Blown 360

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canadian duster

canadian duster

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Well I finally got my setup together and fired it for the first time tonight. seems to be running quite well. Harder starting then I hoped for but I think I'm still getting the fuel pressure set properly. What I'm struggling with a bit is boost. I am getting vacuum, even while under hard throttle. I checked for faulty gauge and there is definitely vacuum on the line. I'm running at 16% underdriven (37T 31B) which should be approx. 5 psi boost.

On my intake I have 2 spots for a gauge. one directly below the blower and one on the plenum to the heads. It shouldn't make a difference where I place the gauge of those 2 locations correct? I'm thinking that I may have to go to a 35 top pulley.

any thoughts?
 
Good to see you have it running. I found the easiest way to start is to pump the gas wide open once before you try to start it then start at closed throttle.
You can mount the gauge anywhere between the bottom of the blower and the heads. When you have no load on the engine it will only make boost for a split second when you take it to WOT. Other than that it will only have vac. The fun stuff starts now, that is getting a proper tune.

Jack
 
With 20* initial my car fires instantly. Jack's on the money - you'll only see boost when you wind it up under a load. Nevertheless you'll still feel a difference in throttle response just cruisin' around - even at 5 lbs.
 
Well I have it starting good now. Idle is rich. Took it for a lap and has a nice idle and low cruise. Has some detonation at mid throttle I need to fix. 20*initial and locked at 28. Running .401 jets (primary and secondary) and 7042 rods. This was initial starting point from edelbrock. My first step is fuel pressure (doesn't seem to want to climb over 6 now) and I believe my second step will be to increase fuel flow for power mode (either bigger jet or next slot on pump).
 
Running a pair of 1405's? Edelbrocks are sensitive to fuel pressure. Should be limited to around 5.5. If you're inside, double check float height too. Part throttle knock? Curious to know the fuel grade you're using and your static compression ratio.
 
Yeah 2 1405's. Static compression, well you'll roast me on that ha. It's a stock bottom end. I lost the darn paper that I wrote down static compression. I worked with dyers to get the go ahead on this build. It was a budget build plan for the short term until I have the cash for a new bottom end.

Im going to try again tonight and get in touch with edelbrock today. Fuel is 91 octane (best we have here).

I have a feeling either my secondary jets or metering rods are to small.

Tonight I'll try pushing through the slight knock and see its range.
 
Be very careful with that knock. Any knock is bad, bad, bad but with a stock rotating assembly in a 360 it will grenade in a real hurry.

Jack
 
Yeah, get any detonation under control. You should be able to do that without a lot of trouble.

If those carbs are going lean in cruise mode, that won't help matters. Even more important to avoid a lean condition in power mode. You'll be much safer starting with a rich mix and then dialing them back.

Spark plugs: Two heat ranges cooler. A spark plugs heat range refers to its ability to dissipate heat from the firing end of the plug and combustion chamber. A colder plug dissipates heat faster. Blowers raise compression and as compression goes up, so does cylinder temperatures. As temperature goes up, so does the chance of detonation. Dyers is the only one I've ever seen recommend two heat ranges hotter - which makes no sense to me. Maybe it's a typo on his site. Worse case, you foul plugs (which I doubt) but that's a lot cheaper than broken/melted pistons.
 
well ive been in contact with edelbrock. timing is matched to their request and plugs changed 2 heat temp's down. all I'm waiting on is needles and seats. question though, how much of an impact will needles and seats make? it still has detonation at about 2000 rpm which seems like a metering rod / jet problem to me.
 
In your case, the larger needle and seats won't hurt, but won't fix the detonation. You're not running the bowls dry. If you're sure you have a lean condition @ 2K rpm, and that lean condition is what's causing the detonation, then yes, rods/jets.

What did Edelbrock advise for timing? How are you controlling timing? And are you attempting to run vacuum advance?
 
Edelbrock advised 14 and 28 all in by 2800 which is setup now. Only other request was the needles and seats. I'm going to order some jets in and start playing. I just dont see the needles and seats contributing this much unless the bowls are starving for fuel.
 
Interesting. I'm running 20* and 34* with no detonation that I can detect, and 8.5:1 compression. I agree that your needle/seat are not likely the issue.
 
70Duster440 said:
Interesting. I'm running 20* and 34* with no detonation that I can detect, and 8.5:1 compression. I agree that your needle/seat are not likely the issue.
Click to expand...

I was wondering the same. I have about 8.2 to 1 compression, timing locked at 31 degrees and no detonation that I can detect. I was also wondering if there was any vac advance involved because that is when most detonation occurs in engines of any type. Just thinking out loud.

Jack
 
How are you pulling timing for boost? What I'm reading says you're actually increasing the timing with mechanical advanced.


At 5psi even with stock bottom end, I'd pull no timing. Lock the distributor out at 31-34* and be done.
 
And if you increase boost, gt a msd 6530, with a map sensor and pull 1* per psi after 5lbs.
 
Success. Locked timing at 29 (conservative for now). Getting full throttle range with no detonation. Getting 3 psi so far. May try a 35 up top to get closer to the 5 psi but for now it runs. Thanks again for all the help everyone.
 
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