I'm to the point where I need a way to control timing while under boost with the stock ECU. There are a few ways I see to do this:

1. MSD box plus another box to retard timing based on boost pressure. This would easily cost over $400 for the DIS2 plus the timing controler. From the advertizing it appears you can only retard 1 deg per psi of boost, which is not what I want. At 22 psi I'd be getting a minimum of 22 degrees of retard.

2. APEXi ITC. RPM based and can only adjust +-15%. This would only allow a few degrees of retard at WOT and would effect timing at all throttle angles. Seems like the best alternative so far. Cost ~$300.

3. J+S Safeguard. Looks like a good product, but really can't take full advantage of the per cylinder knock control as there are only 2 coils on a DSM. Also seems like overkill as the stock ECU already pulls timing when it sees knock. I'm not sure if you can program it to reduce timing based on boost or not. Cost ~$500.

4. Throw the stock ECU in the trash and make the car do what I want with a standalone.

I'm getting tired of all these piggyback computers to fool the stock ECU, but if there is a cheap solution to retard timing about 5-8 degrees under full boost, I'm all ears. My car runs great at WOT with the base timing set to zero, but off idle and part throttle driving respose suffers. The car is fine on race gas with a base of 5 degrees, but unfortunately I can't run race fuel all the time on a daily driver. Maybe a DSMLink in a 1G would be a better option? Seems like all that effort would be better used for a standalone. Any thoughts?

1g DSMLink works well.

To my knowledge there is no DSMlink for the 1Gs. The 611whp Smithoid Eclipse runs a standalone Haltech with the J&S unit. For 1Gs I would recommend the AEM EMS from what I've searched and read.

There isn't a DSMLink for the 1g, but you can now use it on a 1g also with some changes in the wiring harness. Hal Landry did it I believe.

Yes, Hal did this for his brother's 1G.

I feel an APEXi ITC would accomplish the same thing as the DSMLink for my purpose. Both of them adjust timing based on RPM. By the time a DSMLink is all said and done in a 1G, you'd have close to $1k into it, may as well get a Haltek.

Why do you need to pull more timing under boost? The stock ECU already pulls timing as the boost goes up. How much timing are you getting, and how much are you wanting to get? Also, what injectors are you working with?

Brad

600cc injectors at 38 psi base fuel pressure. I will not run less fuel pressure to compensate.

The car runs great at WOT when the base timing is set to zero degrees, but part throttle driving suffers.

When the base timing is set to 5 degrees, I get 20 counts of knock throughout a 3rd gear pull.

The reason I'm having this problem is because it's a 9:1 engine on 93 octane, which makes it more sensetive to timing and more prone to detonation. I need 5 degrees of retard at WOT. The car is set up now with zero degrees of base timing, and I've learned to live with poor off idle response.

How about selling your AFC, and getting an eManage? That would allow you to adjust timing based off of RPM plus load, and not cost too much. A standalone would be best obviously, but it seems kinda $$ to just get a few degrees of timing retard. Or you might contact someone who makes chips to see if they will make one for you with an adjusted timing map(assuming you have an EPROM ECU).

Brad

Originally posted by tanner261
I'm to the point where I need a way to control timing while under boost with the stock ECU. There are a few ways I see to do this:

1. MSD box plus another box to retard timing based on boost pressure. This would easily cost over $400 for the DIS2 plus the timing controler. From the advertizing it appears you can only retard 1 deg per psi of boost, which is not what I want. At 22 psi I'd be getting a minimum of 22 degrees of retard.

2. APEXi ITC. RPM based and can only adjust +-15%. This would only allow a few degrees of retard at WOT and would effect timing at all throttle angles. Seems like the best alternative so far. Cost ~$300.

3. J+S Safeguard. Looks like a good product, but really can't take full advantage of the per cylinder knock control as there are only 2 coils on a DSM. Also seems like overkill as the stock ECU already pulls timing when it sees knock. I'm not sure if you can program it to reduce timing based on boost or not. Cost ~$500.

