I just got back from three days of dyno thrashing on the yellow car. Made 17 runs altogether. If you ever get the chance to run your car, and tune on it in between runs, you will learn soooo much about what your car likes and dislikes. Here is an example of mine: Likes, 36* total timing, more oil pressure, smaller carb/less jetting. Dislikes, not enough/ too much timing, too little oil pressure (65 psi @ WOT), bigger carb (i.e. 1000 hp Holley), too fat of jetting, loose converter. Some of these things are known in the Buick community, yet your combination makes a big difference. Without being able to analyze each run critically you WILL NOT know what works best. Here is my current combo: 1971 TS block, uncut deck, .030 over Stock rods, notched Speed Pro pistons Crank scraper, home made pan baffle. Stage 2 aluminum heads intake flows .338 @ .550 :eek2: ! SP1 intake unmatched, 800 cfm Holley w/1" spacer,Comp Cams 240/246, 1.6 roller rockers, Mallory Unilite w/Crane Hi-6 ignition, Meziere water pump. TH400 w/10" converter 4000 stall (4600 on the brake) 3:73 12 bolt rear end. :Comp: We made a peak of 439.39 HP @ 5350 rpm with Torque 435.4 @ 5200 rpm at the rear wheels. Special Thanks to: Steve Barker for all the help in tuning between runs, and for putting up with a Buick in his shop for three days! Also to Rick Henderson for his help today on tuning and for running to get my 800 carb between runs! :TU: :TU:
Whose chassis dyno did you use Jerry? Turbo Tech's? I wanna spend some time this winter/spring on the dyno, as soon as I get my s*@t together!
It's a Dynojet owned by a private party. He bought it just to run his stuff. So far he has had his own car up to 1100 HP on this Dyno!
Jerry thanks, I had a great time. I still cant believe how quick it was to change something and do another run 10 minutes later. It has taken me all summer what you found out in a couple of dyno pulls. Of coarse I am a slow leaner p Steve is sure a great guy.
I've had my car on a dyno a year or so ago, and I'd really like to do it again. My car is running terribly rich and I'd love to be able to run a wideband O2 and get it really tuned in, I bet I could easily pick up 20-40 hp just from tuning. My best numbers were 330 rwhp @ 5600 rpm and 425 rwtq @ 2500 rpm on a lousy tune. I have a fairly stock 455, 10.2:1 compression, ported non-Stage 1 heads and a Straightline Performance "small" cam.
Hi Jerry, that HP rpm peak seems a little low, any idea why its not more like 5700 or higher? Now on the other hand, the torque peak rpm seem VERY HIGH! I'm used to seeing MUCH lower rpm peaks on a Buick.o No: What gives?o No:
Anyone insteresting in Running there car on the Dyno in the KC area there is a great shop to get it done. MC Racing in Meriam KS has a dyno in the floor. Mark Covey, the owner, is a great guy and has a 1970 Stage-1 GS that has run in the low 11's. The shop number is 913-789-9888. I am planning on taking my GSX up there this fall if anyone is intersted in going with me. They will do a special dyno day if we have enough people. I ran my old GSX, Turbo Regal and supercharged regal already (Baseline Only). It is a nice tool to use to tune your car. His dyno has seen over 1000HP too. Mark
The low revs baffled the dyno operator too. There was a clue to what the problem is when we backed off on the oil pressure. The peak power came down in the rev range and had less power too. A little bird put the bug in my ear that I may be experiencing "lifter crash". This starts making sense when I have to run 85 psi on the top end to get a couple extra ponies. Torque may be effected by the high stall converter. Although the Car Craft engine squared it's power and torque around the same area if memory serves me correctly. o No:
I think 5250 is THE "magic number" for squaring horsepower and torque on ANY engine. What I was asking was, why the HP peak isn't higher rpm-wise, and the torque peak is abnormaly high? Please don't misunderstand, Jerry, I'm not trying to beat you up, or belittle your accomplishments. I'm just confused I don't know ANYTHING about dyno's...
The torque converter is eating up alot of the torque on these runs. I believe that is where I am giving up lower RPM torque, and why the torque is so low (433.2) for such a torquey engine as the 455 is. I'm sure a locked up converter would yield higher #'s down low. The power curve the engine makes is a beautiful arch right up to 5250, when it hits the swamp. I am still researching the "lifter crash" theory. I know the other person with the Comp Cams x-treme energy set-up has to shift around 5300 RPM too. So these cams may be crap for upstairs power. On the dyno there was NO other reason for the power to drop when it did. Carbs going good, heads flow like a Ferguson toilet, modest compression, and a tight lobe center cam. There is a problem that is holding the monster back. I just haven't found it yet... :af:
Comp x-treme energy Jerry did you check TA's web page on those cams? It is a comon problem with those cams. When the circus comes to town donate it for a tent peg:grin: ........Chris
You might want to check out a cam like the Straighline that I have in my Buick. I am VERY pleased with it, very smooth idle at 800 RPM, makes tons of torque down low and the power doesn't fall off up top. My car was running so rich on the dyno it made your eyes water, but it made within 10 hp of peak power from 5300 - 5800 rpm. With a proper tune I'm sure the power curve would have kept going up even higher, but I didn't have new jets for the carb and it was currently tuned for my brother's 600 hp 464. I am also running the Edelbrock Performer intake which is probably holding me back on top end too. With a set of Stage IIs in place of my ported non-Stage I heads I bet your motor would scream up top and make tons of torque down low. If can scan in my dyno sheet if you would like to see it.
Since this was a chassis dyno, and you can approximate about 20% power loss attributed to the drivetrain - does the same not hold true for torque numbers, since they're mathematically "attached" to hp??? If that's the case, then your 433.2 (isn't it 435.4 above?) actually puts you in the 550 at the motor range (550 - 20% = 440). ...am I missing something here?
Your right Steve. The torque and hp should be attatched when figuring total loss throught the drivetrain. The torque figures were in the 430 range most of the pulls. It just depends on which sheet I was looking at. My :error:
