I’ll get right to it. I’m running my TD05-18g, and I have been running 8psi with no problems, obviously. Last night I installed my wideband o2, and turned my boost up to 18psi. I got quite a bit of detonation with that. My timing was still set at the stock 10 BTDC. This morning, I turned it down to 5 BTDC, and ALOT of the detonation went away, but I still get some. I was wondering how much more I should go? I’m going to try 2BTDC, see what happens, but I don’t want to go to 0 (TDC). My A/F ratio is reading 11.3-11.5 at full boost. I know im getting enough fuel. What do you all think I should do?
I think you should turn the boost down till you figure out what you’re doing lol
First of all, if your ECU isn’t mapped till 18psi, then it will take values from the last “column” (say max is 14 psi)… so you’d be using fuel and timing timing values for 14 psi @ 18psi.
Adjusting the dist. can help, but then you are retarding ign for everything else, which will raise EGT, stress ur cooling system, and make the car a dog.
Using the dist to try and “tune” ign for a boosted car is just not a good solution.
Or how about an MSD boost timing control
there ya go
put the dist back to stock and get this, or something like the JRSC BTM which is probably the same thing as the MSD
retarding your timing via the dist. will make you car run hotter at idle and when not in boost. It will be inefficient
Also there is a limit to the amount of boost you can run. Camshaft, compression ratio, cylinder head design all play a part into this equation
Great responses all. :tup:
Changing the computer is the best way to go. Retarding at the distributor is only a bandaid fix because won’t it not give you full timing at the bottom were as a tune with stock distributor location wouldn’t.
I cant change the computer. Im stuck with what I got. Im just wondering if this is the point, where I need to start running race gas, or spraying meth. I am also considering possibly switching my MSD 6AL setup, so I can begin running my knock sensor once more. When I installed the MSD, i had 2 options. To utilize the stock “Ignitor Box” or to totally eliminate it. I chose to eliminate it, just because I did not want to use anything stock related on my new setup. Unfortunately, this also removed the functionality of my knock sensor. I think I may go back to using the ignitor box, along with the MSD, so at least my knock sensor is active, and can do what it can. Its just going to be alot of rewiring. Yuck.
How did you know you you were getting detonation if the sensor isn’t working? Is it audible? Does it cut off? or something else.
You certainly want to keep your base timing close to stock. I personally wouldn’t turn up the boost untill I at least had some way to properly read or log knock/ign timing during a pull.
I would get the Knock sensor working again too.
if you can hear the detonation in the car and you are running 18psi, then you basically juggling lit sticks of dynamite.
is there any reason you went away from the stock ignition? is it known to be weak? i would stick with the stock setup with its knock sensor and good stock components and work with the plug gap till you know for sure what the limit the stock ignition can handle and then do some key upgrades. but to disable the knock detection system is kinda foolish. there is a reason darn near all factory turbo cars run knock detection systems. it doesnt take much to melt down a turbo car… little nick in a vacuum line is all it needs sometimes.
has anyone pulled the rom data from those ecu’s and made a program to edit it?
i myself would build a megasquirt.
Brian
You took the words right out of my mouth.
im running megasquirt on my turbo’d bimmer. For now go set your distributer to 5-10ish degrees and go to sunoco and fill up with 100oct fuel. Not half and half, drain your current gas to empty or till you need more gas and run 100oct. CHeck your plugs regularly. Do a pull and shut down asap, pull a plug and inspect the porcelin (white part) of the plug for any kinda speckling or detonation. If its audible detonation you here now then your probably lucky to still have a runnin motor at this point.lol
its been a while since ive actively browsed the msefi forums and worked on a megasquirt. ive helped build and install two of them… did they get a better knock detection setup for megasquirt yet? (and not that crappy GM module)
ideally i would like to see a rpm vs knock sensor voltage table to define what is knock and what is not.
Brian
Also band-aid solutions. Expensive too.
The more u deviate from stock, the more careful you have to be.
You need to turn it back down, and really sit down and figure out what to do. Like someone said, you are juggling sticks of dynamite right now.
Cure to your problem: