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Discussion Starter #1
Ok, so i'm going to be building a 355 sbc soon.
Specifically I was looking at combo 78 here:
http://www.ryanscarpage.50megs.com/combos11.html

Now, this is already a lower compression 355.
Now mind you I have not done a lot of research on superchargers yet, but once this engine is built and in my car and I have money for it, I would LOVE to put a roots style supercharger on it.

Now I dont want to run alot of boost, maybe anywhere between 6-8psi or so.
My main questions are thus:
Which roots version supercharger would be good for a non-daily driven car that might see the track a few times?

Also, how is that cam for a supercharger? I believe you are supposed to downgrade the cam when you use one, but its not that big too begin with, maybe keep the 1.5 rockers?

And would I need a larger carb to make up forall the extra air i will be getting? If so, how big?

Are there any web pages that I can find alot of supercharger info? Ive found a few with snippets here and there, but id love to see a dedicated Supercharger page or something with lots of info.

Or, can someone suggest a book?

Thanks alot everyone
Steve
 

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Artemis Entreri said:
Ok, so i'm going to be building a 355 sbc soon.
Specifically I was looking at combo 78 here:
http://www.ryanscarpage.50megs.com/combos11.html

Now, this is already a lower compression 355.
Now mind you I have not done a lot of research on superchargers yet, but once this engine is built and in my car and I have money for it, I would LOVE to put a roots style supercharger on it.

Now I dont want to run alot of boost, maybe anywhere between 6-8psi or so.
My main questions are thus:
Which roots version supercharger would be good for a non-daily driven car that might see the track a few times?

Also, how is that cam for a supercharger? I believe you are supposed to downgrade the cam when you use one, but its not that big too begin with, maybe keep the 1.5 rockers?

And would I need a larger carb to make up forall the extra air i will be getting? If so, how big?

Are there any web pages that I can find alot of supercharger info? Ive found a few with snippets here and there, but id love to see a dedicated Supercharger page or something with lots of info.

Or, can someone suggest a book?

Thanks alot everyone
Steve
http://www.carcraft.com/featuredvehicles/116_0609_supercharged_350ci_chevy/

This article sounds similar to what you might want to do....
 

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Discussion Starter #4
Hey thanks for the book suggestion.
And that is a sweet article. Could build a little bit more of a performance bottom end, maybe a bigger cam and some more work done on my vortec heads and then just buy the supercharger and drop it one when I get the cash.

Thanks alot
 

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Pat Ganahl's book has a lot of good advice in it. I noticed the build #78 uses 8:75 compression, getting a bit high for a blower. The Car Craft article used an 8:25 motor, better, but I'd try to keep the compression even lower, maybe 8:1, that'll give you more room for increased boost if you ever got the urge....we all get the urge. Depending on what grade gas is available in your parts, consider a boost retard, nice to have that option.
 

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Discussion Starter #6
Thanks Nova, what is a boost retard? I mean, I assume it just backs off the boost, but how does it work?

Also, what is the difference to a carb used with a supercharger compared to a normal carbed dumped ontop of a engine?
 

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Boost retard, is retarding your timing when you create boost.
I have a MSD boost retard box hooked to my MSD 6AL, you can set it as to how much you want it to retard your timing per pound of boost. Like lets say you have it set at 2 degrees, then for every pound of boost you make, it retards your timing 2 drgrees.

Duke
 

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Discussion Starter #8 (Edited)
Thanks alot Duke, i'll have to look into that once I get the engine together.

Pmeisel, do you know where I can find prices for that magna charger 122? Ive been searching around, cant find it anywhere.

If not, can anyone suggest a smaller supercharger for a 350?

Also, anyone know the difference between supercharger carbs, and normal carbs?
 

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I think that car craft article would be a good place to start. As far as carbs go, it depends on if you have a blowthrough or if the air is drawn through. On the holley site, they have a carbeurator selector to help you find a carb that would work well. It kinda describes the differences.

