72Hondo
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Motors done 327 SBC - I think it made around 420HP and 380-390trq. I'll have to look at the dyno sheet.
Build sheet (yes I took out the name for now) first time using this builder. Everything look good? A tad out of my league with those numbers.
View attachment 536949
Do you mind if I ask about the 'valve timing', and total spark lead on boost ?
To answer your question, the bearing clearances, piston clearance, and ring gaps are all in the correct range for a boosted application.
Really need to know how much boost and camshaft design. HP number is low for a boosted engine.
Builder said he thought it would be up over 500 also. The carbs are hurting me. I know, this is a know fact. It seems there is no absolute way to make to carbs work on a 144, not sure why B&M made that adapter. We spent over an hour on the dyno just playing with the carbs. It seems to be a trade off, looks vs performance.
I'm going to send both to C&J and let him work his magic, if anything.
No idea on the humps - thought it had the bigger valves but I guess not.
The boost was 5lbs, I do not see any EGT readings on the dyno sheet. I've reached out to the builder to see if he can pull them and any other info.
One thing that worried me was we kept putting smaller jets in it during the dyno until we got to the smallest ones on the secondary side. Per the build - it's making more power so it likes it.
Yeah but I don't want to live on the edge. He's the professional though. The dyno sheet says A/F ration 7, that can't be right, shouldn't it be up around 11?
I'm going to send the carbs off to C&J and see if they can play with the carbs. There carter 450's. Everyone has begged me to move to Hollys, but there's a sentimental reason behind it.
From all the talk in here, gives me a knot in my stomach that I got taken. Though this builder came recommended from other boat guys.
Doing the math your setup lands somewhere around 820cfm needed. I think you're close with your carb cfm but you might want to switch to a single carb to get a performance baseline between the two.
You're not making boost until late in the power curve. I'd want to see more boost earlier. What size crank and snout pulleys?
As it sits the blower is replacing about the same amount of horsepower it takes to turn it. There's no return on your investment. The motor builder should've caught this on the dyno so whatever you do don't take it back to that dude.
So much more info needed. I think you have a couple tiny issues that are combining into one big one. No way a motor builder thought those numbers were acceptable and yet he already cashed your check?
I'd also take that blower in unless you yourself were there when it was rebuilt two years ago. Check to make sure it's turning and has oil in it first LOL.
I wish you had a little more info from the dyno runs and how it is 'set up' overall .
Two carbs make A BIG HOLE in the top of that blower, when opened up .
Also, if it was running 'well under peak power' and still making 5 lbs of boost, I have a whole bunch of other questions to ask .
From what I understand; "vacuum powers a carburetor", a strong signal helps make smooth functions and good atomization, a weak vacuum signal needs compensation (parts and adjustments) and takes much more 'tuning' to run correctly .
Was the 10" to 12" on the same gauge that gave '5 lbs of boost' ? If so, that is not the vacuum I need to know about . (load side) I'm talking about at the carb bases at all RPMs .
Blower was rebuilt by BDS, you'd think they knew what they were doing. Upper pully is 5" haven't taken a tape measure to the bottom.
Sad thing was dyno time was $700-800 alone. Only dyno in the area, that I aware of.
So we know this is a carb problem but can it rob that much power? The 7 A/F ratio scares the crap out of me. Isn't that really lean?
Asked for the required info from the builder, no answer, won't return calls.
Anything else I can provide to help?
That little blower is only going to make a lot of boost without creating heat, maybe 7-8 lbs. OC Merrill touched on it earlier.
I think you have a cam that is making power from 2,500-5,000 when you probably need one from 3,000-6,000. 3k-6k is probably where that package will live it's life on the water and you have a cam built for flying down the freeway. Gonna need a longer exhaust duration to get that hot gas out too.
I don't know much about the little blowers and small blocks but the theory works pretty universally when pumping air into a motor.
Keep us posted when you get the info. This is a pretty neat little build but as unique as it is you have a couple little things working against you to make it work right.
That LITTLE BLOWER makes a TON of HEAT, at all boost levels .
It runs at either 45% OVER crankshaft speeds, or 55% over on the smaller 8lbs pulley.
It will need at least .5 A/F ratio RICHER (than a normal blower), just to live at 5lbs .
I'd rip that dual carb setup off and try a single 750 or 800 instead. It's what that blower wants.
If he can make 500 hp with that 327 at 5 - 6 lbs of boost I would call it complete. With proper AF I think he can. All this harping on the builder is hideous except for the DYNO time that was loaded with red flags, unless I missed something in the conversation.
If that engine was run extensively on the dyno at 7:1 A/F then where is a good chance the rings will never seat. Washed. This is what the builder should have told his customer....your parts produce X and your NOT good to go...but it runs. Now what other carbs do you have?
Going in a 18 ft jet.
I have no problem being told, your shit sucks, try it with this. It looks as if a dual carb set up can never work properly on this 327. Which sucks cause I liked the look. But my issue is I put all my faith and trust into the build to tune it right, why dyno it then? And being told it's pretty much on the money then being told here, it's fucked.
Live and learn I guess. First rebuild, first dyno.
Going single carb will be my next step, finding a dyno operator, a bit tougher.
It will be worth the drive and time to find a better tuner. Remember, we don't learn from what we did right. It's usually what we did wrong and know what to do and what to ask next time.
People pay $20k to learn this at a trade school. You're paying a fraction of it and getting a better education. The glass his half full bud. [emoji106]
I learn from doing it wrong several times in a row.
BTW I'm going to need a zip boom rental in the near future. PM me your info. Rather it be you than United.