I changed from 20%nitro to 30% and didn't use the extra shim cause the engine is already with very little pinch so it's OK i beleive to use the 30% fuel.BUT the tuning was soooooo difficult,i couldn'ttune it right,the idle was low after WOT and then instead of loading up it was reving higher and after 15sec it was loading up.
It was shutting down after WOT(sometimes) but after changing plugs (P6) the thing went away,at least the shutting down.
Any ideas except of the plug.
Any other plugs i can use on the v-spec except of the P3 and P6?

how much fuel have u run through the engine?

Well there is one mistake. The shim is there for a reason. It wasn't just a freebie they threw in the box but a HINT that if you read the istructions, you'd notice they tell you to fit it for 30%. The reason: TO KEEP THE TIMING RIGHT.

Your engine IS running with advanced timing, this will start off with pitting to the hea from preignition but will result in in a conrod or crank failure should you continue. No matter how the pinch is With 30% the volume of the chamber must be increased. It'll run cooler and should be happy with a P6 where you are.

Alex, your talking rubbish as usual....

The engine is fine on 30% with stock shimming...

My guess is the middle needle is out of adjustment... or there is an airleak around the carb/backplate..

i did as you suggested once in another thread,i turned in the mid. needle about 1/4th.I just can't find the right tune.This was happening from the begining though but it was easier with the 20%.
Now the plugs seems not to be working well...

Put the extra shim back in. You are having to use a colder plug right now to help bring the timing back to where it needs t be, but instead put the extra shim and and continue using P6 and P3 plugs and you should be fine.

Galifrey- Just because your engine runs fine on 30% and two shims doesn't mean that everyones will. As I have said before there are more variables than anything in the tuning of these tiny little engines. Everything from fuel brand, makeup, barometric pressure, ambient temperature, elevation, humidity, pipe, fuel tubing, gearing etc. etc. etc. can effect these engine. And judging from your last post you obviously don't understand this.
Yes he could have an air leak or a bad carb- but the shim is the first thing I would try before searching for an air leak or bad bearing.

Thanks Sky, you saved me from having to lay the SMAK down. If Galifrey you were indeed the GOD you think you are, then you would have noticed that Chris is in Cyprus. This suggests to me that his ambient temps are 100'F + and Nicosia being quite elavated would suggest a low barometric pressure. So put the god damn shim in and run it with a P3 plug. There will be no air leak and it will just need a minor twiddle of the needles.

alex

Any time you wanna try and lay some smak on me (will make a change from you smoking it) I know chris is in cyprus, I know the temps out there, increased nitro adds air which compensates for the thin atmosphere...

Low barometric pressure also lowers the engines efficiency already, the same as adding a shim... Higher humidity may well be an issue... extra water in the air increases the combustion chamber pressure and a shim can reduce this... reducing the BMEP...

Skyline, thanks for trying to patronise me, I do understand how these engines work, I also understand the variances about fuel etc, but if you actually read what I put, I merely quoted the manual about the shim, where Alex said it said something else... Thats with his 20 and 25 gallon engines he got those manuals i suppose...



Chris, I am coming to Paphos on the 20th August, if you want to meet me, I will sort it for you... Or at least try to... I can also bring another V-Spec you are welcome to try...

We can also check the piston and head for the tell tale sand pit marks that will show whether detonation or pre-ignition is a problem.

One of the things that either of the others fails to mention is a lot depends on how you drive...

If you blip the throttle a lot, you can find that the carb will spend a lot of time in the mid range and this can overheat an engine that seems perfect on top and idle...

Also, make sure you change the filter regularly, if you dont you will always be chasing the needles... especially with the dust out there...

Thank you all for the info.
Of course we can,bring something to race!!!
The temps were very low(210F-220F).Lower than before(240F-250F)
So i don't thin there was any detonation.And the real problem was that the engine sounded rich all the time,with gurgles at higher rpms.

20 or 25 ??? Me thinks it's you that's shootin up. The most I've had from a mill is 16 Gallons and then it was just a loss of compression. One of my V-Spec's gave up last weekend having hit 13 Gallons. The other 2 are still going strong and have 8 and 4 gallons through them each.