You can go through it here, enter your displacement in the top right corner.
http://www.holley.com/

I went through it and came up with this one
http://www.holley.com/0-80572S.asp

Another option would be an intercooled procharger. It would probably be more expensive, but I think you could make about a 600 all else being equal to that in the article. With a procharger, you can run more boost because they produce less heat. On top of that, the intercooler reduces the heat of the air a lot also. At 8:1, you could probably run around 10 psi pretty easily. According to the procharger catalog, with an intercooled procharger, that can increase your your power by a factor of 1.7. 350 hp * 1.7 is 595 hp. If you look at the end of the procharger catalog, it tells you what kind of boost you can run with a given compression on pump gas. It assumes aluminum heads, but I just added a point of compression to simulate iron heads. I dont know if it works that way or not though.

here is a link to the procharger catalog I would read it, there is a lot of good info here.
http://www.procharger.com/pdf/Chevy.Prod.bb.pdf

Adam
 

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Discussion Starter #10
Thanks alot fire, as far as the procharger, I know that would be more efficient, but the roots style is just as much for the look and cause I like them then for the power it will give me. Plus hopefully it will cost less and be less work, Heh.
 

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I understand, you are right about the cost and simplicity. It will still make great hp.

Adam
 

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Discussion Starter #12
Cant seem to find anything on the magna charger 122 they used in the article. Been thinking about going with another small SC, the weiand 142 or 144.

Anyone use one of these, yay or nay?
 

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I've got a real mild 355 with a Weiand 142 in my s-10...Here are some old pics but you get the idea...Runs mid 12's in FULL street trim...Keep in mind that this is with factory iron heads and a very small cam...

http://groups.msn.com/GearheadsPoorboys/huffeddime.msnw?albumlist=2


Some "hidden" costs involved that not many people mention...Plan on purchasing a blower calibrated carburetor unless you are a bonafide carb guru/megatuner...You will more than likely need to upgrade your fuel system to keep it fed at higher RPM...You will realize a GREAT improvement in performance with the blower by installing the largest headers/exhaust you can fit in the chassis with straight thru mufflers...The BTM is nice to have but make SURE you use some form of rev limiter - you WILL need it...You may need to upgrade your tranny for the torque levels you will be putting out and if an automatic will need a converter with a balloon plate...
 

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Discussion Starter #14
jameskirk1 said:
I've got a real mild 355 with a Weiand 142 in my s-10...Here are some old pics but you get the idea...Runs mid 12's in FULL street trim...Keep in mind that this is with factory iron heads and a very small cam...

http://groups.msn.com/GearheadsPoorboys/huffeddime.msnw?albumlist=2


Some "hidden" costs involved that not many people mention...Plan on purchasing a blower calibrated carburetor unless you are a bonafide carb guru/megatuner...You will more than likely need to upgrade your fuel system to keep it fed at higher RPM...You will realize a GREAT improvement in performance with the blower by installing the largest headers/exhaust you can fit in the chassis with straight thru mufflers...The BTM is nice to have but make SURE you use some form of rev limiter - you WILL need it...You may need to upgrade your tranny for the torque levels you will be putting out and if an automatic will need a converter with a balloon plate...
Thanks alot, thats a nice s10, how much does that truck weigh?
Are blower carbs that much more expensive?
Upgrade my fuel system, like a pump upgrade and stuff?
As for exaust I was going with headers right into glasspacks for now, wont be driving the car everyday.

BTM? Dont want to sound ignorant, but huh?
Like what kind of rev limiter?

Also, was your cam a off the shelf supercharger cam, or a custom grind?
And are those the stock pulleys that come with the 142 you are using with 8.5:1 cr?

