Sunsation 323

I'm thinking about installing inter coolers under my B&M 420 superchargers and i'm curious to see if anybody knows what to expect for horsepower increases and whether to increase timing or boost or both? If there is any negatives to doing this I would also like to know that too.

MILD THUNDER

iTrader: (3)

That must be a good running 32 sunsation with Megablowers!! What are the details of the engines builds?

mcollinstn

Adding coolers does two things - it adds a little bit of restriction below the blower, and it increases the density of the intake charge. Both of these things will result in less measured boost in the intake plenum.

If your motor (as pullied) will already allow efficient timing lead (34 degrees) on your usual fuel, then adding the chillers and "doing nothing else" will actually result in a microscopic DROP in engine output. It's darn small and would never be something you would feel or see on the tach. But it is the added restriction that causes the small difference.

BUT, if your motor is currently running 34 degrees of timing, and doesn't run into detonation - adding the chillers will allow you to spin the blower faster and bump the boost - thus giving more power.

Most guys say - I was running 5 lbs of boost without chillers, and then added chillers and went smaller on the top pulley and still made 5 lbs of boost and picked up power and speed. That's correct, since you have to push more cool air into the motor to "see" the same boost as you did with the hot air previously.

OR if you are on the edge of detonation right now, and have pulled timing out for safety - adding chillers will allow you to bump your timing back up to "where it should be" and you will see more power.

MC

Sunsation 323

I'm currently running only 30 degrees of timing at 8 lbs of boost on 93 octane fuel. Been running this set up for 4 years with no problems. I hope to increase timing and gain power without detination but if a bigger blower than i'm currently running will give me the same increase only safer i will go that route. Currently running 420 mega blowers on 502,s that are putting out 770 hp each but looking for 850 hp or more. Is that feasable with coolers or bigger blowers? I have 8 to 1 compression , great internals, Brodix big brodie aluminum heads ported, roller cams for blower motors gen 5 blocks MSD, etc.

MILD THUNDER

iTrader: (3)

Do you know how much you are overdriving the blowers right now?

I'd like to tell you, yes, put the chillers on, bump the timing to 32 or even 34. You will lose probably 1-2lbs after the install, so you will have to swap pulleys to get back to 8 lbs. However, its really hard to tell you what your engines can take before you run into detonation problems over the web. i believe most guys who added chillers, and turned the boost up a couple lbs, saw 2-3mph gains. I wouldn't expect anything crazy like 10mph from adding chillers.

I'd be sure to run a AFR wideband meter, and get your AFR spot on.

I am personally scared of used chillers. So new, your probably looking at 3k for the chillers, and a couple more hundo for rigging/plumbing.

I'd almost consider taking that 3500 bucks or so, and getting some 4.25'' cranks for 540CI. That change alone will probably net about .25 gain in static compression. Then have your heads milled a bit, and get the compression up to say 8.5 or so. With these changes you'll make more HP on motor alone, have the chance to freshen things up/inspect while apart, and run less boost for more power. The megablowers will support a 540CI. My buddy runs them on 580ci mills making 900+ for many years. Just a thought.

At some point though, if your running a gen v production block (non bowtie), i'd be worried about the block itself. Not to mention your drives are probably not very happy with 770hp, let alone much more. Not sure of your current hull setup, but another thing to consider. You have 4 seasons on your motors, and the setup works. If its speed you seek, you may want to consider things like shorty lowers, custom props, hull blueprinting, etc, to gain speed, rather than throwing hp at it. You'd be surprised how much speed there is on the table with stuff like that. Not to mention handling improvements.

Sunsation 323

This is what i'm trying to figure out which way to get more speed. Don't know how much power i can squeeze out of my blocks and which way to go to get more speed? Someone is getting 109 from 850 hp and shorties, this is where i would like to be with the least amount of cost but i don't want to nuke my motors doing it. Not sure what kind of power i can get out of these stock gen v blocks. I need about 80 hp per motor to reach my goal, don't know if this is possible or not without changing blocks or cranks? Thought maybe coolers, more timing and more boost might do it?

CcanDo

Other points to consider, even with new coolers :

1) You would then have water on top of your engine.

2) Fuel distribution may require tuning and jetting.

3) Water flow then becomes even more critical.

4) A backfire may toast/corrupt or otherwise damage your cooler. The occurred damage and effects is unknown.

5) Corrosion and resulting negative effect may occur during storage.

Note: For maximum effort Racing, the above, plus drive damage mentioned, is then mitigated.

mcollinstn

I would lean towards the following:

1) Optimize your "base". Is your piston to head distance less than .055" ? If not, then you're missing out on the power and detonation-suppressing benefits of having a tight squish. Depending on whether your block has been "zero decked" or not, you may be running way too much clearance there and leaving power on the table.
2) Figure out how hard your blowers are currently working. Figure out a way to get an insulated thermocouple into the intake plenum and measure the charge temp at max boost and wide open throttle under load. If your charge is extremely hot, then you may not be able to spin your current blower hard enough to reach the power levels you're after without the heat curve going exponential. A 420 on a 502 at 8lbs is on the high side of the curve for a 420, but it may have some more grunt left in it. I would expect your charge temperature to be pretty high on a WOT pull.
3) With the results in #2, you can see how badly (or not badly) you need a good chiller. Exceptional chillers will bring the charge temp down close to "water temp plus 30F". In 80 degree water, that means a really optimized chiller setup will bring the charge temp to about 110F. More realistic results will be around "water temp plus 50F" but that's still a lot of help.

As far as your compression ratio? For what you're looking for, you probably ought to stay with low static compression - tighten up the squish, and pump more charge thru the motor. I would not deck anything off of the heads, but would move the heads closer to the pistons (by decking the block to give 0.042-0.045 squish height with standard gasket thickness).

Then, as has been said, run EGTS and Wideband O2 sensors to set up this booger.

Best wishes.

MC

Sunsation 323

I talked with Nickerson Performance today who's real good with marine carbs and blower motors , he said that chillers would make my motors more reliable also he said to expect 70 hp per motor by changing pullies to remain at the 8 lbs of boost that i'm at now. This would put me where i want to be. Thank you everybody for your input and please comment on this response also.

MILD THUNDER

iTrader: (3)

I know on the dyno, by turning the water supply on to the chiller, gained someone about 25hp. However, I would have rather saw the comparison between no chiller, and chiller installed and working. My guess is they'd be very close in power. Without the chiller there as a restriction.

Either way be careful with the drives with the boost cranked up!! Dont want one letting go at 100mph in a 32 vee.