Imothph

Hi -

wondering if one of you can desktop dyno this set up for me. I got Virtual Engine, but its a little screwy and I'm not sure its working correctly. I plan on getting Desktop Dyno5 here pretty soon.

Anyway - here are the specs I have and I hope its what you need:

Engine- Chevrolet 350
Bore: 4"
Stroke: 3.48
Compression ratio : 9.2:1

Cylinder Heads
64cc combustion chamber
170 CC intake
60 CC exhaust
2.020" Intake valve
1.600" Exhaust valve
1.460" springs / .575" max lift
3-angle valve seat

Cam Shaft

Hydraulic flat tappet
Duration at 050 lift: .224 intake / .224 Exhaust
Valve lift: .470 intake / .470 exhaust
Lobe Separation: 110
Advertised Duration: 270 / 270

Other

-750 CFM Q-Jet Carb
-Aluminum dual plane intake manifold(Edelbrock performer)
-Dual Exhaust, 2.5 inch. full length headers, flowmaster mufflers
-Roller tip rocker, standard ratio

I hope that's enough info - Thanks in advance to any that can plug this into desktop Dyno.

Allan.

Droshki

If you can find the actual flow numbers on the heads your answer will be more accurate. And by this I mean I/E .001 lift, .002 lift, etc

ratflinger

Plugged in a few numbers, 315h/331t. That may be generous.

Imothph

Alrighty...

Intake / Exhaust
.100:67 / 58
.200:130 / 108
.300:183 / 144
.400:226 / 169
.500:229 / 175
.600:232 / 182
.700: No numbers given

Test pressure was 28"

Hey Thanks Ratflinger - 315HP is reasonable I think. Virtual Engine gave me 380 w/ open headers, 342 with High-flow dual exhaust and 409Hp with a high flow single....which seems a bit screwy to me

billla

Without details on the carb and heads any simulator is kinda uselss. Brands, P/N, etc. needed for anything much.

MotorHead

I am getting 370HP @ 5500 RPM and 400 TQ @ 4000 RPM with large tube headers and open exhaust. This is what it would be close to on an engine dyno. This will drop to 340HP and 388TQ with mufflers and there will be additional losses when installed in the Car.

You should be looking at good power with about 250 HP or more at the rear wheels

Imothph

Ok - (part numbers obtained via Summit racing)

Heads: Edelbrock performer RPM. Part number: EDL-60909
Cam:Comp Cams Magnum 270H: Part number: CCA-12-211-2
Carb: Edelbrock Quadrajet spreadbore: Part number: EDL-1902
Intake Manifold: Edlebrock Performer: Part number: EDL - 2101
Headers: Dynomax, ceramic coated: Part number:WLK-86008

thanks!

Guru_4_hire

I would swith the performer for the Performer RPM for a Q-jet

Imothph

Nice! thanks allot for running the numbers. I don't really have a specific HP number in mind, except that I'd like my vette to perform like one

gkull

371hp@5500

382tq@4500

I used the edelbrock listed flow file with small tube headers and mufflers.

this is also using a good dual plane intake not some restrictive Performer 2101.

Your planned compression is very low for aluminum heads and split duration cams are helpful

With less than 10:1 I would use the Crain 272 power max and over 10:1 the 278 power max

MotorHead

I think the heads are the bottleneck, if you get some heads that flow over 250cfm and bump up the compression to 10:1 then you are looking at 400HP or more

Oh yeah lose the Performer intake, all these HP numbers won't be as high with that manifold.

Imothph

Well see here is the thing....

I'm not sure I want over 400 HP (I know....who say's that) but this car will be driven as a daily driver in the summer (even to work) and my wife also likes to take the corvette out for a spin and so it really needs to be somewhat more tame that 400HP+. I'd be happy with something in the mid 300's - 350HP or so. Don't get me wrong, there is a part of me that wants to squeeze every inch of HP out of the motor, but I do need to control myself. I have a 57 Chevy that I can go nuts on if I want, so I can be "responsible" with the vette

The other concern is that I'm using a stock 78 L48 bottom end. I don't want to go over 400HP with that anyway and its taking the 64cc cambers of the heads to get the CR up around 9.2:1 - so Im not sure how I'd get closer to 10:1 without switching out pistons or finding a even smaller combustion chamber head.

As for the intake - I agree, but, I already have it and would rather not just sit it on a shelf.

ratflinger

Sounds about right I assumed 292 heads

MotorHead

I hear ya, but I have never met anyone yet that built a performance motor and few weeks later didn't want more HP

Steel shim head gasket is the ticket to near 10:1 cr without changing anything and sell the Performer and get RPM Air Gap or just plain RPM

Imothph

Hmm, that's an idea. I'll be mating the aluminum head to a cast iron block, do you know if that particular gasket will work for Aluminum / CI combo?

MotorHead

I just assumed iron heads with the flow numbers given. Or are you thinking of getting better flowing alum. heads ?

I only post what I know from my own personal experiences, steel shim works with iron heads not sure about alum. others might have tried it

gkull

You are not going to have over 380 hp with small cam and heads. The cam kind of determines the heartbeat of a motor and driveability.

The 110 LC of the CC cam would be worse driveability than a Crane 272 with 112 lc

billla

Thanks!

I came away with 387FWHP@5500 RPM and 420FWTQ@400 RPM, with > 400FWTQ available from 2500-4500 RPM. DD Advanced is generally a bit optimistic with TQ.

IMHO, there's nothing wrong with any of those pics. Edelbrock heads aren't the best on the market by any means, but overall it's a good combo!

rham

Just curious, but I thought the Crane Powermax has more overlap than the CC 270. I am assuming it is the Crane 272/284. I thought more overlap equals less driveability.

Imothph

Thanks Billa!

I haven't decided on the Edelbrock heads for sure, but they are "leading the pack" so far. I have considered the Brodix IK180, but the manufacturer recommends a minimum of a 355 and the heads have D-shaped exhaust ports while my headers don't - The Edelbrocks seem to be the most "plug and play", so far. RHS has a similar head (RHS 12317-01) its cast iron, the aluminum version is $1199 - $200 or so over the Edelbrock. Patriot performance 2181 is another similar head (190cc intake), $895.00, but seemed like Edelbrock has a better reputation for quality. I also figured that everything else I have is pretty much Edelbrock.

No decisions yet though, I may yet be swayed