Craigs New Datsun Sunny

mss is wired up, cams are switching.

although unfortunately had a bit of trouble withthe mss - one of the 2 ground wires which connects to the solenoids wasn't completeing the circuit and therefore triggering the solenoid. checked everything and definitely power getting there. Ran a seoerate wire from the bare pin inside the mss and still nothing so unfortunately it seems one channel on my mss is fubarred in some way :(

as it is, both cams are running off the one channel and therefore will only switch at the same level, from reading on the dash forum this might not really be a big deal, just have to wait and see what my curve is like.

Also, seem to be using a bit of oil, but then it isa new eengine and has been running on mineral oil til now. Just changed to fully synthetic. Did a 3rd comp test and still around the 250-260psi area so can't be a ring gone. Got a feeling my valve stem oil seals may be fooked. Should have done them before i built it really but didn't lol, so we'll see how the oil usage goes...

Finally, got my bigger injectors and mera maf ready to go as it's mapping day tomorrow bitches.... places your bets now pleeeeeeez :VVL:
 
the aftermarket VZR ECU's actually change the cam switch points to change both at the same time.

i believe the cams only switch at different points to make a smoother power curve, you will still make the same power you will just have a slightly larger kick.
 
exactamundo rossini

whilst the bigger kick might not be the best thing in terms of smooth power delivery, it sounds quite fun :lol:

vtak y0
 
Bloody nice car mate.

Since I did a lap with laurens in his green P11 VVL on the Nordschleife I totally love the high revving.

Will come and give this one some extra attention when attending JAE.
 
well

a rather mixed day at horsham with jez.

for starters we had to piss about for a couple of hours finding an intermittant vac leak and some dodgy wiring.

finally got it idling ok but ran out of time to map on dyno so had to map on road.

2 main problems noticed aside from mapping are a clutch issue, not totally disengaging. sam's reporting similar and seems like a g-spec release bearing thing.

i'm burning oil which i'm confident is valve stem oil sealls - my comp tests are too high for rings i think.

ANYWAY, for the mapping....

it's mapped, the rev limit is 8k, and between 7 and 8k it feels pretty savage lol. However, jez had the cams switching at 4800, which seems far too early to me. so the cams switch and you feel it actually drop in power! easily sorted though i need to have a play.

also, i think the cam gears need playing with, like i say from 7-8k it pulls hard and then the limiter stops it, so adjusting the cam gears and dropping the power band should help.

Main issue is though, that its been pinking it's tits off since i first started it, and to stop it pinking Jez had to back the ignition timing off to like 4' :wacko: lol Jez was also gobsmacked at the 250psi cylinder comp test readings. I'm starting to think the engine shop took more off the head and block than i asked and i'm running mental high 13+ comp. Also i was on 97 octane fuel, so some 99 vpower would probably help, along with some octane booster - then can hopefully dial in some ignition timing which should help dramatically.

So all in all, it's safe and not pinking now, it's savage for a whole 1000 revs to 8k, it sounds fucking awesome when the vtak kicks in, but there's a lot of room for improvement.

Worst case scenario as far as i see it now, although i'm undecided atm, is to whip the head off, do the valve stem oil seals, refit it with a 1.8mm cosworth gasket or 2mm cometic, run proper fuel with octane boosters and play with the cam switch point and cam gears. I reckon the cam switch a lot higher towards 6k, and the cam gears adjusted to drop the power band.

Any thoughts, advice etc welcome please... particularyl on the cam switch/cam gear power band adjustments, and also how much a 1.8mm or 2mm head gasket would drop the compression over a 1.2

mixed feelings, but overall fairly happy and Jez dida great job given pretty shitty unfortunate circumstances

thaaaaaaaaaaanks
 
4 deg!! :O haha nice! ... can you not work the compression out? would be pretty helpful i think

sounds awsum though mate, any vids?

