Inliners International Forums General Discussion Blown and Injected Chevy 292

I'm kind of debating on whether to run my 292 Chevy naturally aspirated or with a blower.

If I went N/A it would have a Clifford 4bbl intake, lump ports, a Holley 570cfm carb, 1.94int. and 1.60 exh. valves, Ross pistons, long tube headers, and 10:1 compression. Here's the cam specs: 274* advertised duration, .320 cam lift,110* lobe center.

If I went with a blower it would have a Clifford intake, lumps, a Holley 600Cfm carb made for a blower, same valves, Ross pistons, Long tube headers, and stock compression. Should I run the stock cam or some kindof turbo/blower grind(recommendations?)
What do you think about one of the old diesel blowers like off a 6-53 Detroit? that motor is 318 ci, pretty close to a 292. I would go through and put all the needed teflon seals and stuff in it. Do you think it would work? I could play with pulley sizes.
(sorry for the double post,I wasn't sure where this should go...)

A blower cam will give you more power everywhere.

Specs,,,,all depends on how much you want out of the engine.

How much boost,etc.
You have stock rods? If so, that's going to limit your RPM & will allow you to chose accordingly.

For a blower for the street.

I would go w/about 144-116 lobe center.I like a smooth engine for the street,maybe a little lope to the engine idleing.

220 duration @ .050..500" lift or so,,,,like I said,all depends on your goals.

Thats just a guess w/the cam,but need to know what you want out of it.

My 250 had a solid cam w/specs of .540 lift, & 236 int. 246 ex. on a 115 lobe center,IIRC.
With this cam, you could definately here it lopeing @ idle.

Also,I had normally aspirated cams w/about the same duration & it never wanted to rev as fast or as far as it wanted to w/the blower installed,,it just wanted to keep reving & reving,,,the blower had a max RPM & I actually had to shift @ 7500 RPM,otherwise I would have over spun the Paxton & would have damaged it. It probably would have spun to 8000 RPM w/the correct sized pulleys for t Paxton, but this engine had stock,side grinded, polished & shot peened rods,,,it probably would have thrown a rod or 2?

This long block engine is still in my Car & still altogether,minus the intake & exhaust awaiting for my turbo stuff to throw on.
I ran about 10 psi @ the most & the engine would want to spin to 7500 RPM.
This was w/a Paxton SN 89 supercharger.
Estimated HP was about 400 HP @ the wheels & ran low to mid 12's in the 1/4.
This was my street car daily driver.



MBHD

I was thinking anywhere from 350 to 400HP and about the same in torque. I'm still in the planning stages so I'm going going to build around a 400HP/400ft.lbs point of view. I wasn't planning on going above 5500-6000 RPM for street use. What are some good rods for me or are the stock ones fine for this?

The reasons I Was wondering about the diesel blowers was because I have easy and, primarily, cheap access to them. Do you think they would be alright for this application?

i have a 4-71 on my 270 gmc. about all you have to do is find one in good condition. know were to look for wear on the rotors and up grade the bearings. and no teflon for a street blower

Now that I think about it I have a 6-71 blower on the shelf ready for street use, could I just gear that down to about 70% the speed of the engine? Theoretically that would put out around 298 ci.
(6x71=426x.7=298.2)
just saying because I have the 6-71 handy and it's freshly rebuilt.

Go for it man!!
Just remember to factor the abount of boost you want into your equation.

The tests Cart Car & other mags have done in the past comparing a 6-71, B&M 144,Weiand 142?, Paxton super chargers & so-on, when they slowed down the 6-71 blower for low boost of 6-8 psi IIRC?

The 6-71 made the least HP & really added a lot of weight to the car.
The smaller faster turning blowers all made more HP & were more effcient (SP).


MBHD

huh, you'd think the slow moving ones with big rotors would gulp more air than one moving fast with small rotors...
There is a guy on the H.A.M.B site running an 8-71 on his 270 six, and he says it can keep up with the stupid little ricers on the highway, so I was thinking my 6-71 would probably work fine.
I'm not looking for a full out race motor, but I want to be able to show those ricers what a real hot rod looks and sounds like
If I get 350HP and 350ft.lbs I'd be happy, It'll top at about 10psi boost and 6000 RPM, and It's going to be a daily driver anyway...

