Author Topic: 355 HP...really  (Read 4381 times)

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Offline markharvey9077@gmail.com

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355 HP...really
« on: September 23, 2018, 02:09:20 am »
I just had my 69 428 CJ buit...and it shows 355 HP and 455 torque...it was on the dyno outside of the car...it was bored .30 over...a 25 cam....I was expecting more like 400 hp...am I off?

Offline RoyceP

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Re: 355 HP...really
« Reply #1 on: September 23, 2018, 07:44:24 am »
They make more than that in factory stock condition. So something is not as Ford delivered it. Perhaps you changed compression, camshaft, or something else that caused you to lose 50+ horsepower.



I just had my 69 428 CJ buit...and it shows 355 HP and 455 torque...it was on the dyno outside of the car...it was bored .30 over...a 25 cam....I was expecting more like 400 hp...am I off?
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Offline rickmustang

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Re: 355 HP...really
« Reply #2 on: September 23, 2018, 09:44:04 am »
Or that dyno calibration is off.
'70 Double R-Code Black Mach 1 (1995 NMCA National Champion) with 4-speed

Offline crossboss

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Re: 355 HP...really
« Reply #3 on: September 23, 2018, 10:18:03 am »
FWIW,
My stone stock '69 CJ Fastback made 270 on the rear dyno rollers. That equates out to about 355 HP. This was with a fully loaded engine A/C, P/S, air cleaner attached, all belts running with a C-6 automatic and 350 gears. Why does everyone think that a stock Muscle Car made 400-450 HP? It didn't. Now, that said, your engine with the modifications done could have been built incorrectly to make 'only' 355 on an engine dyno. My worthless two cents...
<My old C.J. heap  aka  S-B Racing!
Current lifelong project: 1969 Mustang Fastback/FOX chassis, Powered by a modern Can-Am 494 (Boss 429), Kaase headed, Autolite 1425 cfm 'B' Inline carb, 6 speed, 4 wheel discs, ala Trans-Am style--Whew!

Offline 428 CJ hardtops

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Re: 355 HP...really
« Reply #4 on: September 23, 2018, 10:52:06 am »
Mine has flat top pistons decked block ,heads cut down to 68 cc, stock lift but better solid cam ,manifolds ,compression ratio around 11.7 to 11.8, cast iron intake stock carb and made 475 at 5900 and started to float the valves due to weak springs .Had it at 38 degrees and they usually like 40 probably a bit of hp there too . Was still gaining 6.2 hp from 5800 -5900 if we get it to 6300 with the new springs it should make right at 500 hp. This is not a dyno that is known for giving big numbers either. The engine builder thought the new valve springs will pick it up 20-30 hp .The maximum torque was 476 but made in the 400 plus range from 2600 to 6000 . Some dynos are stingy some make numbers to impress its adjustable by the operator .A small piece of gunk in the passenger side jet knocked the AF on that side and dropped the numbers by 180 hp .Popped another carb on and it made all of it back plus another 30 hp over the previos high at 5500 rpm.
Lots of factors in dynos but it will still be a fun engine at 355 hp and 455 torque .
« Last Edit: September 23, 2018, 09:15:44 pm by 428 CJ hardtops »
had many 428 CJ and SCJ cars over the last 30 years.I currently own a 68 1/2 coupe and a 69 R code SCJ Coupe and a 70 R code SCJ Cougar Eliminator .I am looking for a 70 428 coupe if anybody knows of one for sale.

Offline rockhouse66

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Re: 355 HP...really
« Reply #5 on: September 23, 2018, 12:11:07 pm »
Lots of little details can contribute to any dyno results.  As said, some are just "happy" and some are "stingy".  But some jetting changes, playing with the timing, etc. can possibly make your 355 into 375, which I think is pretty strong.  Was it run with headers or manifolds?  Driving the water pump or not?
Jim

'69 Grande CJ

Offline geraldt52

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Re: 355 HP...really
« Reply #6 on: September 23, 2018, 12:12:55 pm »

...Lots of factors in dynos....

That's really the bottom line.  Repeating a bit of what rockhouse66 said: (because I'm too lazy to retype)

Knowing nothing about the dyno in question, and nothing about the dyno setup used, a number of 355hp means very little...except maybe in comparison to the engines tested on the same dyno, immediately before and immediately after your engine.  When was the dyno calibrated?  Was the engine broken in prior to test?  Being fed cool air at a specific barometric pressure?  Complete air filter assembly used?  All belts on?  Water pump driven by a belt or by an electric motor?  Manifolds, headers, or dyno headers...mufflers?  Play with the a/f ratio and timing?  It's possible to play all sorts of games with numbers off of a dyno, which is why manufacturer's tests are now done to a specific SAE standard for net hp.

I wouldn't worry about the number.  In the end, the only number that matters comes from the 1320' asphalt dyno. 

