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Evo X | Syvecs | Won't do a full WOT pull on e70, but does on e10

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I wanted to share these logs with the community. This is a built Evo X (specs below). It will go a full WOT pull on pump e10 fuel, but when we put it on e70, rpms won't go past ~3.5krpm. Orignially, the symptom worsened and wouldn't do a full WOT pull e10. The spark plugs were replaced with OEM GTR coils and multiple pump gas WOT pulls were good. Now, we're experiencing the same symptom on e70 again. We've never had a full WOT pull to redline on e70.

See datalogs here: https://drive.google.com/drive/folders/1Wu3HBAzt6YDvDqfwR1gAsiJIHin5Ff3u?usp=sharing


90mm pistons, I Beam Rods. 10.8:1

98mm crank

Oversized Ex Valves

FIC 2150 injectors

GTR35 Coils

AMS TMP Camshafts

Twin 38MVS 23lb springs

SST 12 plate

[img="blob:https://www.hpacademy.com/0ec250fa-a4ed-4499-a814-fccec78112b6" alt="" alt="" ]

Is your fuel system up to supplying the additional 25% volume required by E70?

The car in question has a -8feed line utilizing the stock feed line as a return.

Radium fuel hanger with 2 Walbro 450

David - Yes, the fuel is on target. I put a link to the datalogs in the original post.

Hi jason what is the ignition timing difference between the two fuels if it is the same add another 4-5 deg to the boost map CAREFULLY test with a short power run, it is sounding to me like it is blowing out the spark because the e70 needs more ignition advance

Regards Ross

Hi Ross,

Yes, I typically practice adding +4 degrees of ignition timing from my e10 to e85 ignition timing maps to start with. The break-up is happening at low MAP as well. However, I am looking throwing some more timing to test.

I've uploaded a new log and the calibration files associated with the logs.

The issue seems to be that the engine isn't liking the increased cylinder pressure when going from e10 to e85. I increased the ignition timing and zeroed out the MIVEC intake and exhaust cam targets and we were able to make it to 5krpm. He may be able to go to redline, but just going to 5krpm (opposed to 3.2krpm) answers one thing - the increase in cylinder pressure upsets something on this setup.

What are your thoughts on this?

I've also noticed throughout this process that the clutch slip value in the logs is showing some clutch slip. You'll notice some ign timing being pulled out on the latest log i attached, toward the top end. .

Hi Jason and apologies for the slow reply. I must admit this issue is a little confusing and I haven't seen a clear reason for your issues. You're right that it does seem to coincide with cylinder pressure which is going to be affected by boost, MIVEC timing, and ignition timing. A common issue I see is people trying to start out super conservative on timing to be safe but if the timing is too retarded then it can actually result in a misfire. I'd be inclined to go back to E70, get to your wastegate boost setting and then try winding in some timing in 2 deg increments. On moderate boost (you may want to fit some softer springs to get the boost down a little - perhaps 16-10 psi to start with) you will almost certainly be unable to cause knock irrespective of timing (even with your 10.8:1 CR) so this is not a dangerous test. If you can tune to MBT at this boost level and the engine is running clean then you can start to raise the boost.

The other consideration is your plug gap - higher cylinder pressure makes it harder for the spark to jump the gap so I'd try closing the gap down to 0.5 mm/0.020" and test. If that works then it suggests a lack of spark energy which shouldn't be an issue with the GTR coils however those coils are known to be fragile and they can be damaged easily. One question I have on your map is the two coil charge time tables. Table 1 is probably about right, but table 2 is around 1.2 ms @ 14 volts which would cause you problems. I'm struggling to remember know how these tables interact as it's been a long time since I've spent time on the Syvecs platform. If in doubt I'd copy table 1 to table 2 and be done with it.

Hopefully the above is some help. If not I'd suggest escalating this to Syvecs directly.

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