Car Not Making Power - On The Dyno Right Now.

[No Crust Racing]

Car is down over 20kw since the last time it was on this very same dyno. I have replaced a blown head gasket in recent times. Not using coolant, no head gasket symptoms since fixing it.

Same boost, same AFRs, CA18, T28BB.

I have changed the intake cam though, to a CA18DET exhaust cam, I have just gone over the timing again and counted the cogs between the marks, all is spot on as per the FSM, base timing is 10 degree.

It makes more power and more torque than it did previously up until about 4000rpm when it just falls over.

Before it made 180rwkw, now it's struggling to make 160.

I've got acompression tester coming to check and I've just had an idea that maybe the butterflies aren't working, would it make that much difference?

At the moment both cams are set to zero as I hae adjustable gears, don't wanna change them just yet.

Ideas?

[portaz]

Comp test first you have changed a fair bit of things that could be causing it so logic says you did something wrong, I had a issue on my audi and couldn't find it so re did everything I touched and it was all good , my bet is something to do with cam timing but I don't really know those engines but on rb26 a restrictive cat will cost 20 kw easy .

Scott

[GTScotT]

Is the cam swap a proven drop in upgrade or are you somewhat of a guinea pig working on fair assumptions?

Coz if the later I would assume the physical cam timing needs to be redialed...

[sickr33]

Did you use stock gasket or bigger (1.2-1.6mm)

If you used bigger gasket you have lower compression so will need bit more boost to make up for the lost compression!!

[sickr33]

Sorry i just read it again

Sounds like timing if it just "falls over"

[Dave.TAS]

Cam timing is wrong, the centreline of the cam doesn't just drop in, you need to dial the cam back in so it works

[Dave.TAS]

Put the intake can gear one tooth clockwise from

Factory to get it kinda close, from memory

[portaz]

Kinda close sounds a little scarey

[No Crust Racing]

Sorry guys, SAU wasn't giving me updates.

I was working on this issue here if you want the full rundown.

http://www.nissansilvia.com/forums/index.php?showtopic=532583&st=0

Comp test was fine. Turns out I had the butterfly actuator connected backwards. I'm fixing that then will see how it runs.

I quadruple checked the cam timing again and it looks fine, the advance one tooth trick is for people who don't have gears but that's where the bulk of the power comes from so I have adjustables.

This is a tried and tested path.

Cheers for the responses.

Edited February 27, 2013 by ActionDan

[AngryRB]

why would you change the intake cam? i must of missed somthing, is that a good thing to do?

[No Crust Racing]

In a CA the exhaust cam is 248 duration and 8.3mm lift and it's a direct fit on the intake side as well, which is only 240/7.8.

On It's own, not a huge upgrade, but coupled with adjustable gears it's worth up to 15rwkw mid range and top end.

Especially helpful if you have a larger turbo like I do.

[No Crust Racing]

I've just finished putting it all back together. Will post pic tomorrow.

I'm fairly confident it's right because it only fits on that side resting on the pin with the shaft in one position.

With the shaft in any other position other than fully CCW the lever won't attach and be resting on the pin comfortably.

I got under the car with it running and the actuator stayed put, I couldn't spin it up and be under it though but I think it's right now.

Those cam gears look spot on to me too.

I'll test drive it when it's not raining.

[No Crust Racing]

For anyone playing at home.

Before = Wrong.

After = Right (Bolt has not been tightened up in this pic).

Edited February 27, 2013 by ActionDan