Steve
 
Sorry to hear bout the problems m8, surely you can get it mapped with ubber high comp it would be savage if you could, also you can change stem seals with the head on if you'rre gunna keep the high comp, just need to pressurise the combustion chambers.
 
steve55 said:
4 deg!! :O haha nice! ... can you not work the compression out? would be pretty helpful i think

sounds awsum though mate, any vids?

no proper vid yet, well one in the hatfield tunnel sounds quite nice lol,yeh 4 degrees timing, not good lol

Steve
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mongo_tuned said:
Sorry to hear bout the problems m8, surely you can get it mapped with ubber high comp it would be savage if you could, also you can change stem seals with the head on if you'rre gunna keep the high comp, just need to pressurise the combustion chambers.
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yeh i'd do the seals like that if didn't change the HG, i'm not sure on the mapping uber high comp thing, Jez didn't seem convinced said he did his best, the fuel thing could help but if it is at 13 or more i'll be struggling on street fuel i think.

more confused by the flat feeling between 5 and 7k when the cams switch too - then the little surge, but then again 4' timing probably will feel flat!!
 
mongo_tuned said:
Yeah the timing wont help that at all m8, i'm hoping i'll have no issues like this as i ordered 12.5 to 1 pistons
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like i said mate, i've a feeling my head and block may have had more off than i asked for, ie. not the minimum - 250+ psi in each cylinder is fucking high when you think rowdys 16ve pistons got him what? 180psi? funnily enough 180 being what jez would expect from high comp he said...
 
hmmm yeah when you put it like that it does sound a bit iffy. I'll have to check how much the guy took off my head before he does my block.
 
Just checked roughly, if you take you're 250psi readings using 20x compression ratio = compression 250psi would give you roughly 12.5 to 1 which is bang on, although not a very accurate way of working it out.
 
yeh ross mentioned that to me, so dunno. but like you say not a great way to do it.

i need proper v power or summin, not bp ultimate which isn't as ultimate as i thuoght when i filled up with it. and some octane booster.

any thoughts on cam switch points? or any rough ideas on what to do with cam gears to move power band down?

anyone?
 
craiGTi said:
more confused by the flat feeling between 5 and 7k when the cams switch too - then the little surge, but then again 4' timing probably will feel flat!!
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i may be wrong, but i remember seeing when cam switch occurs, injectors overfuel, may be just bogging down because of that
i can rev till 4.5 -5 and lift off immediately and get backfire due to no cat

Steve
 
makes sense steve

just been out again, and upped the cam switch point to 5500. pulls a lot smoother n harder it feels, only problem being i think i heard a bit of pinkin between the old switch point of 4800 and the new of 5500. just playing so i'll drop it back to 5500, but i'm fairly sure with better fuel, octane booster, the cam switch point higher and the cam gears moved all will be well and fuckin savage.

w000p
 
craiGTi said:
yeh ross mentioned that to me, so dunno. but like you say not a great way to do it.

i need proper v power or summin, not bp ultimate which isn't as ultimate as i thuoght when i filled up with it. and some octane booster.

any thoughts on cam switch points? or any rough ideas on what to do with cam gears to move power band down?

anyone?
Click to expand...

make your switch point the same as the first N1 switch point (you have N1 cams yeah?)

your N1 high lobes will only make power high up, its like running C4 cams in a daily drive SR20 that only ever sees 1-4k. too much air gets in so it bogs down at low revs. once you get into the cam power band its fine. obviously N1 cams are tuned to make power from just before switchover to the redline. so use nissans research and development to your advantage.
 
Fucking /vvl/

LooL. Joke.. Glad to hear your making some progress, im sure after coming this far, you'll be able to sort these teething issues out.

Good Luck :clover:
 
cheers ammar

ye exactly ross, if i can bring the power band down a touch with the cam gears, up the rev limit a touch, and definitely switch the cams later it'll be awesome i think

so whats the n1 cam switch point? 5700?

need to find a shell garage nearby and some millers octane booster too
 
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