off before the 60 foot because all I could see was the sky, and didnt get back on it until the wheels had settled from the rebound. I reckon I was off the pedal for 2 seconds before I got back in hard to reel in a 10.1 at only 5mph off my normal 9.6 second mph ?? So I'm more than happy that this could have been my flat 9 pass or better ??

Hi ted!
It was certainly an eye opener. They eye in my behind that is ?

I'd be surprised if you weren't off full power for longer than 2 seconds AND you would have lost 99% of your momentum, which would have also had a HUGE effect on your ET & MPH, so 8s MUST BE A GIVEN NOW!!!!!

lol
i still want you to do it again tho

and i really must get myself one of those pesky torque converters

Thats sort of what I was thinking Trev !
This run was only 5mph short of my normal 9.6 second passes on the strip when I would be under full power for all of the run ?

I can't wait to hear how it runs at your next event and just a shame that'll it will have to wait until next year.

Might be a good idea to invest in some wheelie bars over the winter

wheelie bars...now your talkin

I already have the wheelie bar mounts and the materials to make the wheelie bars

I just need to get my shit together over the winter and weld them up !

But I do have another train of thought as I would love to run my sub 9.5 or better without wheelie bars to be honest. I reckon that I could soften the launch with FRED and feed the power in over 1-2 seconds to keep the front wheels down an improve my ET. This may harm my 60 foot time but I think that this may not be that bad for me over the whole run?

Yes that is the best plan of action Perry but as long as the bars don't touch the ground you can still claim it was without wheelie bars but having them there as a safety net would be worthwhile. Having said that, all credit to you for getting out of that one so quickly (I'm sure a good number of people would have been too slow and flipped the car), so you'll probably be OK without them.

Cheers Trev. I'm back out this Saturday to do test and tune runs as a demo car at Flame and Thunder show which will be good free track time to some logging runs

Can't wait to hear the results.

Damn! Can't watch the Video at work so gonna have to wait till I get home from work!!

Dagnabbit!!!!

The engine developed an odd squeaking noise when I was doing my normal warm up and pre flight checks on the trailer. The noise was coming from the flex plate area underneath when idling once it had warmed for a minute. Nothing loose on the plate or converter but its definately a metallic scuffing noise. So I shut it off and left it on the trailer while I crewed for my mates slingshot for the rest of the day. No way was I going to risk any damage so the engine will be out for a full checkup over the winter. I want to get back out next Jan or Feb fighting fit for a new PB. I'm not rushing. The last test day has showed me that the 8 could well come my way next year

Pel