NITROUS OXIDE ( nos / n2o ) advice forum

Reading the MM&FF magazine they did a nitrous install and had some images that show exactly why a person needs to be careful with single point applications and why we recommend direct port if the power levels are increased greatly on some intake designs.

My suggestion would be too flow test your intake as illustrated in the images even if you have to buy a second manifold from a scrapyard as they are relatively cheap. Injector angle "can" be very crucial.

The kit used is a NOS dry kit.

Whilst I agree that it's essential to determine if a system is suitable for a specific style of manifold and the core of your post and the article are correct in 'theory', there's more to it than just flow testing the system on a manifold 'off' the engine.

The problem with many aspects of nitrous is that it's VERY difficult to replicate EXACTLY what goes off inside the manifold/engine in ACTUAL USE.

There is one HUGE difference between a manifold off the engine and one on it, that is the runners are continually open when off the engine but when on the engine they are mainly CLOSED!!!

Whilst closed they will influence the flow through the main log to whichever runner is open. This will change the distribution from what is seen in a off the engine test.

The best way to determine if a single injector system is adequate is to read the plugs but if in doubt fit a DP system to ensure you get it even.

Regards

I put this in the "general" section Trev as many novices may not fully understand what we mean by distribution issues and the severity.

I just wanted to give a general overview but going along with your post I would be more inclined to transfer over to the "advanced" section as even those guys struggle with reading plugs properly.

Advanced with a link here would be good.

Regards

normally you guys reccommend DP for hits over 50hp right? that would make an even 12.5hp per cylinder.

out of interest, on crftom's celica, was it the angle at which he positioned the main distributor block, the amount of power he was trying to eek, or a combination of both...?

Totally wrong Ron.
I could have used a single crossfire for my 150hp, the decision to go direct port was purely due to distribution in the actual manifold.
If it had flowed evenly i could have kept to a single and gone faster.

The only thing advised at 50hp is retarding the timing on road engines that don't have a progressive.

interesting. so what do you think happened to crftom's motor then?75 shot too much without adjusting the timing? he had a proper system with warmer, gauge, progressive etc. and the engine he had was the lower comp of around 10:1 i think and he still managed to cook a piston!

Actually Loopy we do advise DP for above 50 bhp, because distribution on some modern manifolds is at best 'questionable' when using a single injector.

I've also found that there is no hard rule about which gives best results at any power level, as I've seen bettwe results using both single & dp on different engines.

I'd have to see the full fitting job and the consequences of the problem before I could explain why he had the problem in the first place.

Regards

I'd need roughly a million more details before assuming anything about the cause of death.
Was he low on fuel ? Was he in the wrong gear ? Has fuel flow through the nitrous injectors been checked ?


I take it these are the new "road user" "Better safe than sorry" rules then ?

Correct but based on dyno results from testing in Malta.

Yes plug reading that really is an art , mine change depending on fule make , OBs and type of test run ect im never ever sure what im looking at most of time just try and make sure no damage and all identical and even in colour , even with DP as i found out many thing affect the distribution and looking at my plugs saved me as they gave me an insight some thing may not be just quite right

You know it gets harder to read plugs as they are getting older and its almost imposable to get a clean read on a set of road plugs that you drove to the track on and have had in the car for the past 25000 miles. Here are a few things to put on your wish lists, I would always have a set of track plugs that only got used, yep you guessed it at the track. I would also buy a spark plug cleaning blaster, this is a small hand held glass beader that uses air and has a small hole at the other end where the plug goes and after you insert the tip of the plug in it you push a small button and it glass beads your plugs clean of any passes on the porcelin. The ground strap will be cleaned also but might not remove all the timing mark from it.

One more thing you cant read a plug after you drive it back to the pits. The engine needs a clean shut off just as you go thru the finish line and then coast to the return road and pull your plugs out and put the road plugs in and drive back to the pits. Yes this sounds like alot of work but unless you have a way to be pushed back to the pits it the only way to read a plug properly.You should then make notes on the plugs and the cyl. they came out of.Once you have your tune up let it rip.

There is more to this but I will keep it simple for now...but one last quicky be sure to put the plugs back in the holes they came out of....

how does single point atomise the petrol as the nos will now not be doing it?

Do you mean when the injection points are seperate as in individual fual and nitrous Venom injectors???

yes trev.

The answer to that is SECRET but it does.