ErnestSw

What about exhaust issues?

Darien

Jim,

The coils are the only things that I haven't replaced??

Darien

Exhaust is good, pretty much a straight shot

Tony

There was no pinging, not a sign of it at all. The kid running the dyno is pretty sharp as well, he would have said something. He has a very stock looking 10sec Ford Focus as his daily driver! I was manning the camera but only 15ft away..i would have heard it, especially if it was bad enough to cause that result.

I think it is gear related as the car "breathes and pulls" fine in 1st and 2nd gear. If you look at the chart things occured at the peak torque value. Dunno. If you want, Darren we can go over and do a run in 2nd gear to see if the same issue crops up...perhaps turn the BEGI bleed in another turn, unless you did that already?

See what feed back we get here first. Theres alot of dyno experience on hereand perhaps someone else has seen somehting similar?

Jim_H

I have a couple of spare coils I could send if you want to try them. A run in second gear will confirm whether it's tranny related.

Darien

Thanks for the offer I may take you up on it if the we run it in 2nd and it checks good.

mark kibort

If you have rpms, you had a spark sensor. which means, the dynojet automatically adjusts for wheel and clutch slippage. Usually the "real" actual and internally adjusted are pretty close, within a few hp.
(not to be confused with actual and SAE runs) what we are talking about is the MPH vs HP compared to the rpm vs hp curves.

the fact that the power curve falls off so fast, is probalby related to lack of air flow out of the compressor. getting pressure inputs from the fall off point would confirm this.
Its not fuel related as the fuel is good to the end.

do the run in 4th gear, there is less of a chance of slippage, but 3rd shouldnt be an issue. i did 3rd gear a while ago, and we only lost 5-7hp due to the increased gearing.

if you had spark issues, you wouldnt be making 350hp!

Mk

Darien

Thanks Mark, If I ran it in 4th gear, wouldn't that be getting the mph up around 200, that could get a little scary

Tony

This chart shows the MPH vs RPM.

also..."how things work"
http://auto.howstuffworks.com/automa...smission10.htm

AO

Spark timing is not adjustable, but cam timing is. Hopefully one of you Vegas guys has one of PorKen's cam timing tools.

John Speake

If it is an engine issue, rather than tranny issue, then check you have good manifold vacuum. The "load" info to the EZK is via a vacuum feed...... this might be the problem ?

AO

That's good information... By "load" do you mean as RPM's increase, so does the vacuum => thus the variable input for the EZK. Is this correct? If so, is there a descrete level of vacuum that is required or is it a relative measure?

BrianG

I had a similar looking dyno chart with a CBR 900RR a couple of years ago. They are also dual coil ign systems. We chased the problem for weeks. It would fall on it's face at 9000RPM, with that bizzare scattered tracing falling off the HP curve, just like what yours does. The only difference is that it showed in 3rd and 4th gear pulls. It did not show in 1st and 2nd, and wouldn't pull high enough in 6th. The dyno tech thought it looked a hung float bowl needle, except that the A/F numbers actually went a bit rich at the failure point. We rebuilt the carbs (4) to no avail. Turned out to be a bad ignition coil which, showed no test signs of failure. We only discovered it by switching coils in our last ditch efforts of parts swapping trials.

John Speake

Hi Andrew,
At idle - (low load) you have the highest manifold vacuum. As more air enters the engine, less and less vacuum.

This is fed to the early LH2.2 EZK as a measure of engine load.

If there's not vac to the EZK, you might think this would give the correct ignition advance for high load/rpm. .... but ofren things are not that simple, because the EZK ECU may be programmed to default to a "safe" igntion mapping with no vac.

I haven't analysed the LH2.2 EZK, so I don't know precisely what happens in that situation.

The later LH2.3 EZK (S4 and later) certainly backs of the igntion timmng if the load signal, knock signals or Hall signals are not as the EZK expects.

MarkRobinson

Hi Darien, this looks like a classic belt slip, or blow-throught MAF charged pipe leak. If your drawing through the MAF (ala my turbo kit), and you have a boost leak somewhere (as I did 2x for 2 dynos so far), you'll have excessive fuel out the back pipe, but if you're loosing boost before the MAF, then the MAF will only calibrate for the air entering the motor & your fuel will be fine.

Your charts don't really look like an ignition issue, as your AF and power curves are smoother than what you'd see for a major ignition/detonation hiccup. I"d suspect belt slip and/or a leak somewhere.

Just for kicks, retard your timing 3d with the pigtail & put in a little race gas, see if the problem goes away. Check your plugs for spots on them as well: signs of mild/moderate detonation.