Hank, Or somebody, Could you please suggest some cam specs for me?

That'll have me running a Holley 600 (http://holley.com/0-80592S.asp), Clifford intake, lump ports, 1.94I/1.50E valves, Long tube headers, Ross Pistons, and the 6-71 Blower.

The 6-71 is a big boat anchor (I've read 65 lbs. without mag end plates, needs big brackets, high inertia to spin up) for your purpose, and although capacity is high running it slowly means high leakage at low RPM.
For a roots type (boost at low speed) a Weiand or B&M small GMC replica is a better choice if you can find one used ($$$ new).
The M90 is a bargain, but remember that no OEM Eaton accepts a carburetor - no flange, intake in the wrong place. IMHO an M90 could be converted to top-fill with some surgery, and rotated 90° to use side-draft carbs and keep the hood clearance.
All the centrifugals (Paxton, ATI) must be spun faster, and produce less boost at lower speeds - which may help if your static CR is too high?

I'd also be using a bigger exhaust valve, 1.56" or 1.60" if it fits (even if it means reducing the intake valve).
CFM: 292" @ 90% VE, 6,000 RPM (not with the stock rods!) = 502.
For boost, multiple by the pressure ratio (1.68:1 for 10 psi) = 843 CFM. You can use the 600, but your power valves may need some tweaking - the Holley lit says dual for a V8, or 1200 CFM.

I assume when you say "ricer", you're talking about those irritating little squids with the giant red katakana decals on their fart-can Civics?
A serious Supra is 1,000 hp.

ya, those fart-can civics, OH, don't forget the 3inch exhaust that drags on the ground, and the muffler that looks like it belongs on a dozer... all behind a little 4 banger... (that's what makes it a ricer, or a ricerocket, or a ricecar .)

I am using bigger valves: 1.94 intake and 1.60 exhaust. they fit.

I really kind of want to use the 6-71, because I already have it and have poured money into it (rebuild) and it's left over from another project.
Couldn't I just play with pulley sizes till I find something that works? The old Detroits only rev up to about 3000RPM, so It'd be spinning twice as fast on my motor (depending on pully size)
I'm not trying to argue, I just want to use this blower? if possible?

Ooopps, senior moment - meant small size up from 1.60" may help.

I think tom Lowe said you would hit water soon after 1.94/1.60...?
Sure wish he(TLowe) would get on and say something, or Answer his email!!! hint, hint, nudge, nudge

[quote=qparkerHank, Or somebody, Could you please suggest some cam specs for me?

[/quote]



Comp cams can grind what ever spec cam you want.
A cam with a range of 220-230 degrees duration @ .050.
A lobe center of 115-116.

Lift around .500" is plenty,you are forcing the air in there.
You can look @ there SBC stuff for a blower cam & tell them you want a cam w/the SBC blower specs for your 292.

If all else fails,there tech dept can help you out.
I would not get any Clifford cam.


MBHD

a 2in valve can be installed but you really don't need it. On some of these old heads With the core shift that is in some you can Hit water just by trying to install a hardened seat Even with the USE of the shallow seats.You can even get into the water jacket if useing the wrong cutter (when under cutting for bigger valves)
You can get custom ground cams from most any cam company.

I combined Hank's info with a blower cam Engle had for their small blocks and came out with this:

lift@1.7:i).500"E).510"
Adv.duration:i)272*E)280*
Cam Lift:i)294"E)300"
lobe center:115*
Duration@.050:i)224"E)230"

What do you think? any adjustments?

Parker,
I have not seen any email from you in quite awhile. Answered them as they came too.
I think a 6-71 is going to be hard to drive off the snout of a chevy 6. The 6-71 is a beast, even for a V8. It takes quite abit of power just to turn it. Still think a turbo is the most efficient way to turn up the power.
You are on the right track with a cam. Clifford does not make turbo/ blower grind cams. I like Comp cams for custom grinds. Tom

I decided in the beginning of the build to do the bare minimum amount of business with Clifford. they lie and just want you to buy their products. I am going to have Engle Cams fill my order.
Thats weird you haven't gotten my emails...
Btw: how much is your turbo manifold?