Offline redscj

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Re: 355 HP...really
« Reply #7 on: September 23, 2018, 12:27:57 pm »
     Why did you expect a higher hp? It sounds like a fairly stock build plus you don't mention that any tuning was done. Literally every engine needs to be tweeked to get the best numbers.
     Then as Gerald is getting at. I remember a top name pro stock driver. His highest hp motor was not the quickest in the 1/4 mile. Go figure!
Grant
69 Mach 1 Dearborn SCJ 4.30 4spd 6/17/69 Candy Apple Red
69 Sportsroof Metuchen SCJ 4.30 C6 5/28/69 Acapulco Blue

Offline crossboss

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Re: 355 HP...really
« Reply #8 on: September 23, 2018, 12:41:03 pm »
     Why did you expect a higher hp? It sounds like a fairly stock build plus you don't mention that any tuning was done. Literally every engine needs to be tweeked to get the best numbers.
     Then as Gerald is getting at. I remember a top name pro stock driver. His highest hp motor was not the quickest in the 1/4 mile. Go figure!




Exactly! 355HP will put your car in the 13s with 'tuning' as mentioned….it did with my old heap.
Btw, just because someone 'rebuilds' an engine, they expect it to make 500HP. IF that was the case, every small block Chevy would be making 1,000HP!  lol
Seriously, don't worry on just the 'numbers' from a dyno….Remember, a dyno does not win a race. I beat cars with better HP numbers at the track and on the street.
<My old C.J. heap  aka  S-B Racing!
Current lifelong project: 1969 Mustang Fastback/FOX chassis, Powered by a modern Can-Am 494 (Boss 429), Kaase headed, Autolite 1425 cfm 'B' Inline carb, 6 speed, 4 wheel discs, ala Trans-Am style--Whew!

Offline redscj

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Re: 355 HP...really
« Reply #9 on: September 23, 2018, 07:10:36 pm »
     +1, amen.
Grant
69 Mach 1 Dearborn SCJ 4.30 4spd 6/17/69 Candy Apple Red
69 Sportsroof Metuchen SCJ 4.30 C6 5/28/69 Acapulco Blue

Offline Richard Todd

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Re: 355 HP...really
« Reply #10 on: September 23, 2018, 08:53:22 pm »
Being someone who owns an engine dyno shop (closed due to health) I think its important to know 2 important pieces of information. First were your HP numbers actual HP or corrected HP? It should say this on your dyno sheet. Corrected HP is sea level (29.92 Barometer at 60 deg. FH ) Also what was the vapor pressure ( moisture content ) of the air during the test? An eng. dyno test in Denver Co. would produce far less actual HP than the same eng. in NY thus the correction factor. Also the air temp. must be taken at the carb. intake and may vary as the test progresses. One slight miscalculation in input data can make a big difference in the HP. I am in no way questioning your dyno shop or operator just saying I personally have made this mistake more than once. One more thought would be the eng. acceleration rate. For example a SuperFlow Dyno you can set this and 300 RPM per sec. is considered the standard acceleration rate for high gear. The faster you accelerate an eng. the less time the cylinders have to fill (Volumetric Efficiency) the less HP the eng. will make. Inertia dynos are different so that's another factor. Bottom line here is your eng. might be a lot stronger than you think. Without seeing your dyno sheets I am sorry I cannot help more. Just remember an eng. dyno is just a complex tool and not all are set up for the same purpose. A maximum dyno HP eng. is NEVER as fast as an eng. tuned for maximum acceleration. Learned by accident but never forgotten.

Offline markharvey9077@gmail.com

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Re: 355 HP...really
« Reply #11 on: September 23, 2018, 11:35:13 pm »
I have attached the dyno sheet...please review...not that I am a numbers guy...but I need to confirm I do no have an issue...bored and a racing cam ought to have done better...the test was run after he broke the cam in...fright after the rebuild.
Thanks

Offline 428 CJ hardtops

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Re: 355 HP...really
« Reply #12 on: September 24, 2018, 12:58:14 am »
I see some strange things on your dyno sheet . You are running a lot bigger jets than my engine that makes more power  .I have 64's in the front and 72's in the back . How much total timing did he try . All your numbers fall of real fast before 5000 rpm for some reason might be the cam  .
Your air fuel seems a bit odd being one sides numbers are a fair amount different from side to side .Your oil pressure seems a bit low to me looking at mine it was making over 50lbs from 5000 up and 45+ from 3000.Your engine makes great torque numbers and should feel good driving on the street .
had many 428 CJ and SCJ cars over the last 30 years.I currently own a 68 1/2 coupe and a 69 R code SCJ Coupe and a 70 R code SCJ Cougar Eliminator .I am looking for a 70 428 coupe if anybody knows of one for sale.

Offline 67428GT500

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Re: 355 HP...really
« Reply #13 on: September 24, 2018, 02:15:58 am »
What's the cam specs?
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Offline rockhouse66

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Re: 355 HP...really
« Reply #14 on: September 24, 2018, 07:36:53 am »
Several things to wonder about from this dyno sheet, as Steve mentioned.  Also, does that one line say 9:1 compression?  If so, that is pretty low and more cam probably won't like that.  I assume the 28 degrees noted is the max mechanical advance in the distributor and has nothing to do with the actual engine timing on the dyno?  Wonder where the timing was?

And, again, was it run with headers or what on the exhaust?
Jim

'69 Grande CJ