NITROUS OXIDE ( nos / n2o ) advice forum

Brilliant

ya big tart!

Love it Perry, I like the deep dish top pulley too.

Paul

I'm happy with the first test runs. Only 7 psi of boost and I got to within 1.1 seconds of my previous nitrous pb when running a 300 shot. The blower can be tweaked to run 16 psi with a pulley change ??

If you like that photo Ted take a look at this one ??

i may pinch that perry and put it on my wall great pic

I've just re fitted the blower and manifold after fitting 8 crossfires into the runners for a DP setup.

I'm off to the dyno tomorrow to see how she runs on the blower only at low boost.

I'm hoping for about the 300hp mark with 8psi of boost. Then I can add some gas under the blower for extra power and charge cooling.

This manifold is too shallow for the spider plate. So I'm going to fit the spider to my spare V8 in my Sons Escort with modified legs to see how that runs later this year. I'm going to fit a 3 bar fuel system to feed the spider and extend the fuel legs for a bit of R&D.

Promising results today on the dyno.
Fueling was almost perfect and at 7 psi of boost she ran 335bhp @ 468 ft/lbs.

The blower should be able to make twice this if I want to change a pulley. But I think I'll tweak it just a bit and then start adding nitrous.
She runs 200hp nasp and used to run 402 hp with a 300 shot. So I'm only 65 hp short of my nitrous power.

Now the question. Should I add gas and leave the blower running at low boost. I'm thinking this might be the best way. If I put a 50 shot under the blower this might get me back to where I was to give me a much more economical system??

So far I'm really pleased with the results.

Awesome results If I can make anywhere near that kind of improvement with the turbo setup I'll be more than happy

I'd say yes and you can always add a 75 to take it over what you were running on N2O previously.

Then of course at a blowout run at the end of the season you could throw a 300 at it and see how it goes...lol

Looking good

Just one little question, are you running the same compression and cam as you did pre blower?. Only asking because i'm doing a few changes to the kitten, i'm in the process of fitting throttle bodies/fuel injection at the minute, bosch 044 pump etc etc so i have the all the fuel i might ever need. Obviously that opens the door to maybe fitting a baby super charger in the future, keeping it low pressure with the current compression/cams. Just thinking at the moment, i've got to finish fitting all the injection system and map it first.

Ian

My compression ratio is 9:1 Ian.
This is how its always been. And the cam is the same too

Welcome to the world of boost

Cheers Greeny!
Its a great world isnt it ??

I was testing again today (not going to divulge the setup just yet) But I ran 11.0 at 126.5 mph and I've still got boost left in hand. As you can see from the numbers I had traction problems

I bet you can smell 9's when using nitrous

Paul

So still running the same terminals, with boost to go

Good stuff!

Is this with no nitrous aswell?

My best terminal speed on a 300 shot was 126 mph in 10.66 seconds.
I'm not going to add any nitrous until i'll maxxed the blower out. It can make 16psi but I'll be happy with 14psi at full load.
I've run from 11.0 to 11.9 and from 126mph down to 117mph while experimenting. But all the 60 foots were 1.7 seconds. I'm used to a massive hit off the line with gas and 1.5 second 60 foots. Even though the 60 foot is 1.7 the launch seems really sedate.
I'm hoping that the new pulley will give me more boost when i'm staged and pre loading at 2000rpm. This might just get me away quicker. Once I know what it can do on blower only i can play with the dP system. But I havent got anywhere near finishing it yet. If it will run strong 10's on the blower but still has a sluggish launch I'll add gas for the launch and then maybe shut it off after 2 seconds. lots and lots of testing to do in the next few weeks

I'm really enjoying learning about this side of adding power to an engine.

I now have two new shiny pulleys

Carb is re jetted. 10 psi pulley going on tonight so I'm ready for the dyno on saturday

Only had limited time on the dyno last saturday. But i got some tests in with the 10psi pulley fitted. With another 3psi of boost she made 350hp with 501 ft/lbs of torque

Thats all I had time to do so thats what I'm taking to the Pod this weekend

I so wish I had my DP system fitted and finished because I just know that a small shot of won on top of this setup is gonna make the car fly...

I'm not going to rush the DP setup. I want to make sure I have the fuel system properly installed so I can set it up as Trev advised. This way I can tune the fuelling to each individual cylinder.

I'm hoping to get back in the 10's with no gas. Then I'm going to unleash hell in a couple of months when the DP system is ready to rock

Interesting times ahead mate, for both the MG and the Bimmer

Yep!
This weekend will be another good info gathering event eh Rich !!

good luck for the weekend perry, shame i wont be there to see it but back there next weekend

Last weekend was good info. 10psi of boost with a 100 shot threw the car to 10.4's on the 1/4 mile.

