Well, I went and ran the camaro on the Dynojet this morning. To make things simple, my engine is almost exactly what carcraft built in the "540 horses for 4800 bucks" article. Let's just say I must be doing something wrong - or they're full of shhhh.

If you're not familiar with the article, I have most of the go-fast junk listed in my sig.

First strike against me: we got a reading of 104 degrees in the shop this morning at 46 percent humidity.

second strike against me is my exhaust. I'm running SLP 1-3/4 and blowing through a 3" cat.


The attached run wasn't quite the best, but it was close. best run yielded 350 hp with a little more timing. I'd go and blame it all on my exhaust and a hot day... but in the article mentioned above, they are talking about 520ft-lb of torque. Even with a conservative 20% drivetrain loss, you end up with 416 - that leaves me almost 50ft-lb shy. I'm sure LT's will help the HP, but don't expect it'll change the torque much.

any wisdom for me?

 

What is diffrent about your engine vs. the car craft engine? sometimes just a lil more flow in the head and cam will net you that much more hp.

 

The only two differences I can see are that they ran a super-sucker 2" carb spacer (and claimed about 7 hp gain) - and they probably ran some nice tuned longtube headers. Otherwise it looks identical.

I know that it's a very obvious difference when you drive on a 100 degree day as opposed to a 60 degree day. I just wonder how many ponies that could actually account for. Maybe I'll have to go run it in October or something.

 

Did you port the heads at all? All those articles usually have the heads ported to a certain extent and have 5 angle valve jobs as well as lighter valve train. I read an article with Joe Sherman where he still ported the heads even though they were AFRs so called performance ported heads. They do a lot of little tricks to gain more power that they wont always mention every single one. Every little amount power they gain from those tricks can add up quick. When they do those articles they spend tons of time with flow benches and dynos to get everything working optimum. Something definately looks wrong though.

 

The intake was port-matched to the heads, but to my knowledge the heads are pretty much out-of-the-box (which of course, is exactly what they say in the article). Even little stuff like that should only affect power numbers up top due to increased airflow. My big surprise was the difference in torque compared to what they said, even down low. It's one thing to stretch the torque curve out to make it 'hang in' longer - but if it's not that big to begin with....

 

Maybe try a different Dyno shop and see if the numbers correspond.

 

Are those numbers corrected or uncorrected? You're also not taking into account parasitic loss from the drivetrain and accessories. 350 at the wheels is roughly 425 at the flywheel depending on your setup. Take the car to the track and run it. A dyno is a tool for tuning, not an accurate measure of HP. Could you please list what is done to the motor and what parts are in it? A lot depends, too, on how it was put together

 

Reread that article. They were probably on a dyno stand with no accessories, electric water pump and headers with open exhaust. Also it looks like you only ran your motor to maybe 5500rpm. That is way low for a 248 degree cam. See where the peak horsepower was made in that article.

Your parts look ok save for the cam. That is one huge cam even for a 383 and that may be the problem. By the way your dyno numbers are not much different than mine with a 350CI and a cam that is 36 degrees less on the intake side.

 

I just ran your engine through a dyno simulator and at 5100 according to your dyno sheet it was around 450hp. Now between parasitic loss and accessories your not far off. Even head manufactures have a certain percentage of error when it comes to performance of their cylinder heads. This is why lots of guys opt for head porting to get the best of what the heads have to offer. If you want more power in a lower rpm range then I would get a different cam like suggested.

 

Unless your carb was correctly jetted for best power afr for the 104F air and the correction factor numbers (weather station) aor entered correctly your comparision is invalid.

Also you're not going to make power thru 1 3" cat. you need 2. The long tube headers will make more power and torque.

The power robbing accessories (your water pump, power steering etc etc) suck a lot more power than you think once the engine rpm gets above 5000rpm.
You should slow down all your pulleys by about 25% as the OEM pulley ratios are designed for a motor that doesn't see more than 5000rpm and idles at 600rpm.
The 20% drivetrain rule doesn;t work for a motor that
makes peak power at 6300rpm or so.

Your cammed up modified motor needs a higher rear gear ratio to keep it in its best power band but your engine driven accessories don;t need to be spin any faster at idle and cruise rpm. If the stock motor idles at 600rpm and your motor idles at 750-800rpm you can slow down the alternator and water pump speed by at least 25%

When ya look at the whole deal you actually did pretty good. If you think your motor is not up to snuff, they only real way to verify it is to pull it and dyno it.

 

It you think about it, it all adds up really fast. 1st if all theyre running the electric water pump and thats it, no power steering or alternator so there's 20hp. Plus you mentioned a carb spacer for an additional 7hp plus long tubes vs yours so give another 8hp or so (this is all a possible not a for sure) and there you have 35hp right there minus some of the other items that they might have done and your 100 degree day! I think your not that far off. Even so thats still a very potent power package! good job!

 

So I been thinking about this a bit more. I really wish the guy had pulled the thing through 6k. It would have been helpful to see if the torque dropped right off, or hung in there to make some more power. Another thing is the AFR was RIGHT on 13.5 the whole run. Probably a bit lean for WOT.