Nova P5 XLT off tune?
 

Guys I got a Tekno NB48.3 for xmas and been running a new Nova P5 XLT in it.
with nova 9901 pipe along with 1021 header. I recently switched to the long heaeder (1020). It has become do hard to tune and only has under 2 gallons on it. heres what happens:

1. On the starter box it will idle normally, but when u give it full trottle for more than a second, It screams and stays in the high revs for a bit (i sometimes have to brake to stop it) At this state it seems to be fine apart from hanging up in those revs.

2. When I put it down on the track, It moves very sluggish. A sluggish lazy bottom end with almost no top end.

A guy at the track said it needed to be 'pinched' then another said no cuz its new. Im also hearing to send it back??

Help me out here guys. :cry::cry:

New P5 XLT
 

Guys I jus got a new Tekno NB48.3 for Xmas. Saw a sweet deal on a new P5 XLT online. It came sealed in the box and factory plastic. Decided to combine it with the 9901 nova pipe with a nova 1021 header. It broke in very well and the first gallon was good. great runtime about 9mins. Now after my first big race (and damaging a few parts) I cleaned it up and replaced broken parts (out drive, diff case). Started it up and I realised two problems:

1. It starts right away but after warm up, I give it full throttle and it stays in the high revs for a few seconds and drops back down (sometimes I have to apply brake to stop it from screaming).

2. After I got it to sound okay to me, I put it down on the track and it runs but its so sluggish and lazy, with almost no top end.

One guy told me the engine needs to be pinched, then another that knows more than him said the tune was just off. He tuned it and it ran great.

The next day I didnt touch the tune and it back to the same deal. Staying in the high revs after throttle and sluggish powerband (w no top end).
I checked my linkage properly so I know its not that. Can someone PLEASE shed some light!? Thanks!

Could be a air leak. Sounds like its is running lean. No top end...are you getting lots of smoke? Or no smoke? Do you have a rubber band or spring pulling that linkage back? If not put one on. After warmed up sitting at idle for a min. or more then give it 1/2 throttle, are you getting lots of smoke till it clears out? If not your low end needle is to lean. If getting lots of smoke after idle till it clears out, then seems like your top end is to lean. Need more info. to help you more.

have you checked the clutch???
set idol to .7
LSN flush with ball end then 2 o clock
HSN flush with needle assembly then 2 o clock
if it doesn't run you got issues else were

If you're tuning on the box then you likely do not have it fully heat saturated. Sounds to me like you've got your needle settings backwards. Fat on bottom and lean on top. To fat on bottom will make it hard to reach high enough rpm on the track to ever clear out. Might clear out on the box with no resistance, but won't on the track.

Don't know your experience level so I apologize in advance if you know most of this.

Think of the needle faces like the face of clock. We'll work in 1 hour increments. Leaning is screwing the needle in. Richening is screwing the needle out. The High speed needle or HSN is the top needle, the low speed needle or LSN is the bottom needle on the barrel of the carb where your servo linkage attaches. If you have a mid range needle on the opposite side of the carb from the LSN... DON'T TOUCH IT! Leave it at the factory setting which is usually flush.

Try setting the needles back to flush on top and bottom and see how that does on the track. Get as much heat into as you can, you want it around 190-200F before you start trying to tune. Lean the HSN an hour at a time, running a lap or two before leaning again. If after 3-4 hours you don't see any improvement reset the HSN and screw in the LSN an hour and repeat the HSN process. You may have to do this more than once but you will eventually see changes when you make your 1 hour HSN changes. Once you see that your 1 hour HSN changes affect the top speed continue to lean until you get good top speed and still have a faint trail of smoke. At that point richen 1/2 hour.

To set the LSN you can do a couple of things. First make a few high speed passes then apply full brake and count to 10 and pull full throttle. If the car gives a good puff of smoke and accelerates quickly without trying to cut out then your LSN is close. If it gives a puff of smoke and sluggishly accelerates to full speed lean the LSN 1 hour and repeat a few times. If instead it starts to accelerate very quickly then cuts out or dies as soon as you grab full throttle, richen 1 hour and repeat. Now you need to get the idle to settle down to a low steady idle. High idle could be either due to lean on the top or bottom. The idle should settle down after 3-4 seconds to a nice low idle. If the idle stays high for more than 3-4 seconds richen the LSN 1 hour and repeat. If it takes more than 2-3 hours to do this go back to where you started from and instead richen the HSN 1 hour and repeat the LSN process.

I am by no means an engine tuning guru but this process has been what works best for me. Just keep at it and try to make notes as to what works and what doesn't. Don't get frustrated if none of this works. Instead when at the track just go watch and see whose car runs really well during the heats and ask that guy for help.

Before doing any of the above, set the idle gap. Should be set around .5-.7 mm. I have paper clip that is around a half milometer that I use to set the idle gap on my engines. Set the gap and DON'T TOUCH IT! You need to learn to adjust idle speed using the carb needles. If the idle gap is wrong you'll have a very hard time getting the engine properly tuned.

The Nova engines in my experience are some of the most forgiving and easiest to tune. It's possible you have some air leaks but it sounds to me that LSN is too fat and HSN is too lean.

this guy gives great advice !!!

Thank you. A true honor to get a compliment from someone who is as respected as you are.

great advice. This is how I tune my motors.

Yep, Apco1 gave a quick any easy way to chase a tune, works like a charm. That p5 was running lean on top for some reason. If they pop and start to cutout ....its way lean on top. :lol:

Carb setting
 

i read you setup on the carberator. I am running into this same problem. My question is when I set the slide gap. Do you set it Crome the bottom of the carb? Reason I ask is my carb has a red screw in Venturi. From the top it is pretty hard to get a straight shot at the opening so it isn’t very accurate. Thanks

You should always remove the insert when you set the idle gap, no need to remove the carb. But if it's not completely wrong now you could just tune it, presetting is just done to get it in the ballpark, you will need to adjust it ones it's up and running anyhow.