Call Weiand that makes both mini blower kits and 6/71 on up blower
kits ask them questions on power with lower compression
more boost, or higher compression with small amounts of boost.

Then call comp, crane or whatever brand cam you like ask them about
differences in power with a wide LSA or why they recomend a
wide LSA with boosted engines.

 

Just got off the phone with Weiand tech support. I asked him how much more power I'd be making with 4lbs of boost (which is what their website reccommends for 9.5:1 compression on pump gas). He told me that I'd be making only 25-35 more hp!!! Does this sound accurate to you guys?!

On the plus side he said that my cam wasn't bad for boost, and my 110 LSA might actually help the high compression/ detonation problem a bit.

Comp told me that my cam wasn't all that bad for boost, I will have to compensate slightly with a larger pulley, but it shouldn't be that big of a deal according to Comp.

Just got off the phone with Snow Performance, he told me that I should go with their stage 2 methanol injection kit, and with that I should be able to double my boost (8lbs). So it looks like if I do this, I will be running methanol injection for sure. So now that I have a better grip on my options, here's the determining factor: how much more hp will my 400+hp aluminum headed 383 make with 8lbs of boost? If it's not much more than 100hp, it seems to me that nitrous would be a better alternative.

 

Lets say weiand is not correct for argument sake the 4 pounds
would give you say 70/75 horsepower, not much power for the
expense of a blower. Nitrous with the setup of comp. you now
have is the best alternative. Weiand man may have just gave an honest
answer even though he knew 25/35 horsepower was not going to convince
you to buy his product. I think a mini blower would have to be turned
pretty fast to get to 8 pounds of boost on a 383, thats why b & M
made a 250 size mini blower for large small blocks, I suspect when
b & M was bought out, Weiand did not bother with keeping the 250
most people with large small blocks probably just opted to buy a 6/71.

 

I've been doing a lot of reading up on superchargers lately. Any reason you haven't considered a centrifugal supercharger? Procharger's got some pretty nice setups claiming over 50%-60% gain.

I'd look into a centrifugal supercharger with an intercooler. It'll allow you to run much more psi, because what causes detonation isn't the increased boost, but the heat that comes with it. With a roots style you have no cooling, and therefore are limited by detonation, which then requires you to run a different fuel, retard timing, or both. Run an intercooler and you can run more boost, and it will be delivered into the engine more efficiently.

Plus, you never have to "fill up" a supercharger like Nitrous. 1 time cost sounds better to me.

 

Well I just played around on desktop dyno for a bit. Don't bother looking past the 6,000 rpm figures, it's not realistic.

I input my exact cam specs and all of the flow numbers at varying lifts for my cylinder heads, so this is pretty accurate.

Here is my engine with the Victor Jr. 436hp @ 6,000rpm



Here is my engine with the Weiand 177 (8lbs of boost) 560hp @ 6,000rpm (Keep in mind that to run 8lbs I would need methanol injection) At only 4lbs of boost I would make 484hp @ 6,000rpm



Little Mouse I think you're right. Now I'm leaning back over towards nitrous, not even sure that the compression increase will be worth it. With a one point increase in compression according to desktop dyno I'd be at 454hp @ 6,000rpm.

 

Really I'm not trying to get you to go the nitrous rout, I'am trying
to get you to drop compression put the blower on the car the right
way. Everything I have ever read about blowers you want low
comp. and as high a boost as pump gas will allow . Don't go off
half cocked if you really don't like fooling around with nitrous wait
tell you have the funds or time to drop the comp. do the job the right way. Personally with dropped comp I don't think even the 177
weiand is a good choice for a large small block, you have to spin it to fast to get boost out of it. The 6/71 will give you the boost easy and a lot of wow factor a lot of people like. but if your not wanting
to go the 6/71, believe I would look into someting like the procharger
or a turbo over a mini blower. The lag problems turbos had a lot of yrs ago have been worked out and a turbo is free HP off the exhaust it takes no power off the engine to run it.

 

If you want gobs of torque right off idle, instant throttle response and the ability to haze the tires at will, drop the comp and go with a big blower.
I have somewhere between 8.5 and 9.1. Mild camshaft 230* @ .050. 110 lsa
I spin my blower faster than recomended for my comp. But my rev limiter is at 5000. I don't make make max boost but power is right off idle and there is no need on the street to spin it any faster.
My motor wasn't built for forced induction, but I fell into a good deal on a 6-71.
Hey I have cast pistons for Gods sake
Just some food for thought

 

You set up right now, would be good for a nitrous motor. 150- 200 wouldn't be out of the question if the bottem end is there.