I just like the simplicity of a blower, you don't have to fiddle with the carb for blow thru, mess with as much piping, and it's easier to mess with pullies than it is to mess with turbines/ housings. in my opinion. I still may go the turbo route, if Things get spendy with a blower...

As for the intake, should I use a 4bbl, a 3x1 or a 2x1? I'm already planning on doing alot of fab work, and if I went with a 2 or 3x1 I could put 1 to 2bbl adapters to make a bigger opening for the air to flow through, it'd probably increase velocity too...

???

How does an adapter make the opening bigger?
Bigger opening increases velocity?

look at this:
http://www.stoveboltengineco.com/acartpro/product.asp?productid=174

the bigger opening in the top(2bbl) necks down to the small bottom(1bbl) You'll see what I mean...

You are still restricted by the single barrel opening. Also most turbo users have boost controllers so you can adjust the boost without going into the turbo. Easier than changeing pulleys.

I know what it is. How does it make the opening bigger?

The top opening(the 2bbl part) is bigger than the bottom(the 1bbl part) it goes from a 3x1 manifold to a 3x2 manifold...

I give up.

think of a funnel, the top is bigger than the bottom. you can pour something in the top slow and it comes out faster at the bottom. if you move, say, 500 cubic inches of water through a 1 inch opening in 1 minute it doesn't have to flow as fast, but if you push it through a 1/2 inch hole, it has to flow a lot faster in order to get the same amount of fluid out in the same amount of time. Get it?

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I hope you get it, kuz you're making me start to doubt myself...

I understand what your saying I just don't understand why you would want to cause a restiction in your intake tract. I would think you would want the boost in the cylinder and not hung up in the blower with no way out. I would free up the flow and use the pulleys to adjust boost.

There is already a restriction in it, it's an offy intake made for three single barrel carbs. I'm putting 1bbl to 2 bbl adapters so you could put three two barrel carbs on it. Technically the adapters are just funnels, so I'm funneling the air into the motor.

Maybe get a dual four manifold and adapt the blower to that?

Who makes those for the 292?

Check out prostores1.carrierzone.com IM-17 $289.00 made by Clifford.

That's more like it!!! Thanks!! I'd have never found that...

All Hail Harry!

Or this, but for $200more... Maybe I'll stick with the dual quads...

http://prostores1.carrierzone.com/servle...manifold/Detail

I think that one only fits the small 144ci style blowers. I think that the 6-71 pattern is different. You would have to build an adaptor plate to bolt on top of that. It could be done, I guess, but you'd be in it pretty deep in the pocket when you got done.

Here is a blower manifold for the smaller blowers.
194-292
http://prostores1.carrierzone.com/servle...manifold/Detail
http://www.34-chevy.com/


MBHD

I think I'll just adapt it to the dual quad manifold and save $200

Sure, if you like to fab up parts & can make it happen,,,but if you want to bolt up a blower & save time & probably $$$ in the long end,there is a blower manifold available.

Plus I am thinking the blower manifold would deliver fuel better than running a dual quad manifold & then make an adapter & then stick a blower on top of the adaptor.
Just thinking out loud.
Two cents thrown ;-)

MBHD

I have ALL KINDS of scrap metal from previous projects that I can use, I'm a proficient welder, and don't mind fab work...

I think I'll just use the dual Quad intake, fab the parts, and be done with it.
I can just about pay for the water/methanol injection kit with what I save on using the 2x4 manifold over the blower one...

I agree, for me its always more fun to build it yourself. And if it works all that much better. Thats why I'm building my own water/meth injection system. Save some money for things I can't build.

I was going to do like you and build my own injection system, but i'd have to adjust the flow manually, where as with Snow's kit it's proven, it has a pressure sensor to adjust output, and/or I can manually do it...