I'm looking for possible answers to a confusing dyno session.

<img src="http://www.dsmtuners.com/gallery/files/8/9/8/1/4/image_278593.jpg" alt="2.4 E316g Dyno" />
<img src="http://www.dsmtuners.com/gallery/files/8/9/8/1/4/image_140055.jpg" alt="2.4 E316g Dyno" />
<img src="http://www.dsmtuners.com/gallery/files/8/9/8/1/4/image_420933.jpg" alt="2.4 E316g Dyno" />

Turning up the boost resulted in a higher tq spike, but did little to change peakmhpmor the shape of the curve. Also, past 17 psi we were getting a lot of knock. Timing ended up being -5* at 3k.up to 14*at 6k.

All runs were on a fresh tank of 92 pump gas. I never expected to crack 400, but I was expecting a bit more than 216! Any ideas on where I should start looking? Here are some things that were checked: ign timing, cam timing, boost leaks, fresh bpr7es plugs @ .028 and cyclone activation.

What about fuel pressure. How do your wot afr's look?

Why do I feel like your doing something wrong?

Do you have a log on the dyno session?

Something's seriously wrong if your peak torque is 3300rpms, basically when the turbo reaches full boost, the dies off.

Fuel pressure is 38 psi, AFRs are in the first plot.

I know something is not right, not sure what. The cars drives beautifully, gets 25-26 mpg, idles nice ect.

The operator was using his TMO logger, so unfortunately I don't have a log file to share.

Do you have stock turbo cams or the 2.4 cams? With that setup I would expect massive reversion problems if you had the wrong cams. That would kill your torque/power as you go up. I'd try unbolting the exhaust from the downpipe and seeing what that nets you. If that cat is clogging it will annihilate your power.

Compression test? How fresh is the bottom end?

And whats up with the -5* timing til 3k? Thats about 20* off from the base maps. Something seems really odd.

Stock cams, and I checked the flex pipe and cat, both are clear. I'll try unbolting the exhaust next.

No compression test yet, my tools are 140 miles away and the local stores are rented out. I'll have to look further out. The short block has 1k on it and seems to be in good health. The timing was what was needed to keep knock at bay, obviously a symptom of something else.

At this I'm thinking cam timing, not sure why though. What else could shift the torque curve that far?

Did you ask Shane why? and what could or possibly be wrong?

MN_Eclipze said:

Did you ask Shane why? and what could or possibly be wrong?

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He didn't really have an answer. He was surprised at how timing sensitive it was, and thought it might be an octane issue. He thought that the HP curve wasn't too abnormal.

I tried doing a compression test, but the O'Reilly tester hose spun on the fitting, leaving me fight getting it out. Because of this, I never got a reading and will have to try again with a different tool tomorrow.

I would've drained the fuel and tried different stuff I think.

Maybe the Dyno number 2 is broken?
Instead of 216, should of been 316.

I would suspect the fuel also. With the crappy 92 pump we get here on island, I made more power and had a better timing curve than you are getting.

Bad knock sensor?

Your AFR is also pretty lean for a 16g and 92 octane. With a small 16g and 91 I could only get away with about 10.8-11 before timing took a serious hit. Your in the mid-low 11's until about 5k rpm. I'd try richening things up after 3k and see if that helps. It would be a good idea to get the AFR a bit more consistent too.

Knock sensor was replaced about 3k miles ago, and inspected when I built the 2.4 last summer, could still be bad though.

I'll try lowering the AFRs a bit, but I'm surprised that I couldn't hit 300 on 92. This may be enough to move me to e85.

I wouldnt do that just yet. It seems something is very wrong. Dead cylinder or something. Stuck injector? Maybe pull the plugs and see what they look like for starters. Then run a compression test.

I still dont understand why you can't run any timing below 3k.

Stock cams that were designed for a 2.0L that are being ran in a 2.4L with a larger turbo... I bet swapping to any cam in the 272 advertised Kelford/gsc2/crane 264s/comp 101200s would net massive gains. Timing is decent on a 2.4L It is pretty common to have low timing during the torque hit to soften it up a bit and then bring it back on.

91stocker said:

I still dont understand why you can't run any timing below 3k.

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Sorry, I should have clarified. Timing below 3k is ok, it was just that when it started to spool we had to go down to -5 to avoid knock.

Yesterday I pulled the exhaust off, no significant change.

Thanks for the suggestions!

What were your air temps post intercooler?

I would suggest a semi-stuck brake rotor, if not for decent MPG you're getting.

Shane's Dyno Dynamics is a very solid tuning tool, but it does produce *very* conservative numbers. I typically see around 15% higher numbers going from that unit to a DJ.

mrTachyon said:

What were your air temps post intercooler?

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I don't have hard data for that, but the upper IC pipe was barely above room temp immediately after each run.

Shane's Dyno Dynamics is a very solid tuning tool, but it does produce *very* conservative numbers. I typically see around 15% higher numbers going from that unit to a DJ.

Click to expand...

Agreed, and Shane did mention that. The torque falling like a rock still has me stumped.


On edit:
Compression test came back good, maybe too good. 206,209, 209, 210. I was expecting 180-190ish.

This has me taking a second guess at the cam timing. To use the 2.0 cams gears, on the mill we rotated the gears 176.5* and drilled a new hole for the cam dowel. This was to account for the 2.0 gears being 1/2 tooth (3.5*) off when used with the 2.4 belt. After swapping the gears intake for exhaust, everything lined up and looked great. The dowels are up when the engine is at TDC.

I hate to do it, but I'm going to pull the timing belt and try installing the gears in stock orientation and see what that does to the compression reading, as shown here.
http://www.dsmtuners.com/forums/cyl...-remark-4g63-2-0l-cam-gears-2-4l-engines.html

I had a few cars do this they would knock no matter what. I verified base timing and all the above and ended up the black goo was running out of the knock sensor and making stuff go nuts.

Does it "feel" like more than 215 horse power? You gotta be able to feel that its more than stock. I'd know prior to a dyno run if i was only getting the base HP. Dyno's do have to be calibrated maybe they need to do that. also I thought 42 psi was base fuel pressure, and it only goes up from there if you want more out of your injectors? Any reason to tune that down?

I know when I upgraded to my evo 16G without any other supporting mods it felt like it pulled harder at 10 psi than my old t25 did at 15 psi, however anything over 10 psi didnt feel any stronger, I was told I had a "HOT" intake charge, which cancels any horsepower gains. This was on my stock sidemount intercooler, that was crammed with bugs and bent fins, and no shroud. I cleaned that off, straightened the fins, added a shroud and the gain was noticeable.

Try to improve your intercooler efficiency, make sure it has good flow and put a fan on it during the dyno session. The biggest drawback to a sidemount intercooler is the tiny stock vent to the wheel well, some guys enlarge this to increase airflow off the backside of it. Also did you rewire your fuel pump with 10 gauge wire and a fusable link to the the postive of the batttery? Your gonna want the full 14.4 volts to the pump. Clean your MAF sensor, and air filter. just a few suggestions GL