Frankenmotor dyno results

[presslab]

Here's my dyno results from my EJ25D/EJ22E frankenmotor w/Delta 220 cams.

 

And here's my buddy's EJ251/EJ22E frankenmotor, stock cams, and a half-point lower compression ratio.

 

You can see I have just a bit more torque across the board (maybe because of the slightly higher compression) but the real gain is on the top end at 6k RPM where my torque is better.

[86BRATMAN]

Nice to see some solid results from a frankenmotor. Looks good.

[1 Lucky Texan]

torque seems very flat!

 

my WRX is 'peaky' feeling and I don't like that.

[cal_look_zero]

Seems very low by comparison to the one I modeled mine after; 176 awhp 181awtq

[presslab]

Seems very low by comparison to the one I modeled mine after; 176 awhp 181awtq

 

Is that a super high compression motor on race fuel with 8,000 RPM redline? Your numbers are the same power as a WRX EJ205, as shown below.

 

 

Increasing compression ratio gets maybe 5%. The cams get another 8%. The EJ22E intake and small heads then brings that back down a bit, but keeps good torque down low.

[987687]

I've always wanted to see a dyno of a high comp 2.5. That's pretty good considering a stock sohc 2.5rs puts down about 110 to the wheels.

 

Seems very low by comparison to the one I modeled mine after; 176 awhp 181awtq

 

No way you're getting that much power at the N/A wheels without some serious mods.

[idosubaru]

Neat stuff, good job presslab. What are the dyno numbers for a stock EJ25?

[cal_look_zero]

I emailed the guy, and those were his corrected crank hp numbers. My bad.

[Fairtax4me]

Interesting results. Is the 220 grind recommended by Delta for the Frankenmotor?

 

Also interested in how that compares to what a stock 2.5 would put down.

[987687]

Here's a nasioc thread with stock 2.5 DOHC and SOHC dyno charts.

http://forums.nasioc.com/forums/showthread.php?postid=1577762

[presslab]

Different brand dynos are different enough that it's hard to compare between them. I haven't found a Dynojet plot for a stock EJ25.

 

The Delta 220 cams are "torque" cams. Really though it looks like these mostly give a better top end. There is a lope at idle too, but I've tuned around most of that. Still haven't received my core charge from Delta, after numerous emails. Thinking of telling the credit card company.

[Fairtax4me]

I thought the torque grind was supposed to increase bottom end torque but it appears that the opposite is true. Torque does increase slightly after about 2250, but the stock cam appears to deliver about 15 more ft-lbs at 1500 rpm.

 

There is a nice horsepower increase on the top end though.

 

I had to call Delta to ask for the core credit when I sent in my old cams. Any time I've emailed them their response seems a bit slow.

[presslab]

Yes it does look like it's the opposite of a "torque" grind; the other pulls look similar, so I don't think it's an artifact of measurement. The lope at idle also is a tattletale that there is less performance at low RPMs.

[Fairtax4me]

I suppose we should keep in mind that the 220 cam is probably designed for a stock Ej22. The effect that cam profile has will almost certainly vary between a stock engine and a hybrid 22/25 Frankenstein.

 

Now I'm curious what effects other cam profiles would have.

Also curious to see results for a sock ej22 vs one with delta torque grind cams.

[presslab]

As long as the cam timing is the same between the EJ22E and the frankenmotor, I would think that the cam would have a similar effect. In any case it's interesting here to note that both dynos were with frankenmotors, one with stock cam and one with the 220. On the stock EJ22E cam frankenmotor, it's smooth at idle and feels like it has similar power to the EJ22E longblock; it just has a bit more all over, as would be expected.

 

Now the cam timing is something I've been thinking about. So even with the stock cam, a frankenmotor needs the timing pulled back pretty much all over or else there is knock - even with 91 R+M/2 octane. Is this necessary because of the increased compression ratio? Longer stroke? Or is there something more insidious going on, like the deck height being different causing different cam timing? This doesn't seem to be the case as the timing belt tensioner seems to be in the same spot. Maybe the keyway in the crank is at a different position?

 

For the frankenmotor, I think ideally there would be a cam that the exhaust valve opened sooner because of the increased piston velocity. But the stroke isn't all that different on the 2.5 (79mm) vs 2.2 (75mm), so I'm not sure how much torque would benefit from a cam designed specifically for the frankenmotor.

[Quidam]

Now the cam timing is something I've been thinking about. So even with the stock cam, a frankenmotor needs the timing pulled back pretty much all over or else there is knock - even with 91 R+M/2 octane. Is this necessary because of the increased compression ratio?

I would think so. I don't know what you're running for CR but I've got a SPFI EA82 stock that runs best on a mix of 89 and 92 octane with stock 9.5:1 and timing advanced a bunch. But the combustion chambers aren't as efficient as an EJ.

 

I fed it what it wanted, that's not Zen btw. Choices here for fuel are 87, 89, 92, 93, and 94.

 

How much total advance are you running...25 or so?