(ignores alex)

Okay will try and bring my S3, but wont be able to bring fuel..

See you in 2 weeks Chris

(real help not forum bull)

Because he/she cant admit to failure.

Galifrey- LOL- You must be a stand up comedian on the other side of the pond. BTW- That high horse you just rode in on- Just ran off with your girlfriend and some irish dude on the back.

ahhhhh you 2 make a lovely couple... My wife agrees

But you'll have to wait till Dec 21st to make that marraige official now.

Sheesh and you tell me to grow up...

Look forward to bumping into you in cyprus.... I will be sure to make that bump as hard as I can... So will my (female) 6ft wife....

tw@t

Just Peachy.

DAAAMN!! These forums really bring out the best in people dont they.

this ***** is funny! GEEK ALERT GEEK ALERT!!!
The real prob is you









































bought a V-SPEC............

Getting the thread back on track...

So the engine is not picking up cleanly but the temps are about right...

Did you switch to the cooler plug? or are you still running the P3 V-Hot plug?

Even on a hot sunny day over here, I have been running the V-Hot plug and adjusting the mixture accordingly...

I am assuming as you have just switched fuel, you have fresh fuel... what percentage oil is the fuel? Indeed what fuel is it?

It may be best to reset the needles to stock and start from there... including the mid needle...

First get the car up to operating temp...

Run the car on a long straight flat out, and see if the engine cleans up.... if not, main needle in 1/8th turn, repeat....

Once this is done, set the car at idle, and see how long it idles for before loading up... You want it to idle for at least 10 seconds ideally, to simulate a crash and waiting for a marshall... You can also use the pinch test here... pinch the fuel line just before the carb and see how long it takes the engine to gain rpm/cut

If it cuts without changing RPM, likely it is too lean... if it gains rpm after about 1-2 seconds and then dies, it is about right... if it idles for much longer than 2 seconds then the revs gradually increase and then it dies its too rich...

Using these two benchmarks will give you a good bottom end setting...

Then slowly (1/16th at a time) turn the middle needle in so you just have the slightest hesitation when you open the throttle fully after idling... if you have to adjust this much more than 3/8ths of a turn, then something is wrong...

Now re-check the idle mixture setting...

That should be about right assuming you have good fuel, good plug and the engine is sound, shimming is correct and there are no airleaks in the fuel system... Any further adjustments should only be required to the main needle when something changes, but if you change the carb restrictor, everything will need resetting..

One more thing, the OS runs best with a restrictor in the carb, removal of it can make the engine harder to tune with some pipes... but I think you are running a 2050 arent you? so that should be fine...

Let me know how it goes...

Yes it's a t2050 and a p6 plug(fresh).
The fuel is Red Max(clear color)30% nitro and 12% oil(fire and ice).
I already did that.the thing is that when i come from WOT to idle it revs up a little after 2-3sec,then drops at normal idle and doesn't seem to load up that easy even if i richen up.[:@].

I did turned the middle needle in about 2/8ths and it seemed to help a lot but i think it needs more "care".

If you've done all that and turned the MSN 1/4 (2/8ths to you) turn in. Then I feel there is an air leak from the most likely source. THE FRONT BEARING. I have had this problem you describe since sunday, but after swaping the front bearing, things are sweet and the mill which I had thought was just worn out, is now breathing again.

OK honestly... what is wrong with a v-spec...

I'd like to know before i make the investment into one. Seems to do well at the nationals and regionals.

That means its too lean on top usually... hanging on the pipe... it may be too lean in middle as well, but richening the main may help..

Like alex said, it could be the front bearing and an air leak like I said before... but equally the rear bearing can cause wear to the crankshaft/crankcase tolerances if its shot as well... this will then take out the front bearing...

look for signs of abrasion in the case where the inlet port is.... and around the section where the conrod big end rotates...

and check the bearing for up and down play....

A little off topic, but what size shim is given with the v-spec to use with 30% nitro. My sh 2004-xb is shimmed out of the box for 30% and I want to take one out for running 20%. I'm not asking whether or not I should do it, just wondering what size the v-spec shim is. Thanks