Dyno Sheet..its a heartbreaker

Here are my first Dynos of the Maverick...I was disapointed by the HP rating but its ok. Currently I am running a 302 roller bores .20 over with stock comp pistons. Its got a comp cam, a mildly ported set of stock heads and Holley carb. Its got a 9" rear with 4.56 gears in a C4 box. I think the gears are pulling some HPS, but man that tourqe # is nice. I want to change to some edlebrock heads, and drop a 75 shot of juice on it. I will have to change the gears then cause as of right now it tops out at about 3/4 track. My timslip is in my sig...Tell me what you guys think, maybe Rick can give me some heads up on a nice set of aftermarket heads. I am a 4cyl Kid and am looking to learn more about my 8cyl car...Peace

Lox



High RES Dyno

 

Love it or hate it

The dyno more offen will bring most people back to earth.
What I mean by that is, you tell yourself oh my car has at least 500hp well then you get on the dyno and get your heart broken.

I work part time in a speed shop and see this happen almost everyweek, the biggest let down is from engines that are build from manufacturers that claim that their motors are to produce so many hundreds of horsepower, lets say a 454 chevy BB you pay 10,000.00 for and the Manufacturer says it will give you 900 horses. Once on the dyno you find that it's about 775 to 825 at 10,000.00 that other 125 to 75 horses hurts.

Now on the flip side to that is when you dyno a motor and you find with the right combo you have a kickass motor, 4 months ago a guy comes in and says he want to have is motor put on the dyno and it just so happens to be a 347 SBF stroker, this little beast went 510 WITHOUT spray!! It's all in the flow, and that's a fact!
Without a GREAT set of heads all the pistons, cam, intake and carb in the world won't do you any good. I can't say enough about stage 3 ported heads, this all goes right back to the oldest saying in racing. SPEED COSTS, HOW FAST DO YOU WANT TO GO!

As always just my .02

Terry Gates
AKA Bossmav

 

DYNO

Yeah dude your heads are killing you, I personally believe that is all about matching parts, matching a cam to your application is the hardest part, Look to Crower cams for a custom grind, and know the path that your planning on going with the car, The edelbrock heads are good but there are better ones out there that flow more and are cheaper, I run the pro topline 200 cc head and a victor jr, with a custom grind Nitrous cam a 8" converter a victor jr intake and a 750 proform holley, I run 4.30 gears and have gotten 411 rwhp out of it without the nos. The heads that I run flow better than the AFR 185's out of the box, but the basic power range of the heads intake and cam are all the same, and the converter gears and tire diameter all work in sequence with my combo, The heart of any motor is the cam, but if the cam cant help you move the air because the heads wont flow the air then it is futile! Know the direction you want the car to go, how fast you want it and how streetable or raceable! Make the necessary changes, do it once do it right, you need a cam intake and a set of heads, I have run the stock roller block short blocks way into the 10s with good heads and cams, so you definately have the foundation to go forward with!!!

 

Lox, I'd refer you to the thread below regarding heads:


http://mmb.maverick.to/showthread.php?s=&threadid=5654

 

I wouldn't give up on those heads yet, I would be more concerned with the dip in power at 3800 rpm. I would work carb jetting and timing first to get the max out of the set up you have, there may be some hidden Hp still in there.

Here's what Tammy's car ran with one low cylinder(wrist pin came loose and scraped the cylinder wall) , bad advance curve and rich jetting. I need to do it again because those areas have been addressed.

The engine has edelbrock rpm heads, air gap, 600 holley, e-303 cam, roller rockers, HV water and oil pumps, 10/1 forges pistons, windage tray and accell blue print distibutor.

 

The 13.8 trap was at 95 MPH maybe 98, I'll have to find the slip. Its only got the 3 gears though, so why would a converter make a difference. It tops out at abtou 3/4 track like I said. I trap at like 5800 ish if the tach is correct...Maybe its the tires, we run Mickey Thompson Full Drags slicks, there are like a 28/9/14....I want the new heads and gears first, then maybe I can look at a new cam....

 

If your going to change to better heads, don't bother with E7s. Spend around 900 and get a much better set of aftermarket heads.
With 4.56 gears you are screamimg the engine. Hi rpm needs a lot of airflow that stock type heads don't do to well at.
Your cam needs to match as well as higher compression.
With 4.56 gears, airflow and a cam that matches the rpm band with carburatrion to match is the way to think about it.

 

Cam- Comp- 216-224 duration @ .050 .544-.555 lift
Carb- Holley 600 with vac secondaries
Intake- Edlebrok Performer RPM....
Stall is whatever the stock C4 will hold, nothing aftermarket

I just had to look that stuff up. I didn't build the motor so I wasn't responsible for any of this matching...does that help?

Lox

 

Those Dyno numbers don't seem right to me at all. Something is definitely wrong. It's saying that the torque is the same as it was with the factory stock setup...That's impossible. And only 60HP over stock??! That's can't be right...not with a cam, carb & intake like that. The heads ARE the biggest limitation, but I still think it should be pushing 250HP and 300 Lb.-Ft. of torque with that setup...
:confused:

 

.

Bossmav,

Could you give us a rundown on what that lil fire-breathing 347 had in it? I'm guessing vic jr intake and heads. What was the power band like on it? I'm thinking that it wasn't a streetable motor, correct me if I'm wrong.

 

Cam

I disagree I think that hp and tq are all that that tiny little cam has to offer, So what its got some lift! the heads dont flow the air at 450, 500 or 550 so why bother with high lift????? Remember this was a rear wheel dyno, He really didnt do that bad, He has some lean or maybe fat issues with his timing and carburator, ;;and could improve the peak #s for a greater duration, but everything else is limiting him,
Take all of our advise, there is tons more out there with heads intake and cams, It will all come together, you will, see, But definately lose the heads and the cam you bottom end will handle 500 hp so put some parts upstairs that will make 500 hp not 250!

 

I'll swing by the speed shop today and pick up all the dyno sheets (I saved them on the dyno computer) and all the motor specs.
After the motor was ran the owner must have thought I was crazy for asking all those questions but I just had to know what was in that little beast. Info to follow.

Bossmav

P.S. I agree with N2O maverick, if it won't flow you won't go!

 

Well I'd like to do heads first, then intake and carb, and then have a cam ground around those. Are those AFR's that rick has for sale a good upgrade? I am only looking for around 350-400 RWHP total, so after the intake,heads,carb and cam I am gonna shoot a little N2o but only like a 75 shot. So just let me know wha you guys are thinking.

Lox

 

Well, our good pal Mavaholic has AFR 185 heads with an edelbroch RPM Performer intake, and his car dynoed out at 303 RWHP I think, which is about 370 at the flywheel. So if you want more power than that, you're going to have to get more radical. And when I say more radical I mean you're going to have to get bigger and better heads, a bigger cam, and possibly even a single plane victor jr. intake or something similar. It may be hard to keep it streetable with equipment like that. In the end, you may be better off just supercharging it, which would give you the power you desire plus it would make it streetable. I'll be interested in how this turns out, because I'm planning on going with a 347 stroker, and hope to crank out about 450 hp out of it.

 

Yeah, isin't supercharging tougher with a carbed engine? We are only looking to spend about another 2500 bucks or so right now...