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Video of Chassis Dyno Pull: 392 '57 Firesweep
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Timmo
Posted 2016-01-04 9:03 AM (#499932)
Subject: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Hey Guys,

Been a while since I posted here and nearly 10 years since I had the Desoto on the road. Had the 392 recently rebuilt with minor stuff like a more aggressive cam, Holley 4 barrel, MSD distributor, and cast iron 4-bolt flange exhaust manifolds. Went to the local dyno shop to get the fuel and ignition tuned properly, and also just to get an idea of what kind of power it was making. Peak wheel hp was 220 and peak torque was 325 on the graph. Peak torque figures I think would occur below the rpm range we were operating in, so the 325 lb-ft figure is lower than the actual peak torque at the wheels that the car is capable of. My guess is the driver hit the throttle around 2500 rpm in third and let off at 5000 rpm.

Here's a link to a video: https://www.instagram.com/p/BAFgUbbB2UF/?taken-by=fonseperformance

And the graph from one of the pulls: https://www.instagram.com/p/BAHpehAlb2H/?taken-by=turbobeater
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wizard
Posted 2016-01-04 9:39 AM (#499934 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Sounds really sweet I'll bet that it will be totally awsome to drive her!
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Powerflite
Posted 2016-01-05 9:35 PM (#500125 - in reply to #499934)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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They should have done the plot vs. rpm instead of time. It would tell you more that way. It is odd that the torque is so high, and the power low. Sounds really good though.

Do you have manual steering or power? Did you have to do any mods to use the truck exhaust manifolds on it?
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goat19642004
Posted 2016-01-07 6:52 AM (#500279 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Love that sound!
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Timmo
Posted 2016-01-07 12:57 PM (#500304 - in reply to #500125)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Powerflite - 2016-01-05 9:35 PM

They should have done the plot vs. rpm instead of time. It would tell you more that way. It is odd that the torque is so high, and the power low. Sounds really good though.

Do you have manual steering or power? Did you have to do any mods to use the truck exhaust manifolds on it?


I brought the car in to have the fuel and timing dialed in correctly, not so much interest in power it was putting down. We were running WAY later than we had originally scheduled, so that may be the reason for the plot being the way it is. I did not even get a print out. We just kept doing pulls and playing with adjustments until the power curves smoothed out and looked good. I believe the plot ranges from about idle to 5000-5200 rpm

Car has original power steering. Also. the pulley on the crank is from an 80's 318 dodge and is pretty large in diameter compared to the original. There is also a cyclic vibration in the car above 50 mph or so, which I suspect isn't helping the hp numbers either. I was expecting higher hp number though. Not sure if anyone else here has put this type of setup on a chassis dyno for comparison.

The truck manifolds are recasts from Hothemiheads.com. The exhaust piping is REALLY tight in there to snake past the suspension and starter. The exhaust was was just finished earlier that morning of the dyno run. The guys at the exhaust shop took their time and made certain everything was spot on. I tried to have 2.5" on both sides all the way front to back, but the clearances just after the manifold forced things to drop down to 2.25" for a small section.

Edited by Timmo 2016-01-07 1:04 PM
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Powerflite
Posted 2016-01-07 2:39 PM (#500307 - in reply to #500304)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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So no mods to the manifolds. That is good news. The 300C and 300D modified the manifolds to put a little dip in them to clear the power steering better. But I was wondering if you could get away without them. Sounds like you can.

I also just realized the the low power number is probably not a big deal. It just means that they didn't take it up to high enough rpm to find out what the peak was. Makes sense now why the torque number is so big compared to it. So you could probably expect a peak hp number like 15-20% higher than the peak torque depending on what you have done to the motor. That should be a whole lot of fun to drive.



(392Firesweep.jpg)



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hemidenis
Posted 2016-01-07 4:58 PM (#500324 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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that is estrange, it is showing 100hp less than it should...Sound great!
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57burb
Posted 2016-01-07 5:44 PM (#500332 - in reply to #500324)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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I got news, 220hp / 325tq at the wheels through an automatic is pretty darned good for a 60yr old engine with a handful of power modifications. Gross HP ratings from the '50s through the early '70s were on an engine stand with no belts and open exhaust. Once you add a charging system, fan, and water pump and push the power through an transmission and a rear axle, the numbers go WAY down. Even worse if that transmission is an automatic from the period.