 

Put a 200 shot on it. You already have over 400 HP. Should be a great street engine and will probably roast the tires at will and run on regular gas as is. How often do you need the extra 200 HP? There is a plate setup in the C3 parts section Brand new! Might need a different plate. Pretty cheap on E-bay. One issue with the forced induction is longevity. Hard on internals on a street engine.

 

Now I'm thinking about a centrifugal supercharger, I had my mind made up to go with nitrous when Big G sent me this.

That's 10lbs hot and 15lbs intercooled with 9.5:1 on pump gas. That would obviously be worth it.

If I did it, I would like to buy the charger with the bracket/ pulleys and belt for a SBC seperately. Mount the intercooler myself, buy a low profile carb hat, and have my muffler guy run some 3" pipes for me. I can't find anyone who sells the superchargers and brackets by themselves. Any advice?

 

Did you get two pms with that pro charger graph ??

 

Yes I did, thank you though.

 

I'd vote to use a slightly thicker head-gasket, to drop static compression ratio to 9:1. Go with a blower cam (since you're gonna' be most of the way there), and then go with the mini-blower (I saw one on EBay this morning for $800! ).

If you're only making 4-6# of boost, while it may not sound like much, it'll have much better throttle-response than it would be in NA configuration. You should see >600HP, IF you tune it carefully, and are diligent about timing.

The cool thing about a mini-blower is that you'll have increased power throughout the RPM range, and be able to make that power without either refilling bottles, OR spinning the engine up to the sky to get it.

IMHO, the nitrous is the "poor mans' blower," and like any poor substitute, you get what you pay for...

Let us know what you decide.

 

I will not make 600hp with 4lbs, more like 500... if I'm lucky. The tech at Weiand told me I'd see 25-35hp with 4lbs. Not worth cutting a hole in my hood.

 

IMHO, the nitrous is the "poor mans' blower," and like any poor substitute, you get what you pay for...

Let us know what you decide.[/QUOTE]

I just don't get why some guys (who have probably never run nitrous) have such a dislike for it ??

You can have an extra 50-300 hp on tap for around 500-1000 bucks.....plus the cost of an occasional refill, why the visceral hatred ??

 

i get that on a turbo forum that i go on i run a stock turbo with nitrous some guys run just a big turbo, i get nitrous is for cheaters, you have to fill a bottle for power, nitrous blows stuff up, ect ect ect. if you know what your doing it is every bit as good as any other power adder for a fraction of the price. you need to know what your doing with any power adder.

 

Lots of hear say, and lots of blower guys trying to justify their investment. But in all fairness, nitrous is tougher on... everything. It's instantaneous, as opposed to boost which comes on gradually. Less of a shock to engine and drivetrain components... unless of course you have a progressive nitrous controller that allows it to come in slowly.

Realistically a bottle would last me a long time, as this is not my daily driver. So I'm going to price out the centrifugal supercharger, if I can do it without breaking my bank I will.

Also, 69 N.O.X. RATT where do you fill your bottle(s)? I live close to you and I have no idea where to get it filled. Party City?

As for the centrifugal supercharger, if I do it I will run a hot air kit with plans to add an intercooler with a smaller pulley in the future. I'm leaning towards the Procharger kit as I don't want to have to take off my oil pan to drill for an oil return. Hopefully I can get away with using a low profile carb bonnet to fit under the stock cowl and I plan to cut an oval shaped hole in the corner of my hood to let the top of the supercharger stick out. I may upgrade the float bowls in my Mighty Demon, not sure if I have to and I will probably be upgrading my fuel pump. Other than that, no engine mods. Comp told me that my cam was fine for boost, Procharger told me that I can run 8-10lbs on 91 octane with my compression ratio.

 

Cylinder pressure is cylinder pressure.......until you get into BIG hits of nitrous, it is, on average, easier on the motor than most other power adders because you do not need to turn many rpms to make a lot of power. It is rpm that kills motors most of the time. Both properly tuned; a centrifical blower at 7000 rpms making x boost to make 600 hp is much harder on the internals of an engine than a nitrous motor making the same power at 6000 rpms.

 

If a WWII fighter can get great HP from a blower (ie. P51) I would prefer that route. Plus a blower (or turbo) does not run out and need refilling, it is always there when you need it.

 

ooo realy

it is all what you like

they all add power how much and when is all in design of any of the systems. how much are you looking for, how much can you use, and how often are you going to use it, are all deciding factors. well that and cost (one reason my vette does not have a turbo on it yet, but till then the bottle will do)