Disappointing Dyno Numbers -- I need advice please! I think something isn't right.

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Yea that's it. 420 hp with basically the same build with the exception of intake and headers though he has a cam in the middle between the 212 and 413. Either the timing isn't set up correctly or the iron intake and exhaust is really killing it.

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

When larger valves are installed, doesn't the chamber area around the intake need to be machined to unshroud the valve?

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Those are almost exactly the same numbers I got for my car on a chassis dyno. Although my HP peaked around 5000 rpm's. I was a bit disappointed.

But after seeing the numbers posted by others, particularly Chevy/Ford/MOPAR guys, and seeing their times in the quarter mile (many in the 12's and 13's) I'm satisfied.

As long as the car hooks good, you'll have plenty of smiles on the street and on the track.

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Thank you very much for all of your input. I am going to get the needed information and I will give you an update.

You have given me the talking points I was looking for that I need to bring up with the shop. Much appreciated!

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Numbers looks like he has calculated with 20% drivetrain loss.

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

What was the cam degreed to? Or was it degreed?

What was the final timing?

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

I had a set of small valve heads that John Z did some work to focusing of keeping high air velocity. A stk bottom end motor these heads and a hemi killer cam, and an offy 360 intake and edelbrock 750 carb ran 11.80s, had the valve changed out to stage1 car went 12.20s. The just bowl hogged and fit the valves. They messed it up so bad John just did another set cause it was easier than fixing the mistake.

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

The OP has already stated that he might be mistaken about the rpm at hp peak.
It's probably 5000 rpm, that would fall in line appropriately with the torque # and appears to be close to a factory engine, correction calcs notwithstanding.
It's already been stated that it takes more than 'just cutting seats to fit larger valves' to show an actual benefit.
I see this as blameless so far and maybe that expectations could have been honed in on with more communication up front.

 

Update: I got some numbers

Ok, here is some more info:

See Dyno Print out.

Static compression: 10.1:1 (gasket compressed thickness .041, deck height .01055)gasket (.041)


Dynamic Compression (according to my calculations): 7.21:1
Camshaft was not degreed.
Edit: I am wondering about the static compression. According to the Wallace Racing calculator, it seems like it should be 10.34:1 given the above numbers?

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Looks like it made pretty much what it should have,....

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Agree. I just wonder if they put the cam in straight up or if they advanced it and how the distributor is set up.

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Thanks Hugger. Do you think I should consider bumping up my static compression (thinner head gasket) a point for more power? Would 11:1 static compression still be ok with pump gas 94 octane?

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Thanks Larry,

With that being said in combination with your earlier post, would you recommend that I have the shop go back and degree the cam? I am not sure of the implications, I need to do more reading to learn.

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Checking cam timing certainly couldn't hurt, your not going to find 50hp there, and no don't go upping compression with Iron heads, just put it in put some miles on it to see if the bottom end is a durable piece and then put some TA heads and a more aggressive stick in one weekend then you will be where you want be, or think you should be

 

Re: Disappointing Dyno Numbers -- I need advice please! I think something isn't right

Good point, if it just a single keyway it is what is, I bet that's why it's straight up because there was no other option