Here's an example:
"For a baseline vehicle, we used Project Homewrecker, a '72 Corvette with a 383. We thought it perfect for the job since we had engine dyno numbers similar to gross measurements, but had yet to test it on a chassis dyno. The stroker is backed by an M22 four-speed and the IRS contains 3.70:1 gears. On an engine dyno with open headers, no accessories, and the same 750 cfm double pumper carb, it put out 425.8 hp and 473.8 lb-ft of torque. On Super Chevy's brand-new, state-of-the-art Dynojet (www.dynojet.com), it made 283 hp at 5,000 rpm and 341 lb-ft of torque at 3,900 (SAE net correction). That's with everything hooked up-alternator, power steering pump and Vintage Air A/C compressor. Eye opening, isn't it?"


In the same article, the vaunted 450hp LS6 Chevelle put down 283hp/319tq, a 270hp dual-quad '57 283 made 158/196, and an L72 427 COPO Camaro made 288/320. These are "real" muscle cars and your car is right there with them, especially if the dyno operator let off at only 5000 rpm in your Desoto.

http://www.superchevy.com/how-to/additional-tech/sucp-1102-chevrole...

Taken out to 6000 RPM or so there's a pretty good chance the horsepower number would be even higher. Outstanding job, you may have the highest naturally aspirated HP Forward Look car I know of. There are a couple of supercharged cars (a '57 dodge and a '61 Plymouth) that might make more.

PS - my stock 2012 Mustang makes 390/371 to the wheels so I'm well aware of HP numbers and drag times. Your car will probably crack the 14s. That's very impressive!
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57burb
Posted 2016-01-07 5:53 PM (#500336 - in reply to #500307)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Powerflite - 2016-01-07 1:39 PM

So no mods to the manifolds. That is good news. The 300C and 300D modified the manifolds to put a little dip in them to clear the power steering better. But I was wondering if you could get away without them. Sounds like you can. :)

He mentioned his manifolds came from Hot Heads, and not an actual truck. I believe the HH manifolds have the dip but I could very well be wrong.

I know the reproduction 4-bolt 375/390hp 392 manifolds that I bought from Wayne / StillOutThere DO have clearance for the steering box.
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Powerflite
Posted 2016-01-07 6:48 PM (#500339 - in reply to #500332)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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My main comment still applies in that 220hp is low for a 325 torque number. It should be closer to 290 like your quoted numbers (less than I previously thought because of the parasitic loss that affects hp more than torque because of it's dependence on velocity^2). Maybe it is due to the old automatic having more parasitic loss, but I think it is probably just because he didn't take it up to the peak hp level. It is hard to tell where the peak hp was going to end up without a graph vs. rpm.

The hot heads manifolds were actually originally made and sold by someone on this forum, and they didn't have the cut sections on them. Here is a picture of one from the hotheads website. He ran out of them and a new batch have not been made.



(60018.jpg)



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57burb
Posted 2016-01-07 11:23 PM (#500387 - in reply to #500339)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Gotcha. Here's a pair of the manifolds I got from SOT that show clearly the flat portion of the manifold intended to clear the steering box and control arm.

"For the 1957 300C 399 code race cars (390 HP, manual trans, manual steering) there were designed early in the year, a modification of the truck 4-bolt flange exhaust manifolds. The following year these became the standard exhaust manifold for the '58 300D fuel injection cars and the manifs and 2.5" exhaust system became an option for all '58 300D cars. Recalling the option name as "High Flow Exhaust System" or similar.

The modification was to partly flatten the outside of one ram's horn. When mounted to the left bank the "flat" gave clearance at the steering box. When mounted to the right bank, this "flat" gave gave clearance at the control arm."


http://www.forwardlook.net/forums/forums/thread-view.asp?tid=58022&...





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BigBlockMopar
Posted 2016-01-08 5:57 AM (#500403 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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The hp-curve was already flat and going sideways on the graph so there wouldn't be anymore hp found at higher rpms.

What was the green wavy line in the graph?
How was the AFR-reading at full throttle?
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Timmo
Posted 2016-01-08 10:17 AM (#500427 - in reply to #500307)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Powerflite - 2016-01-07 2:39 PM

I also just realized the the low power number is probably not a big deal. It just means that they didn't take it up to high enough rpm to find out what the peak was. Makes sense now why the torque number is so big compared to it. So you could probably expect a peak hp number like 15-20% higher than the peak torque depending on what you have done to the motor. That should be a whole lot of fun to drive. :inlove:


The mild aftermarket cam is advanced 4 degrees to bring the power curve down in the rpm range, and might hurt the peak hp. The peak torque on this motor i believe is closer to around 1800 rpm, and we were running the car at full throttle between 2500-5000 or so. I'm sure peak torque to the wheels is higher than when what is seen on the graph. Thats why the torque curve spikes straight up and then falls slowly downward. The spike is around 2500, so project the line back closer to where 1800 rpm should be and you have an idea of the torque the car can actually put down at the wheels!

