I wanna put the car on a dyno and get some numbers...when would it be safe for some stranger to crank it up to 6000-6500 rpms? Also, at the dyno, can you tell the guy what rpms to keep it under, or do they just run it until it stops? I have only been to one dyno run (Rick Book's) and listening to his 347 hit those high rpms scared the crap out of me. I don't recall Rick having much say in what they did, he just said "yes" when the guy wanted to fine-tune something and run it again.
If I'm paying to have my car dynoed, they damn well better respect my wishes on how hard to run it, or else I'm taking my ball and going home... JMO.. Could always put a rev limiter on it too.
As soon as my motor was built......it was slapped on an engine dyno, broke in for about 20 minutes (to set the rings.....cam and lifters was a roller).....and then all hell was broke loose as they reved the dickens out of it!!
Lot's of brand new engines come with a Dyno Test performed Before Shipping ... I would think they just break it in for a few minutes before red-lining it for the dyno reading.
engine or car dyno?? Lots of different opinions on break-in. I've seen a lot of totally frewsh engines go for dyno,,, mine included. But they are race engines. If car dyno, I'd get at least 50 miles, change oil and head for dyno. THIS IS JUST ME,,,, Your gonna get lots of direction here. You be the judge. They will only do what you want. Hardest (pounding) on the engine is where the torque an HP cross over, around 5200 rpm, you still dont want to stretch your rpm's with vavles floating through the hood
I used to shift my old engine at 5000-5500, and didn't feel too comfortable going over that, but I did get really close to 6000 once. Usually they give you 2 pulls, I might tell him to stop at 6000 the first time, then depending on what the numbers look like, add another 500. I am just shooting for ballpark figures here, I don't care to tune for he last 10 hp. If the HP and torques are already coming down at 5500, then there is no reason to go any higher, and I will know where I will need to shift from then on. This cam and intake are supposed to have a band good from 2500-6000, so we will see how it works in reality. This is a car dyno, and I was not aware that 50 miles was considered a break-in. Always heard more like 500... Glad I asked.
spin it as high as you expect to make power. If your cam goes 6000 before petering out, there you go. I've screwed up once or twice and seen 8000rpm very briefly before. dang thing still runs. Just think about your bottom end, if your valve springs can keep the valves shut at high rpm and if your heads and intake can support the flow at that sort of RPM.
Scoop,I guess it ultimately comes down to how well you fell you put it together.If its right and built for 6500 rpm.Run that puppy up!! Do your own break in(whatever you feel comfy with) be it 50 or 500 miles,just make shure your tune and your oil are fresh when you do it.If you pop it on the dyno,better than at the strip in front of your buddies and your competition.
I don't know if I agree with that one...I would much rather blow it at the strip with my buddies watching supporting me than with someone else cranking 7k on it in a closed building...unless I have a video camera, there is lots of fire, and I can upload it to share on the forum Craig, what kind of break in did they do on yours? If the pros will run it after 20 minutes, then I can trust that mine should be ready to run after a short time (20 minutes, 50 miles, etc.). I have heard conflicting break in suggestions, run it hard and short, run it easy and for a long time, etc.
Don't trust anything I say....that is why I had the pros build my engine. I may be the only mechanic I can afford, but I don't trust myself. I am pretty sure they fired the motor up...let it run for about 20 minutes at about 3500 rpm (I am guessing). Changed the oil and filter, fired it up again, got it up to temp......then started reving the crap out of it. I was there a few days later and they fired it up for me on the dyno and revved the pi$$ out of it some more. Pretty darn loud I can tell you. Warning: Don't follow my advice. All advice is given out of personal experience. Your experience could be a lot different. You may blow something up. Void in Rhode Island, void where prohibited, consult your tax advisor, 55 saves lives, no refunds, exchanges, or credits.
..you are putting it on the dyno to get the #s...he will ask what cam and go about 3-500 RPMs over. they ain't there to just rev. your motor... the motor will loose power when it runs out of cam... if you have a 6500 cam and tell him not to go over 5000 then you will be wasting your money... they took my 5500 to 5800, thats where it fell off. saw 135MPH on the speedo. 1 pull he let off at 4300 because it was loosing power from being too rich. yes, it will make you back up when they... turn it up... ...8 pulls in the first 500 miles on my motor... ...Frank...:Handshake
...it has one...the cam... if you are...scared... ...keep it in the garage... ...Dynos are to see what it's making... ......
the noise you will hear with your setup, will be the motor breaking up at about 45-4800 from the valves floating. JMO ...or...rev. limiter... as Jamie put it... ...Frank...
I got you Craig... Frank, I never said I would stop them at 5000 (that was 5500-6000 on my old engine). I said I would stop them at 6000, unless it still shows that it is still pulling, then let them go another 500 or so. In increments, until I see where it stops working. I am not "scared"...anxious is a better word. Keep in mind that I am VERY hearing impaired and wear hearing aides to work. When I was at Rick Book's dyno test, I did not hear what was being discussed and asked Rick periodically what was going on. It "appeared" to me like the guy was really beating the crap out of his car, and running it WAY too high. Both of us walked out with jeans up our cracks from too much pucker. (sorry, but that describes it best. If you have been to a dyno run, you know what I mean.) If the guy takes into account the intake and cam, then he will be paying attention and will chill out around 6000-6500 recognizing that those are the high points and maybe hearing/feeling the engine starting to back of.
I've never had an engine dyno'd but if i did. i would tell the operator what i had and what i expected, then let the pros do their job. They don't want anything to happen either.