Bearing in mind Trevs fuelling concerns I just jetted the carb with the biggest jets and needles it had.

I forgot to mention in the previous post that I had been advised to try and keep afr to the 11.2 to 11.4 mark at full power. And with 10psi on the dyno it did this from low rpm up to 5700 rpm where it leaned out just a tad. It went to 12.2 afr.
I'm not bothered about that at this time as I cross the line at 5000-5200 rpm just under 130mph. Plugs all looked ok after 2 clean shut offs. Regarding ign timing I used the advice from the blower guy of 1 degree of retard per psi of boost. And I added another 4 degre's of retard for the 100 shot. So normal timing all in would be 32 degree's BTDC. And at this time it only advances to 18 BTDC. And despite the 10.4's on the track and 60 foot times of 1.4 seconds it still feels quite sedate away from the line and all the way down the track.

Even my Son and friends who know the car well say that it sounds quite tame and smooth on track. But its quicker? I'm using power pour additive for det supression as advised by webster racing. I'm not sure if I need it. But i guess its another safety net for the engine until i get a new block built. The old block was trashed. So i found a scrap block but it had some surface damage on the deck face. It had obviously had head gasket issues as the join between cylinders 6 and 4 has blow by damage about 40thou deep. So its got JB weld in the block face and I used more copper gasket spray glue on the composite head gaskets.
So far so good. But i dont think that 9 will come without a decent block. She has now done 7 dyno pulls. 5 runs at the pod. Then 6 runs at north weald and last weekend another 11 passes on the strip at the Pod while we tweaked and tested.

AND NOW!!!
My first observation of a downside to using a GMC blower for an efficient race application. Heat soak from the engine itself??
As the big chunk of ally is bolted to the engine, and is at the top of the engine it gets up to engine temperature eventually. So when the blower body and rotors are hot they will add heat to the incoming air. As well as heating the air as it is compressed.
I reduced this issue last weekend as I have a cooling fan that blows ambient air over the blower body and engine to make it cool down between runs.

Even with the heat from the weekend. The cooling fan made the blower body feel quite chilly to touch. So thats a good point. My DP system will do most of the work. But I'm now wondering if I should keep adding a small shot above the blower for charge cooling??

If I had a turbo I could use an intercooler.
But a twin turbo system would still cost a small fortune to set up properly.

But with a draw through blower I cant see a simple way of charge cooling by mechanical means with a heat exchanger between blower and carb or even between blower and manifold without having a HUGE heat exchanger that would probably be bigger than the blower itself ??

The car is race only now so the fan cooling between passes isnt a problem. And the nitrous into the top of the blower for charge cooling is simple and nthe DP system will do all it should to top off the system to see the car eventually running a 9 on the 1/4 mile

Hi Perry

I want you to take this post in the manner its offered...as help, not criticism..

I have run a lot of Blowers....you may have noticed them on top of top fuel engines lol

What I think you are doing with that blower is...hmmm how shall I describe this...a little like throwing damp sticks of dynamite into a bonfire and hoping one doesnt dry out and explode...

What I am trying to explain is that you cannot just ramp up a blower and hope all will be fine (and the car faster)

It will and in your case HAS worked so far....

But not for long......

You are already coming across some of the problems that we had in top fuel.... like heat sink upwards to the blower

In my day (80s) we had no cooling at all on a t/f engine and the heat was basically dealt with in two ways...

1, it was transferred into the oil which was a straight 70 weight and dropped after every run and a rather nice bright green colour it was as well lol (due to the Nitromethane forced past the pistons into the oil)

2, we were only running the engine including the run for as few seconds as possible.... and a LOT less than you are...

And yes we put a fan on it afterwards but it didnt help much

You are also about to come across another problem we had.... that is shifting enough fuel for the blower....and that means a BIG pump...we used to have to shift around 6 to 8 GALLONS PER RUN!

Now you are not at that stage yet but you really really need to think about a pump that WILL shift as much fuel as you THINK you need , then double it...

Now back to what I said to start with....

If you get ANY of the above wrong and you WILL (take my word), not through any real fault of yours, but just through bad luck or a small error, then you WILL lose an engine or 10....

As long as you are prepared for that then fine, but I dont mean a holed piston or two, I mean a crank or a couple of pistons blowing big holes in your blocks...

My best advice to you would be that IF you must, run a blower only engine until you understand its limitations (and your block and cranks and pistons limitations ( thats a polite way of waiting for it to go bang - as it will)

Then back off a few psi and THEN try a LITTLE nitrous and go on like that..until you lose another engine and so on....

I am amazed that mixing and matching you have not lost an engine so far, you must be extremely lucky (or maybe you have all of Richards luck as well lol)

Anyway, hopefully this may help you or not lol...

We will see ........

All the best Brett

Buy a huge pump and a methanol carb.