Full build thread....TONS of pics!
#161
#164
Anyway, with these cams, they seemed to like AFRs as you are approaching "0" PSI, about 24-28 degrees of advance from 5500 and an AFR of 11.9:1 and tapering into redline being about 11.0:1. This is the Vac side. This will give you an idea of the type of timing you should see entering boost.
The real key to this engine with these cams seems to lie with a slightly richer AFR and a fair degree of timing. For example, as much as 31 degrees of advance was able to be added at WOT N/A with these cams. Try to keep atleast 18 degrees of advance at worst case scenario in boost.
Don't be overly concerned too much with AFR and making power. I did some testing with adding more timing, richening AFRs, leaning AFRs out and such and in the end, I found out that there was a minimal difference on these cams from power made with a 12.7:1 vs a 11.0:1. There was just a single digit power difference and air flow difference from all of the combos tried.
So, in a nut shell, run the richer AFR for less propensity to knock
Last edited by paul_dezod; 05-25-2010 at 05:28 PM.
#166
Now that I think about it yes the cams are what have the timing pickup so perhaps timing is a bit "off". EGT's seemed low so perhaps I just have to back off timing more so than I would normally do. I guess we can try both ways at lower boost and see what happens. Difficult to do on the street though. May need dyno. Will also play with cam advance as well. AFR's were hovering at 11.5:1 or so. Never really went that high in boost. Started having issues over 1 Bar.
#167
Now that I think about it yes the cams are what have the timing pickup so perhaps timing is a bit "off". EGT's seemed low so perhaps I just have to back off timing more so than I would normally do. I guess we can try both ways at lower boost and see what happens. Difficult to do on the street though. May need dyno. Will also play with cam advance as well. AFR's were hovering at 11.5:1 or so. Never really went that high in boost. Started having issues over 1 Bar.
Richen that up a tad more. You should a very small level off in power, but it will be good for knock control.
#168
We we hit the dyno yesterday finally.
Had to end the day early.....bad gas we think.
Ended up making 330-340whp at 13psi and we started getting knock. the Hydra was pulling timing from 5500 to redline which was 7k. I filled up at a hole in the wall gas station before i got there because there was nothing else around.
So i'm going to burn through the gas and fill up with some better gas and try again. Hopefully that was our problem. I did pull the number 1 spark plug at one point on the dyno to check something and I dropped it on the ground and it was about then we were upping the boost and getting knock so that could be part of the problem as well.
98% humidity didnt help either.
I will keep everyone posted....
Had to end the day early.....bad gas we think.
Ended up making 330-340whp at 13psi and we started getting knock. the Hydra was pulling timing from 5500 to redline which was 7k. I filled up at a hole in the wall gas station before i got there because there was nothing else around.
So i'm going to burn through the gas and fill up with some better gas and try again. Hopefully that was our problem. I did pull the number 1 spark plug at one point on the dyno to check something and I dropped it on the ground and it was about then we were upping the boost and getting knock so that could be part of the problem as well.
98% humidity didnt help either.
I will keep everyone posted....
As I checked the VCT map, from + figures it gradually decreases down to 0 to - figures on top and i think thats where I see the problem is..
Oh 1v knock thresh might be low especially on higher rpm, did you guys hear the actual knock? coz on mine (stock motor) its almost impossible to hear due to turbo system noise.. Maybe you go up a significant amount with the knock threshold, see if you are still making power while you advance and if you do, you're still not at MBT and i doubt those voltage are real knocks.. by theory you should stop making power when you are knocking.
im on E85 by the way.. im dynoing soon and will be doing the VCT map see what happens
#169
Oh 1v knock thresh might be low especially on higher rpm, did you guys hear the actual knock? coz on mine (stock motor) its almost impossible to hear due to turbo system noise.. Maybe you go up a significant amount with the knock threshold, see if you are still making power while you advance and if you do, you're still not at MBT and i doubt those voltage are real knocks.. by theory you should stop making power when you are knocking.
can you post up pics of the data-logs of the dyno runs where you guys think you were knocking? i wanna see what thy look like. if it is around 1 volt and it is somewhat constant with a smooth or flat top to the point, then it is most likely engine noise. if the knock looks like a sharp spike and is above the rest of the engine noise, then you know you have detonation.
#171
They were sharp spikes to the knock voltage. At lower boost pressures all was smooth rising to maybe 0.7-0.75 volts smoothly. No knock. Higher boost pressures, it would go up smoothly to maybe 0.60-0.65 and then spike to 0.85 or higher. Was not noise. Very clearly can be seen on datalogs and I want to play more with timing I think as well as cam timing. Gonna take a while that is for sure but we'll get it.
#175
They were sharp spikes to the knock voltage. At lower boost pressures all was smooth rising to maybe 0.7-0.75 volts smoothly. No knock. Higher boost pressures, it would go up smoothly to maybe 0.60-0.65 and then spike to 0.85 or higher. Was not noise. Very clearly can be seen on datalogs and I want to play more with timing I think as well as cam timing. Gonna take a while that is for sure but we'll get it.
#178
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