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Going to the dyno...

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Alan

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Discussion starter · #1 ·
This Saturday the 12th will be my first time taking my '71 to a chassis dyno
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. There will be 12 others (mostly late model Impala SS's) there to witness my little mouse that could take a run on the rollers.

Since it's my first time, and don't want to be embarrassed can those who have done this before give me any tips on preparing, and what to expect. I'll get three pulls, 5 mins. apart, for $50. I'll post my results or better yet scan the dyno sheet and let you guys critique it
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Thanks for any tips..

-Alan

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1971 Chevelle
1994 Impala SS
1996 Schwinn when both are torn apart :)
The Silver Bullet
"If you don't have extra parts after a rebuild..you did it wrong"
 
#2 ·
I've never done it but i would prep yourself as if you were going to the track. Extra jets and plugs thing to that effect. Is your ombo dialed in at the track yet? If not i would use this as a test and tune. I would also suggest getting another freind to help make any changes faster, four hands are better than 2… good luck…

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1970 chevelle
406 - TH-350 - soon to be 411's
engine
Interior

"I didn't get pulled over for going over the speed limit, i got pulled over for getting there faster than anyone else"
 
Discussion starter · #4 ·
406_70_velle I've never been to the track, so haven't done much with dialing in my combo. I just off 'seat of the pants' feel..which isn't the best way to dail in the setup.

Dennis, yeah the 5 mins. isn't going to give me much time to do a whole lot. I was hoping to swap carbs but I don't think I can do a change that quickly. I might be able to adjust the timing and see what the effects are. Either way It's going to be great to finally see what numbers it produces. We're dynoing over in Fremont at Advanced Tuning Products. Don't know anything about the place though. I'm doing this with the Region of Doom Impala SS club, but bringing some old muscle into the mix
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1971 Chevelle
1994 Impala SS
1996 Schwinn when both are torn apart :)
The Silver Bullet
"If you don't have extra parts after a rebuild..you did it wrong"
 
#5 ·
I'm certainly not an expert, but I would see if I could get all the tuning done before hand and be confident that she's running the best you can get her.

Maybe practice changing jets on a stopwatch
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I would go more for the technique for the 3 pulls. Is it an Auto? Try running thru the gears manually, and just a D run, and my personal favorite - manual 2nd to 3rd only

I wouldn't mess with the timing. Just moving the dist. won't do much except eliminate knock or barking. You really need the springs & weights.

Just go, pay the money and have a good time. And DON"T be depressed by the numbers that come up, just try to improve your technique.

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71-72 Malibu
"I'm high all right, but on the real stuff
High octane gasoline
A clean windshield
And a shoe shine"
 
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#6 ·
I agree, dont let the results get you down if you dont get the numbers you were hoping for.
I went last winter and got a peak of 198 rwhp. Oh man was that depressing. Oh well, now I have a stroker just waiting for its new tranny
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-Matt

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TC Member #1434
1971 Malibu 350/TH350 (383/200-4R/12bolt in the works)
"It's not how much blood and sweat it took to get there, it's whether or not you have what it takes to finish it."
CAR
ENGINE (in car)
NEW 383(soon to be in car)
 
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#7 ·
I don't know about cars, but I've dyoned my bikes and unless the dyno is optimistic, most are alot less than what you'd think when it comes to RWHP. And all dynos are a little different. I run a racebike that I hear people tell me over and over again has 20% more RWHP than what I'm getting on the dyno but down any straightaway it's neck and neck. For that reason I wonder if you just aren't better off going with a G-tech pro accelerometer to test you performance. As long as you test at the same temp and altitude, it will always be consistent.
I'd say the really nice thing about the Dyno is that you can spend a day tuning the jetting, and timing, to get that last 5-10% out of the setup. But, it's only all relative to _that__ dyno!

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-Sui

'72 El Camino SS
'99 Aprilia RS
'86 Honda VFR
'99 Laverda Formula
 
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Discussion starter · #8 ·
Yeah, I'm sure I'll be disappointed in the RWHP figure, but maybe I'll by some chance be surprise
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. It should be fun anyway. As long as she belts out more the late model cars there I'll be happy for now. Suppose to be a BMW something or other there, Vette, Camaro and some Impala SS's. All late models. Too bad I don't have my 454 in yet or I'd show them what raw horsepower is all about
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.

So say an engine puts out an honest 400 hp, what would your best guess be for a RWHP number?? Not saying mine makes 400, but it's probably at least 375. Just wondering how much loss between flywheel HP and RWHP there is. Wish me luck!

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1971 Chevelle
1994 Impala SS
1996 Schwinn when both are torn apart :)
The Silver Bullet
"If you don't have extra parts after a rebuild..you did it wrong"
 
#9 ·
I had my Elky on a chassis dyno last summer at the HotRod Powerfest (free). Best pull was the last of three taken during a 15 min. period... peaked at 327 HP and 358 ft/lbs.
Watched the 5.0 T-Bird in line in front of me pull 186 HP.
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Bill Burke
TC#613
ACES#3920
'67 El Camino "SS"
468, TH400, 4.11 12 bolt, 13.1 @106
'80 Camaro RS
355 Vortec, TH350, 3.73, 13.5@101

'67 El Rat
'80 Camaro RS
 
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#10 ·
Plan on 20 - 25% loss and that 400 at the fly becomes 325 at the rear wheels real fast. You may have problems one up'n a 4th gen SS. Stock they are turning around 310 at the tires... Have fun though and post back and share your numbers...

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...Dennis
The '69 & the '96
Team Camaro
Camaros Limited
 
Discussion starter · #12 ·
for those who want to see my results go here: Dyno Results

I also posted in Bench Racing so you might want to go over there...
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1971 Chevelle
1994 Impala SS
1996 Schwinn when both are torn apart
Image

The Silver Bullet
"If you don't have extra parts after a rebuild..you did it wrong"


[This message has been edited by Alan (edited 01-12-2002).]
 
#13 ·
Isn't the dyno fun! I alway enjoy my dyno time, love to hear the engine run up the rpms and hear what it sounds like outside the car.

Your results are pretty much where I might have guessed. My Bomber's old 350, with lo perf heads showed 219 hp and ~279 tq and pretty much ran 15 flat with the 3.08 gears that are still in place. For sure I would expect you to run mid 14's. If you do go to the track just remember that power is only part of the e.t./mph equation, the other important aspect is suspension - hooking up and planting the rear tires.

Thomas

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"Bomber" '67 El Camino, Beater comes back to life.
Was 350/TH350 14.90 @ 93mph, 360,000+ miles on car
Now 406 roller, 340rwhp, more hp coming, 3.08 gears
Street radials, left in drive, 13.20 e.t.@108.35 mph
8/1/01 added Plum Mist '67 to collection
*New* 468 on its way - going Big Block!
 
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Discussion starter · #15 ·
yeah Dennis, that 2002 Camaro SS kind of surprised everyone. If Chevy's 325hp rating for the LS1 is at the flywheel, then it's grossly underrated. Quite impressive indeed. The guy who owned it didn't have an attitude either, which was cool. He didn't want to dyno it, but his friends coxed him into it. It's was a great time.

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1971 Chevelle
1994 Impala SS
1996 Schwinn when both are torn apart :)
The Silver Bullet
"If you don't have extra parts after a rebuild..you did it wrong"
 
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Alan
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