Thanks Dave,
sounds like your the right guy.
The M3 with the 4.44 gearing/7.65 crank pulley/and 3.5 (if I need it) will give me a pretty good impeller speed of 51,434.
53k is the listed limit. Sounds like it shouldn't be a problem with the 12 rib at all. I could even go with a 3.375 and be just over 53k if I had to.

Good to hear your setup is running so well Valley Guy! Gives me encouragment; especially about the bottom end.
:D

Thanks
Dave

Dave F and NordicHeat

You guys are scaring me...50,000 RPM!!! No wonder you don't have bottom end response problems. Seriously though, has anyone got a compressor map for the M3/M4 blowers? What kind of efficiency are you getting? I'm looking at a Vortech V-7 YS trim compressor map right now, and at 50,000 RPM the most efficient operating point is 90 lbs/min @ 19 psi boost. This is right at the edige of the 70% efficiency curve. That's good for 900 HP, but 19 psi boost just isn't happening on a boat. What's up?

Tom

Ooooh, Dave F, you are opening yourself up for lots of detailed brain picking (I'll start...).

Have twins - so everything is doubled.
I am aiming for around 750hp. Starting with carbed Mk4 502's. Already have a M3 blower and 504 intercooler with carb box. I have 950cfm 4150HP Holley with black floats. Have MSD billet distributor with mechanical advance, MSD Digital 6 box, Crane high voltage coils and wires.

I plan to run Crane 731 hydraulic roller (installed per the spec card) with 138# springs (closed) with moly pushrods and Gold rockers with U-bolt style girdles for insurance. I have titanium retainers with 10degree locks. I plan to run needle brg cam buttons and needle bearing cam sprockets with a cast aluminum timing cover (for cam walk).

I plan to run Edelbrock RPM AirGap intakes and a 1/2" phenolic carb spacer with 4 holes (as opposed to the open style). I plan to run steam lines from the rear water ports and open the intake gasket holes in the back water ports and "halfway" block the ports on the front water passages (to pull hot water out of the rear of the block). I have Fluidamprs to run instead of stock dampers. I will use a water crossover and a pressure relief set to 18psi. Exhaust will be CMI E-tops running reduced water.

I plan to hone (320 grit) and run TSG top ring and standard second ring. I will run a FelPro gasket with the stainless wire ring (not the kind that requires machining). I want to set the squish up to no more than .038" (from the piston "flat" to the head) for turbulence to combat knock. I will replace my exhaust valves with inconel but will run the stock stainless intakes. I plan to do minor bowl work and a 3-angle valve job (with a fat sealing face for longevity). I guess I will run PC guide seals (but would like to find vitons if I have room for them). I will be using studs on the heads.

I plan to run stock bottom end, but will replace bearings with Clevite H bearings at Mercury stock clearances.

I will set the motor up for 92 octane, but will have the option to use the wired retard on the Digital 6 box as a "bad gas" switch to back off the timing 3 or 4 degrees.

I have been looking at the StartGuard ignition control that provides individual cylinder retard per a knock sensor. Unit also has a cool dash display that will show the retard and the output of an O2 sensor ( I plan to have them in the tailpipes before the water). I will also have pyrometers in the CMI primaries.

I have Aeromotive electric pumps and boost-indexed regulators. I will run the return fuel thru coolers before going back to a tee in line on the pump feed side.

I will have gauges for fuel pressure (just before the box), box pressure, manifold pressure/vacuum, EGT, O2, retard, oil temp (adding thermostat for oil), etc...

I am hopeful that I have picked parts that will give me what I am after. I want a motor (s) that idle without loading up, pulls on plane without laboring, cruises "relatively" efficiently, and pumps out big power at 5400-5600rpm. I also want decent life expectations on rings, bearings, lifters, springs, and valve seats.

I am planning on the dual plane intake cause I think it will give me better idling and low speed behavior. Because of the dual plane intake (and spacer with 4 holes) I think I can use the 950 Holley without it being "too big" (each 4cyl uses 475 cfm instead of all 8 sharing 950). I'm not as worried about flow under boost cause the blower will make up the difference.

I haven't planned any big mods for the rect. port heads, but am wondering if I should...

I know my major hurdles come in the areas of the carbs and timing, but hope that i can work out the gremlins one at a time and reach my goals. I am guessing 6 or 7 # of boost is where I will need to be.

Any criticism or advice is welcome.

M

mcollinstn,

The valve train sounds good. The exhaust valve seat should be around .080. The intake doesn't need to be near as wide because of the cool charge going by it. The wide seat is how the exhaust valve cools itself.

One question. How are you gonna get the quench space to be .038 when the gasket is .039? If you're using stock rod length and piston pin heigth that leaves you with .020 below deck add the .039 =.059.
.038 is about perfect but as long as you're under .060.

Keep me posted on how like the dual plane manifold. I've always used a single.

Water flow. I wouldn't worry about a relief valve and all that. I had CMI E tops and simply used no t-stat and flowed all the water to the bottom of the CMI's. Never had problem.
That way I was able to run 6-7# and still had full timing at 35*.
I was using 94 octane though.

Bearings are good choice. I take it that you took your block all the way down and are having it re-done.
That would explane the honing grit of 320. I personally like it done with a 400 grit. But, 320 is acceptable.

I never had luck with the 4 hole spacer. It wouldn't run right for me, maybe you'll have better luck. I switched to the open one and liked it better.

With your combo I'm sure that you'll be around 750hp.
I used the Merlin 345 rectangles. My set up was almost the same as yours. I just had a stage 4.

I also think all your instrumentation is a good idea also. My plan is use O2 sensors next time around also.

I see your fuel return is according to the schematic. I liked to return the fuel back to the tank. Then that way, I didn't need a cooler.

Keep us posted as to your progress.
DAVE

Still collecting parts. Was sitting at 90% in March and decided to postpone the install till fall. 370 hour motors are still sitting happily in the hull ready to run for one more summer.

Was sure hoping that stock deck was closer to -.005 to -.010, but sounds like it is not. I am using stock rotating assy so I figure your #s sound right. I may deck .010 from the blocks but refuse to remove more for all the intake alignment and pushrod issues decking causes.

I am questioning my choice of intake since nobody seems to have much experience with it. I have access to a pair of Darts, but have been figuring that with the additional 4 inches in pitch or so I am staring at, I'd be happier with some more grunt out of the hole and that the dualie would also make the carb selection more tolerable (I already have the carbs).

I did speak to Total seal and they specifically want a 280-320 grit hone at a 25 degree hatch angle. They told me that it WAS okay to knock the peaks off with a 400 stone afterwards though (I still can't help thinking 280 is too coarse).

Interesting, your experience with a 4-hole spacer. I wonder if the results differ for a dual plane versus the single?..

Running "STAT less" with the CMI's, did you have any trouble getting the motor temp up over 140 or so (that's where I'd like to get)?

I agree. 280 grit does seem way to coarse. However, if they (total seal) say they want you to use 280-320 then use it. That's how they get their rings to seal.

From everything I've read, the Darts are a better intake.

If you want 140* then you're gonna need a stat. I didn't use one cause I wanted all the timing the octane could handle.

It's my opinion that I was able to run 7# of boost all last year, with 35* total timing because I was able to keep the heads cool to stay out of detonation.
The temp on the hottest, muggiest day barely got the needle off the seat which starts at 100*
I realize there are other issues with the block being too cold, but non of them more important than staying out of detonation.

If the carbs do not perform properly, ie; idle, still lean with large jets etc. Dont fool with them. Just send them off to Nickerson. It's worth it to by-pass the aggravation. As a matter of fact, I would just start off with him if you had any question about the carbs at all.

Keep me posted as to your progress

DAVE

Obnoxus-.Nothing, 120 hrs isn’t a full season for me. We got a late start installing and missed some boating time. I upgraded to m3sc systems for this year and have about 15 hrs without a problem. Although not totally stock anymore.

Mcollinstn,
You have mentioned the issue about low speed torque with turning a bigger prop, I don't think you will find this much of an issue. Contrary to their stereotype, Prochargers make plenty of power at 2500 or 3000 to get you moving quickly out of the hole. Good luck with you system. MIne is a stage 4 with dual carbs, and I am finding the biggest issue with prochargers is the setting of the box forward with the dual carb setup. corrected it by turning the box around and running MSD crank trigger. Looking at tunnel rams now to further improve my setup so the intake charge has an unrestricted shot into the intake port.

js

keep us informed as to the results of the tunnel ram. I'm still in confused limbo as to what direction to go in my intake choice. (I don't have anywhere near the clearance to run a tunnel ram, though, so that one is out for me).

the low temp with no stat to combat knock is a sensible idea. Had not really given that angle much thought before.

M

mcollinstn - Good luck with your engine, you have some great guys on this thread to help you.

jspeeddemon - I've been thinking about you and Turbojack with the dual carb box. The front carb takes up the space where I want to mount the intercooler (integrated with carb box/ no duct losses) so I didn't see how I could design something for you guys. But, if you go tunnel ram, it is possible. If I look at the Edelbrock catalog it looks like the tunnel ram is about 6" higher than the dual quad manifold you have. This increases the envelope enough to do it. The good news is that this also allows for more intercooler core; the bad news is, the carb/intercooler box is big. The transition from compressor to intercooler would be similar to the one I have designed for the single carb setup. This is where the most of the losses are reduced.

mbam - if you're reading this, this design would work for your engine plans, if you used throttle bodies and injectors on a tunnel ram style manifold. The dual compressor makes the transition more of a challenge, but it can be done. With the huge compressors available now do you need dual?

Anyone feel like fabricating something? Send me an email.

Tom