Nitro tuning

[Lo08nyb]

Hi guys,

Just got into nitro really enjoying it so far only thing I'm concerned about is the engine and it's tuning.

I have it running and idling nicely the LSN seems set just right but it's lacking in the top end.

Currently the engine temps are around 100c when I lean it out it gets to around 125c I'm worried that this is too hot and I don't want to damage it, when I lean it out it still has a good stream of smoke coming out of the pipe and it performs how it should.

It's an OS max 21vz b v spec

Also I'm getting around 6 mins to a tank and I'm lead to believe I should be getting around 8-10 mins.

Look forward to your help!

Edited September 24, 2014 by Lo08nyb

[mrfodds]

Just keep leaning the top end 2 minutes at a time until you no longer see a performance improvement. Once you've reached that point, back it off (richen it) by 2 minutes and you should be set. Chances are that your bottom end might need slight adjustment once the top end has been set. For future reference, the top end should always be set first.

Don't get too hung up on temps, some engines run hotter than others. You should be able to tell just on sound alone whether an engine is tuned correctly. Once properly tuned the engine should pick up quickly from a standing start (no bogging), have good top end and return to idle straight away once off throttle.

[Lo08nyb]

Hi mate,

Thanks for the reply, I will have a mess around with the HSN and see where I end up just didn't want to cook my engine as iv only had the car a couple of weeks and don't want to be buying a new engine!

[jizwizard]

are you using a venturi on the carb? If not you will not see 8-10mins. Definately if you bashing as you will be wiskey throttling all the time

[chrisknights]

Set your lsn back to factory settings and try again , but this time tune the hsn , get it so there is a nice trail of smoke , warm the engine up before you start to tune , keep running it up and down and each time adjust the hsn 1/8 of a turn , keep adjusting it till you see no more top end and nice trail of smoke once you have done that slighy richen it up ,

Now you have the hsn set try the lsn and with a full tank once again warm the engine up and this time run it up and down and then come back and stop and let it idle for 8 second and then full throttle , if it boggs while trying to pull away then lean it slighty and run it up and down and back again and do the same let it idle for 8 seconds then full throttle , you should notice its better off the line , keep doing it till it shoots of and has smoke coming out of the exhaust , when the car shoots off like a rocket once again slighty richen it up and your car should be set , let it cool down and then another full tank and drive it like you stole it and after 5 minutes check your temperatures ,

[Lo08nyb]

Hi guys

Thanks for the input, much appreciated!

In terms of temperatures where abouts should I be aiming for?

Think I have the HSN just where I need to be, but car is sluggish on pick up so will have a go at leaning out the LSN.

Cheers!

[Anthoop]

In terms of temperatures where abouts should I be aiming for?

Think I have the HSN just where I need to be, but car is sluggish on pick up so will have a go at leaning out the LSN.

Cheers!

You should not be "aiming" for any temperature....just making a reference and ensuring it is not wayyy too hot.

 

Yes if you start with both needles rich and you set the HSN then acceleration will be sluggish but top end/wide open throttle should be singing.

HSN controls maximum amount of fuel available...high rpm and wide open throttle (wot) is when most fuel will be used, so that is how we set the HSN.

LSN controls the amount of fuel available from zero throttle until (around) 3/4 throttle opening.....from idle rpm to midrange rpm...so we set that with acceleration tests.

We set the HSN first because that will always have some effect on the LSN......and a warm engine first because the required fuel/air ratio for a cold engine is different to a warm engine......we always ensure there is over half a tank of fuel when tuning because as the fuel level changes so does the fuel pressure.

Edited September 26, 2014 by Anthoop