4. Throw the stock ECU in the trash and make the car do what I want with a standalone.

I'm getting tired of all these piggyback computers to fool the stock ECU, but if there is a cheap solution to retard timing about 5-8 degrees under full boost, I'm all ears. My car runs great at WOT with the base timing set to zero, but off idle and part throttle driving respose suffers. The car is fine on race gas with a base of 5 degrees, but unfortunately I can't run race fuel all the time on a daily driver. Maybe a DSMLink in a 1G would be a better option? Seems like all that effort would be better used for a standalone. Any thoughts?

Click to expand...

Did you ever find a solution, I'm currently in a similar situation.

Yup, Me too, too much timing for a 9:1 motor in 1g ECU...
By the time you get A/F ratio, Timing, Boost, Datalogger, new MAS, etc, might as well have bought a AEM EMS is what its looking like...

I have found a solution, burned an EPROM with compensation for the larger injectors, thus the ECU is seeing actual airflow and is using the correct timing tables. Timing now drops to 19 degrees instantly once there is positive manifold pressure. Before it took about 300ms longer for this to happen when going WOT from 3.5k RPM in 3rd gear. Part throttle boost gives a lot less timing, no knock, and linear power delivery. The car builds torque sooner after a shift. All driveability isses seem to be solved by letting the ECU see actual airflow.

This can only be done with an EPROM ECU, and the correct hex address can be found here: http://users.wpi.edu/~ktarry/dsmromedit.html I also changed my idle RPM to 900 for more oil pressure at idle, and to eliminate stalling issues with cams.

This info came from the DSM-ECU list. If you don't have the capability to burn your own EPROM, you can send it to dsmchips.com. There really is no need for daily drivers to go standalone now that this mod is available. It's amazing it took 15 years to figure out the code, a huge thanks goes out to the DSM-ECU list.

I like your solution the best, but a ghetto way to get results is to:
(1)install a bleeder on the boost line that goes to the FPR, add a check valve to prevent a vacuum leak
(2)adjust your s-afc or other fuel controller device to add back some fuel to compensate for what your bleeder is taking out.

Fools the ECU into seeing more air, so it pulls some timing.

Not nearly as elegant, but very cheap and (theoretically) effective if you already have an S-AFC.

-Adrian

Well, it sounds like it would work, but now you will hit fuel cut faster...

Also, tanner261, can the EPROM be programmed to run with the 2g MAS?
At 12 lbs. boost I hit 2200 Hz w/ the 1g MAS, I've heard thats about the limit for these, and I want a less restrictive MAS as well...

I'll be tearing into the 3 1g ECUs I've got looking for that EPROM socketed ECU. Any way of knowing which 1g ECUs were socketed w/out taking the cover off? (if I need to call junkyards for one) Also, how much did dsmchips.com charge for your custom programming? Can they also do mods like TMO stage 3 while they are in there?

Thanks,
RallyGSX

The EPROM can be programmed to run a 2G MAS without a SAFC. I have both a SAFC and a MAFT, both are zeroed out. I'm running 610cc injectors at 50 psi base fuel pressure, making them 650cc's. BTW, stock injectors flow just under 500cc's at 3 bar. I have no idea where the DSM community came up with 450cc as a stock flow rating, this must be the flow rating at the operating fuel pressure (36 psi) on a 1G with a stock regulator. I have personally flowed these injectors at my work with printouts for proof.

dsmchips.com can do a lot of what a TMO Stage III chip can, but for a lot less money. The most important thing their chips can do is to compensate for larger injectors (which TMO doesn't offer) and eliminate fuel cut. I programmed my EPROM myself as I have means to do so. All the information is available on the DSM-ECU list mentioned above. If you are not electronically inclined, you should send the chip to Jeff at dsmchips.

I'm not sure if you can tell if an ECU has an EPROM without opening it up. There aren't any stock ECUs with the EPROM already socketed, they are soldered to the board, you have to take the ECU somewhere to do this (TV repair shop, computer repair shop, do it yourself, etc.)

It's only 4 screws to check for an EPROM.

ahains, I can't say for certain as I haven't tried it, but your bleeder method wouldn't take out enough fuel to get the ECU into a less aggressive timing map. On top of that, it is an extremely ghetto setup.