Edited by Timmo 2016-01-08 10:38 AM
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Timmo
Posted 2016-01-08 10:25 AM (#500428 - in reply to #500332)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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57burb - 2016-01-07 5:44 PM

PS - my stock 2012 Mustang makes 390/371 to the wheels so I'm well aware of HP numbers and drag times. Your car will probably crack the 14s. That's very impressive!


Thank you for the compliments! The car ran a best of 14.4 sec @ 94.5 mph in the 1/4 mile at Atco Raceway about 12 years ago. The motor has been rebuilt since and is running much better since we took it to the dyno, but is otherwise the same car since then. I'll post the results up when I take it back this summer.

Edited by Timmo 2016-01-08 10:27 AM
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Timmo
Posted 2016-01-08 10:33 AM (#500430 - in reply to #500403)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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BigBlockMopar - 2016-01-08 5:57 AM

The hp-curve was already flat and going sideways on the graph so there wouldn't be anymore hp found at higher rpms.

What was the green wavy line in the graph?
How was the AFR-reading at full throttle?


The green wavy line was the manifold pressure reading, but it was not connected to the car when we ran it.

The AFR was around 12.5-12.8 under full throttle.

On a side not, the numbers shown are without the air cleaner on. We gained about 5 hp when the aftermarket air cleaner was reinstalled.
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BigBlockMopar
Posted 2016-01-08 4:24 PM (#500481 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Nice stuff nonetheless.
With the aftermarket airfilter, I would suggest creating some kind of cool air intakesystem for added 'ponies'.
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57burb
Posted 2016-01-08 5:19 PM (#500489 - in reply to #500428)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Timmo - 2016-01-08 9:25 AM

Thank you for the compliments! The car ran a best of 14.4 sec @ 94.5 mph in the 1/4 mile at Atco Raceway about 12 years ago. The motor has been rebuilt since and is running much better since we took it to the dyno, but is otherwise the same car since then. I'll post the results up when I take it back this summer.


Awesome job. Mid-14s is very impressive for a FL car (with an engine of the era). Go run it again!
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300XMAN
Posted 2016-01-09 7:41 AM (#500536 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep


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Carl Kiekhaefer had, arguably, the most experience in dyno-testing the 300C's 392 Hemi. Here are some excerpts from emails I sent to "StillOutThere" last year:
"Here is the information about the engine Carl Kiekhaefer had on the dyno. These notes were at the bottom of the page for October 16, 1957. He conducted some more pulls on the 17th and then installed the engine in his black 300C. As per the handwritten notes, here is how the engine was set-up on 10/16/57: 1957 Carter carbs, 1957 intake manifold with blocked heat risers, 1957 stock air cleaners, RL50 Lodge spark plugs, timing set at 28°@4,000 rpm, 10-1 heads, new up-flow exhaust manifolds, running with 3” diameter pipes up through exhaust collectors.
According to the dyno log book, the camshaft used for break-in was the standard 300C cam, as of December 6, 1956. The specs plotted included 62° exhaust, 67° intake, .298 intake, .293 exhaust, 66° exhaust, 66° intake, 128° exhaust (open) and 133° intake (open). On December 15, 1956 the standard cam was removed and an Isky cam installed. On December 26, 1956 the T-3 cam was replaced with an Isky C-1 (Crossflow #1). Specs on the C-1 were plotted on January 8, 1957 and were limited to .286 exhaust and .283 intake. The dyno log book indicates no other camshaft changes prior to the engine being installed in ECK’s 300C.
"ECK extensively dyno-tested the 300C engine during the spring and fall of 1957. I believe the high hp number was 383."
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Handygun
Posted 2016-01-13 7:55 PM (#500986 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep


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Your engine sounds about like mine, modification wise, and mine pushes my wagon to 13.70's thru the manifolds and in a 4300lb car that is anything but set up for the track. The manifold-starter-drag link-steering box-TV linkage "area" is the worst cubic foot on any car I've ever owned. Somewhere in this section from 2012 is a video of my Plymouth at the track when I first got it going before I sorted out a lot of HP/ET robbing issues and it ran a 14.30 something. Hemi's make these cars run like they look.
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Powerflite
Posted 2016-01-13 9:11 PM (#501000 - in reply to #500986)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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I think this is the video of Steve's wagon, although there is far too much truck in it

https://www.youtube.com/watch?v=7a_Z0rKEP2w
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Timmo
Posted 2016-01-18 10:52 AM (#501545 - in reply to #500986)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Handygun - 2016-01-13 7:55 PM

Your engine sounds about like mine, modification wise, and mine pushes my wagon to 13.70's thru the manifolds and in a 4300lb car that is anything but set up for the track. The manifold-starter-drag link-steering box-TV linkage "area" is the worst cubic foot on any car I've ever owned. Somewhere in this section from 2012 is a video of my Plymouth at the track when I first got it going before I sorted out a lot of HP/ET robbing issues and it ran a 14.30 something. Hemi's make these cars run like they look.


