What's the safest timing and best performance for a blower motor with the following specs? 540 ci., 8:1 compression, 1071 intercooled with 1050 dominators, 7-9 lbs. boost full MSD. Usually run on 92-93 octane w/ VP octane booster. I've had so many different opinions, I thought I'd inquire who's running what and what is living??

What is your duration at .050? What is your lobe separation? Iron heads or Alum? Are you sure this motor has 8 to 1 compression? Where is your intake centerline? A base line should be around 32 degrees.

I was running 29 degrees locked on a 468 with B&M 250. I was pushing about 5 Lbs. boost. This was a recommendation from Nickerson.

I know I'm very conservative but, I'm also around the 29* mark. I have aluminum heads 8:1 compression and 5 lbs. boost. I always run 92-93 octane. I think that B&M states that you only loose a very small percentage of peak HP with the total set at 28*.

I'm at 30 degrees at 8 psi at 5400 rpm. I'm also EFI which helps a little.

lesser total timing #s show better hp# on the dyno but in your boat



more timing is better ,if you can tune it safely .
lower total timing can cool exhaust temp on dyno pulls ,in your boat you run much longer than a dyno pull & start to increase exhaust temps . a good place to start is 32 total.

32 Locked

10 lbs boost intercooled
547cu
cast iron heads
741 roller
93 octane only

too low............. Hard on exhaust valves
too high.............. risking detonation



Gerry

My timing is computer controlled. Presently it’s programmed to 28* at WOT, 10Ibs at 6000-6500rpm. At lower boost levels or rpm it's set as high as 32*

For your application I would be looking at 28-30* at WOT provided your intercooler intake water temperature is 75* or less. If you’re looking for a specific number I’d go 29*

IMO, detonating an engine is much worse than replacing exhaust valves. I have 70hrs on my 540 Quad rotor with these settings. No timing issues to date.

I also have a 540 (9 to 1 comp, alum heads, 10-71 w/innercooler). I have gotten best perf and ease of starting when the MSD distr was locked out at 30 degrees.

557ci...8.0:1...Alum heads...10-71's at 6.5psi....30* total, all in by 2500rpm.