Sorry for all the questions, but thanks.
Steve
 

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Hello.
You should definatly get the supercharging book and read up before adding one.
But if yer lookin 4 good power without spending a ton, you can get by with a lot more using a smaller roots type (like the Weiand 144 unit).
It will add great looks with around 100-125 horses by just bolting it on.
No need 4 fancy carbs. Get a nice Edelbrock 600-750 or a holley. On the smaller units (1440 you dont need a lot of xtra things.
Even small ports will work but you loose some power over like afr's, but cost is way less.
Im buildin a big 6-71 so let me know if you need help. Cya, HG
Chk out my project journal
 

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Artemis Entreri said:
Cant seem to find anything on the magna charger 122 they used in the article. Been thinking about going with another small SC, the weiand 142 or 144.

Anyone use one of these, yay or nay?
I am running a Weiand 142 on a chevy 350 crate engine and it was a very simple installation. The additional power is pretty impressive. Mine is in a 1600 pound t-bucket so it goes pretty good and can fry the tires for miles. It is by far the easiest bolt on HP an TQ you can add. As mentioned above you will need a specially prepared carb also. I paid under 300 for mine from a carb rebuilder and it works mint.
 

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Discussion Starter #17
Hemmi you said THE supercharging book, is there one I should be reading specifically?
Also, what is the big difference between the 142 and 144? They both say they add the same amount of power I believe..
When I get a game plan together I might just get ahold of you Hemmi.

Tbucket, that is a sweeeeet ride, one day i'll have something like that, lol.

Thanks alot
Steve
 

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Artemis Entreri said:
Thanks alot, thats a nice s10, how much does that truck weigh? Approximately 3200lbs with me and alot of stereo in it.

Are blower carbs that much more expensive? Depends...I paid around $525 for mine after alot of trial and error trying to modify a "N/A" carb. (I'm picky about driveability)

Upgrade my fuel system, like a pump upgrade and stuff? You need to keep at least 6psi at the carb under full boost/high RPM situation; stock pump and lines usually won't keep up with a blown engine.

As for exaust I was going with headers right into glasspacks for now, wont be driving the car everyday. Thats fine...Exhaust tuning goes out the window with a supercharger, you just want the least restriction possible...

BTM? Dont want to sound ignorant, but huh? MSD Boost Timing Master
Like what kind of rev limiter? Anykind of aftermarket rev limiter, my foot isn't fast enough to keep from over-revving like it was N/A.

Also, was your cam a off the shelf supercharger cam, or a custom grind?
It was an off the shelf Comp Nitrous HP cam (also ideal for supercharger)

And are those the stock pulleys that come with the 142 you are using with 8.5:1 cr? Yes. It will make around 6lbs on a stock longblock with "mild" exhaust

Sorry for all the questions, but thanks.
Steve
No problem :thumbup:

***Edit: I answered your questions above, inside the quote. :pain:
 

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Blowers

Yes the roots style is the classic way to go & a blower camgrind is needed, try 'Blower Drive Service' they have full bolt-on kits with the classic GMC style. The 100-150 hp increase is extremely conservative , Forged pistons are a must for the big HP numbers. And yes, intake port flow really doesn't mean much for street engines & exaust flow isn't really relevent either.
With the low CR forged pistons, cam, matching carb & a good ignition 700BHP is very doable...assuming you won't overtax the bottom end.
____________________________________________Rick..............
 

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Artemis Entreri said:
Hemmi you said THE supercharging book, is there one I should be reading specifically?
Also, what is the big difference between the 142 and 144? They both say they add the same amount of power I believe..
When I get a game plan together I might just get ahold of you Hemmi.

Tbucket, that is a sweeeeet ride, one day i'll have something like that, lol.

Thanks alot
Steve
A 142 and a 144 are very similar, I think the 142 is a little newer design and Weiand only. There are a lot of different 144's, Weiand, B&M and a few others make 144's. The number is actually representitive of the airflow displacement.
There is a lot of good info on the blower drive services website as well as other blower sites. If you stick with the stock setup on a 142 it will be fairly safe on a decent engine. The Weiand site also has a ton of good info.
 
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