Just wanted to post this up because there is a lot of conversation about how high of a comp you can run on the stock ECU and pump. As I suspected, you can run 12.5 comp on stock ECU and pump gas (93oct).

The set-up I have is 12.5 comp, Crower 2's, MP60mm, LTH, lightly ported head, ported stock intake, Stock ECU.

Here's a quick vid I just made (don't mind the stumble at the end, I have a vac leak I haven't addressed yet).

YouTube.com

Nice job as usual MB. Makes me want to build the spare block I got.

Do you plan to put it on a dyno? Very nice!

Originally posted by Red90Sev
Do you plan to put it on a dyno? Very nice!

Probably. I'm going to hit the dyno when i tune the Megasquirt, so I will probably do a baseline on stock ECU first. It takes me about 20 seconds to switch from stock to Megasquirt with the plugs I have set-up

Originally posted by bullettdsm

Originally posted by Red90Sev Do you plan to put it on a dyno? Very nice!

Probably. I'm going to hit the dyno when i tune the Megasquirt, so I will probably do a baseline on stock ECU first. It takes me about 20 seconds to switch from stock to Megasquirt with the plugs I have set-up

I like to hear this. If I had the knowledge about MS I have now, I really could have made my own plug and play harness at the stock ECU location, to swap back and forth when needed.

Originally posted by 740 turbo brick
I like to hear this. If I had the knowledge about MS I have now, I really could have made my own plug and play harness at the stock ECU location, to swap back and forth when needed.

Extra connector/pigtail for the coil pack and the injectors and you're good to go.

Originally posted by xcasbonx

Originally posted by 740 turbo brick I like to hear this. If I had the knowledge about MS I have now, I really could have made my own plug and play harness at the stock ECU location, to swap back and forth when needed.

Extra connector/pigtail for the coil pack and the injectors and you're good to go.

Yup. The only other thing I had to do was put the egr tube back on for emish.

Ok, so current update on the 12.5 engine; got some miles on her (idk how many. I'm upstairs right now maybe in the 60 -70 mile range. I haven't had a lot of time to run her around). When I first got her on the road, she seemed to have quite a bit of pick up and go. But as the computer started getting involved, she is definitely getting more "loggy". I believe that that stupid ECU is pulling timing and richening up the mxiture. Is it as bad as stock? No, but I don't really see the difference between my 10.5 and the 12.5. Now she'll still spin into 2nd gear (with a Quaife in there too), but it seems to have gotten slower since the ECU. Now, if I reset ECU, I start back at the quite a bit of pick up and go. I should be tuning her thursday on MS (weather permitting)

keep us updated on how this goes please. and in your opinion do you think you can run a higher comp than 12.5:1 on the stock ecu?

I would say it can, but it will pull timing so much as to make the compression increase almost pointless

Originally posted by 97 Demon
keep us updated on how this goes please. and in your opinion do you think you can run a higher comp than 12.5:1 on the stock ecu?

Originally posted by 740 turbo brick
I would say it can, but it will pull timing so much as to make the compression increase almost pointless

Bingo.

So newest update; got her on the dyno today (not real successfull. Trying to teach a new tuner MS. He's a real good tuner just doesn't know MS so we have wasted a lot of time so far trying to teach him).

The stock ECU has now effectively been "taught". Put her on the dyno for numbers, and they weren't very impressive, lol.

135.5whp with 117torque @6000rpm.

Now I wanted to log timing numbers, but his equipment was malfunctioning. So here's what I think was happening. I think the stock ECU was seeing events and freaking out. I think (judging from the instant power gains when I reset the ecu and then the power loss as she "learned"; as well as the dark spark plugs) that the stock ecu was pulling timing and pumping in fuel.

I believe I got better numbers on the stock ECU and 10.9 comp. I just haven't got the memory (or the time to search) to come up with the info.

So the long and the short of it is; yes, you can run 12.5 comp on pump on stock ecu (I'v egot plenty of miles on her now as a daily), but your gains wil be limited by the stock ECU (and this is an engine with all the NA bells and whistles).

MS tune on this set-up yet to come.....

Can't say I'm surprised, but I'm extrmemly glad you took the time to do it.

Originally posted by DarkOne
Can't say I'm surprised, but I'm extrmemly glad you took the time to do it.

You know the saying, "Inquiring minds want to know" lol.

And now the debate of yes you can/no you can't has a little teeth to it in a real world sense.

hey man, what octane did you have to run for the 10.5:1 setup?

Originally posted by 97 Demon
hey man, what octane did you have to run for the 10.5:1 setup?

at that compression, 91 or better. Why go for performance and skimp $0.15 a gallon at the pump?

ok, just checking as there is only 1 station around me that has better than 91 octane, wanted to know what would be needed to run the motor.

Just to show that this does still work, here's a vid at 2300 miles with a 900rpm idle. Seems to have a bit more power. Maybe it took that much longer for the ECU to "learn" the engine set-up.

YouTube.com

Sounds just like my setup mark on that engine, except the 12.5 to 1 versus stock pistons. But with my head being milled very slightly to make it true back when I had it worked over, I was told I would be about 9.7 ro 9.8 to 1 instead of 9.6. My head was ported sort of "moderate" whatever that means :)

I know dynos are very different one to another, but I did get 148-149 whp on my setup, stock ecu, stock pistons, and a lot of other stuff so it was interesting to see that HP number from that setup.

The stock ECU is a big limiter (as I've discovered and lived with for some time). One day I'll get around to doing more than just maintenance to my car again. Once life gives me a chance.