 

Doug

Edited December 12, 2012 by Quidam

[presslab]

How much total advance are you running...25 or so?

 

Doug

 

Yes, I have about 26 degrees total advance. The stock EJ22E map has about 34 degrees.

 

The thing is though, my buddy's engine with 10.0:1 CR could only be advanced a couple more degrees at most than mine at 10.6:1 CR. So say for every half point of CR, two degrees. But that would put the EJ22E 9.5:1 CR at around 30, with 91 octane. That's a ways off from the EJ22E stock map at 34 degrees, running 87 octane. There's something more going on here.

[Fairtax4me]

Cam timing doesn't greatly affect spark knock. Ignition timing, fuel octane, air/fuel mixture, and combustion chamber design have a larger effect.

 

Higher compression creates more heat prior to ignition, this leads to detonation after ignition when using low octane fuel. Octane is added to help gasoline resist combustion.

Ignition timing too far advanced when combined with low octane creates the same effect, you get too much heat in the combustion chamber around the time of ignition.

Combustion chamber design is another major factor because the chamber shape affects how much turbulence or "swirl" there is in the air fuel mixture as it enters the chamber. The wrong type or amount of swirl can cause the mixture to be uneven, basically lean in some places but rich in others. The lean parts of the mixture will ignite first, and can do so before the flame from primary ignition has spread across the chamber. More swirl means the mixture combines more evenly, and will then burn more evenly as the flame front progresses.

Cam timing can have an effect on the amount of "swirl", but it has to be pretty far out to be detrimental. At that point the compression would also be affected since the valves would close too soon or open too late.

 

I find the numbers you have for total ignition timing advance interesting. I've seen timing advance indicated as much as forty four degrees on the scanner in my 96 Ej22. This only occurs during part throttle cruise, when under heavy acceleration timing advance is usually around 25-30 degrees.

When you say total advance do you mean the amount of advance over the base setting? Base meaning ignition timing at idle, which should be about 14 degrees.

[presslab]

Cam timing can certainly change the dynamic compression ratio; I would say in some cases this could be significant, but I don't think that's the case here. In reality what I mean is that changing the cam timing will therefore change the ignition timing because the cam position sensor is giving the ECU the wrong info. Just a small change here will have a big impact.

 

When I say total advance I mean maximum load at ~3500 RPM+. Under light throttle at higher RPMs, the timing is advanced more, up to 45 degrees BTDC, just like you see.

 

You may or may not have seen my other thread where I have posted the stock maps for the "F9" ECU:

http://www.ultimatesubaru.org/forum/showthread.php?t=134517

 

To get the effective timing, add from both the base timing map and the max advance map. This is what the timing will be if the ECU does not detect knock.

[Fairtax4me]

You've got a lot more experience tuning than I do, but doesnt the ECU use the cam position sensor to determine the fuel injector timing? Crank sensor for ignition timing?

[presslab]

You've got a lot more experience tuning than I do, but doesnt the ECU use the cam position sensor to determine the fuel injector timing? Crank sensor for ignition timing?

 

Well I'm not entirely sure. It could theoretically get the timing information from either one, as it takes the integral of velocity to get the position. With the wasted spark I'm not sure it even needs the crank - in the past I had a bad crank sensor (that triggered a CEL) but I never noticed any running problems other than weird starting. For that matter it could probably run without one or the other if the ECU was smart enough.

 

What I was saying originally before we went down this road, is that I don't think this is the problem as the timing belt tensioner was in the same spot, so the cam (and possibly ignition) timing should be unaffected due to that aspect.

 

I wonder if the way the crank is offset ground to get more stroke could cause a change in timing.

[Fairtax4me]

I'm sure the ECU could figure out crank and cam position from just one sensor, but having two gives it something to check against to determine if the timing is out.

 

There was a thread a few years back where someone was playing with adjustable crank sprockets with the thinking that it would affect ignition timing. Not sure whatever came of that. I'll have to see if I can find it again.

 

Bad crank sensor will prevent the engine from running. An intermittent failure or poor connection to the sensor could allow it to still start but you will have a stored code because the ECU needs that signal. Usually with crank sensor failure it's all or nothing. It either runs or it doesn't.

The cam sensor may be the same way. Easy to find out, just unplug it and see if the engine starts.

[Qman]

Different brand dynos are different enough that it's hard to compare between them. I haven't found a Dynojet plot for a stock EJ25.

 

The Delta 220 cams are "torque" cams. Really though it looks like these mostly give a better top end. There is a lope at idle too, but I've tuned around most of that. Still haven't received my core charge from Delta, after numerous emails. Thinking of telling the credit card company.

 

If you haven't heard from them call them. They may not have your number to call you for the card number...

[cal_look_zero]

 

Show of hands, who thinks I need a tune? LOL

 

Getting a PP6 and heading back up to Pre in about 3 weeks. Anyone have a lead on one for sale?

[Fairtax4me]

Couldn't hurt.