Looks like your car ran nearly the same time and trap speed I was at some years ago. Are you still using the cast iron transmission? Just wondering what you did to the 392 to get that car to run 13's.
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Handygun
Posted 2016-01-18 7:33 PM (#501590 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep


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I have a 518. Most of it was in the car, Chaining the motor down so it wouldn't lift off the cup style mounts helped move the car forward instead of using power to lift the engine up first, putting a shroud on it pointed this out quickly. A snubber helped also. Re-engineered the carb linkage so it would push the carb wide open rather than the 3/4 I was getting helped. I initially had a very basic shifter that wouldn't pull down lower than drive and the trans shifted on it's own around 5200 now I can shift it @ 5700 much beyond that and it starts to nose over. The 4 bolt manifolds are nice but you can really feel it loading up at those revs. A set of headers would be huge but as you pointed out there is so little room (I have the same 2 1/4 into 2 1/2 issue you have) so what the hell it's just a cruiser anyway and the manifolds don't leak.
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Timmo
Posted 2016-01-19 9:32 AM (#501624 - in reply to #501590)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Handygun - 2016-01-18 7:33 PM

I have a 518. .......


518 c.i. motor? As in, you punched out a 392 to 518? Or are you referring to a 518 transmission? I'm missing a bit of info here, or I just haven't had enough coffee yet this morning.

What gears are in the rear? I'm running 3.91's if I remember correctly.

Do you have power steering and all belt driven accessories?

I'm using *nearly* solid motor mounts from Hot Heads, and did away with the stock style mounts long ago. Car has a mild cam and a holley 670 street avenger with the factor 4 barrel intake manifold. I was told I should ditch the steet avenger for a QuickFuel carb. Based on the mods you listed, I'm stilling not understanding how you are breaking into the 13's, unless my stock cast iron torqueflite transmission is sapping more power than I thought.

Edited by Timmo 2016-01-19 9:47 AM
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Handygun
Posted 2016-01-19 7:09 PM (#501664 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep


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518 is the trans it has a 3000 stall 10in conv. I have 4.10's and 275/60/15's, My motor has an indexed crank, K1 rods and Ross pistons at about 9.8.1, it's been balanced, squared and has 8 sleeves. I run 56 354 heads that have been cleaned up a little w/ stock size valves. My cam is an indexed erson w/ .480 lift and 296 adv duration I think it's a EQ-10. I run the HH single 4 DP w/ 830 QF and Wayne's manifolds.It has a 3/8 fuel line. It's all MSD with about 28-9 degrees all in at about 2500. P/S and a alt. 518's are real power robbers supposedly, it would probably be quicker w/ a 727, but it would be pretty busy at 70. It ran the best with a 750 speed demon. It's nothing fancy.
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Timmo
Posted 2016-01-20 12:19 PM (#501765 - in reply to #501664)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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About the carb, I'm running a Holley 670 street avenger, which is much smaller than yours. I spoke to hot heads on the phone yesterday and they suggested a standard 4150 Holley 650 for my setup (just order the DP single 4 intake). This is also using a cam similar to upgrades they offer. Everyone I speak seems to wildly differ in opinion as to what bran/model and CFM carb to run on this car and motor combo. Even 750 cfm seems like it would be way more than these motors need unless you are revving them way past 5500 rpm. The guy running the dyno shop suggested a Quick Fuel 750 vacuum secondary carb. Said they had bad experience with the street avenger. I've heard mixed reviews about them, but never run anything else on the car.

Edited by Timmo 2016-01-20 12:22 PM
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Chrispy
Posted 2016-02-22 3:22 PM (#504867 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Timmo, your my hero here, this is exactly what im trying to do with my firesweep!

If you guys have a 518 or are going to put one in consider this. http://www.hgmelectronics.com/products-compushift-controllers/csm-c...
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Timmo
Posted 2016-02-22 3:27 PM (#504870 - in reply to #499932)
Subject: Re: Video of Chassis Dyno Pull: 392 '57 Firesweep



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Thanks.
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