Possible Power Grid + Crank Triiger Timing Issue

[sikm8]

Hi Guys,

If the crank trigger polarity is reversed, will the Grid 7730 +7720 pull timing oiut at high RPM? we seem to be having a timing problem but can't pinpoint the cause yet, we currently have it locked and phased at 33 but believe we are losing timing above 4500RPM, we are way down in HP, EGT above 2000f, AFR starts fat but increases to lean begining at that point.

The Grid Timing logs steady @33, could it be pulling timing without logging the change with a reverse polarity crank trigger?

C headed 600 BBF
13.6:1 Comp
1425CFM Single Dominator
Setup for nitrous but running NA

Thanks

[Rick!]

You'll probably get a better response on DRR Tech Talk forum. There is an MSD expert there that is pretty sharp. There is also a Tips! thread that has significant Grid information.

[rebelrouser]

Monitor the battery and key on supply voltages at the grid box while you are experiencing the issue. I helped with a grid system that was doing some weird things and the issue turned out to be an intermittent voltage drop issue from the solenoid that was used to stop power when you shut of the vehicle equipped with an alternator. We chased grounds, crank trigger air gap and output voltage, used a scope on it, etc. etc. Simple voltage drop testing with a DVOM found the problem.

[sikm8]

Thanks mate, that's one of things I checked, pretty solid 12.8v-12.9v.

[sikm8]

You'll probably get a better response on DRR Tech Talk forum. There is an MSD expert there that is pretty sharp. There is also a Tips! thread that has significant Grid information.

Thanks mate, I'll check it out.

[motormonkey]

You say the AFR goes lean? Are you sure you are not just lean?

[sikm8]

You say the AFR goes lean? Are you sure you are not just lean?

We have gone 10 sizes up on the main jet with little effect up top, that's why we believe it has something to do with timing given the high exhaust temp as well.

[motormonkey]

Every nitrous engine I've dealt with that was a power maker has a super slow chamber and cam exhaust timing is different. If your only running it n/a you might need allot more timing than its getting. I've seen a couple of engines where the headers would glow running a nitrous tune in n/a. I'd try more timing to get egt down and then jet it up.

[sikm8]

Every nitrous engine I've dealt with that was a power maker has a super slow chamber and cam exhaust timing is different. If your only running it n/a you might need allot more timing than its getting. I've seen a couple of engines where the headers would glow running a nitrous tune in n/a. I'd try more timing to get egt down and then jet it up.

Thanks mate, sounds about right. We'll be back on it next week, I'll confirm crank trigger polarity and try more timing. In your experience, how high have you gone for peak power? considering it's going to get a 500 shot.

[Jeff Lee]

Put a MSD Filter in the system.

[motormonkey]

Every nitrous engine I've dealt with that was a power maker has a super slow chamber and cam exhaust timing is different. If your only running it n/a you might need allot more timing than its getting. I've seen a couple of engines where the headers would glow running a nitrous tune in n/a. I'd try more timing to get egt down and then jet it up.

Thanks mate, sounds about right. We'll be back on it next week, I'll confirm crank trigger polarity and try more timing. In your experience, how high have you gone for peak power? considering it's going to get a 500 shot.

Allot if N/A only. Haha.
Find a hub dynoed if it's a new setup to you, it would be the fastest way of dialing in.
Let us know how it goes ,500 is a pretty decent shot