We just took our EVO to the track and these are the results.
12.54 at 112.21mph with a 1.84sec 60' time
Traction sucked as it was 32deg outside and the track wasn't prepped at all. Either it would bog if dumped to low, burn the clutch if slipped too much or smoke the tires if dumped too high. With a stronger clutch and a little warmer weather there would be a 12.4x in it. Mods are|: a manual boost controller running 20psi dropping to 19psi, S-AFC running about 12.0 A/F, our 3" cat-back system, and 3" downpipe. I just finished some tech articles on our site for the EVO VIII and I learned some new things today also. We only saw a 10-12whp gain with the 3" DP and test pipe. The reason for this is that once the MAF signal start going up the timing goes to ****. At around the 300whp level (FWD) I'd see 10deg adv. at peak torque and then it would slowly climb to 18-19 deg at high rpm's. As soon as we made more power (with cat-back and downpipe) the timing drops to 0-4 deg at peak torque and only climbed to 14-15deg at high rpm's. This can be seen on the dyno curves and felt on the *** dyno as the torque really didn't go up much. There's another 30ft-lbs and probably another 10-20hp in it once we can control the timing (bigger injectors or an ITC like device). I'll get a vid of the run to mpg soon. BTW the car weighed 3400lbs with me in it (I weight 245lbs). See, FWD dyno #'s do mean something

Martin

 

Great numbers !! I am also taking the same route with mods. I have a boost controler now set at 21psi. Got the catback, downpipe and intake coming soon. I was running 23psi and experienced knock. Any ideas when we will be getting a chip or acsess to the ECU to inrease or dissable fuel cut?

 

Hey Martin,
Great track numbers. They are very encouraging.
I am a tiny bit confused on your tech articles though.
In one article you had a SAFC and boost control (which one BTW?) making about 300 WHP. In another article you have a catback making about 300 WHP.
I am going to assume that they are independant tests. Is that correct?
If so what does the combo of all 3 of those measure on your dyno?

Also are you going to start using something like the EMS? It sounds like something like that would work well as a one unit solution to a lot of problems. It may not be the easiest route, but might be the cleanest. I would be really interested in looking into one of those even if I keep my car mostly stock otherwise.
This is just my play car, and I would like to learn how to do something new. If my car is down several weeks while I tune something, its not that big of deal.

 

What gas/octane are you running? Curious if you got any knock sustaining that high boost out to redline...

 

Runnin' 92 octane. Yes I did experience knock sustaining that high boost out to redline. That's exactly where it was happening.

 

what about at 21 psi? is it holding 21 to redline? Is it a lot faster now?

 

For now I think an AFC would be the only way to do that.

 

Martin, I was reading your tech article where you talk about 20 psi probably being the safest for 93 octane. What about for 91? is 20 still safe without messing with the fuel?

 

By knock do you mean fuel cut or did you monitor ignition timing or knock sensor output to see if you where getting knock. The ECU cuts fuel and spark based upon a MAF reading. If the reading gets too high then the ECU initiates fuel cut.
One way of reducing the MAF signal is with an S-AFC, it modifies the MAF signal by increasing or reducing it, thus telling the computer that there is more or less air going through the engine. By reducing the MAF signal (via S-AFC) you are actually raising the fuel cut level. For example lets say the the computer will initiate fuel cut at a MAF signal of 100 (arbitrary number). At 6K rpm the stock MAF signal is 100, the A/F ratio is 10.5:1 and you're hitting fuel cut , now you modify the signal with the S-AFC (or whatever other method is used, ecu mods, ect) and reduce it by 10% to 90 and now your A/F ratio is 11.8:1. (since the computer thinks the engine is getting less air it send less fuel). You've just leaned out the A/F ratio and raised your fuel cut level, but obviously there is a limit since you can only go so lean before combution temps go up and you melt a valve or burn a piston.


Martin

 

It seemed the engine stoped hard with a slight jolt and started again after I let up off the gas.

 

That's fuel cut.

 

Fuel cut. Are you sure you weren't bouncing off the rev limiter? It is somewhere around 7500rpm.

 

That's definitely fuel cut. It would probably be a good idea to reset the ECU after you've hit fuel cut and readjust your boost so that you don't hit fuel cut any more.

 

So it looks like an AFC is in order. How do I go about resetting the ECU?

Does this damage anyting when it happens, fuel cut that is?

 

Hi,

Fuel cut does put stress on the engine and drive train, however, its purpose is protect the turbo and engine. My Talon has 123,000 miles and prior to going to a Vein Pressure Control Unit (MAP) I hit fuel cut many times. Maybe 20 or so. However, it is something you do not want to tune around without the knowledge of AF ratios and EGT, so lower the boost. Here is a primer on the DSM ECU but probably applies to the EVO ECU and you should read it before you start tuning to avoid fuel cut.

http://members.shaw.ca/costall/ECUprimer/ECU_ch7.html

The reason the recommendation for resetting the ECU is that it "learns" the fuel cut parameters relative to temp, press and mass air flow and triggers it next time the same conditions exist; at least it did in our DSM's. Claudius probably has a better handle on the EVO ECU's and whether resetting make sense. However, if you have changed nothing since fuel cut, resetting is not necessary.

To reset the ECU just disconnect the negative terminal on your battery for a couple of minutes, or unplug the ECU although I prefer the battery as it reduces the chance for static arcing.

Speedlimit........

Edit: The primer has a table of contents for the DSM ECU at the bottom and is courtesy of clubdsm which has helped the 4G63 get blown since the early 1990's.