[dburone]

I know detonation is bad, but lots of people know how it sounds so i guess lots of them had detonation, so im not that lucky.
I also stop pushing it when i hear it.
Today ill start making the ignition retarding device.
Im running 8 psi with stock 9.0:1CR

 

[Crazy-Mart]

internals are pretty strong... little detonation that is taken care immediately isnt that bad... consider ive been running pretty lean for the last 15k km, been drag racing for a while before getting my afr... and last time i lifted the head the pistons were as nice as when i installed them... sure thing taught, dont let it go to much, pretty dangerous !!

 

[dburone]

internals are pretty strong... little detonation that is taken care immediately isnt that bad... consider ive been running pretty lean for the last 15k km, been drag racing for a while before getting my afr... and last time i lifted the head the pistons were as nice as when i installed them... sure thing taught, dont let it go to much, pretty dangerous !!

Thanks for the post!!
Yesterday i started to modify the ignition so it can retard with boost.
How lean are you running?
With boost ill try to make it a bit rich, but without boost i would like to have good fuel economy.

 

[velardejose]

I will look for a higher pressure fuel pump today...
And relocate my single wire type O2 sensor, seems to be too far to get an adequate reading (too cold)

 

[dburone]

Finally i modified the vacuum advance to also retard, and it works,

i dont hear any detonation at all.
The problem is that im not sure when the device is retarding

ignition, and think its happening too soon.
Il have to see how i can measure this, because i need the car to

be accelerating on the street for the turbo to build boost, and

its hard to use the timing lamp that way.
Maybe ill need to get a harder spring.
What should stock vacuum advance be on a e16?
Thanks

 

[BII]

I guess this is to much advance for a turbo car.
I tried connecting the vacuum advance to the manifold so it always has vacuum, and then i set initiall timming again to 10BTDC, this way the vacuum advance is always advancing to stock timing and when boost starts it retards 10. It was only a test, but i found out that the detonation i was hearing was less now, then i tried the same thing with initial timing at 5BTDC and the car was slower at low revs, but didnt have any trouble at high revs and couldnt hear any detonation at all. So i guess the engine liked to retard about 15.
This was just a test, but now its clear i have to do something with my timing, ill have to make some device that advances normally with stock timing untill boost starts and then retard about 15 which tells me that max advance with the data above will be about 20btdc with boost if i dont step hard on it it will work almost like stock.
What do you guys think?
__________________

This might help

You generally don't want to use manifold vacuum for the advance, I would think you'd get really bad performance at idle and low RPM, and the transition would be horrible too. Aside from that, your timing would be erratic when shifting. The idea is to match your timing with your engines needs, the best way is to use the vacuum port on the carburetor.

 

[Crazy-Mart]

as for me, i was hitting the fuel cut from the afm... and the stronger piston from the E15et and pushing it, i didnt got any dammage... on the E16, i would try too keep it a little richer rather than leaning it...it will be safer too...

 

[velardejose]

Yup
Richer is safer
Let's stay this side of a 11-12 a/f ratio at boost
You can use a manual vacuum/pressure pump with a vacumeter/manometer, so you can see at which press/vac the advance moves (advance or retard) and how much
This can help:
http://autos.groups.yahoo.com/group/e15et/message/45374
As much as I know 2 inches hg = 1 psi

 

[dburone]

This might help

You generally don't want to use manifold vacuum for the advance, I would think you'd get really bad performance at idle and low RPM, and the transition would be horrible too. Aside from that, your timing would be erratic when shifting. The idea is to match your timing with your engines needs, the best way is to use the vacuum port on the carburetor.

I am using the "the vacuum port on the carburetor", i only used the manifold vacuum for the test i did a couple of days ago, now vacuum, pressure is comming from the carb. I just dont know how much i should retard for each psi of boost.

 

[dburone]

Today y adjusted the vacuum advance - retard device so it retarded what i wanted to, and i managed to make it retard like this:

PSI degrees retard
0 0
1 -2
2 -3
3 -4
4 -6
5 -9
6 -10
7 -11
8 -12
9 -13,5

What do you think about these numbers? I think they arent bad, this would give me a maximum advance of 23 degrees at 8 psi.
No detonation now!!!

 

[Crazy-Mart]

very good indeed. that should feel very good on the road also !!

 

[dburone]

very good indeed. that should feel very good on the road also !!

It runs best on the highway,i really enjoy it!!

 

[dburone]

Yup
Richer is safer
Let's stay this side of a 11-12 a/f ratio at boost
You can use a manual vacuum/pressure pump with a vacumeter/manometer, so you can see at which press/vac the advance moves (advance or retard) and how much
This can help:
http://autos.groups.yahoo.com/group/e15et/message/45374
As much as I know 2 inches hg = 1 psi

Now i am trying with a 120 jet on the first barrel, before i had a 115 and now the sparks are all black and not brown anymore

 

[velardejose]

Do you have a fuel pressure regulator with a boost inlet?
What fuel press do you have?
Maybe yours is too high and your carb is flooding

 

[dburone]

Do you have a fuel pressure regulator with a boost inlet?
What fuel press do you have?
Maybe yours is too high and your carb is flooding

I have a press regulartor,
initial pressure is 4 - 5 psi and it climbs to about 16 at 8 psi of boost
But its not becuase of that, thing changed when i rejetted
I also have air jets closed a bit, ill try opening them up, but i think i was better with the 115jet