Fun time on the dyno and also my dumb mistake....

[john42]

First the good news! Had a very good dyno session and got the new Boss 347 w/ Sniper 2 running really nice. Still some fine adjustments to do but it is SOOOOOOO much better now.




And the bad news... While on the dyno... something that I was warned about... when we (Traveling builder) put the new engine in Mark told me to trim the body around the right side exhaust. I 100% intended to do it soon(tm)... I just had not and that became a hard lesson as it caught fire!

IMG_3602.jpg


Well it's trimmed now... Anyway... when a very smart person like Mark says you should do something..

[JJK]

very cool. for reference, how much of a gap was there between the body and side pipe? The body caught fire?

[john42]

very cool. for reference, how much of a gap was there between the body and side pipe? The body caught fire?

It was touching. Yes it caught on fire.

[JJK]

any idea on the minimum safe gap? I am sitting at about 1/16" and now concerned.

[vtullomk4]

Just curious. What were the hp/torque before and after?

Vince

[john42]

any idea on the minimum safe gap? I am sitting at about 1/16" and now concerned.

Don't take my word for it but after this experience I would think almost any visible gab would be enough. The lengths that it took to, to actually catch fire was. #1 the body was touching the exhaust for a length of about 2 inches. #2 running on the dyno had zero airflow on the exhaust as the fans were pushing air into the front of the car. #3 running at 5000-6000 rpm long enough that the exhaust was beginning to turn a faint pink. Real world conditions those 3 will never all be true at the same time. After it occurred we put fans on the sides blowing air across the exhaust and had no further issues. I cut/clearanced the exhaust yesterday (2 days after the dyno day).

[john42]

Just curious. What were the hp/torque before and after?

Vince

Well we're still working on it. I'm going back in a couple weeks.

Started at about 280tq/270hp (to the wheels). which is... lol. ouch

Things that have been adjusted/fixed:
Timing was 5 degrees off
lots of fuel map changes
was running +25% rich
throttle would only go to 60% of full, with some adjustment we got it to 80%

Then we got to:
390tq/376hp

Things that I am fixing now:
Sniper is still getting confused with the wrong spark plugs. The plugs in it now are for a Carb setup and aren't resister type. I've purchased a set of NGK resister type. The plugs were confusing the heck out of the Sniper 2 causing misfires, rough idle and stalling when returning to idle.
I've also redone the linkage on the sniper 2 and now have full use of the throttle to WOT (100%).


I've been very pleased with Randy @ Horsepower Farm in NH. It took him about 2 minutes to find the spark plug issue. He found the spark plug issue by just hearing the car running for a few minutes. Was amazed it how quickly he could look at the log on the computer and walk over to the car and point at exactly what the issue was. He was also a big fan of Factory Five and they've built a few in their shop.

Best guess (hope) now going back in a couple of weeks with correct plugs and a throttle that actually goes to WOT is to see 410tw/400hp. To the crank this motor is supposed to be 480tq/470hp.

[FF33rod]

Love it, except for the fire part Out of curiousity what's the details on the 347? manifold, heads, compression, cam...

Steve

[john42]

Was back at Horsepower farm this weekend for a Dyno showdown and also helping me out with getting my Sniper2 dialed in. We "found" another 50(ish) horsepower and got it idling right!

Skip to 27:00 for.... Cobra goodness...

[john42]

Dyno vid...